Prevalence of Primary Open-Angle Glaucoma in Central South Korea: The Namil Study

Abstract

To assess the prevalence of primary open-angle glaucoma (POAG) in the Namil-myon area in central South Korea. A cross-sectional, epidemiologic study in a defined population. Residents aged ≥ 40 years in Namil-myon, a rural agricultural area in central South Korea. Each subject underwent a screening that consisted of an interview and ophthalmic examinations, including visual acuity measurement, autorefraction, anterior segment evaluation by optical biometry, slit-lamp examination, Goldmann applanation tonometry, binocular optic disc evaluation, fundus photography, pachymetry, gonioscopy, and screening visual field test using frequency doubling technology. Subjects with suspected glaucoma were referred for definitive examinations. Standard automated field tests and retinal nerve fiber layer analysis using optical coherence tomography (Stratus OCT) or scanning laser polarimetry (GDx VCC) were performed. A diagnosis of glaucoma was made based on the optic disc shape, retinal nerve fiber layer appearance, perimetric results, and other ocular findings. Prevalence of POAG, mean intraocular pressure (IOP), and mean central corneal thickness (CCT). Of 1928 eligible residents in the area, 1532 (79.5%) participated in this study. The estimated prevalence of POAG in the population aged ≥ 40 years was 3.5% (95% confidence interval [CI], 2.7%-4.3%). The prevalence of POAG with an IOP of ≤ 21 mmHg was 2.7% (95% CI, 2.1%-3.3%), and the prevalence of POAG with an IOP of ≥ 22 mmHg was 0.8% (95% CI, 0.4%-1.2%). The mean IOP for POAG eyes (16.3 ± 4.6 mmHg) was significantly higher than nonglaucomatous eyes (13.3 ± 2.7 mmHg; P = .001). The mean CCT of POAG eyes with an IOP of ≤ 21 mmHg was 528 ± 26 μm, and that of POAG eyes with an IOP ≥ 22 mmHg was 531 ± 37 μm; these values were not significantly different from that of nonglaucomatous eyes (530 ± 31 μm; P = .943 and .996, respectively). The prevalences of POAG and POAG with an IOP ≤ 21 mmHg in the Namil-myon region of central South Korea were higher than that in most previous reports worldwide, but were similar to the reported rates in black and Japanese populations. The mean IOP of POAG eyes was higher than nonglaucomatous eyes, but the mean CCTs were not different. The authors have no proprietary or commercial interest in any of the materials discussed in this article.