Safety profile of Intraoperative Corneal Debridement in Descemet Membrane Endothelial Keratoplasty (DMEK) – A Retrospective Comparative Study

Purpose : To investigate the influence of intraoperative corneal debridement on postoperative outcomes in Descemet Membrane Endothelial Keratoplasty (DMEK). Methods : This retrospective comparative study analyzed 3,168 eyes that underwent DMEK between 2012 and 2024. Intraoperative corneal debridement was performed in 215 eyes (6.8%) to improve visualization during the procedure. Survival time analyses with Kaplan-Meier curves and log-rank test and multifactorial Cox regression were conducted to assess the impact of corneal debridement on postoperative visual acuity, endothelial cell density, graft survival, and perioperative complications. Results : Bivariate survival analyses suggested that intraoperative corneal debridement during DMEK may be associated with worse postoperative outcomes in terms of visual acuity, endothelial cell density, graft survival, and perioperative complications. Using the log-rank test significant differences were observed in endothelial cell density, postoperative regrafting, and visual acuity (p < 0.005), while the need for rebubbling was not statistically significant (p = 0.5). However, multifactorial Cox regression analysis, controlling for potential confounding factors, revealed that the difference in hazard ratios between the debridement and no debridement groups was not statistically significant (HR=0.74, 95% CI: 0.49-1.11, p=0.141). Patients with Fuchs' endothelial dystrophy had a significantly lower risk of graft failure compared to other indications (HR 0.41, p<0.001). Conclusions : This study supports the safety of intraoperative corneal debridement in DMEK, demonstrating that it does not significantly impact long-term graft survival or visual outcomes when controlling for potential confounders. The apparent disadvantages observed in the debridement group during the bivariate analysis are likely explained by confounding due to more severe initial conditions. Surgeons can consider this technique as a viable option to improve visualization and facilitate graft positioning in challenging cases without compromising the overall success of the procedure.