Disparities in Visual Acuity Outcomes after Endothelial Keratoplasty: An Intelligent Research in Sight Registry Analysis

Purpose: To assess risk factors for lack of vision improvement after endothelial keratoplasty (EK). Design: Retrospective cohort study. Participants: Patients aged 18 years and older in the Intelligent Research in Sight (IRIS®) Registry who underwent EK surgery in the United States between 2013 and 2018. Methods: Change in visual acuity (VA) relative to baseline were determined at 6 months and 1 year. A multivariable population-average marginal model estimated using generalized estimating equations adjusting for sociodemographic factors, baseline vision, surgical indication, ocular comorbidities, and postoperative complications was used to identify factors associated with worse VA outcomes. Main Outcome Measures: Visual acuity and lack of VA improvement at 1 year compared with preoperative status. Results: A total of 30 600 EK procedures (N = 25 666 unique patients) were included in the analysis. Overall, VA improved from median logarithm of the minimum angle of resolution (logMAR) 0.54 (Snellen 20/69) (interquartile range [IQR] ± 0.70) preoperatively to median logMAR 0.40 (20/50) (IQR ± 0.36) at 6 months and median logMAR 0.30 (20/40) (IQR ± 0.36) at 1 year postoperatively. A total of 30.3% of the overall cohort, 29.8% of Fuchs’ endothelial corneal dystrophy (FECD) subgroup, and 27.4% of the bullous keratopathy (BK) subgroup did not show visual improvement at 1 year postoperatively. In the FECD subgroup, older age (risk ratio [RR], 1.05 per 5-year increase, 95% confidence interval [CI], 1.03−1.07) and female sex (RR, 1.10, 95% CI, 1.04−1.16) were associated with VA worse than or equal to baseline at 1 year postoperatively. In both FECD and BK subgroups, eyes with higher baseline logMAR VA (per 0.1 unit increase in logMAR) were more likely to have visual improvement postoperatively (FECD: RR, 0.82, 95% CI, 0.81−0.84; BK: RR, 0.91, 95% CI, 0.91−0.92), whereas postoperative rebubbling (FECD: RR, 1.10, 95% CI, 1.02−1.19; BK: RR, 1.31, 95% CI, 1.17−1.48) and repeat keratoplasties (FECD: RR, 1.41, 95% CI, 1.32−1.52; BK: RR, 1.42, 95% CI, 1.28−1.57) were associated with higher risk of no VA improvement. Conclusions: In this large national cohort, postoperative rebubblings and repeat keratoplasties were identified as independent factors associated with worse VA outcomes after EK for both FECD and BK subgroups. Older age and female gender were associated with worse VA outcomes after EK in the FECD subgroup.