Even with a fairly high success rate, some problems can develop, such as rejection of the new cornea. Warning signs of rejection are decreased vision, increased redness of the eye, increased pain, and increased sensitivity to light. If any of these last for more than six hours, you should immediately call your ophthalmologist. Rejection can be successfully treated if medication is administered at the first sign of symptoms.
A study supported by the National Eye Institute (NEI) suggests that matching the blood type, but not the tissue type, of the recipient with that of the cornea donor may improve the success rate of corneal transplants in people at high risk for graft failure. Approximately 20 percent of corneal transplant patients?between 6,000 and 8,000 a year-reject their donor corneas. A study found that high-risk patients may reduce the likelihood of corneal rejection if their blood types match those of the cornea donors. The study also concluded that intensive steroid treatment after transplant surgery improves the chances of a successful transplant.This answer is based on source information from National Eye Institute.