Purpose:
In accordance with the World Health Organization (WHO) Vision 20/20 objectives, accurate ophthalmic epidemiological data from Asia is needed to optimize the allocation of limited resources; recently, data from a number of population-based studies in this region has begun to meet this need. However, robust epidemiological data from many Asian regions, including Sri Lanka, remains scarce. This study aimed to determine the prevalence and causes of visual impairment in the Kandy District of central Sri Lanka.
Methods:
A population-based, cross-sectional study was performed. Inhabitants 40 years of age and over from villages in the Kandy District were selected by randomized, stratified, cluster sampling.; 1721 eligible participants were identified and 1375 participated in the study. The ophthalmic examination included presenting and best-corrected Snellen visual acuity with an illiterate E chart, slit lamp examination of the anterior segment and dilated stereoscopic fundus examination. The principal cause of visual impairment was recorded. Visual impairment and blindness were defined by both presenting and corrected visual acuity according to WHO criteria: better eye < 6/18 and < 3/60 respectively.
Results:
Comprehensive examinations, including Snellen vision were performed on 1375 subjects (79.9% participation rate). The prevalence of presenting blindness was 2.9% (95% CI 0.028-0.030; 40 participants), and of WHO blindness was 1.1% (95%CI 0.002-0.020; 15 participants). The prevalence of presenting visual impairment was 22.8% (95%CI 0.264-0.314) and of WHO visual impairment was 5.9% (95%CI 0.043-0.075). Cataract, uncorrected refractive error and age-related macular degeneration were the main causes of visual impairment.
Conclusions:
Visual impairment and blindness remain major public health problems in central Sri Lanka. Specific programmes directed towards reducing the cataract burden need to be implemented.
Keywords: clinical (human) or epidemiologic studies: prevalence/incidence • clinical (human) or epidemiologic studies: risk factor assessment