Biometry and Interdevice Differences in Primary Angle-Closure Disease with Unilateral Zonulopathy: A Paired-Eye Study

Background/Objectives: To compare preoperative clinical and biometric characteristics between primary angle-closure disease (PACD) eyes with intraoperatively identified zonulopathy and their fellow eyes, and to explore interdevice measurement differences. Methods: This single-center paired-eye study included 57 patients with PACD undergoing bilateral cataract surgery and unilateral intraoperatively identified zonulopathy. Preoperative measurements were obtained using IOLMaster, Pentacam, and ultrasound biomicroscopy (UBM). Paired outcomes were compared using Wilcoxon signed-rank or exact McNemar tests, with Benjamini–Hochberg correction applied separately to clinical and biometric comparisons. Results: Eyes with zonulopathy more frequently had primary angle-closure glaucoma and previous acute angle-closure (AAC) attacks, greater angle-closure extent, and more severe mean deviation-based visual-field loss. These eyes had shallower corrected IOLMaster anterior chamber depth (ACD; 1.50 ± 0.40 versus 1.82 ± 0.35 mm), lower lens position (4.03 ± 0.33 versus 4.37 ± 0.28 mm), and smaller anterior chamber volume (59.9 ± 24.0 versus 75.4 ± 22.8 mm³; all q < 0.001). UBM minus IOLMaster ACD, UBM minus Pentacam ACD, and Pentacam minus UBM pupil diameter differed significantly between paired eyes (q = 0.002, 0.017, and 0.023, respectively). Conclusions: PACD eyes with occult zonulopathy showed a shallower anterior chamber, lower lens position, smaller anterior chamber volume, and greater interdevice differences in selected ACD and pupil measurements. These exploratory associations require validation before their use for preoperative identification of zonulopathy.