Intraocular Pressure Following Phacoemulsification with Anterior Vitrectomy in the IRIS® Registry (Intelligent...

To evaluate intraocular pressure (IOP) changes following phacoemulsification with concurrent anterior vitrectomy (AV) using the IRIS® Registry (Intelligent Research in Sight).

Retrospective clinical cohort study SUBJECTS: Eyes in the IRIS Registry that underwent stand-alone phacoemulsification with concurrent AV from 1/1/2013-9/30/2019.

Daily mean IOP was compared to baseline IOP through postoperative day 90. An IOP spike was defined as IOP >30 mm Hg and an increase of >10 mm Hg from baseline IOP within the first postoperative week. A linear mixed-effects model was used to determine when the postoperative daily mean IOP stabilized; the final mean IOP was the average of all daily mean IOPs from that timepoint onward. A multivariable logistic regression analysis was used to identify independent risk factors and odds ratios (OR) with 95% confidence intervals for an IOP spike.

Postoperative daily mean IOP; incidence and OR of IOP spike RESULTS: Phacoemulsification with AV occurred in 1,811 eyes with a baseline median (interquartile range) IOP of 16.0 (14.0,18.0) mmHg. An IOP spike was observed in 164 (9.1%) eyes. After surgery, daily median IOP for all eyes was elevated to 18.0 (14.0, 23.0) mmHg and generally remained significantly elevated above baseline through postoperative week two. Risk factors for all eyes to have an IOP spike were glaucoma diagnosis (OR 1.71 (1.17-2.5), P=0.005), male sex (OR 1.64 (1.15-2.37), P=0.007), and baseline logMAR visual acuity (OR=1.07 (1.01-1.13) per 0.2 logMAR unit increase, P=0.02). In eyes with glaucoma, risk factors for IOP spike included male sex (OR 2.36 (1.32-4.32), P=0.004), increased age (OR 1.45 (1.08-1.97) per ten years, P=0.02), and Hispanic ethnicity compared to non-Hispanic White patients (OR 2.30 (1.07-4.80), P=0.03). In eyes without glaucoma, only baseline visual acuity was a risk factor (OR 1.09 (1.00-1.18) per 0.2 logMAR unit increase, P=0.04).

Ophthalmologists can anticipate a postoperative IOP elevation with resolution to baseline IOP by postoperative week two, but IOP is unlikely to decline below baseline, when AV is required during phacoemulsification. Surgeons should closely monitor for IOP spikes when AV is performed for patients with glaucoma, male sex, and worse baseline visual acuity.