Cataract in central Sri Lanka: prevalence and risk factors from the Kandy Eye Study.

PURPOSE: To estimate the prevalence of and risk factors for cataracts in the Kandy District of central Sri Lanka. METHODS: A population-based, cross-sectional ophthalmic survey of the inhabitants of rural villages in central Sri Lanka was conducted; 1375 individuals participated (79.9%; age > or = 40 years, average age 57) and 1318 (95.9%) had an examinable lens in at least one eye. Data collection included district, age, occupation, education level, smoking history, height, weight and dilated lens assessment using Lens Opacities Classification System III grading: nuclear (> or =4), cortical (> or =2) and posterior subcapsular (> or =2) cataracts. Aphakic and pseudophakic eyes were included as operated cataracts for statistical analysis. RESULTS: The prevalence of any cataract including operated eyes was 33.1% (95% Confidence Interval (CI), 22.4-43.7%): 26.0% cortical; 7.9% posterior sub-capsular and 4.5% nuclear cataracts. No significant association was found between cataract and gender, smoking or outdoor occupation. Low level of education (secondary or higher vs no education: Odds Ratio (OR) 0.6, CI 0.4-0.9, P = 0.04) and shorter stature were associated with a higher likelihood of any cataract (OR 1.7, CI 1.1-2.7, P = 0.02). CONCLUSIONS: The overall prevalence of cataract in central Sri Lanka is similar to that in other developing Asian regions except for the unusually low prevalence of nuclear cataract. Illiteracy and height appear to be significant predictors for cataract in this population and further investigation is required to explore their influence.