Angle Closure in the Andhra Pradesh Eye Disease Study

Objective: To estimate the prevalence and associated risk factors for primary angle-closure glaucoma (PACG), primary angle closure (PAC), and primary angle-closure suspects (PACS) in the Indian state of Andhra Pradesh. Design: A population-based, cross-sectional study using a stratified, random, cluster, and systematic sampling strategy. Participants: Between 1996 and 2000, participants aged >= 40 years from 94 clusters in 1 urban and 3 rural areas were included. Methods: Trained professionals performed a detailed eye examination, including visual acuity, refraction, slit-lamp biomicroscopy, applanation tonometry, gonioscopy, and dilated fundus evaluation after ruling out risk of angle closure. Humphrey threshold 24-2 visual fields (VFs) were performed when indicated by disc criteria or if intraocular pressure (IOP) was >= 22 mmHg. Main Outcome Measures: Angle closure was diagnosed and categorized using International Society of Geographical and Epidemiological Ophthalmology criteria. Results: Primary angle-closure glaucoma was present in 35 of 3724 subjects aged >= 40 years, an age-and gender-adjusted prevalence of 0.94% (95% confidence interval [CI], 0.63-1.24). Primary angle closure was present in 12 subjects (0.3%; 95% CI, 0.1-0.5), and PACS was present in 71 subjects (2%; 95% CI, 1.5-2.3). The prevalence of angle-closure disease (ACD=PACG+PAC) was 1.26% (95% CI, 0.90-1.62). Forty-one of 47 subjects (87.2%) with ACD were unaware of their disease. The prevalence of PACG increased from 0.56% (0.17-0.94) in the fourth decade to 2.5% (0.87-4.12) in the seventh decade. Seven (20%) of the 35 subjects with PACG were blind (visual acuity <3/60). Intraocular pressure increase (odds ratio [OR] 1.16; 95% CI, 1.11-1.22; P<0.001), diabetes mellitus (OR 3.18l; 95% CI, 1.34-7.58; P=0.001), and female gender (OR 2.07; 95% CI, 1.09-3.93; P=0.025) were significantly associated with angle-closure disease. No significant association was found with systemic hypertension (P=0.24) and hyperopia (P=0.05). Conclusions: The prevalence of PACG in this population was 0.94%. Increasing age, increasing IOP, diabetes mellitus, and female gender were significantly associated with angle-closure disease. Blindness due to PACG was 20%.