Risk Factors for Cystoid Macular Edema After Descemet Membrane Endothelial Keratoplasty

PURPOSE: To investigate factors associated with cystoid macular edema (CME) after Descemet membrane endothelial keratoplasty (DMEK) in Asian eyes. METHODS: In this retrospective, interventional, consecutive case series, 77 eyes of 65 patients who underwent DMEK were evaluated; in 53 eyes, cataract surgery was performed 1 month before DMEK (staged DMEK), and 24 eyes underwent DMEK alone (simple DMEK). Central retinal thickness, incidence of CME, postoperative best-corrected visual acuity, central corneal thickness, and corneal endothelial cell density were assessed at 1, 3, and 6 months after surgery. Multiple regression analysis and stepwise variable selection were performed for parameters such as type of surgery, iris damage scores, age, sex, axial length, preoperative visual acuity, rebubbling, air volume in the anterior chamber on postoperative day 1, history of diabetes, and endothelial cell density loss rates at 6 months after surgery. RESULTS: CME occurred in 12 (15.6%) of 77 eyes. There was no significant difference in best-corrected visual acuity between eyes with and without CME (P = 0.27). Multivariable analysis revealed that the difference in iris damage scores between before and after DMEK (P < 0.001), air volume in the anterior chamber (P = 0.012), simple DMEK (P = 0.020), and rebubbling (P = 0.036) were significantly associated with CME. Stepwise variable selection indicated that iris damage (P < 0.001) was the most important risk factor for CME. CONCLUSIONS: Iris damage due to DMEK might be a possible risk and aggravating factor for the development of CME after DMEK. Surgeons should attempt to minimize damage to the iris.