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



Sunday, July 25, 2010

Dialling for danger?

Does the use of cell phones increase the risk of cancer? Even if scientists are divided about it, here are some suggestions that could minimise the radiation.

Radiation is a loaded word that conjures up unreasonable fear. So let's be clear about what we're talking about. Your cell phone is a tiny transceiver — a combination transmitter and receiver. Power is radiated when you use it. But it's not the same kind of radiation produced by nuclear reactions and X-rays. That's the far more dangerous type called ionising radiation.

Cell phones produce less harmful non-ionising radiation. However, as exposure time and power level increases, non-ionizing radiation is a hazard too. The real argument is over how much non-ionising radiation is too much. To be clear, there is no proof that using your cell phone will increase your chances of getting cancer. But several scientists believe there is a correlation between heavy cell phone use and cancer.

Here are some ways to reduce the amount of radiation you get from cell phones. Even if some final study says there is no danger, there's no risk in following these tips.

So let's start with the fact that not all cell phones are created equal. Some produce more radiation than others. Use a low radiation phone. Next, consider spending less time on your cell phone. When you know the conversation will be a long one, use a wired phone. But some people don't even have a regular wired phone. That means exposure to cell phone radiation is a bigger deal than when cell phones weren't as common. So let's talk about ways regular cell phone users can reduce the risk a bit.

The closer your cell phone is to your body, the more radiation you get. Even holding a phone two inches from your ear dramatically reduces the amount of radiation zapping your brain.

You'd think clipping your phone to your belt and using a hands-free earpiece and microphone would be a no-brainer next step. But it isn't. Wired earpieces can serve as an antenna that actually concentrates the radiation that your brain receives. And many wireless earpieces are just tiny transmitter/receivers that produce their own radiation.

The safest way to use a cell phone is to hold it away from your body and use the speakerphone setting. Almost everyone agrees that radiation exposure in that mode is minimal.

Many may not routinely use the speakerphone setting. It eliminates privacy and isn't practical in many situations. But there is still a way to reduce radiation, even when you must hold the cell next to your ear. Simply shift the phone from one ear to the other at regular intervals. That means you aren't concentrating all that radiation on one side of your head.

The last tip involves those bars displayed on the cell phone screen. The bars indicate the strength of the signal. Cell phones are most dangerous when the signal is very weak. Here's why: In weak signal areas the cell phone cranks up its power automatically in an attempt to compensate. So you are exposed to more radiation during times like that.

Adopt as many of these tips as you can. Even if the radiation fears prove groundless, your stress levels and mental health are bound to improve by spending less time on the cell phone.

Principles of modern low vision rehabilitation

Low vision rehabilitation is a new emerging subspecialty drawing from the traditional fields of ophthalmology,

optometry, occupational therapy, and sociology, with an ever-increasing impact on our customary concepts of

research, education, and services for the visually impaired patient. A multidisciplinary approach and

coordinated effort are necessary to take advantage of new scientific advances and achieve optimal results for

the patient.Accordingly, the intent of this paper is to outline the principles and details of a modern low vision

rehabilitation service.

All rehabilitation attempts must start with a firsthand interview (the intake) for assessing functionality and

priority tasks for rehabilitation, as well as assessing the patient’s all-important cognitive skills.The assessment

of residual visual functions follows the intake and offers a unique opportunity to measure, evaluate, and

document accurately the extent of functional loss sustained by the patient from disease. An accurate

assessment of residual visual functions includes assessment of visual acuity, contrast sensitivity, binocularity,

refractive errors, perimetry, oculomotor functions, cortical visual integration, and light characteristics affecting

visual functions. Functional vision assessment in low vision rehabilitation measures how well one uses residual

visual functions to perform routine tasks, using different items under various conditions, throughout the day.

Of the many functional vision skills known, reading skills is an obligatory item for all low vision rehabilitation


Results of assessment guide rehabilitation professionals in developing rehabilitation plans for the individual and

recommending appropriate low vision devices. The outcome from assessing residual visual functions is

detection of visual functions that can be improved with the use of optical devices. Methods for prescribing

devices such as image relocation with prisms to a preferred retinal locus, field displacement to primary gaze

position, field expansion, and manipulation of light are practiced today in addition to, or instead of,

magnification. Correction of refractive errors, occlusion therapy, enhancement of oculomotor skills, and field

restitution are additional methods now available for prescribing devices leading to rehabilitation of visual

functions.The outcome from assessing residual functional vision is detection of functional vision that can be

improved with the use of vision therapy training. After restoration of optimal residual visual functions is

achieved with optical devices, one can follow with training programs for restoration of lost vision-related skills.

If an optical dispensary is available where prescribing of low vision devices routinely take place, this will help

ensure familiarity and specialization of the dispensary and staff with low vision devices and their special

dispensing requirements.The dispensing of low vision devices is an opportunity to introduce the device to the

patient, train the patient in the correct use of the device for the task selected, and create a direct and

continuous connection with the patient until the next encounter. Following assessment, prescribing, and

dispensing of devices, a low vision practitioner, ophthalmologist or optometrist, is responsible for

recommending and prescribing vision therapy training to improve residual functional vision.

An attempt to present a template for a comprehensive modern low vision rehabilitation practice is made here

by summarizing scientific developments in the field and stressing the multidisciplinary involvement required for

this kind of practice. It is hoped that this paper and other initiatives from colleagues, the public, and

government will promote and raise awareness of modern low vision rehabilitation for the benefit of all.