Prevalence and causes of low vision and blindness in northern KwaZulu

A survey of the prevalence of blindness and low vision was conducted in the Ingwavuma district of KwaZulu to assess the effectiveness of existing eye care facilities in the prevention and treatment of impaired vision and blindness. One hundred subjects from each of 60 randomly selected clusters (N = 6,090) were screened. Of these, 293 were identified and referred to an ophthalmologist for examination. Of the 268 (91,5%) examined, 241 were found to have visual impairment. Sixty-one of these people were blind, 85 had low vision, 61 were blind in one eye but had normal vision in the other, and 34 had low vision in one eye but normal vision in the other. The prevalence of blindness was 1,0% (95% confidence interval 0,7-1,2%), and the prevalence of impaired vision was 1,4% (95% confidence interval 1,1-1,7%). Age-related cataract (59,0%) and chronic glaucoma (22,9%) were the two main causes of blindness. Age-related cataract (75,3%), refractive error (10,0%) and chronic glaucoma (4,7%) were the main causes of impaired vision. Existing eye care services for the region have reduced the prevalence of blindness by only 7,0%. The training of ophthalmic nurses and the establishment of a sight-saver clinic in the area are necessary to reduce the prevalence of low vision and blindness.