Comparison of Anterior Chamber Parameters in Patients With Plateau Iris Configuration and Pupillary Block Using ASOCT.

Abstract

To quantitatively analyze the anterior chamber parameters in patients with pupillary block (PB) and plateau iris configuration (PIC) using anterior segment optical coherence tomography (ASOCT). In this cross-sectional study, nonglaucomatous subjects consecutively recruited and a total of 212 eyes divided into 3 groups of PIC (31 eyes), PB (60 eyes), and open angles (121 eyes) based on gonioscopic and ultrasound biomicroscopy findings. All patients underwent ASOCT 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, and angle parameters including angle opening distance, and trabecular iris space area were measured in qualified images using the Zhongshan Angle Assessment Program, and compared using linear mixed model. The data from 1 eye of each subject were used for final analysis. Mean age was 64.5±12.1, 64.8±10.5, and 62.3±9.2 years for PB, PIC, and open angle eyes, respectively (P=0.26). There was no significant difference in angle parameters (angle opening distance and trabecular iris space area at 250, 500, and 750 µm from sclera spur), anterior segment parameters (ACD and ACA), iris area, iris curvature, and LV between PB and PIC groups. PIC eyes had greater IT at 750 µm from sclera spur than the PB group (P=0.05). Normal eyes had greater ACD, ACA, and anterior chamber width, and angle parameters and lesser LV and iris curvature than the other 2 groups. ASOCT parameters are not significantly different between PB and PIC eyes. PIC eyes may have greater IT at its base.