The importance of prenatal factors in childhood blindness in India.

The causes of visual loss in 1411 children attending schools for the blind in different geographical areas in India are described. Ninety-three percent (1318) of the children were severely visually impaired (SVI) or blind (i.e. corrected acuity in the better eye of <20/200 [<6/60]). In 60% of SVI/blind children vision loss was attributable to factors operating in the prenatal period, in 47% the prenatal factors were known and definite, and in 13% prenatal factors were the most probable causes. Hereditary retinal dystrophies and albinism were seen in 19% of SVI/blind children and 23% had congenital ocular anomalies. There were variations in the relative importance of different causes by state. The observed pattern of causes of visual loss is intermediate between those seen in industrialised countries and in the poorest developing countries. This suggests that strategies to combat childhood blindness in India need to address concurrently both preventable and treatable causes. The need for aetiological studies, particularly on anophthalmos and microphthalmos, is highlighted.