Prevalence of visual impairment and blindness in a Nairobi urban population.

OBJECTIVE: To determine the prevalence and causes of visual impairment and blindness among Kibera slum dwellers. DESIGN: Population based Survey. SETTING: Kibera Slums, Kibera Division, Nairobi, Kenya. SUBJECTS: One thousand four hundred and thirty eight randomly selected slum dwellers. RESULTS: The prevalence of blindness and visual impairment was 0.6% (95% CI: 0.21 to 1.0), and 6.2% (95% CI: 4.95 to 7.15) respectively. 37.5% of those found blind were due to cataract followed by refractive errors 25.0%. 58.1% of those with visual impairment had refractive errors while 35.5% had cataracts. Females had a higher prevalence of visual impairment compared to males but the difference was not statistically significant (P = 0.104). CONCLUSIONS: Prevalence of blindness in Kibera slums is slightly lower than the estimated national average (0.7%) while that of visual impairment is almost three times higher. The leading causes of blindness are cataract followed by refractive errors. For visual impairment, refractive error was the leading cause followed by cataract. RECOMMENDATION: Kibera slum dwellers are in need of comprehensive eye care services offering cataract surgery and low cost spectacles.