[The most frequent causes of loss or impairment of vision in children and adolescents].

On the basis of examination of 100 persons aged 3-18 years registered in the Olsztyn Division of the Union of the Blind the authors determined the causes which led to the loss of vision or of its impairment. The most frequent cause of the invalidism of the visual system were: errors of refraction (32%), optic atrophy (24%), congenital cataract (16%), retinal and choroidal degeneration (9%), retrolental fibroplasia (6%), anophthalmia or malformation of the globe (4%), coloboma of the iris or choroid (3%), retinoblastoma (3%), injuries (2%) and congenital glaucoma (1%).