Intraocular Pressure Changes Following Stand-Alone Phacoemulsification: An IRIS Registry Analysis.

Purpose: To describe real-world intraocular pressure (IOP) changes following stand-alone cataract surgery by comparing postoperative IOP to phakic fellow eyes.

Design: Retrospective clinical cohort study.

Methods: A total of 1,334,868 patients (336,060 with glaucoma and 998,808 without glaucoma) in the IRIS® Registry (Intelligent Research in Sight) underwent stand-alone phacoemulsification from 1 January 2013 to 30 September 2019 with a fellow eye that had subsequent cataract surgery. Postoperative daily mean IOP was compared between surgical and control eyes from postoperative day 1 to 90. A generalized linear model determined when the postoperative daily mean IOP stabilized to calculate a final mean IOP, which was then compared to baseline IOP.

Results: Postoperative daily mean IOP was initially greater for surgical than for control eyes because of an early postoperative IOP spike. By postoperative day 13, postoperative daily mean IOP was significantly lower for surgical than for control eyes every day through postoperative day 90 (P < .001). There was a mean (SD) decrease from baseline to final mean IOP of 1.55 (3.52) mm Hg or 7.79% for all surgical eyes, 1.91 (3.93) mm Hg or 8.89% for surgical eyes with glaucoma, and 1.37 (3.28) mm Hg or 7.24% for surgical eyes without glaucoma, respectively. There was a statistically significant decrease from baseline to the final mean IOP for all surgical eyes, surgical eyes without glaucoma, and all categories of pre-glaucoma and glaucoma (P < .0001 for all, excluding uveitic glaucoma [P = .0016]).

Conclusions: Eyes both with and without glaucoma that underwent stand-alone phacoemulsification had a significant decrease in IOP through the 90-day postoperative period compared to baseline and phakic fellow eyes.