[Comparison study for the proportion of underdiagnosed zonulopathy in angle closure glaucoma].

To analyze the proportion and clinical characteristics of underdiagnosed zonulopathy in angle closure glaucoma (ACG) patients and to explore the related risk factors. Case-control study. Continuous cases of ACG patients who underwent phacoemulsification combined with intraocular lens implantation and goniosynechialysis surgery [ACG group, including acute angle closure glaucoma (AACG) and chronic angle closure glaucoma (CACG)] from November 1, 2020 to October 31, 2021 and age-related cataract patients who underwent phacoemulsification combined with intraocular lens implantation surgery in the same period (control group) were included. The diagnosis of zonulopathy was determined according to the intraoperative signs such as wrinkles of the anterior capsule during continuous circular capsulorhexis. The proportion of zonulopathy, preoperative diagnosis rate of zonulopathy, demographic characteristics, anterior chamber depth (ACD), axis length, difference of ACD in both eyes (ACD of the contralateral eye minus ACD of the operated eye) were compared between the two groups. The related risk factors were explored. The paired t-test (comparison between two groups of normally distributed data), non-parametric test (comparison between two groups of non-normally distributed data), Chi-square test (categorical variables), univariate and multivariate logistic regression analysis were used. There were 104 ACG patients (104 eyes), including 63 AACG patients (63 eyes) and 41 CACG patients (41 eyes), and 117 controls (117 eyes). There was no significant difference in age (=0.29) and gender (=0.07) between the two groups. The ACG group had shallower anterior chamber (<0.001), shorter axial length (<0.001) and more ACD difference in both eyes (<0.001). In the ACG group, the proportion of zonulopathy was 46.2% (48/104), which was significantly higher than that (6.0%, 7/117) in the control group (<0.001). In the control group, only zonular laxity was found, while in the ACG group, besides the predominant zonular laxity (68.8%, 33/48), there was zonular dehiscence (31.3%, 15/48). The eyes with AACG (57.1%, 36/63) had a higher proportion of zonulopathy than those with CACG (29.3%, 12/41) (=0.006). In the ACG group, only 14 cases (29.8%) were diagnosed preoperatively according to slit lamp examination and/or ultrasound biomicroscopy. The proportion of underdiagnosed zonulopathy was 70.8% in the ACG group (34/48). A smaller ACD was found to be related to the zonulopathy in the ACG group. All AACG cases with an ACD ≤2.0 mm and CACG cases with an ACD ≤1.9 mm had zonulopathy. Multivariate logistic regression showed that the ACD difference in both eyes (=0.025) and the diagnosis of ACG (AACG vs. cataract, <0.001; CACG vs. cataract, =0.023) were independent risk factors associated with zonulopathy. The proportion of underdiagnosed zonulopathy among ACG patients is high. Better preoperative diagnostic methods for zonulopathy are needed. Zonulopathy is common in ACG patients, especially in AACG patients, suggesting that zonulopathy may be related to the pathogenesis of ACG. The shallower the ACD, the riskier the zonulopathy. ACD differences between two eyes and ACG types (including AACG and CACG) were related risk factors of zonulopathy.