Assessment of Iridotrabecular Contact and Its Association With Intraocular Pressure After Phacoemulsification in Primary Angle Closure

Abstract

Purpose: To investigate the association between the quantitative assessment of iridotrabecular contact (ITC), measured by swept-source anterior segment optical coherence tomography (SS AS-OCT), and intraocular pressure (IOP) control after phacoemulsification in patients with primary angle closure disease (PACD).

Design: Retrospective, clinical cohort study.

Methods: Preoperative and postoperative anterior chamber angle parameters were measured using SS AS-OCT. IOP was measured preoperatively and until 6 months postoperatively. Percent IOP reduction and fluctuation after surgery were calculated, and their relationships with SS AS-OCT parameters were assessed by correlation analyses and locally weighted scatterplot smoothing (LOWESS) regression with change-point analysis.

Results: A total of 51 eyes of 51 PACD patients were included. Preoperative ITC index and area (r = 0.626, r = 0.551), as well as changes in ITC index and area (r = 0.632, r = 0.543) after surgery, were significantly correlated with postoperative IOP reduction, after adjusting for age and gender (all P <.001). Higher postoperative ITC index (r = 0.405, P = .005) and ITC area (r = 0.460, P = 0.001) were associated with greater postoperative IOP fluctuations. Change points on LOWESS curves were observed for preoperative ITC index (33.0%) and change in ITC index (27.0%) and percent IOP reductions were significantly correlated with them above (β = 0.386, β = 0.664, all P < .001) but not below the change points.

Conclusions: Quantitative assessment of circumferential ITC can predict postoperative IOP control after phacoemulsification, and thus it may be used as a reference for determining lens extraction in PACD eyes.