Incidence and risk factors for cystoid macular edema after descemet membrane endothelial keratoplasty

To study the incidence and clinical course of cystoid macular edema (CME) after Descemet membrane endothelial keratoplasty (DMEK) in a large single-centre cohort and to identify risk factors, management, and outcomes. This retrospective, single-centre cohort study included patients who underwent DMEK alone or in combination with cataract surgery (triple DMEK) for Fuchs endothelial corneal dystrophy (FECD) or bullous keratopathy (BK) at the Eye Hospital, University Medical Centre Ljubljana, Slovenia, between 2015 and 2024. Preoperative examination, surgical details, postoperative interventions, and follow-up data were collected. Macular OCT was performed in cases of unexplained reduced vision. Subclinical CME may have passed undetected; therefore, the results reflect clinically significant CME only. Minimum 6-month follow-up was required. Group comparisons were performed using Mann-Whitney U test, Fisher’s exact test, or Chi-square test as appropriate. Univariable logistic regression and receiver operating characteristic (ROC) analysis were used to assess factors associated with postoperative CME. A total of 283 eyes from 208 patients (32% male; median age 72 years) were included. CME developed in 29 eyes (10.2%) at a median of 3.5 weeks. In univariable analysis, BK, thicker central corneal thickness (CCT), lower baseline BCVA, and rebubbling rate were associated with CME. In multivariable logistic regression, BK (OR 3.15; 95% CI 1.21—8.19; p = 0.019) and rebubbling rate (OR 2.74; 95% CI 1.13—6.61; p = 0.025) remained independent predictors, while CCT showed a borderline association (OR 1.003 per µm; 95% CI 1.00—1.007; p = 0.061). ROC analysis demonstrated a moderate predictive value of preoperative CCT (AUC 0.724; cut-off 736 μm). CME mostly responded to topical therapy; second-line therapy was required in 45% of cases. Resolution occurred after a median of 5 (IQR 2.5—7.5) weeks, with no significant difference in final BCVA compared with non-CME eyes. Clinically significant CME after DMEK is relatively common, typically presents more than 3 weeks postoperatively, and is associated with advanced corneal decompensation. Treatment was successful, but prevention may require early surgery, careful attention to preoperative corneal status and possibly intensified postoperative corticosteroid regimens in high-risk eyes.