Purpose:The incidence of and risk factors for cystoid macular edema (CME) after Descemet membrane endothelial keratoplasty (DMEK) remain uncertain. This study examines the incidence of and risk factors for CME after DMEK.Methods:This retrospective, single-center study included patients with no history of CME who had undergone DMEK. Patients were examined weekly for 1 month after surgery and at 3 and 6 months after surgery. Follow-up examinations included visual acuity (VA) assessment, pachymetry, anterior segment optical coherence tomography, biomicroscopy, intraocular pressure measurement, and fundoscopy. Eyes suspected of having CME (reduced VA and/or abnormal fundoscopic findings) underwent macular optical coherence tomography. Potential risk factors for CME examined included age, axial length, anterior chamber rebubbling, not using a topical nonsteroidal antiinflammatory after surgery, and concurrent DMEK and cataract surgery (triple-DMEK).Results:Eighty eyes (74 subjects) were included. Eleven eyes (13.8%) developed CME within 6 months after undergoing DMEK. Univariate analyses did not identify any significant CME risk factors. Interestingly, the triple-DMEK procedure did not put subjects at risk for developing CME (P = 0.184). Visual prognosis after medical treatment for CME was excellent, and subjects with and without CME had comparable VA at 6 months [CME: logarithm of the minimum angle of resolution (logMAR) VA = 0.3 (first–third quartile: 0.1–1.0), 20/40; no CME: logMAR VA = 0.3 (0.1–0.5), 20/40; P = 0.391].Conclusions:Although CME frequently occurred after DMEK, no CME risk factors were identified. In addition, CME did not significantly affect long-term visual outcomes when it was appropriately treated.