Purpose: The aim of this study was to describe the challenges in Descemet membrane endothelial keratoplasty (DMEK) donor preparations and provide new strategies to achieve success.
Methods: A series of 263 consecutive DMEK preparation attempts by a novice surgeon during a corneal fellowship are described. In all cases, the Descemet membrane (DM) and the endothelium were peeled off from the donor cornea while it was submerged in corneal storage medium.
Results: The success rate of preparing DMEK tissue was 99%. Three donor preparations of 263 (1.1%) could not be completed successfully because spots of strong adherence between the DM and the stroma caused multiple horseshoe-shaped tears (HST) to form in the DM. Lamellar splitting of the DM ("partial thickness HST") preceded the formation of most HSTs. At least 1 HST occurred in 13% of donor preparations. In donor pairs (right and left corneas of 1 individual donor), if 1 cornea had any HSTs, there was a 60% chance that the contralateral cornea would have at least 1 HST. If 1 cornea had multiple HSTs, there was an 80% chance that the contralateral cornea would have at least 1 HST. Noting this trend, 3 donor corneas were returned to the eye bank unopened for other uses after their mates had multiple HSTs.
Conclusions: With appropriate techniques, DMEK donor preparation can be highly successful, even for a novice surgeon. When a donor develops multiple HSTs, we recommend not using the mate for DMEK because of a higher risk of encountering a preparation difficulty.