Predictors for incidence of primary open-angle glaucoma in a south Indian population: The Chennai eye disease incidence study

Objective To determine the 6-year incidence of primary open-angle glaucoma (POAG) and its associated predictors. Design Population-based cohort study. Participants A total of 4316 subjects without POAG at baseline who were 40 years of age and older from a south Indian population. Methods Participants were examined at baseline and after a 6-year interval. Detailed ophthalmic examination included applanation tonometry, gonioscopy, pachymetry, optic disc evaluation, and automated perimetry. Glaucoma was defined using the International Society of Geographical and Epidemiological Ophthalmology Classification. Multivariable logistic regression was performed to identify the baseline risk factors that could predict the incident POAG. Main Outcome Measures Six-year incidence of POAG and its associated risk factors. Results In 6 years, incident POAG developed in 129 subjects (2.9%; 95% confidence interval [CI], 2.4-3.4; male-to-female ratio, 65:64). Baseline age was a risk factor. In reference to the group 40 to 49 years of age, the incidence increased from 2.3 (95% CI, 1.4-3.7) for the group 50 to 59 years of age to 3.5 (95% CI, 2.2-5.7) for the group 60 to 69 years of age (P < 0.001). Other baseline risk predictors were urban residence (odds ratio [OR], 1.6; 95% CI, 1.1-2.2; P = 0.01), higher intraocular pressure (IOP; OR, 2.0; 95% CI, 1.5-2.6 per 10 mmHg; P < 0.001), myopia (OR, 1.7; 95%, CI, 1.1-2.5; P < 0.001), and axial length (OR, 1.5; 95% CI, 1.0-2.2 per millimeter; P = 0.03). Thinner corneas with higher IOP at baseline had the highest incidence of POAG. In 80% of the urban population and 100% of the rural population, incident glaucoma was previously undetected. Conclusions A significant proportion of this population demonstrated incident POAG. The baseline risk factors could help in identifying those at highest risk of disease.