Blindness in schoolchildren: importance of heredity, congenital cataract, and prematurity

Of 99 children in the Royal Blind School, Edinburgh (which serves Scotland and part of N E England), 15 had optic atrophy (hydrocephalus 4, intracranial haemorrhage 2, prematurity 2, fetal distress 2, birth asphyxia 2, cerebral atrophy 1, cardiac arrest during hernia operation 1, and leukaemia 1).Fourteen had congenital cataract, 12 congenital retinal aplasia (Leber's congenital amaurosis) and 11 retinopathy of prematurity.There were small numbers in many other diagnostic categories, including three with non-accidental head injury.Mental retardation, spasticity, and nystagmus were frequent other correlates in all diagnostic categories.'Very probably hereditary' was a conservative attribution in 36, while 'probable' seemed appropriate for 12 -that is, almost 48% were hereditary.Only about 11 cases might have been prevented through genetic counselling, which testifies to the frequency of autosomal recessive hereditary disease, although no parents were consanguineous.The Royal Blind School (RBS), Edinburgh, is a residential school for the severely visually handicapped with a visual acuity almost invariably 3/60 or less or, occasionally, with very severe field loss.Our diagnostic survey of its 99 pupils does not include all Scottish blind children of school age, because educability is another criterion for admission, though many of the pupils are mentally retarded, some quite severely so.We have no information about blind children in other institutions for the very severely (multiply) handicapped.The only other school for the blind in Scotland is a small one in Glasgow: it has few residents, and caters for the deaf and the blinddeaf as well as some blind.The catchment area of the Edinburgh school also includes the north of England, especially the north-east, since a blind school in Newcastle upon Tyne closed; six pupils-have present home addresses in England.This survey of the RBS is more comprehensive than our previous statistics of only hereditary cases there.'Another motive for the study was to compare the diagnoses in Scotland with those in 67 pupils in the Blind School of Yamanashi Prefecture, 120 km south-west of Tokyo, Japan.'One common observer in each study should make comparisons reasonably valid.The present information is also a selective update of the comprehensive survey of 776 blind children in England and Wales by Fraser and Friedmann published in 1967' and of Sorsby's study of blindness in all age groups for 1963-8 in the same countries4 and of the Report of the Department of Health and Social Security for England 1969-76.