The last trimester of pregnancy is critical in many ways for the development of vision of the unborn child. There is a network of blood vessels within the retina which grow quickly in the last few weeks of pregnancy and any event that upsets this is likely to have its consequences. Incidentally, all the images that we see are focussed on the retina at the back of the eye, covered in special nerve cells that respond to light.
Explaining what happens when babies arrive early and the risks they face, Dr. Nitin S. Shetty, Head Retina Services, Department of Ophthalmology, Manipal Hospital, Bangalore observes “As in other organs the retina is also not completely developed in a premature baby. In a few babies the retinal blood vessels may develop abnormally causing bleeding and retinal detachment. This is called Retinopathy of prematurity (ROP). Without prompt treatment, the baby can become blind or suffer from poor vision for life.”
While thanks to excellent neo natal care available, survival rates of even very low birth-weight babies and very premature babies have gone up dramatically, it is important to prevent conditions like ROP to ensure survivors lead a full life.
Screening early on therefore is very important. Profiling babies at risk Dr. Nitin S. Shetty adds: “All babies born before 32 weeks of gestation, infants with birth weight of less than 1500 grams and those who have had infections, blood transfusions, breathing difficulties or lack of oxygen must be seen by a Retinal Specialist before day 30. Babies who weigh even lower should be examined at two to three weeks of age.”
Most parents however, will recoil in horror at the mention of a retinal examination for such a tiny infant. However, it is a small price to pay to ensure that the child has clear and unimpaired vision. The test is not so much painful as uncomfortable and babies however small, protest at being held down and put through it. But in the hands of a good retinal specialist the entire exercise – dilation of the pupils, administration of anaesthetic drops on the eyes and the examination of the retina with the help of delicate instruments is over fairly quickly (these instruments are necessary to keep the eyes open and facilitate focussing which a distressed baby will obviously not do).
What if the child is diagnosed as having ROP? All is not lost. Says Dr. Nitin S. Shetty: “Most often ROP does not need treatment – but periodic visits are necessary to ensure that the retinal growth is satisfactory and that ROP is in regression. Treatment for such of those babies in whom ROP has progressed is often by means of the LASER and is pretty much like an eye examination.”
LASER treatment more often than not, does the job, but in rare instances, despite the LASER or on account of delay in treatment the condition worsens leading to more complicated surgery which comes with risks of higher failure rates and poorer vision. In rare instances a freezing treatment is done to help arrest further growth of abnormal blood vessels and prevent vision loss. Diagnostic equipment like the RETCAM (sophisticated Retinal camera) and injections in the eye for severe cases spell hope.
In conclusion Dr. Nitin S. Shetty says: “All premature babies need regular eye examinations beginning from a few weeks after birth until school going age as 20 per cent of them develop the need for corrective spectacles or might develop squints.”
