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

Purpose: To compare changes in the swept-source anterior segment optical coherence tomography (SS 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 postoperatively at 1 day, 1 week, 1 month, 3 months, and 6 months. 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: primary angle closure suspect or primary angle closure; group B: primary angle closure glaucoma). The changes in IOP and anterior chamber angle (ACA) 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 (16.3 ± 2.5 vs 16.9 ± 3.2 mmHg, P=0.297) between the two groups, but the number of glaucoma medications used (0.6 ± 1.0 vs 2.0 ± 0.9, P<0.001) was greater in group B. Postoperatively, IOP was not significantly different, but the number of medications used was greater in group B (0.2 ± 0.7, 0.9 ± 0.8, P<0.001). ACA 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 (5.6 ± 7.0 vs 10.7 ± 12.1, P=0.014) was significantly greater in group B. A greater change in the ITC index was related to a greater degree of IOP reduction (beta coefficient = 0.429, P<0.001).
Conclusions: Eyes with PACG 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.