Population-Based Utility of van Herick Grading for Angle-Closure Detection

Primary angle-closure glaucoma accounts for half of glaucoma-related blindness worldwide with a disproportionate burden of disease found in Asian populations. The clinical reference standard for diagnosis of angle closure is gonioscopy, but van Herick (VH) grading of limbal anterior chamber depth (LACD) has been used as a screening tool, with varying sensitivities and specificities on classifying gonioscopically occludable angles reported in Chinese and other East Asian populations. A cutoff of VH grade ≤1 (modified grade ≤15%) has been found to have sensitivities ranging from 19% to 84% and specificities from 86% to 100%, whereas a higher cutoff VH grade ≤2 (modified grade ≤25%) has had sensitivities ranging from 54% to 99% and specificities from 65% to 96%. However, the efficacy of using the VH test as a screening tool in community-based screening programs to identify gonioscopically occludable angle has not been investigated. The purpose of this study was to determine the sensitivity and specificity of modified VH grading of LACD in detecting gonioscopically defined primary angle-closure suspects (PACS) among subjects screened for participation in the Zhongshan Angle Closure Prevention (ZAP) Trial in southern China