Angle-closure glaucoma in an urban population in southern India - The Andhra Pradesh Eye Disease Study

Objective: To assess the prevalence and features of angle-closure glaucoma (ACG) in an urban population in southern India. Design: A population-based, cross-sectional study. Participants: A total of 2522 (85.4% of those eligible) persons of all ages , including 1399 persons 30 years of age or older, from 24 clusters represe ntative of the population of Hyderabad city. Testing: The participants underwent an interview and detailed eye examinati on that included logarithm of minimum angle of resolution visual acuity, re fraction, slit-lamp biomicroscopy, applanation tonometry, and gonioscopy; p upil dilatation and stereoscopic fundus evaluation was performed if the ris k of angle-closure as a result of dilatation was not believed to be imminen t. Humphrey threshold 24-2 visual fields (Humphrey Instruments Inc., San Le andro, CA) were performed when indicated by standardized criteria for disc damage or if intraocular pressure (IOP) was 22 mmHg or move. Main Outcome Measures: An occludable angle was defined as pigmented posteri or trabecular meshwork not visible by gonioscopy in three quarters or move of the angle circumference. Manifest primary angle-closure glaucoma (PACG) was defined as IOP of 22 mmHg or more or glaucomatous optic disc damage wit h visual field loss in the presence of an occludable angle. An IOP of 22 mm Hg or more or glaucomatous optic disc damage in the presence of an occludab le angle secondary to an obvious cause was defined as secondary ACG. Results: Manifest PACG and occludable angles without ACG were present in 12 and 24 participants, respectively, with age- and gender-adjusted prevalenc e (95% confidence interval [CII) of 0.71% (0.34%-1.31%) and 1.41% (0.73%-2. 09%) in participants 30 years of age or older, and 1.08% (0.36%-1.80%) and 2.21% (1.15%-3.27%) in participants 40 years of age or older, respectively. With multivariate analysis, the prevalence of these two conditions conside red together increased significantly with age (P < 0.001); although not sta tistically significant, these were more common in females (odds ratio 1.70; 95% CI, 0.82-3.54) and in those belonging to lower socioeconomic strata as compared with middle and upper strata (odds ratio, 1.82; 95% CI, 0.88-3.74 ). The odds of manifest PACG were higher in the presence of hyperopia of mo re than 2 diopters ([D]; odds ratio, 3.69; 95% CI, 0.89-15.2). Only four of 12 participants (33.3%) with manifest PACG had been previously diagnosed, and one of 12 (8.3%) had peripheral iridotomy performed previously. Manifes t PACG had caused blindness in one or both eyes in five of these 12 partici pants (41.7%); best-corrected distance visual acuity less than 20/400 in on e or both eyes in four patients, and acuity less than 20/200 in one eye in another patient. Most (83.3%) of those with manifest PACG could be classifi ed as having chronic form of the disease. We may have underestimated manife st PACG because visual fields were performed only on those with clinical su spicion of optic disc damage. Secondary ACG was present in two participants . Conclusions: The prevalence of PACG in this urban population in southern In dia is close to that reported recently in a Mongolian population. A large p roportion of the PACG in this population was undiagnosed and untreated. Bec ause visual loss resulting from PACG is potentially preventable if peripher al iridotomy or iridectomy is performed in the early stage, strategies for early detection of PACG could reduce the high risk of blindness resulting f rom PACG seen in this urban population in India. Ophthalmology 2000;107:171 0-1716 (C) 2000 by the American Academy of Ophthalmology.