Change in Iridotrabecular Contact and Intraocular Pressure after Phacoemulsification in Primary Angle Closure Disease Spectrum

Purpose: To compare changes in the swept-source (SS) anterior-segment optical coherence tomography (AS-OCT) parameters and intraocular pressure (IOP) control after lens extraction in various spectra of primary angle-closure disease (PACD).Methods: A total 92 eyes from 92 patients with PACD who underwent lens extraction were included in the study. All patients underwent IOP measurement preoperatively and at 1 day, 1 week, and 1, 3, and 6 months postoperatively. SS AS-OCT was performed in all subjects preoperatively and 1 month postoperatively. All participants were divided into two groups depending on the presence of glaucomatous optic disc or visual field damage (group A, PAC suspect or PAC; group B, PAC glaucoma). The changes in IOP and anterior chamber angle parameters of SS AS-OCT of each group were compared. Regression analysis was performed to find factors associated with the degree of IOP reduction after lens extraction.Results: Preoperatively, there was no significant difference in IOP between the two groups (16.3 ± 2.5 mmHg vs. 16.9 ± 3.2 mmHg, p = 0.297), but the number of glaucoma medications used was greater in group B (0.6 ± 1.0 vs. 2.0 ± 0.9, p < 0.001). Postoperatively, IOP was not significantly different, but the number of medications used was greater in group B (0.2 ± 0.7 vs. 0.9 ± 0.8, p < 0.001). Anterior chamber angle parameters including angle opening distance and trabecular-iris angle had a greater increase in group B after lens extraction. However, the residual iridotrabecular contact (ITC) index was significantly greater in group B (5.6 ± 7.0 vs 10.7 ± 12.1, p = 0.014). A greater change in the ITC index was related to a greater degree of IOP reduction (β coefficient, 0.429; p < 0.001).Conclusions: Eyes with PAC glaucoma had a greater residual ITC index after lens extraction compared with eyes of other PACD spectrum and required a greater number of glaucoma medications to maintain a similar level of IOP.