Hereditary diseases as causes of blindness in Newfoundland: preliminary report.

Hereditary disease appeared to account for more cases of registered blindness in Newfoundland and Labrador than indicated by the statistics of the Canadian National Institute for the Blind. The files of all 1013 people registered as of Dec. 31, 1981 were therefore reviewed, many persons were interviewed and examined, and pedigrees were researched. In 14.6% of cases either the diagnostic or the etiologic code had to be revised. The largest etiologic category was "genetic, established", which accounted for 24.0% of the cases registered. When cases of blindness presumed to be of genetic origin or due to polygenic inheritance were included it was estimated that 33% of all 1013 registered persons had a hereditary eye disease; this figure is higher than most of the previously published figures. Strategies for preventing blindness must be reconsidered, and genetic counselling and low-vision services must be made more widely available.