The rejection is due to the immune recognition mechanisms detect that the transplanted corneal graft does not belong to the host tissues, of the person to whom the transplant has been performed. They do not recognize it as their own and initiate a defense reaction aimed at eliminating that tissue, as if it were an invading microorganism. We know that in the cornea, The layer with the greatest immunological load is the endothelium.. For this reason we try to preserve the patient's endothelium for avoid rejection. In previous lamellar keratoplasties, we always try to maintain the patient's endothelium, and current techniques allow all layers to be dissected, down to the barely 20-micron endothelium, and replace everything else. With this surgery, we managed to reduce the rejection of the transplant and that the grafts exceed 10-15 years of survival, compared to 5-10 before.