Descemet membrane endothelial keratoplasty (DMEK) for graft failure after penetrating keratoplasty and in vascularized high-risk eyes

Background Descemet membrane endothelial keratoplasty (DMEK) is considered the gold standard for the treatment of corneal endothelial dysfunction and generally leads to good postoperative results. Recently, studies have also analyzed the outcome of DMEK in so-called high-risk eyes. Material and methods The relevant literature and own data on DMEK for graft failure after penetrating keratoplasty and in vascularized high-risk eyes are presented and discussed. Results A DMEK for the treatment of transplant failure after penetrating keratoplasty can be considered for eyes without stromal scars and without high astigmatism. A retrospective analysis of 52 patients with failed penetrating grafts showed that DMEK leads to a significant increase in visual acuity, albeit to a lesser extent than after primary DMEK. Rejection and transplant failure rates seem to be similar those seen after penetrating re-keratoplasty and are thus higher than after primary DMEK. A DMEK might also be a feasible option for eyes with corneal neovascularization and stromal edema without stromal scars. A retrospective analysis of 24 eyes with at least 2 vascularized corneal quadrants demonstrated that DMEK leads to a significant improvement in visual acuity and regression of corneal neovascularization. The rejection rate in this cohort was 4.2% and is therefore slightly higher than after low-risk DMEK in eyes without corneal neovascularization but still much better compared to penetrating keratoplasty. Conclusion Indications for DMEK are expanding and it can be a therapeutic option for transplant failure after penetrating keratoplasty with acceptable outcomes. Furthermore, DMEK seems to be a good option for the treatment of endothelial dysfunction in vascularized high-risk eyes without stromal scars.