Endothelial keratoplasty. See this excerpt which I've posted from this link:
http://www.allan.vu/corneal.jsp
EK (Endothelial Keratoplasty)
In EK, a new method of corneal transplantation, a healthy new endothelium is transplanted on a thin layer of donor corneal tissue which is floated into place and adheres without sutures. The eye wall is left intact. This helps to preserve a normal corneal shape, normal strength and a normal focussing power for the eye.