Prevalence and causes of blindness in the northern Transvaal.

During November 1985 a survey was carried out to determine the prevalence and causes of blindness in the Elim Hospital district of Gazankulu in the Northern Transvaal, South Africa, and to assess the Eye Department's effectiveness in preventing blindness. Using a random cluster sample technique, we screened 18,962 of the estimated 71,200 inhabitants of the district (26.6%). We found 109 blind people. The prevalence of blindness was 0.57% (95% confidence interval 0.46%-0.68%). The main causes of blindness were senile cataract (55%), corneal scarring due to trachoma (10%), uncorrected aphakia (9%), and open-angle glaucoma (6%). There were 14 aphakic blind persons who did not have aphakia glasses (43% of all persons operated on for cataract). Women had a significantly higher prevalence of blindness than men. After the age of 60 years the prevalence of blindness increased sharply. Women were 1.6 times less likely to have undergone cataract surgery than men. The two most effective steps to reduce the prevalence of blindness in the Elim district further are to provide aphakia glasses to all aphakic patients and to improve the accessibility of the Eye Department's surgical services.