Prevalence and Risk Factors for Primary Glaucomas in Adult Urban and Rural Populations in the Andhra Pradesh Eye Disease Study

Purpose To compare the prevalence of and risk factors for primary open-angle glaucoma (POAG) and primary angle-closure glaucoma (PACG) in urban and rural populations in the Andhra Pradesh Eye Disease Study. Design A population-based, cross-sectional study using a stratified, random, cluster, and systematic sampling strategy. Participants Between 1996 and 2000, participants from 94 clusters in 1 urban and 3 rural areas representative of the population were included. Methods We performed a detailed eye examination, including applanation tonometry, gonioscopy, and dilated fundus evaluation after ruling out risk of angle closure. Humphrey threshold 24-2 visual fields were performed when indicated. Main Outcome Measures Glaucoma was diagnosed and categorized using International Society of Geographical and Epidemiological Ophthalmology criteria. The prevalence and risk factors for POAG and PACG in subjects aged ≥40 years were compared between the urban and rural cohorts. Results There were 3724 subjects ≥40 years, with 934 in the urban and 2790 in the rural cohort. The prevalence of POAG was greater in the urban compared with the rural cohort (4% vs 1.6%; P