Novel Association of Smaller Anterior Chamber Width with Angle Closure in Singaporeans

Abstract

To describe variations in anterior chamber width (ACW) and investigate its association with the presence of narrow angles. Cross-sectional study. We recruited 2047 subjects aged 50 years or more from a community polyclinic and 111 subjects with primary angle closure (PAC) or primary angle closure glaucoma (PACG) from an eye hospital in Singapore. All participants underwent gonioscopy, anterior chamber depth (ACD) and axial length (AL) measurement (IOLMaster; Carl Zeiss, Jena, Germany), and anterior-segment optical coherence tomography (AS-OCT, Visante, Carl Zeiss Meditec, Dublin, CA). Customized software was used to measure the ACW, defined as the distance between the scleral spurs in the horizontal (nasal-temporal) axis of AS-OCT scans. An eye was deemed to have narrow angles if the posterior trabecular meshwork was not visible for at least 180 degrees on non-indentation gonioscopy with the eye in the primary position. Anterior chamber width and narrow angles. Data on 1465 community-based subjects were available for analysis. Anterior chamber width was significantly smaller in women compared with men (11.70 mm vs. 11.81 mm, respectively, P<0.001) and decreased significantly with age (P for trend <0.001). Significant predictors of smaller ACW were lower educational level, lower body mass index, shorter AL, shallower ACD, and Chinese race. Of the 1465 subjects, 315 (21.5%) had narrow angles on gonioscopy. Mean ACW was smaller in eyes with narrow angles compared with those without narrow angles (11.60 mm vs. 11.80 mm, P<0.001). The age- and gender-adjusted odds ratio for the highest quartile compared with the lower 3 quartiles of ACW with the presence of narrow angles was 3.4 (95% confidence interval, 2.3-5.0; P for trend <0.001). Hospital-based subjects with PAC/PACG had even smaller ACW than community subjects with narrow angles (11.33 mm vs. 11.60 mm, P<0.001). In this cross-sectional study, ACW was smaller in women, Chinese persons, and older persons, and was associated with narrow angles in 2 different study populations. These data suggest that a smaller ACW may represent a novel risk indicator for angle closure.