Survey of blindness in rural communities of south-western Nigeria.

A population based survey of rural communities in the Akinlalu-Ashipa ward of Ife North Local Government in Osun State, Nigeria, was conducted to determine the prevalence and causes of blindness. 2921 inhabitants were screened by a random cluster sample technique, out of whom 27 were blind in both eyes. The overall prevalence rate of blindness (best corrected visual acuity less than 3/60 in the better eye) was found to be 0.9% (95% confidence interval 0.84-0.96%). The rate of blindness increased with age, especially from age 60. The major causes of blindness were cataract and its sequelae (48.1%), onchocerciasis (14.8%), primary open angle type glaucoma (11.1%), corneal scar/phthisis bulbi (7.4%) and optic atrophy (7.4%). About half of the blindness is potentially curable through cataract surgery, and a third preventable through health education, early diagnosis and prompt treatment.