LAUSR

PURPOSE To assess risk factors for lack of improvement in visual acuity (VA) after endothelial keratoplasty (EK). DESIGN Retrospective cohort study. SUBJECTS Patients aged 18 years and older in the IRIS Registry who underwent EK surgery in the United States between 2013 and 2018. METHODS EK procedures performed between 2013 and 2018 in the IRIS Registry were identified. Change in visual acuity relative to baseline was determined at 6 months and 1 year. A multivariable population-average marginal model estimated using Generalized Estimating Equations (GEE) adjusting for socio-demographic factors, baseline vision, surgical indication, ocular comorbidities, and post-operative complications was used to identify factors associated with worse VA outcomes. MAIN OUTCOME MEASURES VA and lack of improvement in vision at 1 year compared to pre-operative status. RESULTS A total of 30,600 EK procedures (N= 25,666 unique patients) were included in the analysis. Overall, VA improved from median logMAR 0.54 (Snellen 20/69) (IQR±0.70) pre-operatively 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 post-operatively. 30.3% of the overall cohort, 29.8% of Fuchs endothelial corneal dystrophy (FECD) subgroup, and 27.4% of bullous keratopathy (BK) subgroup did not show visual improvement at 1 year post-operatively. In FECD subgroup, older age (RR 1.05 per five-year increase, 95% CI:1.03-1.07) and female sex (RR 1.10, CI:1.04-1.16) were associated with VA worse than or equal to baseline at 1 year post-operatively. 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 post-operatively (FECD: RR 0.82, CI:0.81-0.84; BK: RR 0.91, CI:0.91-0.92), whereas post-operative re-bubble procedures (FECD: RR 1.10, CI:1.02-1.19; BK: RR 1.31, CI:1.17-1.48) and repeat keratoplasties (FECD: RR 1.41, CI:1.32-1.52; BK: RR 1.42, CI:1.28-1.57) were associated with higher risk of no improvement in VA. CONCLUSIONS In this large national cohort, post-operative re-bubbling procedures 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 also associated with worse VA outcomes after EK in FECD subgroup.