To evaluate the ocular biometric parameters associated with intraocular pressure (IOP) reduction after phacoemulsification.

Prospective, observational case series.

The study included 999 patients who had undergone uncomplicated phacoemulsification. IOP and ocular biometric parameters were checked preoperatively and 3 months postoperatively using anterior segment optical coherence tomography, optical biometry, and ultrasonic biomicroscopy. The relationship between IOP change and the parameters, including preoperative IOP, anterior chamber depth, axial length, angle opening distance at 500 μm, anterior chamber area, corneal thickness, lens thickness, and iris thickness at 750 μm, was evaluated.

The mean patient age was 67.1 ± 4.3 years. The average change in IOP was −1.6 mm Hg (−11.8%). In univariate analysis, axial length, corneal thickness, and iris thickness were not significantly associated with IOP reduction. However, preoperative IOP, anterior chamber depth, angle opening distance, anterior chamber area, and lens thickness were significantly associated with IOP change (P < .05). Furthermore, changes in anterior chamber depth (standardized coefficient beta [B] = −0.082), angle opening distance (B = −0.095), and anterior chamber area (B = −0.380) were more strongly correlated with IOP change than were preoperative factors (B = −0.078, B = −0.071, and B = −0.067, respectively). In multivariate analysis, preoperative IOP, lens thickness, angle opening distance change, and anterior chamber area change were significantly associated with IOP change (P < .005).

In addition to preoperative IOP and lens thickness, parameters such as changes in anterior chamber area and angle opening distance were significantly associated positively with reduced IOP after phacoemulsification.