Causes and prevalence of blindness in the Northern Province of Sierra Leone.

The causes of blindness in Sierra Leone were studied in 7286 new patients attending the eye clinic in the year 1981. Blindness, defined as an inability to count fingers at 3 meters with the better eye (WHO, 1973), was present in 762 persons, due to cataract (39%), ocular onchocerciasis (30%), primary glaucoma (8%), measles keratitis (3%), trachoma (3%) and other causes. The prevalence of blindness was estimated from simple field surveys covering 41 villages with an estimated population of 10,559. The average prevalence of blindness was found to be 1.3% of the total population.