RESUMO
BACKGROUND: The aim of this study was to assess the impact of the ratio between the graft and host corneal size (RGH) on postoperative complications, such as immune reactions, re-bubbling rate and endothelial cell loss (ECL) after Descemet membrane endothelial keratoplasty (DMEK). PATIENTS AND METHODS: Retrospectively, 457 patient eyes were included which had undergone surgery between 2016 and 2019 in the Department of Ophthalmology, Saarland University Medical Center in Homburg/Saar using DMEK or triple DMEK, diagnosed as Fuchs' endothelial dystrophy (nâ¯= 431), pseudophakic bullous keratopathy (nâ¯= 9) and others (nâ¯= 17). The follow-up period extended until the end of 2020. Main outcome measures included immune reaction (IR), re-bubbling rate and the postoperative endothelial cell loss (ECL) at 6 weeks, 6 months and 12 months and whether these measures depended on the RGH. RESULTS: The RGH in this study ranged from 0.35 to 0.62 (0.46⯱ 0.04). There were 33 (7.2%) postoperative IRs (DMEK nâ¯= 25; triple DMEK nâ¯= 8). The average RGH without IR (0.46⯱ 0.04) was significantly (pâ¯= 0.038) smaller than in the group with IR (0.47⯱ 0.05). Re-bubbling was necessary in 159 of 457 (34.8%) patient eyes. The RGH in patient eyes with re-bubbling (0.47⯱ 0.04) was significantly (pâ¯= 0.014) higher than that in eyes without re-bubbling (0.45⯱ 0.04). The mean preoperative endothelial cell count (ECD) was 2603⯱ 251 cells/mm2 (min: 2161, max: 3500 cells/mm2). It was shown that a larger RGH had no positive influence on endothelial cell loss (râ¯= 0.001; pâ¯= 0.974). CONCLUSION: Our results suggest that a larger graft diameter compared to host corneal size is associated with an increased rate of immune reactions and a higher re-bubbling rate after DMEK. Otherwise, a larger RGH had no positive influence on endothelial cell loss after DMEK. Accordingly, the graft size for DMEK should not be unnecessarily large, especially in eyes with Fuchs' endothelial dystrophy.
