Prevalence of Glaucoma in a South Brazilian Population: Projeto Glaucoma

Abstract

To assess the prevalence of glaucoma in a South Brazilian population. Subjects older than 40 years underwent a screening examination that included a medical interview, slit lamp examination, tonometry, and fundoscopy. Those with suspected glaucoma (based on optic disc appearance and/or intraocular pressure) underwent a comprehensive ophthalmic evaluation during the definitive examination. Glaucoma was diagnosed based on the International Society of Geographical and Epidemiologic Ophthalmology classification. A total of 1636 subjects were examined (76.5% participation rate); 71% of the study population self-reported their race as white and 24% as nonwhite (most black and mixed-black/white). Glaucoma was found in 56 subjects (crude prevalence of all glaucoma: 3.4%; 95% CI, 2.5-4.3), primary open-angle glaucoma (POAG) was found in 40 (2.4%; 95% CI, 1.7-3.2), and primary angle-closure glaucoma (PACG) in 12 (0.7%; 95% CI, 0.3-1.1). Six (12%) subjects with primary glaucoma had a previous diagnosis of the disease. Nonwhite persons had a higher prevalence rate of POAG than did white participants, although this difference was not significant (3.8% vs. 2.1%, respectively, P = 0.11). Unilateral blindness due to primary glaucoma was observed in seven subjects (five POAG/2 PACG), and nonwhites had a higher rate of unilateral blindness than did whites (five versus two cases, respectively, P = 0.014). Compared to incidence in Hispanic and European populations, PACG was more common among South Brazilians, whereas the POAG rates were similar. The rate of undiagnosed glaucoma was almost 90%. The higher POAG prevalence in the population self-reported as nonwhite may affect the estimation of glaucoma in Brazil, as more than 40% of the population self-report their race as nonwhite.