Purpose: To determine the causes of primary failure of donor Descemet membrane transplants in Descemet membrane endothelial keratoplasty (DMEK).
Design: Laboratory and clinical study.
Methods: From a larger series of eyes that underwent DMEK for Fuchs endothelial dystrophy or bullous keratopathy, 11 transplanted corneas did not clear within the first week after surgery. During a secondary 'Descemet stripping endothelial keratoplasty' procedure, the first graft was carefully removed and analyzed with light microscopy. For each patient, the surgical video of the initial DMEK procedure was analyzed to determine the cause of transplant failure.
Results: With light microscopy, all but two explanted transplants had a endothelial cell density of 1700 cells/mm2 or higher. Three Descemet grafts may have been positioned upside down and three may have failed due to manipulation. One transplant could not be properly attached onto the recipient posterior stroma because of insufficient air-support in a post-vitrectomy eye. For four eyes, no obvious cause of failure could be determined.
Conclusion: Unexpectedly, graft failure after DMEK may not primarily result from tissue damage during implantation and associated endothelial cell loss. Detached grafts may therefore be managed by early reposition. When the graft is attached after surgery but fails to clear, secondary surgical intervention may be postponed, because these corneas may clear spontaneously after several weeks.