Biometric indicators of eyes with occult lens subluxation inducing secondary acute angle closure

BACKGROUND: To compare the anterior biometrics in eyes with secondary acute angle closure induced by occult lens subluxation (ASAC-LS), misdiagnosed as acute primary angle closure (APAC) at the first visit with APAC, chronic primary angle closure glaucoma (CPACG), and cataract. METHODS: This retrospective case study included 17 eyes with angel closure due to occult LS, who were misdiagnosed as APAC on their first visit, 56 APAC eyes, 54 CPACG eyes, and 56 cataract eyes. Axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), aqueous depth (AD) and lens thickness (LT) were recorded. Lens position (LP), relative lens position (RLP), corrected lens position (CLP) were calculated. Quantitative data were subject to one-way analysis of variance and correlation analysis. Categorical data were analyzed using the chi-squared test. Receiver operating characteristic (ROC) curves were plotted to obtain a suitable cutoff value of ocular biometrics. RESULTS: The ASAC-LS patients had a longer ocular axial length than APAC and CPACG patients. Central corneal thickness of the ASAC-LS patients was not significantly different from APAC patients, but was significantly different from CPACG and cataract patients. The APAC patients had the smallest ACD, while the ASAC-LS patients had the smallest AD. The ASAC-LS patients had the largest lens thickness. According to ROC curve analysis, RLP, ACD, AD, CLP, LP had high power of discrimination. CONCLUSIONS: This study revealed that LS secondary PAC patients had a shallower AD, thicker CCT comparing to those of APAC, CPACG and cataract patients. For patients with acute angle-closure glaucoma, it is necessary to exclude lens zonula relaxation. TRIAL REGISTRATION: NCT03752710, retrospectively registered.