Descemet Membrane Endothelial Keratoplasty after failed penetrating keratoplasty – Case series and review of the literature

Background This study aims to evaluate visual outcome, central corneal thickness, and re-bubbling rate in a cohort with undersized secondary Descemet Membrane Endothelial Keratoplasty (DMEK) due to endothelial graft decompensation following primary penetrating keratoplasty (PK). Methods All patients who received a secondary DMEK (n = 16) or triple DMEK (n = 2) after failed primary PK between November 2020 and June 2022 were retrospectively evaluated. Analyzed parameters were corrected distance visual acuity (CDVA), central corneal thickness (CCT), re-bubbling rate and graft survival. Results 18 eyes of 18 patients were included. All patients underwent a DMEK with undersized graft after failed PK(s). Mean time between the last PK and DMEK was 102 ± 82 weeks. CDVA increased significantly from 1.12 ± 0.60 logMAR preoperatively to 0.64 ± 0.49 logMAR 6 weeks postoperatively (p = 0.013). Mean CCT decreased significantly from 807 ± 224 µm before to 573 ± 151 µm 6 weeks after DMEK (p = 0.003). Re-bubbling was necessary in eight eyes (44.4%) after a median time of 7 days. The 12-month Kaplan Meier survival was 66.7%. Conclusion In case of endothelial graft decompensation without stromal scars after primary PK, a (triple) DMEK can be performed for patients who had satisfying CDVA before the endothelial decompensation. Prior to DMEK indication, an AS-OCT should be routinely performed to circularly search for posterior steps at the PK graft margin, as well as shortly after DMEK to exclude a detachment of the endothelial graft. All patients should be informed about a higher re-bubbling rate in comparison to primary DMEK.