Aetiological survey of visually handicapped children in Northern Ireland.

A survey of visually h,ndicapped children in Northern Ireland identified 486 subjects aged 0 to 20 years on January 1, 1976, with a corrected visual acuity of 6/18 or less in the better eye. The prevalence of visual handicap was 81/100,000 of the population with an estimated ascertainment rate of 80%. Genetically determined diseases accounted for 51% of the cases. Birth hypoxia secondary to prenatal and perinatal complications was the second most important aetiological factor contributing towards visual handicap.