THE EPIDEMIOLOGY OF TRACHOMA IN RURAL KENYA - VARIATION IN PREVALENCEWITH LIFE-STYLE AND ENVIRONMENT

Purpose: Ocular examination surveys were carried out in Kenya by the I nternational Eye Foundation as a component of the Kenya Rural Blindnes s Prevention Project to determine the national prevalence of blindness and ocular morbidity and major causes. A goal of the surveys was to d etermine the overall geographic distribution and severity of trachoma throughout Kenya. Methods: Using a random cluster household sampling t echnique, 13,803 people of all ages and of diverse cultural and ethnic backgrounds were identified in eight regions of Kenya. A detailed exa mination for active and inactive trachoma was carried out on each pers on surveyed as part of the general ocular examination. Results: The pr evalence rate of visual loss (<20/60) due to trachoma in the better ey e was 7.2/1000, Active trachoma was present in 19% of all persons exam ined, and 50% of all those with trachoma were found to have moderate t o severe inflammation. Prevalence varied according to survey region fr om less than 1% in four regions where agriculture is the economic base , to 57% and 63% in two arid pastoral regions. Trachoma prevalence var ied from 28% in children younger than 3 years of age to 11% in persons older than 60 years of age. Potentially blinding eyelid deformities s econdary to chronic trachoma occurred in 5.0% of the rural population, and 1.2% of the rural population displayed associated corneal scarrin g. Lid scarring, corneal scarring, and lid deformities were greater in prevalence among females of all age groups when compared with males. Conclusions: Trachoma prevalence in Kenya varies widely from region to region. High prevalence is associated with high climatic aridity, and lower prevalence is associated with areas of greater rainfall, sustai nable agriculture, and a higher general standard of living. Within hig h-risk regions, there are wide variations in age-specific prevalence a nd severity of the disease, Potentially blinding sequelae of trachoma are more prevalent in females than in males.