Donor tissue characteristics in preparation of DMEK grafts

The aim of the study was to determine donor tissue characteristics that contribute to longer peeling times or tissue tears during peeling during Descemet membrane endothelial keratoplasty (DMEK) graft preparation.

The data analyzed included donor age, gender, postmortem tissue age, contralateral eye data, peel time, and peel complications of 116 consecutive DMEK donor tissues, which were prepared by a single surgeon with the submerged cornea using backgrounds away (SCUBA) technique.

The mean peel time was 10.1 ± 3.3 minutes (range, 6-24 minutes). Tears were noted in 7 cases (6%) and occurred more commonly with longer peel times. Three of the torn grafts had either peripheral tears or small, noncentral buttonholes or horseshoe tears and were successfully transplanted, for a transplant rate of 97%. However, the host stroma in these cases took longer to clear postoperatively. The donor gender and postmortem day of peeling did not have any statistical significance for the peeling time or tear rate (P > 0.05). Interestingly, tissue from donors older than 65 years had slightly faster peel times, but this difference did not reach statistical significance (≤65 = 11.0 ± 4 minutes; >65 = 9.3 ± 3.1 minutes; P = 0.07) and had equal rates of graft tears (6%). Most importantly, however, there was a strong correlation between peel times for the 2 eyes from the same donor (r = 0.78, P = 0.03), and the risk of a tear during peeling in the second eye was much greater if the first graft also had a tear during preparation (odds ratio = 7.2, P = 0.02).

Exclusion of the contralateral eye tissue when there was difficulty in graft peeling for the first eye may prove to be a unique quality of DMEK donor tissue.