eye disorders
Corneal Transplantation
Prognosis for Corneal Transplantation
The chance of long-term transplant success is 90% for Keratoconus , traumatic corneal scars, early 80 to 90% for more advanced bullous keratopathy or inactive viral keratitis 50% for active corneal infection 0 to 50% for chemical or radiation injury Use of a rigid corneal lens can result in earlier and better vision for many patients who have had penetrating keratoplasty. Maximum improvement in vision usually occurs after 6 months in DSEK and 2 months in DMEK. 20/20 vision is more common with DMEK than with DSEK. The generally high rate of success of corneal transplantation is attributable to many factors, including the avascularity of the cornea and the fact that the anterior chamber has venous drainage but no lymphatic drainage. These conditions promote low-zone tolerance (an immunologic tolerance that results from constant exposure to low doses of an antigen) and a process termed anterior chamber–associated immune deviation, in which there is active suppression of intraocular lymphocytes and delayed-type hypersensitivity to transplanted intraocular antigens. Another important factor is the effectiveness of the corticosteroids used topically, locally, and systemically to treat graft rejection. 