Cystoid macular edema following repeat DMEK: incidence and risk factors.

Purpose: To describe the incidence of CME in re-DMEK procedures and identify the associated risk factors.

Methods: Retrospective case series of 88 patients who underwent re-DMEK surgeries from January 2013 to October 2023. Surgical results were analyzed based on the cause of corneal decompensation, associated ophthalmologic factors, occurrence of CME after primary DMEK surgery, incidence of CME after re-DMEK, time interval between surgery and onset of CME, and management and outcomes of CME.

Results: Primary DMEK indications were Fuchs endothelial corneal dystrophy (FECD) in 40 eyes (44.9%), PBK in 30 eyes (33.7%) and herpes simplex virus (HSV) in 10 eyes (11.2%). After the first DMEK surgery, CME occurred in 16 eyes (18%) with a mean interval of 23.4 ± 16.7 weeks. After re-DMEK surgery, CME occurred in 22.5% with a mean interval of 14.2 ± 21.9 weeks. It was a new onset in 13 eyes (65%), recurrent in 6 eyes (30%), and persistent in 1 eye (5%). On multivariate analysis, no significant association was found between the presence of ERM and CME following re-DMEK. Eyes with a history of PPV and prior CME were significantly associated with CME occurrence with odd ratios of 4.9 (95% CI: 1.04-23.1, p = 0.04) and 4.1 (95%CI: 1.2-13.5, p = 0.02) respectively.

Conclusion: CME following re-DMEK occurs in 22.5% of cases, primarily within the first three months post-operatively. The main risk factors include a previous occurrence of CME after the initial DMEK and a history of PPV. However, CME does not seem to negatively impact the final visual outcomes of re-DMEK.