Surgical alternatives to penetrating keratoplasty II: endothelial keratoplasty

Penetrating keratoplasty (PK) became the standard of care for optical and tectonic rehabilitation of corneal blindness and visual impairment in the second half of the twentieth century. Posterior corneal disorders or endotheliopathies are the reason for one-third to one-half of all corneal transplants today in the US. Any procedure that replaces the endothelium ideally should accomplish the following results: (1) a smooth surface topography without significant change in astigmatism, (2) a highly predictable corneal power, (3) a healthy donor endothelium that resolves all edema, (4) a tectonically stable globe, safe from injury and infection, and (5) an optically pure cornea. Although PK consistently can achieve results 3 and 5 above, the other goals of stable topography, predictable corneal power and tectonic stability, have remained elusive despite our best efforts at ingenious suturing and trephination techniques. Endothelial keratoplasty (EK) is a new surgical procedure designed to replace diseased corneal endothelium with healthy donor endothelium through either a lamellar corneal flap approach or through limbal scleral incision, leaving the surface of the recipient cornea untouched by surface corneal sutures. This manuscript evaluates the impact and future of EK in ophthalmology.