Angle closure in the Namil study in central South Korea

Abstract

Objective: To assess the prevalence and associated risk factors of angle closure in a defined population as part of the Namil Study.

Methods: In this cross-sectional epidemiologic study for residents aged 40 years or older in Namil-myon, a rural area in central South Korea, the examination included slitlamp biomicroscopy, applanation tonometry, gonioscopy, autorefraction, fundus photography, corneal thickness measurement, visual field test with frequency-doubling technology, and anterior chamber depth (ACD) and axial length (AL) measurements with partial coherence interferometry. Standard automated field test and optical coherence tomography or scanning laser polarimetry were performed to confirm the glaucomatous visual field/optic disc damage. Angle closure included primary angle-closure suspect (PACS), primary angle closure (PAC), and primary angle-closure glaucoma (PACG). Definitions of PACS, PAC, and PACG were based on the recommendations from the International Society for Geographical &Epidemiological Ophthalmology.

Results: Among the 1426 individuals enrolled for the assessment, with exclusion of cataract surgery, the prevalence rates of PACS, PAC, PACG, and overall angle closure in at least 1 eye were 2.0% (95% CI, 1.3%-2.8%), 0.5% (95% CI, 0.1%-0.9%), 0.7% (95% CI, 0.3%-1.1%), and 3.2% (95% CI, 2.3%-4.2%), respectively. Multivariate analysis found that older age (odds ratio [OR], 1.8797; 95% CI, 1.4624-2.4162), shallower ACD (OR, 0.9982; 95% CI, 0.9977-0.9987), and shorter AL (OR 0.9978; 95% CI, 0.9969-0.9988) (P < .001 for each) were significantly associated with angle closure.

Conclusions: The overall prevalence of angle closure was 3.2% in the present study. On the basis of these findings, increasing age, shallower ACD, and shorter AL appear to be associated with angle closure. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00727168.