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Purpose To investigate the ocular biometric characteristics of eyes with acute angle closure (AAC) secondary to zonular laxity to further explore the sensitive parameters for preoperative diagnosis. Methods This study included 50 patients with AAC secondary to zonular laxity and 54 patients with acute primary angle closure (APAC). Demographic data, ocular examination results and biometric parameters on ultrasound biomicroscopy (UBM) images were compared between the affected and fellow eyes in two groups. Parameters significant in the multiple linear regression model were included in a regression equation and the diagnostic efficiency was evaluated by area under the curve (AUC). Results In patients with AAC secondary to zonular laxity, the binocular difference of central anterior chamber depth (ACD), lens vault (LV) in affected eyes and binocular difference of LV were significantly larger than those in patients with APAC respectively and these three parameters were all significant in multiple linear regression analysis (all P [LV in affected eyes (mm)] + 3.657[binocular difference of LV (mm)] + 6.542[binocular difference of ACD (mm)], with the accuracy of prediction reaching 94.05%. Conclusion Binocular difference of ACD, LV in affected eyes, and binocular difference of LV had high efficiency in diagnosing AAC secondary to zonular laxity.

Purpose: To investigate the error rate of segmentation in the automatic measurement of anterior chamber volume (ACV) and iris volume (IV) by swept-source anterior segment optical coherence tomography (SS-ASOCT) in narrow-angle and wide-angle eyes.Methods: In this study, fifty eyes from 25 narrow-angle subjects and fifty eyes from 25 wide-angle subjects were enrolled. SS-ASOCT examinations were performed and each SS-ASOCT scan was reviewed, and segmentation errors in the automatic measurement of ACV and IV were classified and manually corrected. Error rates were compared between the narrow-angle and the wide-angle groups, and ACV and IV before and after manual correction were compared.Results: A total of 12,800 SS-ASOCT scans were reviewed. Segmentation error rates of angle recess, iris root, posterior surface of the iris, pupil margin, and anterior surface of the lens were 84.06, 93.30, 13.15, 59.21, and 25.27%, respectively. Segmentation errors of angle recess, iris root, posterior surface of the iris, and pupil margin occurred more frequently in narrow-angle eyes, while more segmentation errors of the anterior surface of the lens were found in wide-angle eyes (all P < 0.001). ACV decreased and IV increased significantly after manual correction of segmentation errors in both groups (all P < 0.01).Conclusion: Segmentation errors were prevalent in the volumetric measurement by SS-ASOCT, particularly in narrow-angle eyes, leading to mismeasurement of ACV and IV.

Purpose To explore whether oxidative stress and premature senescence occur in the anterior segment of acute primary angle-closure (APAC) eyes after increased intraocular pressure. Methods The eye samples of 21 APAC patients, 22 age-related cataract patients, and 10 healthy donors were included. Aqueous humor (AqH), iris, and anterior lens capsule samples were collected. The levels of oxidative stress markers and senescence-associated secretory phenotype (SASP)–related cytokines in AqH were estimated using relevant reagent kits and multiplex bead immunoassay technique. The intensity of relevant markers in anterior segment tissues was examined by immunofluorescence- and senescence-associated β-galactosidase (SA-β-gal) staining. Results Oxidative stress marker levels elevated significantly in the AqH of APAC eyes. Reactive oxygen species (ROS) and 8-hydroxydeoxyguanosine levels were positively correlated with preoperative peak intraocular pressure and age, whereas reduced glutathione/oxidized glutathione (GSH/GSSH) ratio was negatively correlated with both parameters. The levels of several SASP-related cytokines were markedly increased. ROS and malondialdehyde levels were positively correlated with the levels of some SASP-related cytokines, whereas superoxide dismutase level and GSH/GSSH ratio showed an opposite trend. The number of cells positive for oxidative mitochondrial DNA damage and apoptosis-related markers increased in the iris and anterior lens capsule of the APAC group. Senescence-associated markers (p16, p21, and p53) and SA-β-gal activity were increased in the iris of the APAC group. Conclusions Oxidative stress and premature senescence occurred in the anterior segment of APAC patients, suggesting that they may be involved in the development of pathological changes in the anterior segment of APAC eyes.