Evaluation of Anterior Segment Parameters of First-Time Acute Primary Angle Closure Eye and the Fellow Eye: A Cross-Sectional Study

Background: To evaluate the anterior segment parameters of first-time acute primary angle closure(APAC) eye and the fellow eye (primary angle closure suspect, PACS) with anterior segment optical coherence tomography (AS-OCT) and analyze the possible factors associated with the attack of APAC. Methods: Thirty patients with first-time unilateral APAC (APAC 30eyes, PACS 30eyes) were collected from August 2013 to August 2014 in the ophthalmology department of Peking Union Medical College Hospital. Central cornea thickness (CCT), pupil diameter (PD), anterior chamber depth (ACD), lens vault (LV), anterior chamber width (ACW), angle open distance at 500μmand 750μm from the sclera spur (AOD500, AOD750), trabecular iris area at 500μmand 750μm from the sclera spur(TISA500, TISA750), sclera spur angle (SSA) of both eyes were measured by AS-OCT. Paired t-test was applied to find the differences and conditional logistic regression analysis was performed to find the associatedfactors with the prediction of APAC. Results: Compared with the fellow PACS eyes, first-time APAC eyes showed significantlarger CCT (522.7±31.3vs557.3±42.7mm,P=0.000), PD (2.90±1.19vs3.78±1.29mm, P=0.000) and LV (1.08±0.36vs1.24±0.42mm, P=0.006),smaller ACD (1.81±0.45vs1.64±0.44mm,P=0.001), AOD500 (0.097±0.065vs0.059±0.039,P=0.004), AOD750 (0.157±0.10vs0.120±0.068mm,P=0.017), TISA500 (0.036±0.021vs0.020±0.016mm2, P=0.001), TISA750 (0.065and 0.041mm2, P=0.018) and SSA (11.13±6.92and 6.68±4.43°, P=0.001). The results of conditional logistic regression analysisshowed greater LV(OR=40.259[1.021,1779.193],P=0.014) hadthe strongest correlation with the attack of APAC. Conclusions: Greater LV is the most significant factor associated withfirst-time APACcompared with the fellow PACS eye and may play a critical role in the progression of PACS to APAC.