Descemets Membrane Endothelial Keratoplasty.  Similar to DSEK, DMEK also involves the removal of the diseased endothelial cells and the placement of a donor graft including healthy endothelial cells. In DMEK, however, the graft is thinner which may allow improved visual outcomes and reduction in the chance of rejection. Once the healthy cells are implanted, a gas bubble will hold the graft in place. The patient must lie on their back looking up at the celling for 48-72 hours following the surgery in order to allow the graft to heal in position.