Immunosuppression in corneal transplantation.

This paper reviews the clinical post-operative management of keratoplasty and the management of corneal graft rejection. In both instances corticosteroids remain the mainstay of treatment; however, the literature shows a wide range for both route and frequency of administration. Grafts at 'high risk' require more immunosuppressive therapy, but no universally accepted definition of high risk exists and consequently different treatment regimens are difficult to compare and evaluate. Studies using univariate and multivariate survival analysis suggest that recipient corneas can be divided into low, medium and high risk depending on the number of quadrants of vascularisation (avascular, 1-2 quadrants and 3+ quadrants respectively). This wider classification would make the devising and comparing of treatment regimens more consistent. In high-risk cases, corticosteroids alone provide insufficient immunosuppression and systemic cyclosporine is needed in exceptional cases. When managing rejection episodes, a severe reaction involving the endothelium often does not respond to topical steroids alone, and systemic corticosteroids are required. Instead of oral steroids, we now prefer to use an intravenous 'pulse' of 500 mg methylprednisolone: this is at least as effective, avoids prolonged medication, and may confer some long-term benefit.