Intraocular pressure following phacoemulsification with retained lens fragments in the IRIS® Registry (Intelligent Research in Sight).

Purpose: To describe intraocular pressure (IOP) changes following cataract surgery resulting in retained lens fragments (RLF).

Design: Retrospective clinical cohort study.

Participants: Eyes in the IRIS® Registry (Intelligent Research in Sight) that underwent stand-alone phacoemulsification from 1/1/2013-9/30/2019 resulting in RLF.

Methods: Daily mean IOP was calculated from postoperative day 1-90. IOP spike was defined as a daily mean IOP >30 mmHg and >10 mmHg above baseline IOP within the first postoperative week. A linear mixed model was used to determine when the postoperative daily mean IOP stabilized and a final mean IOP was calculated by averaging the final daily mean IOP for all eyes with data from that timepoint onward. Odds ratios (OR) with 95% confidence interval (CI) for demographic and clinical characteristics were calculated with univariate and multivariate logistic regression analyses. Eyes were censored upon additional intervention that could affect IOP such as secondary surgery or addition of IOP-lowering medication.

Main outcome measures: Postoperative daily mean IOP; incidence and OR of IOP spike RESULTS: Retained lens fragments were noted in 6105 eyes with mean (standard deviation, SD) baseline IOP of 15.8 (3.6) mmHg. There was an initial elevation in daily mean (SD) IOP after cataract surgery to 21.2 (8.5) mmHg that gradually declined but remained greater than baseline IOP until postoperative day 14. The final mean (SD) IOP and weeks until IOP stabilization was 15.0 (4.1) mm Hg at 5 weeks. Intraocular pressure spike occurred in 766 (12.5%) eyes. Factors associated with IOP spike include male sex (OR 1.47, 95% CI 1.28-1.70), P<0.0001), higher baseline IOP (OR 1.24 per 3 mmHg, 95% CI 1.18-1.31, P<0.0001) and glaucoma diagnosis (OR 1.18, 95% CI 1.01-1.39, P=0.038).

Conclusions: The initial IOP elevation after phacoemulsification resulting in RLF is higher than standard cataract surgery due to an increased incidence of IOP spike. Surgeons should be more vigilant for possible IOP spikes in eyes with higher baseline IOP, male sex, and glaucoma. Eyes without an indication for secondary intervention will have IOP gradually return to baseline level and stabilize after an average of five weeks.