Retinopathy of prematurity (ROP), previously known as retrolental fibroplasia (RLF), is an eye disease that affects prematurely-born babies who have received intensive neonatal care. It is thought to be caused by disorganized growth of retinal blood vessels which may result in scarring and retinal detachment. ROP can be mild and may resolve spontaneously, but it may lead to blindness in serious cases. As such, all preterm babies are at risk for ROP, and very low birth weight is an additional risk factor. Both oxygen toxicity and relative hypoxia can contribute to the development of ROP.
Populations of preterm infants at risk: There is increasing evidence that ROP and blindness due to ROP are now public health problems in the middle income countries of Latin America, Eastern Europe and the more advanced economies in South East Asia and the Middle east region. In these countries ROP is often the most common cause of blindness in children. ROP is highly likely to become an increasing problem in India, China and other countries in Asia as these countries expand the provision of services for premature infants.
There is also evidence that the population of premature infants at risk of severe ROP varies depending on the level of neonatal intensive care being provided. In countries with high development indices and very low neonatal mortality rates (e.g. north America, western Europe), severe ROP is generally limited to extremely preterm infants i.e. those weighing less than 1000g at birth. At the other end of the development spectrum, countries with very low development indices and very high neonatal mortality rates (e.g. much of subSaharan Africa) ROP is rare as most premature babies do not have access to neonatal intensive care and so do not survive. Countries with moderate development indices are improving access to neonatal intensive care, and in these settings bigger, more mature babies are also at risk of severe ROP as neonatal care may be suboptimal(i.e. those weighing 1500-2000g at birth). These findings have two main implications: firstly, much can be done in countries with moderate development indices to improve neonatal care, to reduce the risk of severe ROP in bigger babies and increase survival of extremely preterm infants, and secondly, in these settings bigger more mature babies need to be included in ROP programs and examined regularly so as to detect those babies developing ROP requiring treatment (see below).
The World Health Organization has recently published data on rates of preterm birth and the number of premature babies born in different regions of the world. The main findings of this report are threefold: 1. premature birth has many different causes, and prevention is challenging 2. prematurity is the commonest cause of neonatal death in many countries: 1 million infants die every year due to complications of preterm birth, and 3. the number of preterm births is currently estimated to be 15 million, and increasing.