R Venkataramanan

R Venkataramanan

R Venkat's Blog

R Venkat's Blog
"To be an Inspiring Teacher,one should be a Disciplined Student throughout Life" - Venkataramanan Ramasethu

SNK

SNK

Sunday, February 22, 2009

Optometry Education - Elite School of Optometry - ESO - Your Destination for World Class Optometric Education in India

















For Hard workers Only

For Hard workers Only.. A man came home from work late, tired and irritated, to find his 5-year old son waiting for him at the door.SON: "Daddy, may I ask you a question?"DAD: "Yeah sure, what is it?" replied the man.SON: "Daddy, how much do you make an hour?"DAD: "That's none of your business. Why do you ask such a thing?" the man said angrily.SON: "I just want to know. Please tell me, how much do you make an hour?"DAD: "If you must know, I make Rs.100 an hour.""Oh," the little boy replied, with his head down.Looking up, he said, "Daddy, may I please borrow Rs.50?"The father was furious, "If the only reason you asked that is so you can borrow some money to buy a silly toy or some other nonsense, then you march yourself straight to your room and go to bed. Think about whyyou are being so selfish. I work hard everyday for such this childish behavior."The little boy quietly went to his room and shut the door. The mansat down and started to get even angrier about the little boy's questions. How dare he ask such questions only to get some money?Afterabout an hour or so, the man had calmed down, and started to think:Maybe there was something he really needed to buy with that Rs.50 andhe really didn't ask for money very often. The man went to the door ofthe little boy's room and opened the door."Are you asleep, son?" He asked.No daddy, I'm awake," replied the boy."I've been thinking, maybe I was too hard on you earlier," said the man."It'sbeen a long day and I took out my aggravation on you. Here's the Rs.50you asked for." The little boy sat straight up, smiling. "Oh, thank you daddy!" He yelled.Then, reaching under his pillow he pulled out some crumpled upbills. The man, seeing that the boy already had money, started to getangry again. The little boy slowly counted out his money, and thenlooked up at his father."Why do you want more money if you already have some?" the father grumbled."Because I didn't have enough, but now I do," the little boy replied."Daddy,I have Rs.100 now. Can I buy an hour of your time? Please come homeearly tomorrow. I would like to have dinner with you."Share this story with someone you like....But even better,share Rs.100 worth of time with someone you love. It's just a shortreminder to all of you working so hard in life. We should not let timeslip through our fingers without having spent some time with those whoreally matter to us, those close ! To ourhearts.*******

Sunday, February 15, 2009

Human Realty - Just how desperate is Dan Taylor for a job?

A graduate with six years' executive experience. A proven ability to work well in a team. Highly proficient at Microsoft Office products, with particularly strong customer service and project management skills. Experience of presentations, training, events organisation and working with senior-level staff.
Six jobs in six years. A proven ability to conflict with the boss. Highly proficient at surfing Wikipedia for hours on end, with particularly strong interest in sexual fetishes and school shootings. Experience of long lunch breaks, stealing office supplies, hung over Mondays and pissing off senior-level staff.
References on request.
After fifteen recruitment agencies, four failed interviews and a discussion with a street beggar who earned more than him, Dan Taylor wasn't standing quite as proud and straight in his flashy ex-rental suit anymore.
The familiar urge to jack it all in rose in his chest. The urge to reject the societal contract, to stick it to the man, to climb atop a plinth and rip his clothes off and cry and laugh and never come back.
One more agency, he told himself, just one more. So he found himself at Pan Twardowski's. He noticed something odd from the outset. The window contained index cards bearing bombastic messages, as all the other agencies did, but these cards were not promoting jobs; they were promoting people. Like capitalist lonely hearts. Male, 26, four years' retail experience, always punctual, seeks corporate opportunity, pref LTR. That kind of thing.
Dan pushed the door open and stepped inside. The main feature at the entrance of the strip-lit room was a ridiculously long counter, presided over by a smirking man with slicked-back black hair.
Dan always suffered from terrible nerves at times like this. He took a deep breath and tried to stand up straight, to project an air of confidence. He walked stiffly up to the oversize counter. As he approached, his heart dissolved into his stomach. The countertop was at eye-level.
"Hello?" he ventured.
"Welcome to Pan Twardowski's," beamed the plastic-looking man leaning over the counter above Dan. "How can we help you today?"
"I'm looking for a job," whimpered Dan.
The man's perfect smile loomed larger. "This isn't human resources, sir, this is human realty."
"Realty?"
"Yes, like an estate agency. Except we deal in spiritual property."
"What do you -"
"Souls, sir. We buy and sell souls. On behalf of our clients."
Dan stared up at the imposing smile, his own mouth hanging slightly open. The Cheshire smile did not flinch.
"I - uh..." stammered Dan, "I just want a job."
The Pan man tilted his head in a gesture of condescension. "You can apply to work here if you like."
Dan battled an instinct to flee. He really needed a job.
He sighed. "Ok. What do I need to do?"
"You just repeat after me. I pledge my allegiance to Pan Twardowski's..."
"I pledge my allegiance to Pan Twardowski's..."
"...Forsaking it for all others..."
"...Forsaking it for all others..."
"...Till death do us part..."
"What?"
The man behind the counter paused encouragingly for a moment, then his perma-smile broke into a mirthless laugh. "Well, some people fall for it, we have to try. Right this way please, sir."
A crack appeared in the towering counter, which resolved itself into a doorway. Dan's eyes darted back and forth, then up to the grinning attendant.
"Straight on through," instructed the man, descending a small flight of stairs so that he was level with Dan. "I'll show you to your desk."
Dan crept through and found himself in a characterless corridor. "My desk?" he asked. "Don't I have to do a proper application or an interview or something?"
"This isn't a job," explained the smirk as they walked through winding passageways, "we're going to harvest your soul."
"How are you going to do that?"
"Oh, the usual way. We'll start with the small things; insisting you dress unimaginatively, making sure you don't really know what you're supposed to be doing, not paying you enough. Then just as you're getting really fed up we'll give you a chance of a big promotion - we'll make you work longer and longer hours for it - but there'll be a company restructure at just the wrong moment that frustrates your meaningless ambitions. And, of course, the whole time we'll surround you with thoroughly unpleasant colleagues that have a nasty habit of getting promoted above you. That kind of thing."
Dan thought about this for a few seconds. "And what do I get in return?" he enquired.
"Total abdication of responsibility for your own life."
"Eh?" asked Dan.
"Finding a niche used to be pretty straightforward," mused the man. "Men did their father's job, women kept the family home. Church every morning and twice on Sundays. You were expected to make do with what you had. But now there's the burden of so much freedom. Mind you, it means that souls aren't worth what they used to be. Which is why Pan Twardowski's opened, to help keep up with the demand."
"I've changed my mind," said Dan, stopping in the corridor. "I want to keep my soul."
"Oh, it's too late for that," said the toothy grin.
"What do you mean?"
"Well, you've rent to pay, and bills. You want that video game that just came out. You want to eat at that flashy restaurant. You've got to buy a birthday gift for your friend, and you don't want to seem mean. You're tied into a high standard of living, sir. You're addicted. No use fighting it."
"But - there must be alternatives," Dan entreated, his arms open wide, palms up.
"Of course there are. You could go out and look for a job you'll really enjoy. They don't tend to pay half as well, though, and you run the risk of ending up as a junior administrator for a pet insurance company. Why not sell your soul to one of the major corporations and live well for a while? Look, your desk is just around the corner here."
"It's not a fair deal. I won't accept it." Dan crossed his arms and propped himself against the wall.
"How about a trial period?" snaked the salesman. "Technically, EU regulations require that we offer you the option to reclaim your soul after a contracted period."
Dan leant forward. "You mean I would get my soul back?"
"If you chose to, yes."
"With no further commitments?"
"That's right, sir." The smiling man took advantage of the crack in Dan's resolve, and went in for the kill. "So, shall we sign you up for twenty years, sir?"
Dan arms flew up. "Three years! That's all I need."
"Oh no, I'm afraid I can't go any lower than eighteen years."
"I'll do eight, and that's my final offer."
The man sucked his teeth. "We might be able to stretch to seventeen."
"Ten."
"Done."
If it was possible for the man's smile to get any wider, it did. Dan, eyebrows raised, allowed himself to be ushered into a small cubicle office. He sat down, and the door clicked closed behind him.

Babloo goes for an eye-test





Addressing the "eye-care" issue to a young child in a simple, amusing but factual style, which children find both fun and reassuring, is the core idea behind the publication of the small, illustrated booklet "Babloo goes for an eye-test".
Besides being a maiden effort in writing for children on eye-care, the purpose is to create the much-needed eye-care awareness. And the highlighted areas include
School
Cricket
T.V.
Animal welfare
Veterinary doctor
Pharmaceutical drops
Eye doctor (Optometrist-Ophthalmologist)
Battery torch
Retinoscope
Ophthalmoscope
Distant vision test types
Spectacle frame, and
Plastic ophthalmic lenses.
To promote the concept of basic eye-care, the booklet is intended to be subscribed by school libraries as also by ophthalmic medical and other professionals for their reception areas.

Please supply………......copies of “Babloo goes for an eye test” booklet @ Rs.200/- per copy (Overseas countries: US $ 50 per copy air-mail)
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Enclosed: DD/At Par Cheque No…………………for Rs………………….payable to “Optometry Today”.
Please send completed form with payment to:
Optometry Today, C4F/216 Janakpuri, New Delhi 110058. Ph 25599839

Sunday, February 8, 2009

The Role of Communist Ideology in Insurgency

One of the most frequently perpetrated myths in some professional and in most popular writing on the subject of insurgency is the importance attributed to the role of Communist ideology in insurgency.* 1Often considered an essential ingredient in the development of an effective revolutionary movement, Communist ideology has been viewed as the primary force responsible for motivating physically isolated and socially divergent guerrilla cadres and molding them into cohesive groups. Thus the reader of some contemporary literature on insurgency operations in such widely separated geographic regions as Latin America, Sub-Saharan Africa, and Southeast Asia often is left with the impression that members of these movements who are students, young intellectuals, and peasants all derive their basic inspiration from Communist doctrine.2 This impression is further heightened by frequent press comment on the alleged close correlation between the Marxist-Leninist “dedication” of guerrilla cadres and their “exceptional” combat capabilities.
In view of the continuing belief that Communist ideology is an important motivational force for the rank and file in most successful insurgency movements, it seems desirable to examine why this premise has become so persistent in American writings on the subject as well as to test its validity in the light of experience.
The tendency to see Communism as a central element in most insurgency movements may stem from three interrelated developments: (1) the highly charged ideological nature of the current East-West divergence, which, in relation to the lesser developed world, tends to exaggerate the role of Communist doctrine and thereby often obscures the less political but more realistic causes of insurgency; (2) U.S. inexperience in the general field of insurgency/counterinsurgency operations; and (3) the French doctrine of “la guerre révolutionnaire,” which was used to justify the military operations against the National Liberation Front in Algeria.
The ideological divergence inherent in the present East-West confrontation has tended to focus undue attention on the allegedly significant part played by Communism and indoctrinated Communists in the revolutionary movements that continue to emerge throughout the lesser developed regions of the world. Many Americans are reluctant to accept the fact that real social and economic change in these areas often is virtually impossible without a violent revolution, from which frequently emerge governments that are authoritarian in nature and socialist or Marxist inclined. These Americans have tended to equate all revolutionary change with Communism.3 The ultimate result of this rather simplistic view is to see Communist doctrine as the basic motivational force responsible for most revolutionary and insurgent movements, even in instances where Communist participation is minimal or nonexistent.
Unfortunately, this fixation with the inflated importance of Marxism-Leninism has made it difficult for most Americans to realize that revolutionary activity and insurgency almost never spring from a single cause (such as Communist ideology) but rather from a combination of highly diverse political, socioeconomic, and interrelated personal/situational factors. Particularly significant among these is the nationalistic spirit so prevalent throughout much of the underdeveloped world today. Within many former colonial possessions and newly independent states, this spirit is often brought to a boil by young student/intellectual elements and directed toward the achievement of absolute independence from any form of foreign economic or political control. In other nations, characterized by backward and reactionary governments drawing support from traditional landowning oligarchies, similar student and young intellectual forces frequently focus on demands for rapid and thoroughgoing social, political, and economic change. Aware that the technological revolution of the past several decades now makes such changes a real possibility, the young reformers are also acutely aware that entrenched traditionalist elements frequently will resist to the end any erosion of their power. Accordingly, the only apparent alternative often is the violent overthrow of existing governmental and economic structures. Thus, nationalism and a corollary drive for social, political, and economic change—rather than Communist ideology—have been the factors contributing most directly to the generation of a number of those successful revolutionary movements that have evolved during the past two decades within many areas of the underdeveloped world.
While Communist ideology per se is rarely responsible for the generation of an effective insurgency movement, Communist Party elements have been most successful in penetrating and influencing revolutionary groups, including those completely non-Communist in origin. Being excellent organizers and highly skilled propagandists, the Communists have also been most effective in exploiting popular and often legitimate discontent to accelerate the development of a potential revolutionary situation into an armed insurgency, thereafter directing it toward the achievement of Communist objectives rather than those sought by rank-and-file guerrillas. Indicative of this capability is the significant Communist influence now evident within those insurgency movements active in several Latin American nations as well as the increasingly strong Communist presence in a number of African revolutionary groups that were non-Communist in origin also.
Intimately linked to nationalism and demands for political change as causative factors of insurgency are several basic motivational issues which the effective insurgent leader can exploit to develop popular support for his cause. In most underdeveloped nations the appeal of these issues is to the landless peasant, the underpaid and underemployed urban worker, and the small middle-class merchant. An insurgent leader’s promises to initiate an effective agrarian reform program aimed at breaking up the large estates of the landed oligarchy almost inevitably draws strong indorsement from the exploited and landless peasant. This issue is particularly important in areas such as Latin America, where a still substantial rural population presses heavily upon available resources of arable land.4 For the landless peasant, whose livelihood frequently depends upon subsistence agriculture and who sees no action by the incumbent government to carry out any reform through which he can acquire title to land, the call to revolution by an insurgent leader often seems the only solution to his problem. In a similar manner, the obvious concentration of available wealth in the hands of a small elite—so characteristic of many lesser developed states—is another strong inducement to violent change. Aware of the chance for a better life but denied it by traditional economic and political systems and his own lack of familiarity with them, the peasant or underpaid urban worker often sees little possibility for change except through revolution.
Closely associated with the issues of nationalism, land reform, and concentration of wealth in the hands of a small elite is the revolutionary potential flowing from an economy based totally on the export of one or a few basic agricultural or mineral commodities. Although characteristic of most nations within the underdeveloped world, young nationalist-oriented students see such dependence as clear-cut evidence of economic imperialism on the part of the foreign states that purchase the bulk of these commodities. The student/intellectual elements, who often are themselves unable to find positions commensurate with their academic training in a stagnant economy or corrupt governmental bureaucracy, see industrialization and rapid economic development as essential to ending their nation’s client status. And they see little possibility for change outside the revolutionary process, since the government in power is usually representative of the interests producing these commodities. Thus, these and similar factors, when exploited effectively by popularly based leaders, form the actual cement necessary to fuse disaffected elements of a nation into a revolutionary force dedicated to overturning an incumbent government and creating a new social, economic, and political system. Within this process, however, Communist ideology sometimes does not come into playas a motivational factor influencing the rank-and-file insurgent, even when the guerrilla leader himself is a Communist.5 Accordingly, the net effect of emphasizing Communist ideology as a key element in the generation of insurgency often has been to downgrade the real causes of such activity and thereby render them more difficult to eradicate.
The unwarranted importance attached to Marxist-Leninist ideology as a cause of insurgency also results, in part at least, from limited American experience in this field. In contrast to a number of Western European nations that for many years have faced the problem of revolution and guerrilla warfare in their colonial possessions, the United States has not undergone a like experience except for earlier military ventures in noncolonial areas such as Haiti, Nicaragua, and the Philippines. Accordingly, much of our knowledge of modern-day revolutionary warfare, and insurgency in particular, has been derived from study and analysis of Communist writings. Thus guerrilla leaders such as Mao Tse-tung, Ho Chi Minh, Nguyen Giap, and even “Che” Guevara have seen their commentaries, diaries, and writings turned into virtual reference works on the subject. As a result there has been a natural tendency for many students of insurgency and revolutionary warfare to accept not only the strategic and tactical analyses of these authors but also the importance they accord to the role of Marxist-Leninist ideology. This tendency, in turn, has done much to re-emphasize the alleged importance of Communism as a “critical” unifying and motivating force in the development of an insurgent movement.
Contributing to the general acceptance by many American military and political leaders of Communist ideology as a motivating force in insurgency was the French doctrine of “la guerre révolutionnaire.” Although this doctrine had its roots in the Indochina war against the Viet Minh, France used it also to provide an acceptable rationale for military operations in Algeria by alleging that that insurgency was either directed, controlled, inspired, or exploited by Communists. To reinforce this view, it was further inferred that the insurgency in Algeria was part of the overall Soviet plan to encircle Europe.6
Despite the fact that many if not most Americans continue to view insurgency as ideologically inspired, the rather substantial evidence accumulated in studies of both present and past revolutionary movements clearly refutes this belief. As pointed out previously, successful insurgent operations normally result from a combination of two basic elements: (1) significant and deeply felt political and socioeconomic factors strongly affecting one or more key population segments (usually including the young intellectuals/students and the peasantry); and (2) a charismatic leader capable of mobilizing armed dissent around these grievances.7 Thus in the Cuban revolution of 1956-59 Fidel Castro, one of the most magnetic Latin American leaders of the past decade, exploited very effectively the real and imagined grievances of Cuba’s peasantry and dissatisfied students/intellectuals in order to develop a climate suitable for insurgency. For the peasants he demanded a much-needed program of agrarian reform,8 and for the middle-class students and intellectuals he demanded a much-desired end to corrupt politics, a thoroughgoing reform of governmental administrative practices, and a return to the constitution of 1940.9 Ideology, specifically Communist ideology, was never a factor of significance in mobilizing popular support for this revolution. In this connection it is interesting to note that even a professing Marxist such as Regis Debray has admitted that ideological arguments and Communist propaganda are totally ineffective in generating support for an insurgent movement.10
As in the Cuban revolution, Communist ideology played an insignificant role in motivating the rank-and-file participants in most of the insurgent movements that have developed within other nations of Latin America and the lesser developed world. In each of these movements—even those in which the leaders were practicing Marxists—the issues exploited by them to generate popular support have been those very real and basic socioeconomic or political grievances of important population groups. One insurgency, reportedly resulting in an estimated 180,000 or more deaths during the decade 1948-1958, grew largely from such nonideological issues as a stagnant domestic economy, large landholdings and absence of any effective agrarian reform program designed to get land into the hands of landless peasants, intense rivalries between non-Communist political groups, and an economy geared to a single basic export crop.11 While Communist guerrilla leaders did not hesitate to exploit such issues in developing the insurgent movement, Communist ideology per se was conspicuously absent as a motivational force inspiring the guerrillas.
In Africa and Southeast Asia, basic and nonideological issues have been exploited by revolutionary leaders to mobilize popular support for an insurgent movement. In this connection, perhaps one of the best illustrations is the successful insurgency waged by the Algerian National Liberation Front ( FLN ) against the French from 1954 to 1962. In spite of the then relatively widespread belief of the American public that the Algerian insurgency was Communist inspired, directed, and controlled, there is little evidence to support this conclusion. The basic issues used by the FLN leadership to popularize their movement were nationalism and the economic and social discontent widespread among the Muslim segment of the Algerian population. Communist influence in the FLN was virtually nonexistent in the formative stages of the revolt. In fact, individual Communists did not join the FLN until well after the insurgency began, and the Soviet Union itself did not recognize the provisional government of the Algerian Republic (GPRA) until the fall of 1960. The role of Communist ideology, therefore, was indirect at best, and some argument can be made that the insurgency might never have developed at all if the French had acted to reduce the economic, social, and political causes of Muslim discontent.12
In Southeast Asia, another example can be drawn from the Malayan insurgency that spanned the period from 1948 to 1960. Although the insurgency was directed and controlled by the Malayan Communist Party (MCP), its roots were in the deep-seated historical problem of communal relations between the indigenous Malays and the immigrant Chinese, who were systematically excluded from participation in the civil administration of the country. The MCP, which traditionally drew its membership from the Chinese community, exploited the sense of social isolation experienced by the Malayan Chinese. This exploitation was significantly assisted by the wartime record of the MCP and the success of the Communists on mainland China. To combat the insurgency, the British instituted a number of counterinsurgency measures, not the least effective of which was the announcement that Great Britain intended to grant self-government and independence as soon as order was restored and a common Malay citizenship and government established. The widespread publicity accorded the British avowal reduced the appeal of the MCP to the Chinese community and lessened the latter’s support of the MCP.13
While Communist ideology has been relatively unimportant as a motivational force during the military phases of any insurgency, it often plays a much more significant role once the revolution has been completed. After the victory, certain goals that had been useful inducements to insurgent participation during actual antigovernment military operations have to be realized: agrarian reform, social and economic change, elimination of a wealthy oligarchy, an end to foreign economic and political domination, etc. To achieve these goals, the often undisciplined guerrilla and his unit leader are unsatisfactory instruments. Instead, a unified and trained political cadre, able to implement revolutionary change, is essential. In the organization of this cadre, the unifying bonds of a common and seemingly progressive economic and political ideology such as Marxism-Leninism are quite valuable. The experience in Cuba, following Castro’s January 1959 assumption of power, illustrates clearly the importance of such a trained cadre and ideological base. Not long after placing his guerrilla leaders in control of various governmental agencies during 1959, Castro began to realize that little but chaos was flowing from the disorganized efforts of these insurgents-turned-administrators. To correct this situation, the Cuban leader began the movement of trained and disciplined organizers of the old-line Cuban Communist Party into key governmental, industrial, and union positions during the early 1960s, thereby providing the new regime a much-needed sense of stability and organization.
In the process of making these changes, Castro apparently also foresaw the need to create an “indigenous” ideological basis upon which to build a “new Cuba.”14 Accordingly, he initiated an intensive “educational” campaign aimed particularly at the indoctrination of young revolutionaries in his peculiarly nationalistic interpretations of traditional Marxist-Leninist doctrine. Personally loyal to Castro and well indoctrinated in his revolutionary concepts, these “new Communists” have gradually replaced the older party members in most key government posts. Thus the net effect of these activities has been to create not only a reliable political cadre, able to initiate revolutionary change, but also a body of common revolutionary doctrine that links together members of the ruling hierarchy and provides the essential philosophical and ideological underpinnings for the regime. Of particular interest in regard to this aspect of the Cuban experience is the fact that rather similar patterns of development have been evident in some radical postrevolutionary governments within Sub-Saharan Africa.
In the growth of revolutionary movements in the underdeveloped areas of the world, available evidence indicates that neither Communist ideology nor a nationalized variant thereof has been a significant motivating force for those insurgent cadres involved in the military phases of a revolution. Instead, they are most often moved to action by a combination of two factors: (1) the belief that only violent revolution can achieve effective social, political, and economic change within their nation; and (2) the often deep-rooted feeling that such change is essential for the achievement of a better life. With these considerations in mind, the skilled insurgent leader—whether Communist or non-Communist—normally plays down any ideological commitments he might have and instead focuses his appeals directly on the problems affecting those population groups whose support he seeks. These generally include the peasantry, urban workers, and elements of a nationalist-inclined student/intellectual community. The appeals usually stress such practical issues as land reform for the landless peasantry, full employment for unemployed urban workers, and an end to governmental corruption and foreign economic/political intervention.
While these issues are equally exploitable by both non-Communist and Communist insurgent leaders, the latter are particularly well skilled in their use. Well trained in the techniques of propaganda and agitation, they move quickly into positions of leadership within an insurgent movement, subsequently directing it toward the attainment of purely Communist goals and objectives—aims not necessarily synonymous with those sought by the rank-and-file insurgents. After the revolution has been successful, some form of Communist ideology plays an important role as an ideological underpinning and rationale for those political and economic changes programmed by the new regime. Thus, Communism, even when not a primary motivator for guerrilla warfare, retains a meaningful role in revolutionary activities within the underdeveloped world.
* For the purpose of this discussion, insurgency is denned as a subversive, illegal attempt to weaken, modify, or replace an existing government through the protracted use or threatened use of force by an organized group of indigenous people outside the established governing structure.1
Directorate of Special Investigations, Hq USAF
Notes
1. Human Factors, Considerations of Undergrounds in Insurgencies (Washington: American University, Special Operations Research Office, 1966), p. 1.
2. Illustrative of this literature are publications on the Cuban revolution by authors of a rightist persuasion, such as Nathaniel Weyl (Red Star Over Cuba), and those of a leftist orientation, such as Leo Huberman and Paul Sweezy (Cuba, Anatomy of a Revolution) and Jean Paul Sartre (Sartre on Cuba).
3. For an evaluation of the dangers flowing from this view see, among others, Chas. O. Lerche, Jr., The Cold War and After (Englewood Cliffs: Prentice-Hall, Inc., 1965), pp. 58-59; Edmund Stillman and William Pfaff, The New Politics: America and the End of the Cold War (New York: Coward McCann, Inc., 1961), pp. 40-60; Morton A. Kaplan, ed., The Revolution in World Politics (New York: John Wiley & Sons, 1962), pp. 216-23.
4. Thomas F. Carroll, “The Land Reform Issue in Latin America,” in John D. Martz, ed., The Dynamics of Change in Latin American Politics (Englewood Cliffs: Prentice-Hall, Inc., 1965), p. 174. In Latin America as a whole, roughly 90 percent of the land is controlled by 10 percent of the people. As pointed out by Carroll, this degree of concentration is far greater than in any other region of the world of comparable size.
5. For an excellent discussion of those factors generating insurgency and the insignificant role of Communist ideology in that regard, see P. Kecskemeti, Insurgency as a Strategic Problem (RAND Corporation Memo RM-5160-PR, February 1967), pp. 21-24.
6. See D. M. Condit et al., Challenge and Response in Internal Conflict, Vol. III, The Experience in Africa and Latin America (Washington: American University, Center for Research in Social Systems, 1968), p. 177.
7. Merle Kling, “Cuba: A Case Study of a Successful Attempt to Seize Power by the Application of Unconventional Warfare,” in Annals of the American Academy of Political and Social Science, May 1962, vol. 341, p. 47.
8. Fidel Castro, Pensamiento Político, Económico y Social de Fidel Castro (Havana: Editorial Lex, 1959), pp. 44-45. See also Edwin Lieuwen, Arms and Politics in Latin America, rev. ed. (New York: Frederick A. Praeger, 1961), p. 264; and Merle Kling.
9. A careful analysis of the development and susceptibility of Cuba’s middle class to Castro’s appeals is contained in J. Alvarez Diaz et al., Cuba: Geopolítico y Pensamiento Económico (Miami: Duplex Paper Products, 1964), pp. 397-418. As pointed out so well by Theodore Draper in Castro’s Revolution, Myths and Realities (New York: Praeger, 1962), the Cuban middle class (including strong student, intellectual, and professional elements) was the population group primarily responsible for the success of the revolution.
10. Regis Debray, Revolution in the Revolution (New York: Grove Press, Inc., 1967), pp. 53-54. Another significant refutation of Communist ideology as an important motivating force for an insurgent movement is contained in Fidel Castro’s 10 August 1967 speech to the final session of the Latin American Solidarity Organization (LASO), reprinted in Discursos (Havana: Instituto del Libro, 1967).
11. John J. Finan, “Colombia (1948 until 1958)” in Condit et al., pp. 419-20.
12. Paul A. Juredini, Case Studies in Insurgency and Revolutionary Warfare: Algeria 1954-1962 (Washington: American University, Special Operations Research Office, 1963), pp. 7-15.
13. Condit et al., p. 462.
14. Castro’s awareness of the need for such an ideological base was clearly evident in a speech he made in December 1961 at Havana’s “Universidad Popular.” This speech was reprinted in the Cuban magazine Bohemia, No. 50, 10 December 1961, pp. 48-55 and 84-87, under the caption “El Programa del Partido Unido de la Revolución Socialista Será un Programa Marxista-Leninista, Adjustado a las Condiciones Objetivas Precisas de Nuestro País.”
Contributor
Charles A. Russell (M.A., American University), is Chief, Analysis and Dissemination Branch, Counterintelligence Division, Directorate of Special Investigations, Hq USAF. He was a special investigations officer, 1951-54. With Major Hildner, he has lectured at Air Command and Staff College and USAF Special Operations School on insurgency in the underdeveloped world and the role of counterintelligence in counter-insurgency.
Major Robert E. Hildner (M.S., University of Colorado) is Chief, Middle East, Africa, South Asia (MEAFSA) Section, Analysis and Dissemination Branch, Counterintelligence Division, Directorate of Special Investigations, Hq USAF. He served in counterintelligence with OSI in Japan, 1962-65, and was Commander of the OSI Detachment at Da Nang Air Base, Vietnam, for a year preceding his current assignment in February 1970.

Divine Discourse delivered on the occasion of Guru Poornima Day,06-07-1963

(Baba was brought down the winding stairs to the room on the ground floor, since He insisted on giving Darshan to the thousands of devotees who had come on that auspicious day. He had an attack of cerebral thrombosis and tubercular meningitis and was in bed for eight days from the morning of Saturday, 29th June to the evening of 6th July. His left hand, leg and eye were affected; His right hand had also slight palsy; the words were indistinct and the face was twitching. He was placed on the Silver Throne in the Prayer. As soon as He was seated, He communicated the following message which was interpreted and announced.
This is not Swami's illness; this is an illness which Swami has taken on, in order to save someone. Swami has no illness, nor will He get ill at any time. You must all be happy; that alone will make Swami happy. If you grieve, Swami will not be happy. Your joy is Swami's food.
Then, Baba indicated to Sri Kasturi to speak, and after his short speech was over, Baba wanted the mike to be held before Him. He asked, "Vinipisthundhaa?" (Do you hear Me?) But, though He asked again and again, the voice was so indistinct that no one could make out what it meant. He then signaled for water and when it was brought, He sprinkled a little with His trembling right hand on the stricken left hand and on His left leg. He stroked His left hand with the right. Immediately, He used both hands to stroke His left leg; that touch was enough to cure it. He doffed the disease in a thrice! He started to speak! It was the same musical voice.)
“Dhikkulenivaariki dhevude gathi” - "For those who have no refuge, God is the refuge." That is exactly the reason why I had to take on the disease that one helpless Bhaktha (devotee) was to get. He had to suffer this dire illness, as well as the four heart attacks that accompanied it; and he would not have survived it. So, according to My Dharma of Bhakthasamrakshana (protection of devotees), I had to rescue him. Of course, this is not the first time that I have taken on the illness of persons whom I wanted to save. Even in the previous shareeram (body) at Shirdi, I had this responsibility. The suffering that you saw was too much for this particular devotee and so, I had to save him, by Myself going through it. This is My Leela: My nature. It is part of the task for which I have come: Sishtarakshana (protection of the virtuous).
Persons who were near Me during the last week were asking Me to divulge the name of the person whom I had saved. I told them that it will make them angry against that person, for they would say that Swami had to undergo so much of pain in order to save that one person.
Then they replied that they would honour the person for his extraordinary Bhakthi (devotion) which persuaded Swami to run to his rescue, on Saturday morning. Some people even asked Me whether it was this person or that, giving names of those who had attacks of paralysis, especially on the left side! This is even more ludicrous, because when I save a person, I save him completely. I do not wait until he gets the disease and I do not leave in him a fraction of the disease, so that he may be identified later. It all looks so funny to Me, the guesses and surmises that you make. Even in Shirdi, Dhadha Saheb, Nandharaam, Balawanth, all were saved by these means. Balawanth was destined to get plague, but, the bubo was taken over and the boy saved. This is perhaps the longest period when I kept the devotees wondering and worried. That was because of the heart attacks which had to come later on the Bhaktha, from which also he had to be saved. Then, there is another reason too, why the eight-day period had to be observed. Well, I shall tell you why. That means I must tell you about Myself, about something I have not disclosed so far, something which I was keeping to Myself, for the last 37 years. The time has come to announce it. This is a sacred day, and I shall tell you.
You all know that I declared on the very day when I decided to disclose My Identity, My Mission and My Advent, that I belong to the Apasthamba Suthra (Vedic ritual system) and the Bharadhwaja Gothra (lineage). This Bharadhwaja was a great sage, who studied the Vedas for a full one hundred years; but, finding that the Vedas were anantha (endless) he did thapas (penance) for prolonging his lifespan, and from Lord Indra he got two extensions of a century each. Even then, the study of the Vedas could not be completed, so he asked Indra again for another hundred years. Indra showed him three huge mountain ranges and said, "What you have learned in three centuries form only three handfuls from out of the three ranges, which the Vedas are. So, give up the attempt to exhaust the Vedas. Do a Yaaga (sacrifice), instead, which I shall teach you: that will give you the fruit of Vedic study, full and complete."
Sage Bharadhwaja decided on performing the Yaaga as per Indra’s instructions and made all preparations. The sage wanted that Shakthi (the consort of Lord Shiva) must preside and bless the Yaaga, and so he went to Kailasha (the abode of Lord Shiva). But, the time was not opportune for presenting his petition, for Shiva and Shakthi were engaged in a competition, trying to find out who could dance longer. Eight days passed thus, before Shakthi noticed Bharadhwaja standing in the cold. She just cast a smile at him and danced along as before! The sage mistook the smile as a cynical refusal to notice him; so he turned his back on Kailasha and started to descend. To his dismay, he found his left leg, hand and eye put out of action by a stroke. Seeing the sage collapse, Shiva came up to him and consoled him and assured him that Shakthi had indeed blessed him and his Yaaga. Then, Shiva revived him and cured him, sprinkling water from the Kamandalu (a kettle-shaped container used by ascetics). Both Shiva and Shakthi presided over the Yaaga.
After the Yaaga was over, they were so pleased that they conferred more boons on the sage. Shiva said that they would take human form and be born in the Bharadhwaja Gothra (lineage) thrice: Shiva alone as Shirdi Sai Baba, Shiva and Shakthi together at Puttaparthi as Sathya Sai Baba and Shakthi alone as Prema Sai, later. Then Shiva remembered the illness that had suddenly come upon Bharadhwaja at Kailasha. He gave another assurance, "As expiation for the neglect which Shakthi showed you at Kailasha for eight days, this Shakthi will suffer the stroke for eight days, when we both take birth as Sathya Sai. On the eighth day, I shall relieve her from all signs of the disease by sprinkling water, just as I did to cure your illness." It was the working out of this assurance that you witnessed today, just now. This had to happen, this stroke and the cure. The assurance given in the Thretha Yuga had to be honoured. I may tell you now that the Bhaktha who had to suffer the stroke which I took upon myself, was a convenient excuse which was utilised. You see, a railway engine is not made available to haul just one bogey; they wait until a number of bogeys are ready to be taken along and only then do they put the engine into action. So too, the disease had to be gone through, the Bhaktha had to be saved, the assurance to be carried out, the mystery had to be cleared, the Divinity had to be more clearly announced by the manifestation of this grand miracle. All these were accomplished by this one incident.
Let Me tell you one more thing: nothing can impede or halt the work of this Avatar. When I was upstairs all these days, some people foolishly went about saying, "It is all over with Sai Baba" and they turned back many who were coming to Puttaparthi! Some said I was in Samadhi (trance), as if I am a Sadhaka (spiritual aspirant)! Some feared I had become a victim of black magic, as if these things can affect Me! The splendour of this Avatar will go on increasing, day by day. When the Govardhanagiri (the legendary mountain that Lord Krishna had raised on his little finger) was raised aloft by the little boy, the Gopis and Gopalas (the cowherd maids and men) realised that Krishna was God. Now, it is not one Govardhanagiri, but a whole range that will be lifted, you will see! Have patience and faith.

Friday, February 6, 2009

How to assess a patient for glaucoma

Introduction
Glaucoma affects approximately 65 million people around the world and an expected 7.5 million are blind due to the disease. It is the second most common cause of blindness worldwide.1 It is estimated that perhaps half the blindness from glaucoma in the world is caused by angle closure.2 Accordingly, in order to be effective, any case detection has to include methods to detect angle closure.
A clinic examination is different from a screening programme in the community. In the clinic the patient has sought us out and the responsibility is ours to detect and treat any pathology, including glaucoma. Some short cuts that may be satisfactory in screening programmes are not acceptable in a clinic. The best method to detect (and assess) glaucoma is to perform a comprehensive eye examination for all patients who attend the clinic, irrespective of the complaints they present with.
Components of a comprehensive eye examination to assess glaucoma
Five components of the comprehensive eye examination are specifically relevant to assess glaucoma.
Slit lamp examinationSpecifically in this instance to rule out secondary causes of glaucoma.
Intraocular pressure (IOP)This is preferably measured by applanation tonometry. Tonometry has poor sensitivity and specificity for the detection of glaucoma. Half the patients with primary open-angle glaucoma (POAG) have IOPs below 22 mm Hg at the first measurement. Further, as shown by the ocular hypertension treatment study (OHTS), only 9.5 per cent of patients with IOP above 21 mm Hg develop early glaucoma if left untreated for five years.4 Intraocular pressure measurement alone is an inefficient tool to detect glaucoma, but, if consistently elevated, IOP does play a role in the diagnosis.
It is important to remember that the Goldmann applanation tonometer may record falsely high IOP if corneal thickness (not corneal oedema) is increased. This message is reiterated by the OHTS finding that in a thick cornea the risk of progression is minimal for patients with ocular hypertension. There is no consensus about which correction formula to use to adjust for corneal thickness; we use Elher’s formula, which applies a 5 mm Hg correction for every 70 μ of corneal thickness. Routine central corneal thickness (CCT) measurement is ideal; it should at least be measured in all patients with ocular hypertension and suspected normotensive glaucoma (NTG). As far as management is concerned, IOP is the only known causal factor and the only factor that we can alter therapeutically.
GonioscopyGonioscopy is the current gold standard for the diagnosis of angle closure and is mandatory for the diagnosis and management of all glaucomas. POAG is a diagnosis of exclusion, after a careful examination, including gonioscopy, to rule out angle closure and secondary causes. The presence of a single peripheral anterior synechia in an occludable angle (Figure 1) confirms the diagnosis of angle closure.
The ideal technique is dynamic gonioscopy with an indentation-type lens like the 4-mirror Susmann gonioscope.
The anterior chamber angle is a dynamic structure and it can change over a period of time due to changes in lens thickness, position, and other factors. It is therefore essential to perform gonioscopy on a routine basis, even in a ‘known’ case of POAG.
The flashlight and van Herrick tests are sometimes suggested as surrogates for gonioscopy. On its own, the flashlight test is close to useless.5 The van Herrick test may be of some use in screening programmes, but is of little help in the clinic where gonioscopy is the gold standard.5
Disc and retinal nerve fibre layer examinationGlaucoma is essentially an optic neuropathy and the key to diagnosis rests on examination of the disc and nerve fibre layer. While stereo disc photography is the gold standard, clinical examination of the disc and retinal nerve fibre layer (RNFL) is best performed by a dilated stereoscopic examination on a slit lamp using a 60, 78 or 90 dioptre lens. The best stereoscopic view is with a contact lens, but logistics prevent its routine use. When there is a doubt, we would still use a contact lens. Unless contra-indicated, the disc, RNFL, and fundus should not ordinarily be assessed with undilated pupils.
The numerous signs that need to be sought during disc assessment are beyond the scope of this article; they include rim thinning or notch, disc haemorrhage, wedge-shaped RNFL, etc. (Figures 2 & 3).
Newer imaging techniques are now available for documentation of the optic disc. These include the Heidelberg retinal tomogram (HRT), scanning laser polarimetry (GDX), and optical coherence tomography (OCT). The Association of International Glaucoma Societies (AIGS) consensus meeting concluded that at present there was insufficient evidence to validate the routine use of these instruments. The meeting also concluded that, in the hands of a specialist, imaging techniques can provide valuable information. We concur with these conclusions. We also feel that these instruments have a great potential for follow-up.
PerimetryThe goal of glaucoma management is to preserve the patient’s visual function and quality of life. The gold standard for the detection of functional glaucomatous damage is automated ‘white on white’ perimetry. This test is mandatory to document functional damage, its progress and its response to treatment. In areas where primary surgery is necessary, the presence of a confirmed functional defect puts a decision for such intervention on a firm(er) footing.
We first need to obtain baseline fields, both for diagnosis and for comparison on follow-up. The first few fields usually demonstrate a learning curve and cannot be used as a baseline. To determine progression, we currently use the overview programme (Figure 4) and the glaucoma progression analysis (GPA). The GPA provides statistical help to determine progression (Figure 5).
Frequency Doubling Perimetry (FDP) is a rapid and relatively inexpensive test that can accurately detect established field defects. FDP has a high sensitivity and specificity. It can fulfill the objective of confirming a field defect prior to surgery, but does not have the programmes for follow-up.
The Bjerrum Screen is good enough for documenting a defect, and, if it correlates with the other findings, is enough to go to surgery. The demonstration of a functional defect becomes especially important in the areas where we would go for primary surgery. The Bjerrum Screen, however, is not good for follow-up.
Primary angle-closure glaucoma (PACG)
Tonometry will only detect angle closure in a patient with raised IOP. The structural and functional tests described for POAG (optic disc examination, perimetry) will only detect angle closure that has damaged the disc or visual field. As approximately 75 per cent of subjects with PACG in Asia have optic nerve damage, strategies that detect functional damage in POAG may also be suitable for PACG. However, such tests will not detect eyes without functional damage or eyes at risk for angle closure. Such eyes at risk, and those with early disease, are the ones we need to detect. In these cases, an iridotomy can be curative.
GonioscopyThe ideal way to identify angle closure and eyes at risk is to examine the angle using a gonioscope. The clinical expertise required renders gonioscopy inappropriate for screening; however, it is necessary for clinical practice. The AIGS consensus meeting on angle closure concluded that gonioscopy is mandatory in the clinical situation.
Torchlight examination (flashlight test)In the flashlight test a light is shone from the temporal side onto the cornea, parallel but anterior to the iris. A shadow on the nasal limbus identifies an eye with a shallow anterior chamber, at risk of closure. Considering the sensitivity and specificity of this test, the AIGS consensus meeting concluded it has no role to play in the detection of angle closure.
Slit lamp examination (van Herrick test)The van Herrick test uses a slit beam to compare the depth of the peripheral anterior chamber to the thickness of the cornea. When the depth of the peripheral anterior chamber is less than 1/4th of the corneal thickness, it is considered shallow (Figure 6). The sensitivity and specificity of the test does not meet the recommendations of Prevent Blindness America for screening.
It is also important to remember that the flashlight and van Herrick tests do not detect angle closure but occludable angles, which are only a risk factor for angle closure. This distinction is important because only a minority of occludable angles progress to angle closure. Using the van Herrick test for screening will result in too many false positives.
In summary, the clinical assessment of a patient for glaucoma requires a complete comprehensive examination (including gonioscopy) on all adult patients seen in the clinic, followed by appropriate investigations (visual fields) to document damage and follow up patients with suspected glaucoma as well as confirmed cases.
References
1 Quigley HA. Number of people with glaucoma worldwide. Br J Ophthalmol 1996;80: 389-93.
2 Foster PJ, Johnson GJ. Glaucoma in China: how big is the problem? Br J Ophthalmol 2001;85: 1277-82.
3 Thomas R, Parikh R, Paul P et al. Population-based screening versus case detection. Indian J Ophthalmol 2002;50: 233-7.
4 Kass MA, Heuer DK, Higginbotham EJ, et al. The ocular hypertension treatment study: a randomized trial determines that topical ocular hypotensive medication delays or prevents the onset of primary open-angle glaucoma. Arch Ophthalmol 2002 Jun;120: 701-13.
5 Thomas R, George T, Muliyil J. The Flashlight and van Herrick’s Test are poor predictors of occludable angles. Aust N Z J Ophthalmol 1996;24: 251-6.

2nd CFP: HYCAS 2009 @ IJCAI-09: Hybrid Control of Autonomous Systems

HYCAS 2009INTERNATIONAL WORKSHOP ONHYBRID CONTROL OF AUTONOMOUS SYSTEMSIntegrating Learning, Deliberation and Reactive ControlHeld in conjunction with IJCAI-09 in Pasadena, CA, on July 13 2009http://www.hycas.org/************************************************************************CALL FOR PAPERSOBJECTIVESHigh-level control for Autonomous Systems (e.g. robots) is concerned withselecting the next action the system should perform. Known paradigms forthis action selection problem are learning, deliberation, reactive controlschemes or combinations of these, i.e. hybrid approaches.These paradigms have been known for over two decades, and in today'sapplications often combinations of learning, deliberation, and reactivecontrol are used. Usually these combinations are used in an ad-hoc oreven unconscious fashion. Although there is a number of proposedarchitectures and huge body of literature, the issue of combininglearning, reactive and deliberative control never has been intensivelyinvestigated.With this workshop we wish to bring together researchers from differentareas who concentrate on combinations of learning, planning, and/orreactive schemes for decision making and the control of autonomoussystems. The workshop is open to all members of the AI and Roboticscommunity. We would specifically like to encourage students toparticipate.RELEVANT TOPICSThe questions to be addressed in this workshop are: * How can learning, deliberation and/or reactive control be combined such that the methods can benefit from each other -- e.g. by using a common representation? * What are the challenging domains demanding for hybrid control? * What are its successful applications?Papers are invited on all aspects of hybrid methods for the control ofautonomous systems, including, but not limited to: * Decision Making * Modelling of Domains, Capabilities/Affordances and Robot Behaviours * Agent Learning * Cognitive Robotics * Behaviour-based Robotics and Emergent Control * Developmental and Epigenetic Robotics * Architectures and Architectural PatternsIMPORTANT DATES * March 6 2009: Paper Submission * April 17 2009: Notification of paper acceptance * May 8 2009: Camera ready paper submission * May 15 2009: Early registration deadline * July 13 2009: WorkshopAuthors of selected articles will be invited to submit an extended versionof their workshop paper to a special issue of an international journal onrobotics and automation.WORKSHOP CHAIRSNils T SiebelChristian-Albrechts-University, Kiel, GermanyGerald SteinbauerGraz University of Technology, AustriaAlexander FerreinRWTH Aachen University, GermanyJosef PauliUniversity of Duisburg-Essen, GermanyPROGRAMME COMMITTEEAlexander FerreinAlfredo GabaldonFredrik HeintzChristian IgelYohannes KassahunTim KovacsGerhard K KraetzschmarGerhard LakemeyerAles LeonardisPedro U LimaDaniele NardiJosef PauliJan PetersDaniel PolaniMartin RiedmillerJuergen SchmidhuberNils T SiebelGerald SteinbauerRon SunMarc ToussaintHans UtzMarkus Vincze

Summer course on MEMORY AND THE MIND Central European University

We would like to solicit your help to promote the summer course onMEMORY AND THE MIND: LEARNING AND REPRESENTING STRUCTURES IN THEBRAIN AND MIND among your colleagues, your graduate students, or anyinterested researchers.Course Dates: JUNE 22 - 26, 2009Location: CentralEuropean University (CEU), Budapest, Hungary,Detailed course description:http://www.sun.ceu.hu/memoryCourse Director:Jozsef Fiser, BrandeisUniversity, Department of Psychology and theNeuroscience Program, USAFaculty:Richard Aslin, University of Rochester, Department of Brain andCognitive Sciences, USA; Irwing Biederman, University of SouthernCalifornia, Department of Psychology, USA; Mate Lengyel, University ofCambridge, Department of Engineering, UKTarget group: graduate students and junior faculty interested in one ofthe disciplinary fields belonging to the interdisciplinary area ofcognitive psychology. Undergraduates without a university degree willnot be considered.Language of instruction: EnglishFinancial aid is available.Application deadline: February 16, 2009Online application: http://www.sun.ceu.hu/ (http://www.sun.ceu.hu/responsibility )applyAttachments to be sent to: sun09-memory@ceu.huWe'd be grateful if you could forward this email to those potentiallyinterested in our summer school (individuals, listservs, blogs,electronic journals, etc.) and/or have a short announcement placed on arelevant web site.Thank you for your kind assistance.Sincerely yours,Kornelia VarghaKornelia VarghaCEU Summer UniversityProgram OfficerBudapest, 1051Nador u. 9.HungaryTel.: (36-1) 328-3699Fx.: (36-1) 327-3124email: varghak@ceu.hu

Visual Neuroscience : Postdoctoral Position in Australia

Opportunity for a junior post-doctoral researcher to join Paul Martinand Sam Solomon on projects funded by the Australian National Healthand Medical Research Council. The topic is physiological andanatomical substrates of colour and form vision in primates.Demonstrated experience with in-vivo or in-vitro electrophysiology isessential, as is a strong desire for intellectual advancement andwillingness to work as part of a team. We offer a competitive salaryand a vigorous intellectual environment in well-equipped laboratories.Please direct enquires and/or a current Curriculum Vitae to PaulMartin (prmartin@unimelb.edu.au). More information about our researchactivities can be found at: http://vco.org.au/nvri/ http://www.physiol.usyd.edu.au/span/samuels/Paul R. MartinDirector of Research,National Vision Research Institute of Australia.Professorial Research Fellow,Dept Optometry & Vision SciencesThe University of Melbourne.Cnr Keppel & Cardigan Streets, Carlton, VIC 3053Australia.prmartin@unimelb.edu.auTel: +613 9349 7481Fax: +613 9349 7484

Call for Nominations to the VSS Board of Directors

Nominations are open for two 4-year positions on the Vision Sciences Society Board of Directors to replace outgoing Board members Mary Peterson, Allison Sekuler and Steve Shevell.

Responsibilities of the Board include scheduling the Annual Meeting, implementing and monitoring VSS policies, budget oversight, and other VSS-related activities. The Board meets twice a year, during the Annual Meeting and in late January.

Any regular VSS member in good standing may be nominated, with the exception of current members of the Board and past members whose term ended within the last 4 years.

NOMINATION PROCEDURE:
- Each nomination must be “signed” by 3 regular VSS members. One person should email the nomination to shauneywilson@visionsciences.org with a cc: to the other two nominators. The other two nominators should indicate their concurrence by forwarding the nominating email to shauneywilson@visionsciences.org.

- Include a recent vita and a short paragraph of qualifications with the nomination.

- Prior to making a nomination, please seek assurance that the nominee is willing to serve.

SELECTION OF SLATE OF CANDIDATES:
(http://www.visionsciences.org/nominating.html)

The VSS bylaws provide for a Nominating Committee, composed of VSS members who are highly respected scientists chosen to represent the broad range of disciplines representative of VSS members (the VSS president chairs the Nominating Committee). The current members of the Nominating Committee are Bill Geisler, Mel Goodale, Norma Graham, Eileen Kowler, and Concetta Morrone. For each open Director position, the Nominating Committee selects from the nominees a slate of two candidates who are highly respected scientists and who, when added to the Board of Directors, would result in broad representation of the disciplines representative of VSS members.


CURRENT BOARD OF DIRECTORS:
(http://www.visionsciences.org/board.html)

The names, term-end dates and areas of expertise are listed below (terms end immediately after the VSS meeting of the year listed).

Marisa Carrasco (2012)
Visual attention, visual search, perceptual learning, spatial vision; psychophysics and neuroimaging

Wilson Geisler (2010)
Spatial vision; natural scenes; visual search; psychophysics and computational modeling

Zoe Kourtzi (2012)
Shape processing, object recognition, perceptual learning, brain imaging

Pascal Mamassian (2011)
3D perception; binocular vision; motion; ambiguous and rivalrous perception; multisensory perception; perception and action; psychophysics and computational modeling

Tony Movshon (2011)
Neural mechanisms; motion perception; spatial vision; visual development; neurophysiology, psychophysics, animal behavior
Mary Peterson (2009) TERM ENDING IN MAY 2009
Perceptual organization; object perception and recognition; perceptual learning; psychophysics and imaging

Allison Sekuler (2009) TERM ENDING IN MAY 2009
Motion, pattern, and face perception; perceptual learning; aging; psychophysics and neuroimaging

Steven Shevell (2009) TERM ENDING IN MAY 2009
Color; brightness; adaptation; psychophysics and genetics

SCHEDULE FOR ELECTION:
February 2, 2009 Nominations open
March 2, 2009 Nominations close
April 1, 2009 Election begins (online)
April 22, 2009 Election ends
May 1, 2009 Election results announced
hasEML = false;

New Issue: Journal of Vision, Volume 9, Issue 1

Journal of VisionVolume 9, Number 1http://journalofvision.org/9/1/ARTICLES1. Multivoxel fMRI analysis of color tuning in human primary visual cortex Laura M. Parkes Jan-Bernard C. Marsman David C. Oxley John Y. Goulermas Sophie M. Wuerger http://journalofvision.org/9/1/1/2. Rapid visual categorization of natural scene contexts with equalized amplitude spectrum and increasing phase noise Olivier R. Joubert Guillaume A. Rousselet Michele Fabre-Thorpe Denis Fize http://journalofvision.org/9/1/2/3. Failure of facial configural cues to alter metric stereoscopic depth Barbara J. Gillam Barton L. Anderson Farhan Rizwi http://journalofvision.org/9/1/3/4. Visual adaptation reveals asymmetric spatial frequency tuning for motion Timothy Ledgeway Claire V. Hutchinson http://journalofvision.org/9/1/4/5. Emotion perception in emotionless face images suggests a norm-based representation Donald Neth Aleix M. Martinez http://journalofvision.org/9/1/5/6. The Mixture of Bernoulli Experts: A theory to quantify reliance on cues in dichotomous perceptual decisions Benjamin T. Backus http://journalofvision.org/9/1/6/7. Object perception: When our brain is impressed but we do not notice it Jurgen Kornmeier Michael Bach http://journalofvision.org/9/1/7/8. Limits of stereopsis explained by local cross-correlation Heather R. Filippini Martin S. Banks http://journalofvision.org/9/1/8/9. Shifts in spatial attention affect the perceived duration of events Guido M. Cicchini Maria Concetta Morrone http://journalofvision.org/9/1/9/10. Binocular depth discrimination and estimation beyond interaction space Robert S. Allison Barbara J. Gillam Elia Vecellio http://journalofvision.org/9/1/10/11. Driving is smoother and more stable when using the tangent point Farid I. Kandil Alexander Rotter Markus Lappe http://journalofvision.org/9/1/11/12. Flawless visual short-term memory for facial emotional expressions Eva M. Banko Viktor Gal Zoltan Vidnyanszky http://journalofvision.org/9/1/12/13. Effect of visual field locus and oscillation frequencies on posture control in an ecological environment Jean-Claude Piponnier Jean-Marie Hanssens Jocelyn Faubert http://journalofvision.org/9/1/13/14. Perceptual and physiological evidence for a role for early visual areas in motion-induced blindness Camilo Libedinsky Tristram Savage Margaret Livingstone http://journalofvision.org/9/1/14/15. World-centered perception of 3D object motion during visually guided self-motion Kazumichi Matsumiya Hiroshi Ando http://journalofvision.org/9/1/15/16. Effect of target spatial frequency on accommodative response in myopes and emmetropes John Taylor W. Neil Charman Clare O'Donnell Hema Radhakrishnan http://journalofvision.org/9/1/16/17. Size matters: A study of binocular rivalry dynamics Min-Suk Kang http://journalofvision.org/9/1/17/18. Differences in fixations between grasping and viewing objects Anne-Marie Brouwer Volker H. Franz Karl R. Gegenfurtner http://journalofvision.org/9/1/18/19. Acceleration carries the local inversion effect in biological motion perception Dorita H. F. Chang Nikolaus F. Troje http://journalofvision.org/9/1/19/20. Contrast dependence of center and surround integration in primary visual cortex of the cat Chun Wang Cedric Bardy Jin Yu Huang Thomas FitzGibbon Bogdan Dreher http://journalofvision.org/9/1/20/21. The time course of contrast masking reveals two distinct mechanisms of human surround suppression Yury Petrov Suzanne P. McKee http://journalofvision.org/9/1/21/22. Amblyopia masks the scale invariance of normal central vision Dennis M. Levi David Whitaker Allison Provost http://journalofvision.org/9/1/22/23. Monochromatic aberrations in hyperopicand emmetropic children Aldo A. Martinez Padmaja R. Sankaridurg Thomas J. Naduvilath Paul Mitchell http://journalofvision.org/9/1/23/24. Humans use visual and remembered information about object location to plan pointing movements Anne-Marie Brouwer David C. Knill http://journalofvision.org/9/1/24/25. Spatial characteristics of center-surround antagonism in younger and older adults Lisa R. Betts Allison B. Sekuler Patrick J. Bennett http://journalofvision.org/9/1/25/26. Using geometric moments to explain human letter recognition near the acuity limit Lei Liu Stanley A. Klein Feng Xue Jun-Yun Zhang Cong Yu http://journalofvision.org/9/1/26/27. Tilt aftereffects and tilt illusions induced by fast translational motion: Evidence for motion streaks Deborah Apthorp David Alais http://journalofvision.org/9/1/27/28. Psychophysical properties of two-stroke apparent motion George Mather Kirsten L. Challinor http://journalofvision.org/9/1/28/29. Influence of disparity on fixation and saccades in free viewing of natural scenes Lina Jansen Selim Onat Peter Konig http://journalofvision.org/9/1/29/30. Spatial and temporal limits of motion perception across variations in speed, eccentricity, and low vision Joseph S. Lappin Duje Tadin Jeffrey B. Nyquist Anne L. Corn http://journalofvision.org/9/1/30/31. Homo economicus in visual search Vidhya Navalpakkam Christof Koch Pietro Perona http://journalofvision.org/9/1/31/32. The influence of clutter on real-world scene search: Evidence from search efficiency and eye movements John M. Henderson Myriam Chanceaux Tim J. Smith http://journalofvision.org/9/1/32/33. Do we have direct access to retinal image motion during smooth pursuit eye movements? Tom C. A. Freeman Rebecca A. Champion Jane H. Sumnall Robert J. Snowden http://journalofvision.org/9/1/33/34. The specificity of the search template Mary J. Bravo Hany Farid http://journalofvision.org/9/1/34/35. An anisotropy of orientation-tuned suppression that matches the anisotropy of typical natural scenes Edward A. Essock Andrew M. Haun Yeon Jin Kim http://journalofvision.org/9/1/35/36. Characterizing motion contour detection mechanisms and equivalent mechanisms in the luminance domain Szonya Durant Johannes M. Zanker http://journalofvision.org/9/1/36/37. Search for gross illumination discrepancies in images of natural objects P. George Lovell Iain D. Gilchrist David J. Tolhurst Tom Troscianko http://journalofvision.org/9/1/37/38. Attentional influences on the dynamics of motion-induced blindness Marieke L. Scholvinck Geraint Rees http://journalofvision.org/9/1/38/39. Reliable identification by color under natural conditions Jeroen J. M. Granzier Eli Brenner Jeroen B. J. Smeets http://journalofvision.org/9/1/39/40. The detection of multiple global directions: Capacity limits with spatially segregated and transparent-motion signals John A. Greenwood Mark Edwards http://journalofvision.org/9/1/40/

Good Job for a bright senior

FULL-TIME RESEARCH ASSISTANT POSITION AVAILABLE in VISION/COGNITIVE SCIENCE

LOCATION: CAMBRIDGE, MA

START DATE: Summer '09

This position is in the lab of Jeremy Wolfe and Todd Horowitz. We conduct psychophysical/behavioral research primarily in the area of visual attention. How do you find what you are looking for in a world full of things you are not looking for? How does a radiologist find a tumor in an x-ray? How does a baggage screener find a bomb? What is vision like without attention? How is attention deployed? How do you attend to an object if it moves around? What if it disappears? Healthy young adults are the experimental observers for most experiments. The position involves all stages of the research process from planning experiments and preparing documents for the ethics review board to helping to write up results for publication, but the main focus is data collection and analysis. Funding permitting, RAs usually attend and present at one scientific meeting each year.

This position requires a Bachelor of Arts or Bachelor of Science degree. A major in Psychology or related field would be plus, but
is not necessary. Some research experience would also be useful. The lab is primarily Macintosh based. A candidate should have some computer experience and should be willing to learn how to use our statistics, graphics, and word processing packages. Programming experience is not necessary, but familiarity with MatLab would be a plus. A candidate must work in an organized, independent manner on multiple tasks and should be able to interact with subjects in a tactful and pleasant manner.

This is an excellent position for a new college graduate who wants
to spend two or more years in a research setting before going on to
graduate or medical school. NOTE: A two-year commitment is required. The position is not appropriate for those with advanced degrees. Visa and funding issues make it extremely difficult to hire non-US residents.

If interested, please contact
Jeremy M Wolfe - wolfe@search.bwh.harvard.edu
and/or Todd Horowitz - toddh@search.bwh.harvard.edu

Visual Attention Lab
Brigham & Women's Hospital
64 Sidney St., Cambridge, MA 02139
Visit our website: http://search.bwh.harvard.edu/
Jeremy M Wolfe
Professor of Ophthalmology
Harvard Medical School
Mailing Address:
Visual Attention Lab
Brigham & Women's Hospital
64 Sidney St. Suite. 170
Cambridge, MA 02139-4170
Phone: 617-768-8818
Fax: 617-768-8816

Neurorehabilitation of Hemianopia

Advert for 2.5 year Research Associate Position at Durham University: Start date: April 2009/Closing date: 10th of March 2009.
Applications are invited for a three year Research Associate position, working with Dr. Thomas Schenk and Dr Daniel Smith on a Clinical Neuroscience Project. This project will be carried out in collaboration with the Department of Neurology at the Newcastle General Hospital. The aim of this project is to investigate the effectiveness of a new therapy for patients who develop visual problems after brain damage. This project will be the first randomised control trial of this type of treatment, and will offer the opportunity to develop clinical skills with neuropsychological patients, and potentially produce a therapy which could improve the quality of life for many thousands of brain-injured individuals.
Applicants should hold a first degree in Psychology, Medicine, Biology or Neuroscience and preferably have a PhD/MD in a Clinical, Neuropsychological or Neuroscience related field. Candidates should be enthusiastic about Neuropsychology or Clinical Neuroscience, and should have, or be keen to learn, the skills of human eye movement measurements and the clinical assessment of visual disorders.
The appointment is available immediately for 30 months but the start date can be negotiated. Please direct informal inquiries to Dr. Thomas Schenk (phone: 0191-3340438; or e-mail: Thomas.Schenk@dur.ac.uk or Dr. Daniel Smith (phone: 0191-40436; or e-mail: Daniel.smith2@dur.ac.uk) and see the laboratory web page: MailScanner has detected a possible fraud attempt from "exdurf.dur.ac.uk" claiming to be http://www.dur.ac.uk/thomas.schenk/
Closing date: 10th of March, 2009.


-------------------------------------
Dr Daniel Smith
Wolfson Research Institute
Durham University, Queens Campus
Stockton-on-Tees
TS17 6BH
+44 (0)191 3340436

Sunday, February 1, 2009

All About Diabetes

Diabetes is a disease in which the body does not produce or properly use insulin. Insulin is a hormone that is needed to convert sugar, starches and other food into energy needed for daily life. The cause of diabetes continues to be a mystery, although both genetics and environmental factors such as obesity and lack of exercise appear to play roles.
There are 18.2 million people in the United States, or 6.3% of the population, who have diabetes. While an estimated 13 million have been diagnosed with diabetes, unfortunately, 5.2 million people (or nearly one-third) are unaware that they have the disease.
In order to determine whether or not a patient has pre-diabetes or diabetes, health care providers conduct a Fasting Plasma Glucose Test (FPG) or an Oral Glucose Tolerance Test (OGTT). Either test can be used to diagnose pre-diabetes or diabetes. The American Diabetes Association recommends the FPG because it is easier, faster, and less expensive to perform.
With the FPG test, a fasting blood glucose level between 100 and 125 mg/dl signals pre-diabetes. A person with a fasting blood glucose level of 126 mg/dl or higher has diabetes.
In the OGTT test, a person's blood glucose level is measured after a fast and two hours after drinking a glucose-rich beverage. If the two-hour blood glucose level is between 140 and 199 mg/dl, the person tested has pre-diabetes. If the two-hour blood glucose level is at 200 mg/dl or higher, the person tested has diabetes.
Type 1 diabetesResults from the body's failure to produce insulin, the hormone that "unlocks" the cells of the body, allowing glucose to enter and fuel them. It is estimated that 5-10% of Americans who are diagnosed with diabetes have type 1 diabetes.
Type 2 diabetes Results from insulin resistance (a condition in which the body fails to properly use insulin), combined with relative insulin deficiency. Most Americans who are diagnosed with diabetes have type 2 diabetes.
1. Why do I need to see a dietitian?
Registered dietitians (RDs) have training and expertise in how the body uses food. RDs who understand diabetes can teach you how the food you eat changes your blood glucose level and how to coordinate your diabetes medications and eating. Do you know how many calories you should eat each day? How to cut down on the fat in your meals? How to make eating time more interesting? An RD can help you learn the answers to these, and lots of other questions. Your dietitian will work with you to create a healthy eating plan that includes your favorite foods.
2. Can I eat foods with sugar in them?
For almost every person with diabetes, the answer is yes! Eating a piece of cake made with sugar will raise your blood glucose level. So will eating corn on the cob, a tomato sandwich, or lima beans. The truth is that sugar has gotten a bad reputation. People with diabetes can and do eat sugar. In your body, it becomes glucose, but so do the other foods mentioned above. With sugary foods, the rule is moderation. Eat too much, and 1) you'll send your blood glucose level up higher than you expected; 2) you'll fill up but without the nutrients that come with vegetables and grains; and 3) you'll gain weight. So, don't pass up a slice of birthday cake. Instead, eat a little less bread or potato, and replace it with the cake. Taking a brisk walk to burn some calories is also always helpful.
3. Why does losing weight help my diabetes?
Weight loss helps people with diabetes in two important ways. First, it lowers insulin resistance. This allows your natural insulin (in people with type 2 diabetes) to do a better job lowering blood glucose levels. If you take a diabetes medicine, losing weight lowers blood glucose and may allow you to reduce the amount you're taking, or quit taking it altogether. Second, it improves blood fat and blood pressure levels. People with diabetes are about twice as likely to get cardiovascular disease as most people. Lowering blood fats and blood pressure is a way to reduce that risk.
4. How can I cut the fat in my diet?
Here are some beginning hints. See a dietitian for more advice. Stir-fry foods in tiny amounts of oil and lots of seasonings. Choose nonfat or low-fat selections, such as nonfat or 1% milk or low-fat cheese. Keep portion sizes on target. Avoid fried foods -- bake, grill, broil, or roast vegetables and meat instead.
5. Are some fats better than others?
Yes. Monounsaturated fats are the healthiest for your body. Nuts -- like almonds, cashews, hazelnuts, and peanuts -- and avocados contain this type of fat. Choose olive or canola oil for cooking. Polyunsaturated fat is the next healthiest fat. This is found in corn oil, safflower oil, soybean oil, and mayonnaise. Use small amounts of foods that contain saturated fats like butter, lard and meat fat, bacon, and shortening. There are lower-fat versions of foods that contain saturated fats, like sour cream and cream cheese. A healthy diet includes less than 30% of calories from fat, with less than 10% of these from saturated fat.
6. What foods can I eat a lot of?
Forget about eating with abandon. The key to healthy living is moderation. Air-popped popcorn may be low in fat, but it still has calories. And calories count. If you can control the portion sizes of the food you eat, you will be able to eat a wider variety of foods, including your favorites, and still keep your blood sugar in your target range.
7. What can I do if I overeat over the holidays?
Put on your walking shoes and head for the pavement. Being more active helps lower your blood sugar, blood pressure and cholesterol. Physical activity uses up extra sugar in your blood and helps your insulin work better.
8. Can I use low calorie sweeteners?
Low calorie sweeteners are safe for everyone except people with phenylketonuria, who should not use aspartame. Calorie-free sweeteners like aspartame, saccharin, sucralose and acesulfame-K won't increase your blood glucose level. The sugar alcohols -- xylitol, mannitol, and sorbitol -- have some calories and do slightly increase your blood glucose level. Eating too much of any of these can cause gas and diarrhea.
9. How much weight should I lose each week?
Limiting your weight loss to 1/2 to 1 pound a week will keep you healthy, and let you enjoy the foods you love in small amounts. A slow steady weight loss is the key to keeping lost weight off.
10. Can I drink alcohol?
Yes, in moderation. Moderation is defined as two drinks a day for men and one drink a day for women. A drink is a 5-ounce glass of wine, a 12-ounce light beer, or 1-1/2 ounces of 80-proof distilled spirits. Make sure that your medications don't require avoiding alcohol, and get your doctor's okay.
11. Isn't glucose control easier if I eat the same things every day?
Probably, but this method of blood glucose control isn't very nutritious, not to mention boring. One of the keys to nutrition is eating a variety of foods each day. By checking your blood glucose two hours after starting to eat a meal, you can learn how different foods affect you. Over time, you will be able to predict how foods, and combinations of foods, affect your blood glucose level.
12. What vitamins will help my diabetes?
If you have a vitamin or mineral deficiency, it could be causing problems with your glucose control. For instance, one study found that taking the trace element chromium improved glucose control in subjects who had a chromium deficiency. More studies need to be done. If you choose a variety of fruits, vegetables, grains, and meat each day, and keep your blood sugar close to your target range, you probably don't need to take vitamin supplements because of diabetes.
13. Are there herbs that will help my diabetes?
Many herbs supposedly have glucose-lowering effects, but there are not enough data on any herb to recommend it for use in people with diabetes. Herbs are not considered food by the Food and Drug Administration and are not tested for quality or content. Therefore, products can be promoted as helping health conditions without having to show evidence of this. Discuss the herbal dietary supplements with your doctor or dietitian before trying them. They may interact poorly with your diabetes medication.
Diabetes Symptoms
Often diabetes goes undiagnosed because many of its symptoms seem so harmless. Recent studies indicate that the early detection of diabetes symptoms and treatment can decrease the chance of developing the complications of diabetes.
Some diabetes symptoms include:
Frequent urination
Excessive thirst
Extreme hunger
Unusual weight loss
Increased fatigue
Irritability
Blurry vision
Most people with diabetes have health problems -- or risk factors -- such as high blood pressure and cholesterol that increase one's risk for heart disease and stroke. When combined with diabetes, these risk factors add up to big trouble. In fact, more than 65% of people with diabetes die from heart disease or stroke. With diabetes, heart attacks occur earlier in life and often result in death. By managing diabetes, high blood pressure and cholesterol, people with diabetes can reduce their risk.

Important Definitions - Optometry and Vision Science

aberration
Blurred or distorted image quality that results from inherent physical properties (shape, curvature, density) of an optical device such as a lens or prism.
ablate, ablation
To remove by cutting. The surgical removal of any part of the body.
absorbtion spectrum
The relationship between wavelengths of light striking a pigment and how strongly the light is absorbed.
achromatopsia
Congenital absence of the ability to see colors. Caused by absence or defects in light- sensitive retinal receptor cells (cones) that provide sharp visual acuity and color discrimination.
light adaptation
The automatic adjustment of the pupil or the retina to the amount of light that is present at any given time.
add
Amount of plus (+) refractive power required for near use (over eyeglass correction for distance).
afterimage
A sensation of seing an object that is no longer in your sight. Also called aftersensation, aftervision.
age-related macular degeneration
Degeneration of the photoreceptors in the macula or central region of the retina. This area of the retina is responsible for central vision, used for reading, seeing faces, and so on. Often associated with aging.
AIDS-related eye disorders
Anyone who is HIV positive should have regular eye examinations by an opthalmologist, especially if their T-cell count falls under 250 or if vision changes are obvious. The most common eye problem from AIDS is called Cotton Wool Spots and is not a serious threat to vision. Tiny white spots on the retina, caused by bleeding, are called Cotton Wool Spots because of how they look. A more serious problem is an eye infection caused by cytomegalovirus (CMV) which can permanently impair vision. Symptoms include flashing spots or “spiderwebs,” flashing lights, and blind spots or blurred vision. Other AIDS-related eye problems include red eye, shingles, detached retina and Kaposi’s sarcoma, a slow growing tumor on the eyelid or spot on the white of the eye.
AK
Acronym for Astigmatic Keratotomy. A surgical procedure used to correct moderate cases of astigmatism. Often performed at the same time as the Radial Keratotomy (RK) procedure for correcting nearsightedness. The procedures are somewhat similar, differing primarily in the pattern of incisions made in the outer periphery of the cornea in order to change its shape to the curvature needed to correct the refractive problem. Both AK and RK have been largely replaced by newer refractive surgery procedures.
ALK
Automated Lamellar Keratoplasty. A refractive eye surgery procedure that uses an instrument named a microkeratome to lift a flap of corneal material and to sculpt the underlying corneal tissue. Has been used successfully in correcting relatively high degrees of nearsightedness and some cases of farsightedness, but has been largely replaced by LASIK and other laser procedures that offer greater accuracy.
allergies of the eye
Allergic reactions triggered by the body’s immune system to protect eyes from injury. Ocular allergies can be seasonal, such as those caused by pollens, or caused by bacterias, food sensitivities, cosmetics, fabrics, soaps and other substances. Visible symptoms of eye allergies may include swelling, hives, itching, watering, eye pain and sensitivity to light.
amacrine cell
A type of neuron seen in the retina.
amblyopia
Also called lazy eye, this is a condition of decreased vision in one or both eyes that occurs without detectable structural abnormalities or disease in the eye or visual pathways. Best corrected vision is usually less than 20/20.
AMD
Acronym for age-related macular degeneration. A degeneration of the photoreceptors in the macula or central region of the retina. This area of the retina is responsible for central vision, for reading, seeing faces, and so on. Often associated with aging.
Amsler grid
Home eye test featuring equally spaced horizontal and vertical lines in a grid pattern. Used for determining the presence of macular degeneration and other defects that affect central vision.
aneurysm
Weakness of the wall of an artery causing abnormal enlargement or bulge. Tiny aneurysms may occur in the veins of the retina of the eye as a complication of diabetes.
angiography
Test used to examine blood vessels in the retina, choroid and iris of the eye.
angioma
Benign tumor consisting of small blood vessels. Can be located anywhere on the body and is not dangerous or contagious. Can affect eye with tumors beneath or on top of the retina, which may lead to blood leakage and possible retinal detachment.
ANSI 287.1
The American National Standards Institute’s guidelines for Occupational and Educational Eye and Face Protection. ANSI 287.1 ensures the quality and safety level of eye protection.
anterior
Front or forward area of an object.
anterior segment
Front third of eyeball, including the cornea, anterior chamber, iris and ciliary body.
anterior capsulotomy
Cataract surgery technique used to make a round opening in the front (anterior) of the capsule, which encases the eye’s natural lens.
antioxidants
General label for vitamins, enzymes and minerals that may help prevent damage to the body caused by oxygen free radicals, harmful byproducts produced during normal metabolism. Some evidence suggests that antioxidants may be beneficial for arthritis, cancer, blood vessel disorders, inflammation, allergies, heart disease, blood pressure, gum disease, eye problems, lung and nervous system problems and skin care. Many over-the- counter vitamins now contain anti oxidants, including some formulated especially for the eye. Commonly recognized antioxidants include vitamins A, C and E, and yellow-colored carotenoids such as beta-carotene.
antireflective (AR) coating
Thin layer(s) applied to an eyeglass lens to decrease glare and surface reflections.
aphakia
Absence of the eye’s natural crystalline lens, usually after cataract extraction.
A-Scan
Type of ultrasound device that emits very high frequency waves that are reflected by the ocular structures and converted into electrical impulses. Used for differentiating normal and abnormal eye tissue or for measuring length of eyeball.
Astigmatic Keratotomy (AK)
Surgical procedure used to correct moderate cases of astigmatism. Often performed at the same time as the Radial Keratotomy (RK) procedure for correcting nearsightedness. The procedures are somewhat similar, differing primarily in the pattern of incisions made in the outer periphery of the cornea in order to change its shape to the curvature needed to correct the refractive problem. Both AK and RK have been largely replaced by newer refractive surgery procedures.
astigmatism
Uneven curvature of the cornea in which refractive light rays are bent out of focus resulting in distorted vision. Those people with astigmatism are usually born with the disorder and it does not worsen with age. Often occurs in conjunction with nearsightedness or farsightedness.
antireflective (AR) coating
Thin layer(s) applied to an eyeglass lens to decrease glare and surface reflections.
Automated Lamellar Keratoplasty (ALK) (index to Automated Lamellar Keratoplasty)
Refractive eye surgery procedure that uses an instrument known as a microkeratome to lift a flap of corneal material and to sculpt the underlying corneal tissue. Has been used successfully in correcting relatively high degrees of nearsightedness and some cases of farsightedness, but has been largely replaced by LASIK and other laser procedures that offer greater accuracy.
apparent motion
An optical illusion in which stationary objects viewed in quick succession or in relation to moving objects appear to be in motion. Also called apparent movement.
asthenopia
The term for eye strain.
automatic keratometer
Instrument used to measure curvature of the front surface of the cornea.
automatic lens meter
automatic lensometer
Instrument used by an eyecare professional to determine the refractive power of an eyeglass or contact lens.
automatic refractor
Electro mechanical device that provides an “objective” measurement of an eye’s refractive error.
automatic perimeter
A computer-driven instrument used during an eye examination to plot possible defects in the field of vision (visual field). During the procedure, points of light are projected to various spots inside a large “globe” while the patient indicates whether or not the lights can be seen.
Bardet-Deidl Syndrome
A genetic disorder characterized by degeneration of the light sensitive cells in the periphery of the retina causing night blindness, tunnel vision, decreased visual acuity, and photophobia. Other conditions include obesity, developmental delays, spastic paraplegia and renal disorders.
basal cell nevus syndrome
An inherited group of multiple defects that result in an unusual facial appearance and a predisposition for skin cancer. The disorder affects the eyes as well as the skin, nervous system, endocrine glands and bones. Children with the disease have wide-set eyes, a broad nose and heavy protruding brow. The disorder results in the appearance of skin cancers, particularly around the cheekbones, upper lip and eyes.
Batten Disease
A group of inherited neurological disorders that affect children and are marked by progessive vision failure and other disorders that affect the brain. Most prominent in families of Northern European-Scandinavian ancestry.
Bell’s palsey and the eye
Paralysis of muscles controlled by the facial cranial nerve. Eyelid on affected side does not close properly, so corneal drying may become a problem.
bifocals
Eyeglasses incorporating two different powers in each lens, usually for near and distance vision corrections.
binocular vision
The ability to maintain visual focus on an object with both eyes, creating a single visual image. Lack of binocular vision is normal in infants. Adults without binocular vision experience distortions in depth perception and visual measurement of distance.
bioluminescence
The giving off of light from living organisms.
blastoma
Never used without “retino or “neuro” in front of it.
blepharitis
Common, persistent and sometimes chronic inflammation of the eyelids, resulting from bacteria that reside on the skin. In certain individuals, these bacteria thrive in the skin at the base of the eyelashes or even in the oil glands near the eyelid, resulting in dandruff-like scales and particles. Blepharitis is usually only a minor irritation.
blepheroplasty
Surgery to improve the appearance of the eyelids. In addition to detracting from overall appearance, drooping eyelids may cause functional problems such as impaired field of vision or difficulty wearing glasses. Blepharoplasty is usually outpatient surgery performed by ophthalmic plastic and reconstructive surgeons.
blepharospasm
Condition characterized by uncontrollable, forcible closure of the eyelids caused by a progressive dysfunction of the nerve that controls muscles around the eye. Less serious form may cause eyelid twitches or tics.
blindness
Inability to see. Legal blindness is corrected visual acuity of 20/200 or less, or corrected visual field to 20 degrees or less, in the better seeing eye.
blind spot
1. A small area of the retina where the optic nerve enters the eye, this type of blind spot occurs normally in all eyes. Also called optic disk. 2. Any gap in the visual field corresponding to an area of the retina where no visual cells are present; this type of blind spot is associated with eye disease.
blindsight
A phenomenon reported in individuals who have damage to the primary visual cortex resulting in blindness. Individuals with blindsight report that they are unable to see, yet when examined are able to indicate the presence and location of objects.
botox
Toxin produced by the same bacteria responsible for a type of food poisoning called botulism. Injected in very small amounts into the eyelid muscles, botox has been found to be effective in stopping uncontrollable eyelid spasms such as those found in blepharospasm.
bridge
The portion of the eyeglass frame which extends across the top of the nose. Because the nose supports 90 percent of the weight of the glasses, a properly sized and adjusted bridge is critical to the fit and comfort of the eyeglasses.
B-Scan
Ultrasound procedure in which high frequency waves are reflected by eye tissues and orbital structures and then converted into electrical pulses which are displaced as bright spots on a black background. Provides a cross-sectional view of tissues used for evaluating structures that cannot be seen directly.
cable temple
Type of eyeglass temples (side pieces) that wrap around the ear to keep them well- fastened.
calcarine sulcus
The portion of the occipital lobe of the brain where sight takes place. The central visual field is represented in the posterior calcarine sulcus. The peripheral visual field is represented in the anterior portion of the calcarine sulcus.
cancer: eye
Cancer is a disease characterized by abnormal and uncontrollable growth of cells. The resulting mass, or tumor, can invade and destroy surrounding normal tissues. Cancer cells from the tumor can spread starting new cancers in other parts of the body. Melanoma is the most common cancer within the eye. Although rare, congenital or acquired eye cancer is a very debilitating disease. Early diagnosis and treatment is critical.
cataract
Clouding of the natural lens of the eye, usually a process of aging or excessive exposure over the years to ultra violet sun rays, causing blurred vision. Most people over 60 years of age have some degree of cataracts. During modern cataract surgery, this natural lens is removed and replaced by an intraocular lens.
chalazion of the eyelid
Inflammatory lump in a meibomian gland of the eyelid. This gland, located just inside the eyelid, supplies the outer portion of the tear film, preventing rapid tear evaporation and overflow and providing airtight eyelid closure.
children: eyeglass frames
Eyeglass frames for children come in many attractive, fashionable and durable styles. Metal frames with flexible hinges for durability and nose pads for comfort are recommended. In recent years, eyeglass frame companies have introduced many frame styles that meet these criteria and provide children with selections that are attractive to them – an important consideration in a child’s willingness to wear eyeglasses regularly.
children: eyeglasses
Children’s eyeglasses should be fitted by a trained eyecare professional (optician) experienced at working with children. Comfort, safety and durability are top considerations in the selection of eyeglasses for children. Lenses in children’s glasses should be made of impact-resistant polycarbonate that resists breakage and provide greater safety.
choroid
Layer of major blood vessels, which lies between the retina and the sclera (white of the eye), that provides oxygen and nutrients to the retina.
choroidal hemangioma
A noncancerous growth within the “choroid” blood vessel layer, which lies beneath the retina. Many choroidal hemangiomas never grow or leak fluid, and the ophtalmologist observes them without treatment. However, if the growth is located in the macula (center of vision) or if it leaks fluid, it requires treatment because it can cause a retinal detachment or other vision problem.
choroidal melanoma
Relatively rare malignant melanomas that form in the choroid, the blood vessel layer beneath the retina. Small melanomas can be treated and are usually watched for growth prior to treatment. Medium to large sized melanomas are usually treated with either radiation therapy or removal of the eye.
choroidal metastasis
Sometimes, malignant tumors from other parts of the body can spread to areas in and around the eye. In women, these are usually from the breast, while in men they are more often from the lung. Chemotherapy can sometimes be used to treat these tumors, although radiation is usually a more definitive treatment.
choroidal nevus
Rare tumors that can grow into a malignant melanoma. Like a raised freckle on the skin, nevi can occur inside the eye and should be seen by an eye doctor.
choroidal osteoma
Benign bony tumors that can arise within the choroid blood vessel layer beneath the retina. They are usually located near the optic nerve and can cause vision loss.
closed-angle glaucoma
Serious form of glaucoma that can result in a sudden rise in intraocular pressure. Condition develops when the drainage angle, which allows the aqueous (fluid behind the iris) to flow out of the eye, is suddenly blocked. Symptoms of a partial blockage can include blurred vision, halos around lights, pain and redness of the eye. A sudden blockage can result in severe pain. To avoid permanent damage to the eyes, an ophthalmologist should treat the symptoms immediately.
collagen
In referring to the eye, collagen is the protein fibrils within the corneal tissue that help sustain its shape. Some new refractive vision correction procedures heat these fibrils with a special laser causing them to shrink and change the shape of the cornea.
CO2 laser
High-energy laser that can be used for making surgical incisions and for skin resurfacing. Emits short, intense bursts of energy that vaporize the outer layer of skin without damage to the underlying skin.
color blindness (link to encyclopedia)
Color blindness occurs when color-sensitive cone cells in the eye fail to properly pick up or send correct signals to the brain. Red-green deficiency, the most common form, results in the inability to distinguish certain shades of red and green. Those with a less common type have difficulty distinguishing blue and yellow. In rare cases, no colors can be detected, only shades of black, white and gray. Color blindness is usually inherited and cannot be cured, but those affected can often be taught to adapt to the inability to distinguish colors. In some cases, a special red tinted contact lens is used in one eye to aid persons with certain color deficiencies.
color deficiency
Partial or total inability to distinguish specific colors.
computer eyestrain
computer vision syndrome
Collection of symptoms brought about by eyestrain associated with prolonged use of the computer. Symptoms include eyestrain, blurred vision, headaches, flickering or flashing sensations, loss of appetite, nausea and dry or irritated eyes.
computers and your vision
Extensive viewing of the computer screen can lead to eye discomfort including dry, burning eyes, blurred vision, delayed focusing, altered color perception and headaches. Eyestrain is caused by such factors as lighting, location of screen and quality of monitor and/or inherent problems with eyes including refractive disorders, binocular vision, accommodative disorders, dry eye, and poor tear flow over the eye due to reduced blinking.
cone
A type of specialized light-sensitive cell (photoreceptor) in the retina that provides sharp central vision and color vision. Highly concentrated in fovea. Three classes of cones exist: short, medium, and long wavelength cones.
conjunctiva
Thin, transparent membrane that lines the inner surface of the eyelid and covers the sclera where it becomes the white of the eye.
conjunctival tumor
Malignant cancers that grow on the surface of the eye. The most common conjunctival cancers are squamous carcinoma, malignant melanoma and lymphoma.
conjunctivitis
Inflammation of conjunctiva or membrane that covers the white of the eye and inner surfaces of the eyelid. Characterized by discharge, grittiness, redness and swelling. May result from virus, bacteria, allergens, chemical exposure or ultraviolet light exposure and, depending on cause, can be contagious. Sometimes called pink eye.
contact lens
Thin plastic or glass lens designed to fit over the surface of the cornea, usually for correction of a refractive error, but can also be cosmetic (colored lenses).
contact lens: aspheric
Premium contact lens for borderline astigmatic patients and emerging presbyopes.
contact lens: bi-toric
Toric contact lens used to correct residual astigmatism.
contact lens: cleaning
All contact lenses, including soft and rigid designs, require cleaning, disinfecting and rinsing solutions. Enzymatic cleaners may also be needed to reduce the buildup of protein deposits on the lens surface. Wearers should follow carefully the cleaning instructions provided by their eye care professional.
contact lens: care
For maximum success with contact lenses, wearers should follow the wear schedule prescribed by their eye professional, practice good hygiene by keeping lenses free from contamination, and use cleaning, disinfecting and rinsing solutions as directed.
contact lens: enzymatic cleaner
Contact lens cleaner that removes protein deposits and other debris. Some come in liquid form while others are in tablet form that is dropped into a solution along with the lens.
contact lens: daily wear
Contact lenses worn only during waking hours.
contact lens: disposable
Contact lenses intended to be worn for a certain time period — daily, weekly, bi-weekly, monthly — and then discarded. Disposable lenses last from one day to two weeks, while “frequent replacement” lenses are thrown away monthly or quarterly.
contact lens: drops
Lubricant eye drops to soothe and moisten lenses to minimize dryness and make lens wear more comfortable. Care should be taken by contact lens wearers to use eye drops specifically formulated for contacts. Other drops may stain lenses.
contact lens evaluation (link to free online eye test)
contact lens: extended wear
Contact lenses that can be worn continuously, even while sleeping, up to a maximum number of days, as specified by the eye doctor, usually one to seven days. Extended wear lenses are manufactured from a high water content material and/or a thin center thickness to allow maximum oxygen transmission.
contact lens: frequent replacement
Contact lenses replaced on a planned schedule, usually every 2 weeks, monthly or quarterly. Can be daily or extended wear lenses.
contact lens: hard
Hard contact lenses are manufactured using rigid materials that essentially provide a new front surface for the eye. These lenses help in the correction of astigmatism because the tear film of the eye fills in the gap between the lens and the irregularly shaped cornea.
contact lens: rigid gas permeable (RGP)
Durable contact lenses made of polymers that transmit oxygen and allow longer wearing times than other rigid lenses. Because RGPs do not contain water, they resist deposits and are not prone to harboring bacteria. These lenses are large in diameter to increase comfort.
contact lens: soft
Made from flexible plastic, these lenses absorb water and thus enable greater amounts of oxygen to pass through the lens to the cornea. Soft lenses are more comfortable for most wearers than hard lenses, and most lenses prescribed today are a version of a soft lens. They vary in design depending on the type of materials and required refractive correction.
contact lens: solution
Variety of solutions for caring for contact lenses, including cleaning, rinsing and disinfecting. There are also multi-purpose solutions that provide all three functions. Rewetting solutions are designed to lubricate the lenses while they are worn.
contact lens: spheric
Single prescription contact lenses with smooth spherical surfaces that bend light rays equally in all directions (360 degrees).
contact lens: toric
Contact lenses that contain a cylinder component to correct astigmatism by bearing two different optical powers at right angles to each other. These lenses may be thicker in one meridian to enable the lens to maintain proper orientation on the eye.
contact lens and children’s vision
Although children adapt well to contact lenses, they may have problems with proper care. Without adequate supervision, they often wear lenses too long, fail to care for them properly and lose them frequently. Children are also more affected by seasonal allergies and therefore have increased levels of mucoprotein, a naturally occurring substance in tears. This means the contact lenses require more cleaning. Parents should rely the recommendations of an eye care professional because there are cases in which contact lenses are the best choice for a child.
contrast sensitivity
Measure of visual ability to distinguish details between an object and its background under varying degrees of contrast.
convergence
Coordinated movement of the two eyes so that the images of a single point fall on corresponding points of the two retinas
cornea
Clear structure that covers the front part of the eye including the iris and pupil. The cornea provides most of the eye’s optical power, while the crystalline inner lens, located behind the iris serves to “fine tune” the focus of the images. When both are working properly, a sharp image is focused on the retina and transmitted through the optic nerve to the brain.
corneal abrasion
A tearing, scrape or puncture of the cornea, sometimes accompanied by a loss of epithelium, the outer tissue layer of the cornea. Although a corneal abrasion can be very painful, the corneal layer of the eye heals more quickly than most other tissues in the human body.
corneal dystrophy
Any of a number of rare hereditary abnormalities that are characterized by an accumulation of abnormal material in the cornea. This accumulation may occur later in life and result in cloudiness of the cornea and reduction in vision.
corneal implants
Refractive surgery procedure in which a prescription implantable contact lens (ICL) is inserted within the corneal tissue to correct problems of nearsightedness. Two types of lenses are currently being used in the ICL procedure, both under FDA investigational protocol.
corneal mapping
Procedure whereby a detailed map of the corneal surface is drawn by a corneal topography instrument. Maps are used to evaluate the cornea prior to treatment and are especially valuable as a tool in preparing for refractive vision correction.
corneal ring
Plastic half-ring segments used in a particular type of refractive surgery. This procedure involves implantation of the ring segments in the peripheral area of the cornea in order to change its contour to the shape desired to correct cases of nearsightedness. These rings may later be removed or replaced.
corneal topography
Procedure that creates detailed maps of the surface of the eye using an instrument that combines a computer and video camera. The maps are used to evaluate the cornea prior to treatment and are especially valuable as a tool in preparing for refractive vision correction.
corneal ulcers
Wound on the surface of the eye similar to a scrape or cut on the skin. The cornea is covered by a layer of tissue called the epithelium which, when damaged can result in infection if left untreated. Corneal ulcers have many causes including injury, abnormal eyelashes, absence of tear production and infections. Persistent irritation or redness is reason to see an eye doctor.
crossed eyes
Also known as strabismus, this condition is a visual defect in which the eyes are misaligned and point in different directions. Strabismus usually occurs in childhood, but it can occur later in life. Children with crossed eyes usually adapt when the brain learns to ignore the image of the misaligned eye, although they lose depth perception. Adults who develop the problem often have double vision because the brain is already trained to see two images.
daily wear contact lens
Contact lenses worn only during waking hours.
diabetes and your eyes
Diabetes can cause many problems that result in changes to the eye. The most common and serious diabetes-related disease is diabetic retinopathy, but diabetes can also cause cataracts and affect the nerves that control eye alignment. The disease can also cause the optic nerve to be more easily damaged by glaucoma. Diabetics should be very careful about regulating their level of blood sugar to protect themselves from serious eye problems.
diabetic retinopathy
Potentially serious complication of diabetes that results in the weakening of tiny blood vessels that nourish the retina. These vessels may leak causing a variety of complications including the formation of scar tissue on the retina, a decrease in nourishment to the retina or blood in the vitreous humor (fluid that fills the inner cavity of the eye) causing cloudy vision. If the condition is not caught and treated during the early stages, it can result in blindness. For this reason, diabetics should have regular and frequent eye examinations.
diamond knife
Surgical knife with a high-quality diamond edge often used in delicate eye surgery.
diet and nutrition
A well-balanced diet is essential for overall good health and a variety of vitamins and minerals are necessary for normal cell growth and repair. Eyes contain highly specialized tissues, and studies show that a healthful diet rich in several specific nutrients and vitamins helps maintain lifelong eyesight.
diffraction
The scattering of rays of light when they bump into an object or when they pass through air or water, or go by an edge or narrow opening. Plays a role when the pupil is small.
diopter
Unit that measures the degree of refractive error in an eye or the light-bending power of a lens. In an eyeglass or contact lens prescription, a negative number refers to nearsightedness, while a positive number refers to farsightedness. For instance, a –8.00 diopter lens is very nearsighted, while a +0.75 is slightly farsighted. Astigmatism can be measured as either a positive (+) or a negative (-) but will be accompanied by another number such as “@ 90” indicating the direction (axis) of the astigmatism.
disposable contact lens
Contact lenses intended to be worn for a certain time period – daily, weekly, biweekly, monthly – and then discarded. Among most eye doctors, “disposable” usage ranges from one day to two weeks, while “frequent replacement” lenses are thrown away monthly or quarterly. (index to contact lens: disposables)
drooping eyelids
Condition (usually hereditary) in which the upper eyelid(s) sag. May be congenital or caused by a later problem associated with a nonfunctioning levator muscle.
dry eye
Condition due to a deficiency in the production and/or composition of tears by the eye’s lacrimal glands. Symptoms are redness, swelling and irritation, often accompanied by excessive watering of the affected eye. The condition is more common as the eye ages and may be worsened by a dry climate, exposure to wind, smoke, smog, air conditioners and ceiling fans. Most dry eye can be corrected by the use of artificial tear drops prescribed by your eye doctor.
ECCE
Acronym for Extracapsular Cataract Extraction. A surgical procedure that involves removing a cloudy or opaque lens (cataract) while leaving the back lens capsule intact.
emmetropia
Refractive condition in which no refractive error is present. In other words, perfect 20/20 vision. Distant images are focused sharply on the retina without the need for corrective lenses.
enzymatic cleaner
Contact lens cleaner that removes protein deposits and other debris. Some come in liquid form while others are in tablet form. The tablet is dropped into a solution along with the lens.
enzyme
A protein involved in important biochemical reactions in the body, affecting the rate at which chemical changes take place. These proteins can build up on contact lenses, requiring the use of special cleaners that remove the deposits.
enucleation
Surgical removal of a diseased or damaged eyeball, leaving eye muscles and remaining orbital contents intact.
epiphora
Overflow of tears down the cheek caused by defective tear drainage system or by excessive flow of tears.
Erbium laser
Laser developed as a refinement to the CO2 laser used in skin resurfacing for acne removal and removal of shallow wrinkles. Erbium laser shows promise in a new procedure to emulsify the lens nucleus during cataract surgery.
esophoria
A tendency of one eye to turn inward
esotropia
Misalignment of the eyes in which one eye deviates inward toward the nose while the other fixates normally.
Excimer laser
A high-energy, cold laser that is used in the Photorefractive Keratomy (PRK) and Laser In-Situ Keratomileusis (LASIK) procedures to sculpt the central zone of the cornea to correct nearsightedness, farsightedness or astigmatism. Guided by a computer under the direction of an ophthalmologist, the laser emits a pulsating beam of ultraviolet light that ablates, or vaporizes, the corneal tissue to the precise depth and area required for refractive vision correction.
exophoria
A tendency of one eye to turn outward from the nose
exotropia
Misalignment of the eyes in which one eye deviates outward away from the nose while the other fixates normally.
extended wear
Contact lenses that can be worn without interruption, even while sleeping, up to a maximum number of days, usually one to seven, as specified by the eye doctor. Extended wear lenses are manufactured from a high water content material and/or a thin center thickness to allow maximum oxygen transmission.
eye
A sensitive, sphere-shaped sense organ that acts as a “window,” allowing light waves to enter the body and be sent to the brain where they are converted into images. The eye works much like a camera with two lenses. Light entering the eye passes first through the cornea where it is focused through the pupil on the inner lens. The inner lens “fine tunes” and focuses the light on the retina at the back of the eye, which acts much like the film in a camera. The retina then transmits the light pattern to the brain through the optic nerve where an image is created.
eye care practitioner
Eyecare practitioners fall into two categories: ophthalmologists and optometrists. Ophthalmologists are medical doctors (M.D.s) who treat eye diseases and perform surgery. Optometrists (O.D.s) are able to diagnose eye diseases and provide some types of treatment but are not licensed to perform surgery. Both ophthalmologists and optometrists can dispense eyewear. The two professions often work together in providing comprehensive eye care to patients.
eye evaluation (list and link to all Free Eye Tests)
eye exam
An eye examination includes a visual acuity check (vision test) plus tests for a variety of conditions that affect overall eye health. Average time for a complete exam is from one to two hours and the procedures performed are comfortable and painless. In addition to a vision test, most exams will include an inspection of the interior structure of the eye including the retina, a test for glaucoma, an eyelid exam, a check of the pupil’s response to light, a peripheral (side) vision check and an eye muscle coordination test. Additional tests may be performed depending on past eye and medical history or current symptoms.
eye exam: routine
Regular eye examination of the type given by most eye care practitioners every one or two years. Usually includes tests and checks for visual acuity for distance and near vision (with and without corrective eyewear); intraocular pressure; pupil functions; checks for external and internal infection, disease or defects; extraocular muscle function; and lens and retina inspection through the dilated pupil.
eye safety
Because eyesight is considered by many to be the most important of the five senses, protecting the eye from hazards should be a priority. The most common eye hazards comprise flying objects from grinding, sawing, hammering and other projectiles, such as BB guns. Dusts, welding sparks, fumes and chemical splashes are also major hazards, particularly in workplace situations. High-intensity light rays from arc welding, acetylene equipment and even from staring into the sun can cause painful burns and permanent damage to the retina. More than 90 percent of all eye injuries could be prevented if safety guidelines are followed and protective eyewear is worn.
eyeglasses
Also called spectacles, eyeglasses are the most common device for the correction of vision problems including hyperopia (farsightedness), myopia (nearsightedness), astigmatism (corneal distortion) and presbyopia (inability of eye to focus up close due to hardening of natural lens). The most common types of eyeglass lenses are single vision, bifocals, trifocals and multi-focals (progressive lenses). Eyeglass lens materials include glass and various types of plastic, including new materials that allow thinner, lighter-weight lenses. Various treatments to the lenses include antireflection coating, photochromic (which darken when exposed to sunlight), polarized and toughened (for safety).
eyeglass evaluation (link to free online eye test)
eyelid
Structures covering front of the eye that protect the eye, limit the amount of light entering the pupil, and distribute tear film over the exposed corneal surface.
eyelid plastic surgery (blepharoplasty)
Surgery to improve the appearance of the eyelids. In addition to detracting from overall appearance, drooping eyelids may cause functional problems such as impaired field of vision or difficulty wearing glasses. Blepharoplasty is usually outpatient surgery performed by ophthalmic plastic and reconstructive surgeons.
eyelid plastic surgery evaluation (link to free online eye test)
eyelid skin cancer
Any cancer involving the skin of the eyelid or adjacent face. Eyelid cancers occur most often on the lower eyelid, but may be found anywhere on the eyelid margins, corners of the eye, eyebrow skin, or adjacent areas of the face.
eyespot
A concentrated patch of photoreceptor cells on the skin of some species.
eyewear: sports vision
Specialized field of prescribing eyewear designed to be worn during sporting activities. Growing specialty in many eye care offices, focusing on the promotion and enforcement of proper ocular protection, including ultra-violet and sun protection, glare protection and safety from direct impact. Protective eyewear includes any frame or goggle made with polycarbonate lenses (plano or prescription) designed to protect the player by maximizing ocular protection.
extracapsular cataract extraction
A surgical procedure that involves removing a cloudy or opaque lens (cataract) while leaving the back lens capsule intact.
farsightedness (hyperopia)
Vision that results when the distance from the cornea to the retina is too short. This occurs when the eye that has a vertical oval shape, or it has a cornea that is flatter than normal. In either event, a person who is farsighted sees well at a distance but has poor reading vision. Those who are farsighted are usually born with the disorder.
FDA
Acronym for the Food and Drug Administration. It is a United States government agency responsible for the evaluation and approval of medical devices, including contact lenses, intraocular lenses and Excimer lasers. In the U.S., the FDA must approve these products before they can be marketed. Contrary to popular belief, the FDA does not evaluate surgical procedures unless they require a new medical device.
field analyzer
Automated projection perimeter instrument which uses projected points of light to determine central or peripheral field of vision. Used for early diagnosis, treatment and management of diseases resulting in visual field loss.
fixation
The act or an instance of focusing the eyes on an object.
fixation point
The point in the visual field on which the two eyes focus in normal vision, and for each eye is the point that directly stimulates the fovea of the retina.
flashers
Bright bursts of light that are sometimes seen when the eyes are closed. These occur normally as the eye ages and the vitreous humor, which is jelly-like substance that fills center cavity of eye, begins pulling away from the retina. The flashes can appear off and on for several weeks or months. If there is a sudden appearance of many light flashes, an ophthalmologist should be consulted immediately to see if the retina has been torn.
flicker
The wavering or fluttering visual sensation produced by intermittent light.
floaters
Particles that float in the vitreous, which is jelly-like substance that fills center cavity of eye, and cast shadows on the retina. The particles appear to be strung together with a web-like thread. Some floaters are formed before birth while others occur normally with aging. The sudden appearance of many floaters can be an indication of a serious eye disorder and should be checked by an eye care professional.
fluorescein angiography
Test used to examine blood vessels in the retina, choroid and iris of the eye. Fluorescein dye is injected into an arm vein and rapid, sequential photographs are taken of the eye as the dye circulates.
focal length
The distance of a focus from the surface of a lens or concave mirror. Relates to the distance between an image source and a lens and the distance of the lens to the image.
Food and Drug Administration
The Food and Drug Administration is a United States government agency responsible for the evaluation and approval of medical devices, including contact lenses, intraocular lenses and excimer lasers. In the U.S., these products must be approved by the FDA before they can be marketed. Contrary to popular belief, the FDA does not evaluate surgical procedures unless they require a new medical device.
frequent replacement contact lenses
Contact lenses replaced on a planned schedule, usually every 2 weeks, monthly or quarterly. Can be daily or extended wear lenses.
general eye exam (link to free online eye test)
glaucoma
Condition caused by excessive buildup of fluid inside the eye putting pressure on the retina. The leading cause of blindness among adults in the United States. There are two types of glaucoma; the most common being open angle and the less common, but more serious, called narrow angle. Glaucoma has few if any symptoms, but a simple, painless eye test detects the problem. If untreated, glaucoma can result in gradual, painless, irreversible loss of vision.
glaucoma evaluation (link to free online eye test)
Graves disease
Condition caused by overactivity of the thyroid gland. Patients with Graves disease may experience these eye symptoms: inflammation of the eyes, swelling of the tissues around the eyes, and protrusion of the eyes.
hard contact lens
Hard contact lenses are manufactured using rigid materials that essentially provide a new front surface for the eye. These lenses help in the correction of astigmatism because the tear film of the eye fills in the gap between the lens and the irregularly shaped cornea.
health evaluation: eye (list and link to all Free Eye Tests)
heterophobia
A constant tendency of one eye to deviate in one or another direction due to imperfect balance of ocular muscles.
high index lenses
Eyeglass lens manufactured from a special plastic material that allows the lens thickness to be reduced substantially while maintaining the optical properties.
histoplasmosis
Disease caused when airborne spores of the fungus Histoplasma Capsulatum are inhaled into the lungs. This fungus is found throughout the world where bird or bat droppings accumulate. Initial symptoms are usually mild, similar to a common cold. Even mild cases can later cause a serious eye disease called ocular histoplasmosis syndrome, a leading cause of vision loss in Americans ages 20 to 40. Although most people infected with the fungus never develop the disease, people who have lived in an area with a high rate of histoplasmosis should have their eyes examined regularly.
Holmium laser
Infrared (thermal) laser developed in the late 1980s. The laser’s beam is cool and can remove small areas of tissue without affecting surrounding tissue. In a refractive surgery procedure called Laser Thermal Keratoplasty (LTK), the Holmium laser is used to shrink the peripheral area of the cornea in order to make its shape steeper and correct mild to moderate cases of farsightedness. The laser works when moisture in the cornea absorbs energy from the laser pulses causing corneal tissue to heat up and shrink.
horopter
For a given fixation point, the set of points on the retina that are perceived to have zero retinal disparity. The points sweep out an arc in space that intersects a fixated point in space.
hue
The perception of color as red, yellow, green, blu, or any intermediate shade.
hyperopia (farsightedness)
Vision that results when there is too short a distance from the cornea to the retina. This can be caused by an eye that has a vertical oval shape or a cornea that is flatter than normal. In either case, a person who is farsightedness sees well at a distance but has poor reading vision. Those who are farsighted are usually born with the disorder.
ICCE
Acronym for Intra-capsular Cataract Extraction. Older method of cataract surgery that involves removal of the entire lens. Some surgeons may still use this method in selected cases.
illumination
The amount of light falling onto a surface.
infant vision development
At birth, infants can see patterns of light and dark but have blurred vision of specific objects. During the first 4 months, the two eyes will begin working together, with visual horizon expanding, vision becoming clearer and color vision developing. It is believed that by 4 months, an infant’s color vision is similar to an adult’s. By 6 months of age, babies acquire eye movement control and eye-hand coordination skills. It is normal at this stage for an infant’s eyes to appear at times as crossed or out of alignment. Persistent misalignment should be reported to an eye care professional.
inferior
In eyecare terminology, referring to the lower half of the eye.
Intacs
Trade name for the plastic half-ring segments used in a type of refractive surgery called intrastromal corneal ring procedure (ICRS). This procedure involves implantation of the ring segments in the peripheral area of the cornea. This changes the cornea’s shape to correct cases of nearsightedness. These rings may later be removed or replaced.
interferometer
An instrument that uses the interference of waves (as of light) for precise determination especially of wavelength, spectral fine structure, indices of refraction, and very small linear displacements.
Intra-Capsular Cataract Extraction (ICCE)
Older method of cataract surgery that involves removal of the entire lens. Some surgeons may still use this method in selected cases.
intrastromal corneal rings
Plastic half-ring segments used in a type of refractive surgery called intrastromal corneal ring procedure (ICRS). This procedure involves implantation of the segments in the peripheral area of the cornea in order to change its contour to the shape desired to correct cases of nearsightedness. These rings may later be removed or replaced.
intraocular lens (IOL)
Plastic lens surgically implanted to replace the focusing power of the natural crystalline lens following cataract extraction or during a refractive surgery procedure called Clear Lens Extraction.
intraocular pressure (IOP)
Measurement of fluid pressure inside the eye. All eye exams include a measurement of this eye pressure with an instrument called a tonometer. Glaucoma, the leading cause of blindness in adults, is caused by a buildup of pressure inside the eye and often occurs without noticeable symptoms. This buildup puts pressure on the optic nerve, which can permanently damage eyesight or even cause blindness.
IOL
Acronym for intraocular lens, plastic lenses that may be surgically implanted to replace natural crystalline lenses of the eye.
iris
Ring of pigmented tissue lying behind the cornea that gives color to the eye and controls the amount of light entering the eye by varying the size of the pupil.
iritis
Inflammation of the iris causing pain, tearing, blurred vision, small pupil, and a red congested eye.
isopter
A contour line in a representation of the visual field around the points representing the macula lutea that passes through the points of equal visual acuity.
itchy eyes
Condition that can be caused by many factors such as pollutants in the air, allergies, chemical exposure (swimming pool for instance), sun glare, viral and bacterial infections and conjunctivitis (pink eye). Home care may involve warm compresses or eye drops. If symptoms persist, an eye doctor should be contacted.
keratitis
Infection or inflammation of the cornea which can be caused by a variety of conditions, including infections, dry eyes, foreign objects, contact lenses, intense light, vitamin A deficiency or allergies. Usual treatment is with antibiotic or anti-viral eye drops and ointments. An eye care professional should provide medical advice.
keratoconus
Hereditary, degenerative corneal disease characterized by generalized thinning and cone- shaped protrusion of the corneal area usually affecting the vision of both eyes.
keratome
Knife with a triangular blade used for corneal incisions.
keratometer
Device for measuring the curvature of the cornea and for detecting and measuring astigmatism. The keratometer measures the frontal curvature, or steepness, of the cornea and compares high and low points to determine if a refractive problem exists.
lacrimal system
Orbital structures of the eye responsible for tear production and drainage. Tears are produced in the lacrimal gland above the outer corner of the eye. They flow across the eye surface and drain into the upper and lower puncta, which are openings at inner eyelid margins. They then go through the upper and lower canaliculi to the common canaliculus, into the tear sac. From there, tears flow through the nasolacrimal duct, down into the nose.
laser
Acronym for Light Amplification by Simulated Emission of Radiation. A very narrow, hi- intensity light, which can vaporize tissue and/or join structures. Eye care practitioners use several types of lasers for treating various eye conditions.
lateral geniculate nucleus
Structure in the thalmus, which is a major recipient of axons from the retina.
laser: Excimer
A high-energy, cold laser that is used in the Photorefractive Keratectomy (PRK) and Laser In-Situ Keratomileusis (LASIK) procedures to sculpt the central zone of the cornea to correct nearsightedness, farsightedness or astigmatism. Guided by a computer under the direction of an ophthalmologist, the laser emits a pulsating beam of ultraviolet light that ablates, or vaporizes, the corneal tissue to the precise depth and area required for refractive vision correction.
laser: CO2
High-energy laser which can be used for making surgical incisions and for skin resurfacing. Emits short, intense bursts of energy that vaporize the outer layer of skin without damage to the underlying skin.
laser: Erbium
Laser developed as a refinement to the CO2 laser used in skin resurfacing for acne scarring and wrinkle removal for shallow wrinkles. Erbium laser shows promise in a new procedure to emulsify the lens nucleus during cataract surgery.
laser: Holmium
Infrared (thermal) laser developed in the late 1980s. The laser’s beam is cool and can remove small areas of tissue without affecting surrounding tissue. In a refractive surgery procedure called Laser Thermal Keratoplasy (LTK), the Holmium laser is used to shrink the peripheral area of the cornea. This makes the shape of the cornea steeper and corrects mild to moderate cases of farsightedness. The laser works when moisture in the cornea absorbs energy from the laser pulses, causing corneal tissue to heat up and shrink.
Laser In-Situ Keratomileusis (LASIK) (link to encyclopedia)
Currently the most widely used refractive eye surgery procedure. Combines the minimal post-operative discomfort of Automated Lamellar Keratoplasty (ALK) with the computer- controlled precision of Photorefractive Keratectomy (PRK). As in ALK, a flap of corneal tissue is lifted to expose underlying tissue, which is then sculpted by the Excimer laser as in PRK.
laser pointers
Pointing devices that use a laser beam. Light energy that some laser pointers can deliver into the eye may be more damaging than staring directly into the sun. Even momentary exposure can cause discomfort and temporary vision impairment.
laser: Summit
One of two primary manufacturers of the Excimer laser used in refractive eye surgery.
Laser Vision Correction
Any of several surgical vision correction techniques that use a computer- controlled laser to gently sculpt the corneal tissue to correct vision error caused by corneas that are too steep (nearsighted), too flat (farsighted) or uneven (astigmatic).
laser: Visx
One of two primary manufacturers of the Excimer laser used in refractive eye surgery.
laser: Yag
Short pulsed, high-energy light beam that can be precisely focused by computer to optically cut, perforate, or fragment tissue.
LASIK (index to Laser In-Situ Keratomileusis)
Acronym for Laser In-Situ Keratomileusis. Currently the most widely used refractive eye surgery procedure. Combines the minimal post-operative discomfort of Automated Lamellar Keratoplasty (ALK) with the computer-controlled precision of Photorefractive Keratectomy (PRK). A flap of corneal tissue is lifted to expose underlying tissue, which is then sculpted by the Excimer laser as in PRK.
lateral
In eye care terminology, denoting a position farther from the median plane or midline of the eye.
lazy eye
Condition of decreased vision in one or both eyes without detectable structural abnormalities or disease in the eye or visual pathways. Also known as amblyopia. Best-corrected vision is usually less than 20/20.
lens: aspheric
Premium contact lens for borderline astigmatic patients and emerging presbyopes.
lens: bifocal
Eyeglass lens made up of a main lens on top for distance vision and an additional lens on the bottom for near vision.
lens: bitoric
Toric contact lens used to correct residual astigmatism.
lens: crystalline
Natural lens of the eye that lies behind the iris and helps bring light rays to focus on the retina. Muscular elastic fibers contract or expand the lens so that it can focus on objects at varying distances. In this manner, the lens fine-tunes the focus of the light rays refracted by the cornea so that a sharp, clear and colorful image is focused on the retina. The lens of the eye is often compared to the lens of a camera.
lens: high index
Eyeglass lenses manufactured from higher refractive index material enabling the thickness and weight to be reduced while maintaining the same optical qualities.
lens: meter
Device used for determining the refractive power of an eyeglass or contact lens.
lens: multifocal
Eyeglasses or contact lenses that enable the wearer to focus through two or more prescriptions for different distances on one lens. Bifocals have two points of focus, one for distance and the other for near, while trifocals have three points of focus — distance, intermediate and near. Progressive “no-line” eyeglass lenses offer a continuous range of focus from top to bottom.
"lens: progressive
“No-line” multi-focal eyeglass lenses with progressive powers that graduate from distance to reading power. Although progressive lenses often require a greater period of adjustment, these are the most versatile of all multi-focal designs because of the continuous range of focus.
lens: prescription
Any lens, eyeglass or contact that has been fabricated to correct for nearsightedness, farsightedness or astigmatism.
lens: spheric
Eyeglass or contact lens with a single continuous curve across the entire front surface.
lens: toric
Contact lens that contains both a spherical and cylinder component to correct astigmatism. Thickness of lens may be modified from one meridian to another, thereby enabling the lens to maintain correct orientation on the eye.
lens: trifocal
Eyeglass or contact lens design that includes three focal areas: usually a reading lens, a lens for faraway viewing, and a lens for mid-distance viewing.
lensectomy
Surgery to remove the natural crystalline lens of the eye. During most cataract surgery, the cloudy cataract lens is removed and replaced with a plastic prescription lens. In a procedure called “Clear Lens Extraction” or “Clear Lensectomy,” the eye’s natural lens is also removed and replaced with a plastic prescription lens in order to correct refractive disorders. The word “clear” denotes that the natural lens that is removed is clear, rather than a cloudy cataract lens.
lenses
Pieces of glass or other transparent materials used for magnification or increased visual acuity.
lensometer
Device used for determining the refractive power of an eyeglass or contact lens.
"lenticular
Special noncataract lenses for patients who have cataracts.
lipid
A fat or fatty substance that collects on contact lenses, making them uncomfortable.
low vision
The condition that exists when ordinary eyeglasses, contact lenses, intraocular lens implants or refractive surgery do not provide clear vision. Should not be confused with blindness. People with low vision have useful vision that can be improved with vision devices. The terms “legally blind” or “partially sighted” are often used in association with low vision. A person is considered legally blind when the best-corrected vision in the better eye is no more than 20/200 and/or the field of view is less than 20 degrees. A person with best-corrected vision of no more than 20/70 in the better eye is considered partially sighted or visually impaired.
"luminance
The amount of light coming off a surface.
lutein
Yellow carotenoid pigment found in body fats, egg yolks and green plants that promotes healthy eyes. One of two primary pigments found in central part of the retina which helps filter out damaging light.
macula
Small centralized area of the retina responsible for acute central vision. Damage to this portion of the retina severely limits a patient’s ability to read, recognize faces and perform any other task that requires straight-ahead vision.
"macula lutea
The cone-rich area of the human eye that contains the fovea. Also called yellow spot.
macular degeneration
Degeneration of the photoreceptors in the macula or central region of the retina. This area of the retina is responsible for central vision, used for reading, seeing faces, and so on. Often associated with aging.
medial
Medical term used to indicate “nasal or towards the nose.”
"melanin
Black pigment in the pigment epithelium cells that absorbs light not captured by the retina, thereby preventing the light from being reflected off the back of the eye.
"mesopic
Intensities of light under which both cones and rods operate.
microkeratome
Sophisticated surgical device used to shave a very thin amount of the cornea at a predetermined depth. Used in LASIK refractive vision correction procedure to create the corneal “flap” which is lifted. Then the Excimer laser sculpts the underlying corneal tissue.
"microspectrophotometry
A procedure that involves passing a narrow measuring beam through the outer segments of individual photoreceptors to measure absorbancy in excised retinas.
miosis
Condition in which the pupil is constricted. Occurs as a normal response to a bright light stimulus, to focusing on a near object (known as accommodation), or to administer certain drugs.
monochromat
An individual who is completely color-blind.
mucoprotein
mucoid
Any of a group of various complex conjugated proteins that occur in body fluids and tissues.
multi-focal
Eyeglasses or contact lenses that allow the wearer to focus through different prescriptions for different distances on the same lens. Bifocals have two points of focus, one for distance and the other for near, while trifocals have three points of focus — distance, intermediate and near. Progressive “no-line” eyeglass lenses offer a continuous range of focus from top to bottom.
multiple sclerosis
Chronic central nervous system disorder in which there is loss of the protective myelin sheath surrounding nerve tissue. Effects on the eye include optic nerve inflammation with reduced vision, double vision and involuntary eye oscillations.
mydriasis
Increase in pupil size (dilation) occurring normally in the dark. May occur artificially through the use of drugs.
mydriatic
A drop that dilates the pupil.
myope
Medical term for nearsighted person. A person with good reading vision, but who has difficulty seeing distant objects.
myopia
Also called nearsightedness. The front curvature of the cornea is too steep in a nearsighted person, causing good reading vision but poor distance vision.
nasal
When referring to the eye, this term indicates inward direction toward nose. Also refers to that half of the eye or visual field from the middle of the eye inward.
nasal lacrimal system
That portion of the lacrimal (tear producing) system that includes ducts which drain tears from the eye into the nose.
nasal lacrimal duct
Tear drainage channel that extends from lacrimal sac to opening in mucous membrane of nose.
nearsightedness
Also called myopia. The front curvature of the cornea is too steep in a nearsightedness person resulting in good reading vision but poor distance vision.
nutrition
Process by which a living organism assimilates food and uses it for growth and tissue replacement. In the prevention of ocular disease, the role of vitamins and minerals has taken on a major role. To maintain the health of the eye, a high-fiber, high-carbohydrate, high-antioxidant, low-fat, low-protein diet is best.
nystagmus
Involuntary, rhythmic side-to-side or up-and-down eye movements in which movement to one direction is faster than movement to opposite direction.
occlusion
The transient approximation of the edges of a natural opening, i.e., occlusion of the eyelids.
ocellus
A patch of light-sensitive receptor cells in the skin, present in some species.
ocular
Of, pertaining to, or affecting the eye.
ocular hypertension
Condition in which the intraocular pressure of the eye is elevated above normal without any obvious optic nerve damage or visual field defects. Over time, ocular hypertension may develop into glaucoma.
open-angle glaucoma
The less serious of two types of glaucoma, a condition caused by excessive buildup of fluid inside the eye putting pressure on the retina. Sometimes called chronic glaucoma, it is caused by a gradual blocking of aqueous outflow from the eye. It can develop slowly with no noticeable symptoms. If untreated, open-angle glaucoma results in a gradual, painless, irreversible loss of vision.
ophthalmologist
A medical doctor (M.D.) with education, training and experience in medical and surgical treatment of eye diseases and disorders.
ophthalmology
Branch of medical science that deals with the structure, functions and diseases of the human eye.
ophthalmoscope
An instrument for viewing the interior of the eye. It comprises a concave mirror with a hole in the center through which the observer examines the eye, a source of light that is reflected into the eye by the mirror, and lenses in the mirror that can be rotated into the opening in the mirror to neutralize the refracting power of the eye being examined. It makes the image of the retina clear.
opsin
Protein portion of the visual pigment of rod cells.
optic disc
The circular area in the back of the inside of the eye where the optic nerve connects to the retina. Also called the optic nerve head. Contains no photoreceptors and therefore creates a blind spot in the visual field.
optic nerve
Connects the eye to the brain. It carries the impulses formed by the retina, the nerve layer that lines the back of the eye and senses light and creates impulses. The brain interprets the images. Using an ophthalmoscope, the head of the optic nerve can be seen. It can be viewed as the only visible part of the brain (or extension of it).
optic nerve head
The circular area in the back of the inside of the eye where the optic nerve connects to the retina.
optic nerve pathways
The left and right branches of the optic nerves join behind the eyes, just in front of the pituitary gland, to form a cross-shaped structure called the optic chiasma. Within the optic chiasma, some of the nerve fibers cross. The fibers from the nasal (inside) half of each retina cross over, but those from the temporal (outside) half do not. Specifically, the fibers from the nasal half of the left eye and the temporal half of the right eye form the right optic tract; and the fibers from the nasal half of the right eye and the temporal half of the left form the left optic tract. The nerve fibers then continue along in the optic tracts. Just before they reach the thalamus of the brain, a few of the nerve fibers leave to enter nerve nuclei that function in visual reflexes. Most of the nerve fibers enter the thalamus, forming a junction (synapse) in the back of the thalamus. From there the visual impulses enter nerve pathways called the optic radiations, which lead to the visual (sight) cortex of the occipital (back) lobes of the brain.
optic neuritis
Inflammation of the optic nerve. Characterized by rapid onset of decreased vision and usually accompanied by discomfort upon eye movement and central visual field defect.
optic neuroma
A benign tumor of the optic nerve.
optic tract
The portion of each optic nerve between the optic chiasma and the diencephalon proper.
optician
Technicians trained and, in some states, certified to fill lens prescriptions and contacts and to fit eyeglasses. Some specialize in contact lenses and work in optometric or medical offices, working with an optometrist or ophthalmologist to fit contact lenses.
optometrist
Doctors of Optometry (O.D.) are primary health care providers who examine, diagnose, treat and manage diseases and disorders of the eye and associated structures. In accordance with state law, optometrists prescribe, fit and dispense ocular medications, glasses and contact lenses. An optometrist cannot perform surgery but often works with an ophthalmologist on pre- and post-surgical care.
optometry
The profession of examining the eyes, measuring vision and prescribing corrective lenses, diagnosing diseases of the eye and treating certain conditions that do not require license as a medical doctor.
orbit
Pyramid-shaped cavity in the skull containing the eyeball, its muscles, blood supply, nerve supply and fat.
orbital tumor
Process by which a living organism assimilates food and uses it for growth and tissue replacement. In the prevention of ocular disease, the role of vitamins and minerals has taken on a major role. To maintain the health of the eye, a high-fiber, high-carbohydrate, high-antioxidant, low-fat, low-protein diet is best.
orthokeratology
Controversial nonsurgical contact lens procedure designed to eliminate nearsightedness and astigmatism. The procedure involves the programmed use of a series of rigid oxygen permeable contact lenses that are designed to gradually change the contour of the front of the cornea. The lenses are changed every two to eight weeks until the maximum desired result is achieved. Then, retainer contact lenses are worn as necessary to stabilize the shape.
overconvergence
Condition in which the eyes come too far inward when focusing on a near object, resulting in blurring.
oversize lens
A lens that exceeds 61 millimeters in diameter
pachymeter
Ultrasound machine used in measuring thickness of the cornea. Especially important in determining treatment depth in refractive surgery.
pachometer
Instrument that uses optical principle of split images to measure corneal thickness or anterior chamber depth.
pallucid macular degeneration
Pallucid is an out-of-date, seldom used term.
Pediatric Wellness
Pediatric Evaluation (link to free online eye test)
perimeter
Instrument used for determining central or peripheral field of vision. v
perimetry
Method of charting extent of visual field as seen by the stationary eye. Aids in the detection of damage to the sensory visual pathways.
peripheral vision
Side vision; vision not in the straight-ahead direction.
phacoemulsification
Technique for removing eye’s natural crystalline lens in cataract surgery or clear lens extraction. Procedure makes use of an ultrasonic instrument called a phaco machine, which produces vibrations at a rate of 40,000 cycles per second, thereby dissolving the lens into small fragments. Using a hand piece, the surgeon then uses the same machine to aspirate (suck out) the contents of the lens and irrigate the eye.
phaco machine
Ultrasonic instrument used in phacoemulsification technique for removing the natural lens of the eye during cataract or clear lens extraction surgery. Using a hand piece connected to the phaco machine, the surgeon dissolves the lens into small fragments, aspirates the contents and irrigates the eye.
phoropter
An instrument used by the eye doctor to determine the degree of myopia (nearsightedness), hyperopia (farsightedness) or astigmatism that is present in the patient’s eye.
photochromatic
Eyeglass lenses that darken when exposed to short wavelength radiation or ultra-violet light. These are the “transition” lenses that change from clear to dark when exposed to sunlight.
photophobia
Abnormal sensitivity to, and discomfort from, light. Frequently associated with excessive tearing and often due to inflammation of iris or cornea.
photopic
Bright light conditions where only the cones are functional.
phoropter
An instrument used by the eye doctor to determine the degree of myopia (nearsightedness), hyperopia (farsightedness) or astigmatism that is present in the patient’s eye.
photocoagulation
A surgical process of sealing off, or clotting, tissue by means of a laser beam. It is used in cancer treatment to destroy blood vessels entering a tumor and deprive it of nutrients, in the treatment of a detached retina, to destroy abnormal blood vessels in the retina, to treat tumors in the eye; etc.
photochromatic
Eyeglass lenses that darken when exposed to short wavelength radiation or ultra-violet light. These are the “transition” lenses that change from clear to dark when exposed to sunlight.
photoreceptor
Cells specialized for receiving light.
Photorefractive Keratectomy (PRK)
Refractive eye surgery procedure that employs a computer-controlled Excimer laser system to sculpt by ablation (vaporize) the central corneal zone, or visual axis. By changing the shape of the patient’s cornea, the eye care surgeon can correct some cases of nearsightedness, farsightedness and astigmatism.
pink eye
Also known as conjunctivitis. Inflammation of conjunctiva or membrane that covers the white of the eye and inner surfaces of the eyelid. Characterized by discharge, grittiness, redness and swelling. May result from virus, bacteria, allergens, chemical exposure, or ultraviolet light exposure. Can be contagious.
plano
Term used by eye care professionals to describe lenses with no focusing power. The term is most often applied to nonprescription sunglasses or contact lenses that are worn for cosmetic purposes only.
plastic surgery of the eyelids
Also known as blepheroplasty. Surgery to improve the appearance of the eyelids. In addition to detracting from overall appearance, drooping eyelids may cause functional problems such as impaired field of vision or difficulty wearing glasses. Blepharoplasty is usually outpatient surgery performed by ophthalmic plastic and reconstructive surgeons.
PMMA
Acronym for polymethylmethacrylate. Original material used in the manufacture of “hard” contact lenses. In today’s rigid contact lenses, PMMA is often used in combination with other polymers to increase the oxygen permeability and allow longer wearing times.
polarized lenses
Eyeglass lenses designed to protect the eye against UV rays and reduce the glare of reflected light. May be constructed of glass, plastic or lightweight, hi-index plastic.
pole
Posterior pole refers to back curvature of eyeballs, usually to the retina between optic nerve and macular area. Anterior pole refers to center of front surface of cornea.
polycarbonate
Plastic marked by a high softening temperature and high impact strength, sometimes used for eyeglass lenses and frames.
posterior
Back area of an object.
posterior chamber
In referring to the eye, that space between the back which is filled with aqueous fluid between the iris and front face of the vitreous.
posterior capsulotomy
Laser surgical procedure which is sometimes necessary to clear vision after cataract surgery. During cataract surgery the front part of the capsule which contains the eye’s natural lens is removed, but the rear of the capsule (posterior capsule) is left intact. This membrane sometimes becomes cloudy after cataract surgery and requires a return trip to the ophthalmologist for treatment. Treatment comprises a very brief, in-office, painless laser procedure that opens a new pathway allowing light to reach the back of the eye. Vision improvement is very fast, usually within a day or two.
presbyope
Person who has difficulty reading print and seeing nearby objects because of age-related loss of elasticity of the eye’s natural crystalline lens.
presbyopia
Deterioration in the ability of the eye’s natural crystalline lens to expand or contract in order to focus on close objects.
prescription lenses
Eyeglass or contact lenses that provide vision correction as prescribed by an eye care practitioner.
PRK
Acronym for Photorefractive Keratectomy. Refractive eye surgery procedure that employs a computer-controlled Excimer laser system to sculpt by ablation the central corneal zone, or visual axis, to change its shape in order to correct some cases of nearsightedness, farsightedness and astigmatism.
propionate
Flexible, soft material that is sometimes used in eye goggles.
prosopagnosia
The inability to recognize faces.
protective eye wear
Eyewear made with impact-resistant lenses, often polycarbonate, to protect the eyes, usually sports or working situations.
protein
Common form of soft contact lens deposits which, if not removed, may lead to reduced lens wearing comfort, decreased visual acuity and general reduction in ocular health.
ptosis
Condition in which the upper eyelid(s) sag. May be congenital or caused by a later problem associated with a nonfunctioning levator muscle. Usually hereditary.
pupil
Black opening behind the cornea in the center of the iris that regulates the amount of light entering the inner lens of the eye.
punctum plug
Small, nondissolvable silicone plugs inserted in the tear draining ducts to close the openings of the tear draining system in order to slow drainage and loss of tears. Used to provide dry eye relief and/or reduce or eliminate the major cause of contact lens discomfort.
pupil dilation
Enlarged pupil resulting from contraction of dilator muscle or relaxation of iris sphincter. Normally occurs in dim illumination conditions. Comprehensive examination of the interior of the eye requires pupil dilation through the administration of appropriate eye drops by the examining eye professional. Dilation can also be caused by injuries, including blunt trauma.
Radial Keratotomy (RK)
Surgical procedure where patterned surgical incisions are made in the peripheral area of the cornea. As these incisions heal, the cornea is flattened to the degree required to make the desired refractive error correction. This early refractive vision correction procedure has been largely replaced by newer, more accurate procedures such as LASIK.
red eye
Any condition that causes the white part of the eye to look red. Redness usually is because of engorged blood vessels on the surface of the eye or hemorrhaging on the surface. In making a diagnosis, an eye doctor will pay close attention to the location and pattern of redness.
reflectance
The fraction of light that is reflected toward the eye by an object.
refraction: objective
Eye test utilizing an automated device called an Auto Refractor that instantly measures the power of the eye and the outer shape of the eye. The device needs no input from the patient such as that required by the “Which is better? 1 or 2” question used in a phoropter exam.
refraction: subjective
Eye test using a phoropter where patient is given choices between lens 1 and 2, providing the examining eye doctor with “subjective” information regarding which prescription will make the patient more comfortable.
refractive error
Optical defect of the eye that causes light rays to focus in front of the retina (nearsighted), behind the retina (farsighted), or in several different places on the retina (astigmatic), resulting in less than perfect vision. These defects can normally be corrected with eyeglasses, contact lenses or refractive eye surgery.
refractive surgery
Elective eye surgery which corrects optical defects of the eye by either changing the shape of the cornea or by inserting a plastic lens to supplement the eye’s natural focusing ability.
refractor
Instrument that aids an eyecare professional in determining the proper corrective prescription for a patient with less-than-perfect vision.
replacement schedule
Schedule for the length of time a specific type of contact lens should be worn. Extended wear lenses can be worn without interruption, even while sleeping, up to a maximum number of days as specified by the eye doctor, while other types of lenses may require removal every evening before bedtime. It’s important to differentiate between wear schedules for various lenses.
retina
Thin membrane that covers the inside of the back two-thirds of the eye. Retina converts images into electrical impulses to be sent along the optic nerve to the brain and be converted into images that allow vision.
retina evaluation (link to free online eye test)
retinal detachment
Painless disorder where patient may notice gradual raising or lowering of a curtain over the visual field of the affected eye. May occur with aging of eye or as a result of trauma. Caused by a detachment of the retina from the back of the eye, often from the “pulling” effect of the vitreous, the jelly-like ball that fills most of the eye behind the lens. Patient may also notice a sudden increase in “floaters” or flashing lights. Any such symptoms require an immediate visit to an ophthalmologist.
retinal
A form of vitamin A called retinal is responsible for transmitting light sensation in the retina of the eye. Deficiency of vitamin A leads to night blindness.
retinal rivalry
The perception of first one then the other of two visual stimuli, which differ in color or form when they are presented at the same time to congruent areas of both eyes
retinal hole
With age, the retina starts to thin and weaken especially near its attachments with the front of the eye (periphery). In addition, the jelly-like ball that fills most of the eye behind the lens, called the vitreous, changes from a firm substance to a loose fluid. When the vitreous becomes fluid, it can easily move and tug on its attachments and become detached, pulling a small bit of retina with it. When this happens, a hole is left in the retina.
retinitis pigmentosa
Hereditary, progressive retinal degeneration in both eyes. Night blindness develops, usually in childhood, followed by loss of peripheral vision, progressing over many years to tunnel vision and finally blindness.
retinoblastoma
Hereditary, malignant intraocular tumor that develops from retinal cells. If untreated, numerous seedling nodules produce secondary tumors, gradually filling the eye and extending along the optic nerve and to the brain, ending in death. Most common childhood ocular malignancy.
rhodopsin
The visual pigment in rod cells. Also called visual purple.
RGP
Acronym for Rigid Gas Permeable. Durable contact lenses made of polymers that transmit oxygen and allow longer wearing times than other rigid lenses. Because RGPs do not contain water, they resist deposits and are not prone to harboring bacteria. These lenses are often larger in diameter to increase comfort.
RK
Acronym for Radial Keratomy. Surgical procedure where patterned surgical incisions are made in the peripheral area of the cornea in order to reshape the cornea to the degree required for the desired refractive error correction.
rod
A type of specialized light-sensitive cell (photoreceptor) in the retina of the eye that provides side vision and the ability to see objects in dim light (night vision).
safety: eye
Because eyesight is considered by many to be the most important of the five senses, protecting the eye from hazards should be a priority. The most common eye hazards include flying objects from grinding, sawing, hammering and other projectiles, such as BB guns. Dusts, welding sparks, fumes and chemical splashes are also major hazards, particularly in workplace situations. High intensity light rays from arc welding, acetylene equipment and even from staring into the sun can cause painful burns and permanent damage to the retina. Following established safety guidelines and using appropriate protective eyewear can prevent 90 percent of all eye injuries.
saturation
The richness of hue. Indicates how much color has been diluted by grayness.
sclera
Tough outermost layer of the eye that is visible as the white of the eye.
scleral buckle
Surgical procedure that repairs a retinal detachment by indenting, or buckling? the sclera inward, usually by sewing a piece of preserved sclera or silicone rubber to the scleral surface. This pushes choroid and pigment epithelium closer to the retina and helps relax the vitreous tug on the retinal surface.
scotopic vision
Dim light conditions where only rods are functional. Also called twilight vision.
scotoma
Nonseeing area, or blind spot, within visual field, resulting from damage to visual pathways or to the retina. Blind Spots exist normally in all eyes and mark the site of the optic nerve.
segment
Term used in designating different areas of eye, as in “posterior segment” or “anterior segment.”
slit lamp
Microscope used in eye examination that projects a thin, intense beam of light into the eye through a controlled diaphragm. Used in examination of interior eye segment from the cornea epithelium to the posterior capsule. Aids in the diagnosis of diseases or trauma which affect the structural properties of the anterior eye segment.
Snellen acuity
Visual acuity as measured by the Snellen Chart. A person with a normal optical system (20/20 vision) can see standardized symbols on the chart at a distance of 20 feet. A person with 20/30 vision can see symbols on the chart from 20 feet that a person with normal vision could see from 30 feet.
Snellen Eye Chart
Test chart for assessing visual acuity. Rows of letters, numbers and symbols in standarized graded sizes, with a designated distance at which each row should be legible to a normal eye.
soft contact lens
Made from flexible plastic, these lenses absorb water and thus enable greater amounts of oxygen to pass through the lens to the cornea. Soft lenses are more comfortable for most wearers than hard lenses, and most lenses prescribed today are a version of a soft lens. They vary in design depending on the type of materials and required refractive correction.
solution
Variety of solutions for caring for contact lenses, including cleaning, rinsing and disinfecting. There are also multi-purpose solutions that provide all three functions. Rewetting solutions are designed to lubricate the lenses while they are worn.
SPF
Acronym for sun protection factor. Measures the length of time a sunscreen product protects against skin reddening from UVB (short-wave solar waves) compared to how long the skin takes to redden without protection. For example, if reddening takes 20 minutes without protection, using an SPF 15 suncreen theoretically prevents reddening 15 times longer.
spherical
Single prescription contact lenses with smooth spherical surfaces that bend light rays equally in all directions (360 degrees).
sports vision
Growing specialty in many eye care offices, usually focusing on the safety aspects of sports, but may also include vision therapy designed to strengthen eye coordination and/or overcome congenital weaknesses. Sports safety usually includes ultra-violet and sun protection, glare protection and safety from direct impact.
spots
Particles that float in the vitreous, which is jelly-like substance that fills center cavity of eye, and cast shadows on the retina. Some spots are formed before birth while others occur normally with aging. The sudden appearance of many spots can be an indication of a serious eye disorder and should be checked by your eye doctor.
spring hinge
Type of hinge on eyeglass temple that is more flexible and durable than a conventional hinge and holds eyeglasses more tightly to the head.
stereopsis
Perception of depth, depending on the differences in the images projected on the retinas of the two eyes.
stereoscope
Device for creating a 3-D image of drawn objects. Works by projecting two different images of the objects to the eyes.
Stiles-Crawford effect
An optical phenomenon in which light passing through the center of the pupil is perceived as more intense than light passing through the periphery of the pupil.
strabismus
Also known as crossed eyes. Visual defect in which the eyes are misaligned and point in different directions. Strabismus usually occurs in childhood but can occur later in life. Children with crossed eyes usually adapt when the brain learns to ignore the image of the misaligned eye, although they lose depth perception. Adults who develop the problem often have double vision because the brain is already trained to see two images.
STY
Inflammation of one or more sebaceous, or fluid-producing, glands of an eyelid.
summit laser
One of two primary manufacturers of the Excimer laser used in refractive eye surgery
sunglasses
Eyeglasses that enhance the normal light-filtering capabilities of the eye and protect against the sun’s damaging ultraviolet (UV) rays. Good sunglasses should be judged by their ability to reduce glare, filter out 99 percent to 100 percent of UV rays, provide visual protection, be comfortable and not distort colors.
superior
In eye care terminology, referring to the upper half of the eye.
superior colliculus
Part of the brain that constitutes a primitive center for vision. Also called optic lobe, optic tectum.
surgicial vision correction
Any of a number of surgical procedures that either alter the shape of the cornea to correct refractive error, or involve the insertion of a device within the front (anterior) of the eye to enhance the eye’s natural focusing ability.
sympathetic ophthalmia
Inflammation of one eye following inflammation in the other eye.
tapetum
Silvery lining behind the retina in some animals active in dim light. Reflects light back through the eye and allows the photoreceptors a second chance to absorb photons.
tears
Watery, slightly salty secretion of the lacrimal glands that serve to lubricate the front of the eye and wash away particles and foreign bodies. Natural tears are composed of three layers: the outer oily layer, the middle watery layer, and the inner mucus layer.
temple
Side pieces of an eyeglass frame that hook over or behind the ear to hold the glasses firmly in place.
temporal
Eye care terminology referring to the direction leading toward the ear or temple, away from the nose.
thermokeratoplasty
Refractive eye surgery procedure that involves use of the Holmium laser to heat and shrink tissues in the peripheral area of the cornea in order to change the shape of the cornea to correct farsightedness and/or some cases of astigmatism.
tonometer
Instrument used by the eye care professional to determine the intraocular or internal pressure of the eye.
tonometry
Measurement of intraocular pressure of the eye in millimeters of mercury.
toric
Contact lenses that contain a cylinder component to correct astigmatism by bearing two different optical powers at right angles to each other. These lenses may be thicker in one meridian to enable the lens to maintain proper orientation on the eye.
trachoma
Severe, chronic, contagious conjunctival eyelid and corneal infection caused by a virus. Leads to corneal blood vessel formation, corneal clouding, conjunctival and eyelid scarring and dry eyes. Leading cause of blindness in the world.
trifocals
Eyeglass or contact lens design that includes three focal areas: usually a reading lens, a lens for faraway viewing, and a lens for mid-distance viewing.
twenty-twenty vision (20/20)
Normal visual acuity as gauged by the Snellen Eye Chart. A person with a normal optical system (20/20 vision) can see standardized symbols on the chart at a distance of 20 feet. A person with 20/30 vision can see symbols on the chart from 20 feet that a person with normal vision could see from 30 feet.
ultrasound: A-Scan
Type of ultrasound device that emits very high frequency waves that are reflected by the ocular structures and converted into electrical impulses. Used for differentiating normal and abnormal eye tissue or for measuring length of eyeball.
ultrasound: B-Scan
Ultrasound procedure in which high frequency waves are reflected by eye tissues and orbital structures and then converted into electrical pulses that are displaced as bright spots on a black background. Provides a cross-sectional view of tissues used for evaluating structures that cannot be seen directly.
ultrasound: eye
Transmission into the eye of high frequency sound waves that are reflected by ocular tissues and displayed on a screen so the internal structures can be visualized. Aids in diagnosis of eye and orbital problems.
ultraviolet rays Invisible part of the light spectrum whose rays have wavelengths shorter than the violet end of the visible spectrum and longer than X-rays. UVA and UVB light are harmful to your eyes and skin.
UV protection
Protection offered by sunglasses against UVA and UVB light that is harmful to the eyes. Sunglasses should protect against 99 percent of these harmful rays. Particularly important when around water or snow where failure to use protection can result in painful burn to outer layer of eye and temporary blindness.
uveitis
An disease, often misdiagnosed, that causes inflammation of the structures of the uveal tract: iris, ciliary body or choroid. Inflammation may occur suddenly, be chronic, or be recurrent. Symptoms include eye pain, sensitivity to light, blurred vision, tearing and redness. Uveitis is often related to a systemic condition such as rheumatoid arthritis, multiple sclerosis, sarcoidosis and ankylosing spondylitis. Usual treatment is administration of eye drops to relieve symptoms and reduce inflammation.
Varilux lenses
Popular brand of progressive addition contact lenses (sometimes called multifocal lenses). Allows the wearer to focus through different prescriptions at different distances through the same lens.
visual acuity
Measure of eye’s ability to distinguish object details and shape. Assessed by smallest identifiable object that can be seen at a specified distance, usually 20 feet for distance vision and 16 inches for near vision.
visual angle
The angle formed by two rays of light or two straight lines drawn from the extreme points of a viewed object to the nodal point of the eye Roughly speaking, the width of your thumb at arm's length is approximately 2 degrees.
visual field
Extent of space visible to an eye as it looks (fixates) straight ahead. Measured in degrees away from fixation.
visual field test (link to free eye test)
vision correction
Any of a variety of appliances or surgical techniques used to correct less-than-perfect vision. Includes eyeglasses, contact lenses and refractive vision correction techniques such as Laser In-Situ Keratomileusis (LASIK), Photorefractive Keratectomy (PRK), intrastromal corneal rings and clear lens extraction.
vision tests
Any test which assist in measuring the visual acuity of the eye.
Visx laser
One of two primary manufacturers of the Excimer laser used in refractive eye surgery.
vitamins
Essential organic compounds required in trace amounts for normal growth and metabolism in the body. Scientists are just beginning to understand the important roles of vitamins in the health of eyes. Significant evidence suggests that some vitamins are critical to the maintenance of healthy eyes. For instance, Vitamin A is proven to help prevent night blindness; Vitamin C helps increase visual acuity and reduces the risk of developing glaucoma; and vitamin E may help prevent cataracts. In addition, minerals like Copper, Selenium, Manganese and Zinc all seem to play a part in maintaining eyes. Several commercial vitamin products are now available specifically for the eyes.
Vitreous
A clear, jelly-like liquid that fills the middle of the eye. Also called the vitreous humor.
vitreous detachment
Separation of vitreous, which is the jelly-like substance that fills the eye behind the lens, from the retinal surface. Frequently occurs with aging, but may occur in diseases such as diabetes and severe myopia. Usually harmless, but can create retinal tears, which may in turn lead to retinal detachment.
Von Hippel’s angioma
Also known as Von Hippel-Lindau disease, this hereditary disorder is characterized by tumors of the retina, central nervous system, and visceral organs. In the eye, the disease shows up as blood-filled retinal tumors that may lead to blood leakage and retinal detachment.
wear schedule
Schedule for the length of time a specific type of contact lens should be worn. Extended wear lenses can be worn without interruption, including sleep, up to a maximum number of days as specified by the eye doctor, while other types of lenses may require removal every evening before bedtime. It’s important to differentiate between wear schedules for various lenses.
Yag laser
Short pulsed, high-energy light beam that can be precisely focused by computer to optically cut, perforate, or fragment tissue.
ablate, ablation
To remove by cutting. The surgical removal of any part of the body.
accommodation
The ability of the eye to change its focus from distant to near objects as well as from near to distance objects. This process is achieved by the crystalline lens changing its shape.
aniridia
A birth defect in which a child is born without an iris, so there is no way to control the amount of light that enters the eye. The only treatment is to use colored eye lenses to reduce the amount of light entering the eye.
anisometropia
A condition that occurs when each of a person's eyes have a different refractive power.
basal cell carcinoma
A type of skin cancer in which the cancer cells look like the basal cells of the skin.
binocular vision
The ability to maintain visual focus on an object with both eyes, creating a single visual image. Lack of binocular vision is normal in infants. Adults without binocular vision experience distortions in depth perception and visual measurement of distance.
Braille
A system of raised-dot writing devised by Louis Braille (1809-1852). Each braille character or "cell" is made up of 6 dot positions that are arranged in a rectangle comprising 2 columns of 3 dots each. A dot may be raised at any of the 6 positions, and each combination of raised dots corresponds to a letter of the alphabet, a punctuation mark, and another symbol.
carotenoids
Any plant or animal with yellow to red pigments
crystalline lens
The lens of the eye.
depth perception
The ability to judge how far away an object is as well as how far away objects are from each other.
diathermy
The use of heat to destroy abnormal cells. Also called cauterization or electrodiathermy.
diplopia
The condition whereby a single object appears as two objects. Occurs because the eye muscles do not act equally. Also called double vision.
druse
drusen, plural
Tiny yellow or white deposits in the retina of the eye or on the optic nerve head, visible to an eye care specialist during an eye examination. One of the most common early signs of age-related macular degeneration (ARMD). The presence of drusen alone does not indicate disease, but it may mean that the eye is at risk for developing more severe ARMD.
ectropion
An abnormal turning out of an eyelid.
electro-oculogram
A record of the standing voltage between the front and back of the eye that is correlated with eyeball movement, as in rapid eye movement (REM) sleep, and obtained by electrodes suitably placed on the skin near the eye
electroretinogram
electroretinograph
electroretinography
A test that measures the electrical impulses of the retina when the eye is exposed to light. For an ERG, an electrode is placed on the cornea at the front of the eye. The electrode measures the electrical response of the rods and cones, the visual cells in the retina at the back of the eye. An abnormal ERG is found in conditions such as arteriosclerosis of the retina, detachment of the retina, and temporal arteritis with eye involvement. The instrument used to do electroretinography is an electroretinograph, and the resultant recording is called an electroretinogram.
fovea
A small rodless area of the retina that affords the sharpest vision because the layers of the retina spread aside to let light fall directly on the cones, which are the cells that give the clearest vision.
keratometry
Measurement of the form and curvature of the cornea
lysozyme
A basic protein that is present in egg white, saliva, and tears
malignant melanoma
Cancer of the melanocytes, the cells that produce pigment in the skin. Most common in people with fair skin, but can occur in all races. Appears as a dark, mole-like spot that spreads and, unlike a mole, has an irregular border. Tendency toward melanoma may be inherited, and risk increases with overexposure to the sun and sunburn. Fair-skinned people and people with a family history of melanoma should always use a high-SPF sunscreen when outdoors. Detected early, melanoma is almost always treatable, but undetected melanoma can spread and become fatal.
meibomian gland
Little glands in the eyelids that make a fatty lubricant which they discharge through tiny openings in the edges of the lids. The meibomian glands can become inflamed, a condition termed meibomianitis or meibomitis. Chronic inflammation of the meibomian glands leads to a cysts, also called chalazion, which is a pimple in the margin of the eyelid. The meibomian glands are also known as the palpebral glands, tarsal glands, or tarsoconjunctival glands.
mucoprotein
Any of a group of various complex conjugated proteins that occur in body fluids and tissues. Also called mucoid
ocular motility
The movement of the eye.
onchocerciasis
River blindness, a disease caused by a parasitic worm (Onchocerca volvulus) transmitted by biting blackflies (buffalo gnats) that breed in fast-flowing rivers. The adult worms can live for up to 15 years in nodules beneath the skin and in the muscles of infected persons, where they produce millions of worm embryos (microfilariae) that invade the skin and other tissues including the eyes. About 18 million persons are affected, mostly in Africa and also in Yemen and Latin America. Both living and dead microfilariae cause severe itching in the skin and sometimes blindness after many years. Since 1987, the drug ivermectin (brand name: Stromectol) has been provided by the manufacturer (Merck) free of charge. A single oral dose administered once a year prevents the accumulation of microfilariae in persons at risk. No drug suitable for mass treatment can kill the adult worms in the body, and therefore, onchocerciasis cannot be wiped out. The blindness, however, can be eliminated.
ophthalmoscope
An instrument for viewing the interior of the eye. It comprises a concave mirror with a hole in the center through which the observer examines the eye, a source of light that is reflected into the eye by the mirror, and lenses in the mirror that can be rotated into the opening in the mirror to neutralize the refracting power of the eye being examined. It makes the image of the retina clear.
photocoagulation
A surgical process of sealing off, or clotting, tissue by means of a laser beam. It is used in cancer treatment to destroy blood vessels entering a tumor and deprive it of nutrients, in the treatment of a detached retina, to destroy abnormal blood vessels in the retina, to treat tumors in the eye; etc.
retinitis pigmentosa
Any of several hereditary progressive degenerative diseases of the eye marked by night blindness in the early stages, atrophy and pigment changes in the retina, constriction of the visual field, and eventual blindness. Also called pigmentary retinopathy
rhabdomyosarcoma
A malignant tumor composed of striated muscle fibers
selenium
An essential mineral that is a component of a key antioxidant enzyme in tissue respiration. Deficiency of selenium causes disease of the heart muscle. Food sources of selenium include seafoods, kidney and liver, and some grains and seeds.
Sjogren's syndrome
An inflammatory disease of glands and other tissues of the body that classically combines dry eyes, dry mouth, and another disease of the connective tissues such as rheumatoid arthritis, lupus, scleroderma, or polymyositis. About 90 percent of Sjogren syndrome patients are female, usually in middle age or older. Sjogren syndrome can be complicated by infections of the eyes, breathing passages, and mouth. Also called sicca syndrome
squamous cell carcinoma
Cancer that begins in squamous cells, which are thin, flat cells resembling fish scales. Squamous cells are found in the tissue that forms the surface of the skin, the lining of the hollow organs of the body, and the passages of the respiratory and digestive tracts.
Tay-Sachs disease (TSD)
A progressive neurodegenerative disorder affecting babies. The child with TSD usually develops normally for the first few months of life. Then the baby gets an exaggerated startle reaction, and loses head control by 6 to 8 months of age. The infant cannot roll over or sit up, spasticity and rigidity develop, and excessive drooling and convulsions become evident. Blindness and head enlargement set in by the second year. It is fatal by age 5. TSD results from an enzyme deficiency, which in turn allows a fat, named lipid, to be deposited in the brain. It occurs primarily in Ashkenazi Jews of European origin, a group comprising 95 percent of the Jews in the United States.
vitrectomy
Removal of the gel from the center of the eyeball, because blood and scar tissue in the gel block sight. An eye surgeon replaces the clouded gel with a clear fluid
cauterization
The use of heat to destroy abnormal cells. Also called diathermy or electrodiathermy.
electrodiathermy
The use of heat to destroy abnormal cells. Also called cauterization or diathermy.
double vision
The condition whereby a single object appears as two objects. Occurs because the eye muscles do not act equally. Also called diplopia.
palpebral glands
Little glands in the eyelids that make a fatty lubricant which they discharge through tiny openings in the edges of the lids. The meibomian glands can become inflamed, a condition termed meibomianitis or meibomitis. Chronic inflammation of the meibomian glands leads to a cysts, also called chalazion, which is a pimple in the margin of the eyelid. The meibomian glands are also known as the meibomian glands, tarsal glands, or tarsoconjunctival glands.
tarsal glands
Little glands in the eyelids that make a fatty lubricant which they discharge through tiny openings in the edges of the lids. The meibomian glands can become inflamed, a condition termed meibomianitis or meibomitis. Chronic inflammation of the meibomian glands leads to a cysts, also called chalazion, which is a pimple in the margin of the eyelid. The meibomian glands are also known as the meibomian glands, palpebral glands, or tarsoconjunctival glands.
mucoid
Any of a group of various complex conjugated proteins that occur in body fluids and tissues. Also called mucoprotein.
river blindness
Onchocerciasis, a disease caused by a parasitic worm (Onchocerca volvulus) transmitted by biting blackflies (buffalo gnats) that breed in fast-flowing rivers. The adult worms can live for up to 15 years in nodules beneath the skin and in the muscles of infected persons, where they produce millions of worm embryos (microfilariae) that invade the skin and other tissues including the eyes. About 18 million persons are affected, mostly in Africa and also in Yemen and Latin America. Both living and dead microfilariae cause severe itching in the skin and sometimes blindness after many years. Since 1987, the drug ivermectin (brand name: Stromectol) has been provided by the manufacturer (Merck) free of charge. A single oral dose administered once a year prevents the accumulation of microfilariae in persons at risk. No drug suitable for mass treatment can kill the adult worms in the body, and therefore, onchocerciasis cannot be wiped out. The blindness, however, can be eliminated.
pigmentary retinopathy
Any of several hereditary progressive degenerative diseases of the eye marked by night blindness in the early stages, atrophy and pigment changes in the retina, constriction of the visual field, and eventual blindness. Also called retinis pigmentosa.
sicca syndrome
An inflammatory disease of glands and other tissues of the body that classically combines dry eyes, dry mouth, and another disease of the connective tissues such as rheumatoid arthritis, lupus, scleroderma, or polymyositis. About 90 percent of sicca syndrome patients are female, usually in middle age or older. Sicca syndrome can be complicated by infections of the eyes, breathing passages, and mouth. Also called Sjogren's syndrome