Influence of Donor Characteristics on Descemet Membrane Endothelial Keratoplasty

Purpose: Penetrating keratoplasty is being replaced by posterior lamellar techniques like Descemet stripping automated endothelial keratoplasty or Descemet membrane endothelial keratoplasty (DMEK) for the surgical treatment of patients with endothelial insufficiency. Although DMEK leads to the best visual results, Descemet stripping automated endothelial keratoplasty is still the standard procedure for many surgeons because it is technically more standardized. Here, we investigated how donor characteristics may influence DMEK surgery. Methods: After in vitro preparation of DMEK grafts (n = 28), we measured the width of the graft roll, which we correlated to various donor characteristics. In 31 DMEK cases, we measured the intra-operative time from implantation to attachment of the graft, which we correlated to the respective donor characteristics and endothelial cell loss. We used Pearson's method and a multifactorial linear model for the statistical assessments. Results: We found a statistically significant correlation between donor age (P < 0.001) and endothelial cell density (P < 0.05), and the width of the DMEK rolls. That is, older donors and grafts with higher endothelial cell densities formed broader graft rolls. Donor age also showed a trend to directly influence the unfolding time that took longer using younger grafts. Furthermore, the relative endothelial cell loss increased with longer unfolding times. Conclusions: We found that donor age and endothelial cell density influence the properties of DMEK grafts, and thereby the duration of the surgical procedure. Increased unfolding times result in higher endothelial cell loss. Therefore, it seems reasonable to accept preferably older donors with high endothelial cell densities for DMEK, which may be particularly true for inexperienced surgeons or complex clinical situations.