Anterior chamber depth and vitreous zonule integrity as biomarkers for intraoperative capsule laxity in angle closure.

OBJECTIVE: To investigate preoperative predictors for anterior and posterior capsule laxity during phacoemulsification combined with anti-glaucoma surgery in eyes with angle closure. METHODS: Cross-sectional study. Patients aged ≥40 years diagnosed with angle closure who underwent phacoemulsification combined with anti-glaucoma surgery between May 2023 and May 2025 were enrolled. Eyes were classified into four groups based on intraoperative findings: anterior capsule laxity, posterior capsule laxity, combined capsule laxity, and normal capsule. Mixed-effects logistic regression analysis was employed to determine the independent predictors of anterior and posterior capsule laxity, respectively. RESULTS: A total of 241 eyes of 203 patients were included. 36 eyes (14.9%) had anterior laxity, 51 eyes (21.2%) had posterior laxity, 73 eyes (30.3%) had combined capsule laxity, and 81 eyes (33.6%) had normal capsule. Eyes with anterior laxity had shallower anterior chamber depth (ACD) than normal capsule eyes (2.05 (1.82,2.29) mm vs. 2.33 (2.13, 2.52) mm, P<0.001) and were more frequently acute primary angle closure (APAC) (P=0.001). Posterior/combined laxity eyes showed higher vitreous zonule (VZ) absence (both P<0.001); combined laxity having thicker lens than normal eyes (5.16 ± 0.35mm vs. 4.95 ± 0.43mm, P=0.006). Regression analysis identified APAC diagnosis (odds ratio (OR) 3.04, 95% confidence interval (CI): 1.01-9.38, P=0.049) and shallower ACD (OR 0.05, 95% CI: 0.01-0.26, P=0.001) as independent predictors for anterior capsule laxity, while APAC diagnosis (OR 3.89, 95% CI: 1.20-13.50, P=0.026), VZ absence (OR 0.11, 95% CI: 0.04-0.27, P<0.001), and increased ciliary body maximum thickness (CBMT) (OR 1.92, 95% CI: 1.22-3.17, P=0.007) predicted posterior capsule laxity. The anterior and posterior capsule laxity prediction models achieved AUC values of 0.817 (95% CI: 0.739-0.896) and 0.781 (95% CI: 0.690-0.872), respectively. CONCLUSIONS: APAC diagnosis and shallow ACD predict anterior capsule laxity, whilst VZ absence, APAC diagnosis, and increased CBMT indicate posterior capsule laxity in eyes with angle closure. Identification of these biomarkers before surgery may help surgeons anticipate complications and optimize postoperative outcomes.