CAUSES OF BLINDNESS IN CANADA: AN ANALYSIS OF 24,605 CASES REGISTERED WITH THE CANADIAN NATIONAL INSTITUTE FOR THE BLIND.

A survey of blind persons in Canada, based on registrations with The Canadian National Institute for the Blind (C.N.I.B.), is reported. This is the first study of its type having national scope and based on data registered in a central file. It covered 24,605 living registered blind persons ranging from premature infants to very elderly persons. Causes of blindness are broken down with respect to topography (site and type of lesion) and etiology. In terms of frequency, the principal causes were lesions affecting the globe (e.g. glaucoma, myopia), 36%; the retina, 23%; the lens, 16%; and the optic nerve, 11%. In this study, 32% of the blindness was due to prenatal causes. The prevalence of blindness per 100,000 persons in Canada, based on C.N.I.B. data, was 131, varying among the provinces from 108 to 376. Serious ocular disease was four times more prevalent than blindness; 101,436 such cases (the prevention group) were listed by the C.N.I.B.