Comparison of Anterior Segment-Optical Coherence Tomography Parameters in Phacomorphic Angle Closure and Acute Angle Closure Eyes.

Purpose: The purpose of this study is to compare anterior segment-optical coherence tomography (AS-OCT) parameters in phacomorphic angle closure and acute primary angle closure (APAC) eyes.

Methods: In this cross-sectional case series, a total of 134 patients with phacomorphic angle closure (28 eyes) or APAC (54 eyes), as well as normal control subjects (52 eyes), were enrolled. Patients underwent AS-OCT imaging and A-scan biometry of both eyes. Anterior chamber depth (ACD), anterior chamber area (ACA), iris thickness (IT), iris curvature, lens vault (LV), anterior vault (AV), and angle parameters including angle opening distance (AOD 500 and AOD750) and trabecular iris space area (TISA500 and TISA750) were measured in qualified images using the Zhongshan Angle Assessment Program and compared among eyes with phacomorphic angle closure, APAC, and normal control subjects.

Results: Phacomorphic angle closure and APAC eyes had smaller AOD, ACD, ACA, ACW, AV, and posterior corneal arc length and greater LV than normal controls (P < 0.001 for all comparisons). After adjustment for age, sex, and pupil diameter, phacomorphic angle closure had greater AOD500 (P = 0.02), TISA500 (P = 0.003), TISA750 (P = 0.05), axial length (P = 0.03), and LV (P = 0.001) and less ACD (P = 0.001), ACA (P = 0.003), IT750 (P = 0.01), and IT2000 (P = 0.04) than APAC eyes: ACD < 1.59 mm (odds ratio [OR], 29.57; P < 0.01) and LV > 1042 μm (OR,12.12; P < 0.01) were the two biometric parameters that could highly discriminate phacomorphic angle closure from the APAC eyes. In multivariate analysis, ACD, LV, AOD500, and axial length could significantly distinguish the two entities.

Conclusions: Ocular biometric parameters can differentiate phacomorphic angle closure from APAC eyes. Shallower ACD and greater LV, axial length, and ACA are the main parameters that distinguish phacomorphic angle closure from APAC.