 Penetrating keratoplasty is one of the most commonly performed transplantation surgeries. Graft rejection is a major complication. HLA compatibility has already been demonstrated an effective prophylaxis in several retrospective investigations. The purpose of the investigators randomized clinical trial is to demonstrate superiority of HLA matching in comparison to random graft assignment with respect to the endpoint time to first endothelial graft rejection in penetrating keratoplasty. The investigators will perform DNA-based allele resolution typing. 