Comparison of Slitlamp Optical Coherence Tomography and Scanning Peripheral Anterior Chamber Depth Analyzer to Evaluate Angle Closure in Asian Eyes

Objective: To evaluate the effectiveness of slitlamp optical coherence tomography (SL-OCT) and Scanning Peripheral Anterior Chamber depth analyzer (SPAC) in detecting angle closure, using gonioscopy as the reference standard. Methods: A total of 1.53 subjects underwent gonioscopy, SL-OCT, and SPAC. The anterior chamber angle (ACA) was classified as closed on gonioscopy if the posterior trabecular meshwork could not be seen; with SLOCT, closure was determined by contact between the iris and angle wall anterior to the scleral spur; and With SPAC by a numerical grade of 5 or fewer and/or a categorical grade of suspect or potential. Results: A closed ACA was identified in 51 eyes with gonioscopy, 86 eyes with SL-OCT, and 61 eyes with SPAC (gonioscopy vs SL-OCT, P<.001; gonioscopy vs SPAC, P=.1.0; SL-OCT vs SPAC, P<.001; McNemar test). Of the 51 eyes with a closed ACA on gonioscopy, SL-OCT detected a closed ACA in 43, whereas SPAC identified 41 (P=.79). An open angle in all 4 quadrants was observed in 102 eyes with gonioscopy, but SL-OCT and SPAC identified 43 and 20 of these eyes, respectively, as having angle closure. The overall sensitivity and specificity for SL-OCT were 84% and 58% vs 80% and 80% for SPAC. Conclusion: Using gonioscopy as the reference, SLOCT and SPAC showed good sensitivity for detecting eyes at risk of angle closure.