[Interim results from the prospective "Erlanger Non-high-risk Penetrating Keratoplasty Study" in 207 patients]

Immunologic graft rejection targeted against corneal endothelium is the most frequent cause for graft failure after corneal transplantation. The purpose of this prospective study was to assess the frequency, early symptoms, prophylaxis and therapy monitoring of corneal graft rejection following non-high-risk penetrating keratoplasty (PK).

From February 1997 to May 1999, 237 patients undergoing non-high-risk PK have been enrolled in this prospective study. We evaluated 207 patients (103 female, 113 right eyes, recipient age 54 +/- 20 years, donor age 59 +/- 17 years). In 2 randomized treatment studies we compared the efficacy of postoperative short-term (ST = 6 months) versus long-term (LT = 12 months) topical steroid therapy on the incidence of graft rejection and the effect of high- versus low-dose systemic steroid therapy on the prognosis after a graft rejection. Follow-up examinations included, laser-tyndallometry, corneal topography analysis, endothelial cell count and pachymetry.

The main indications for PK were keratoconus (n = 93), endothelial dystrophy Fuchs (n = 52) and bullous keratopathy (n = 35). In 151 (73%) patients, non mechanical trephination with the 193 nm Excimer laser was performed. Up to now, 78 patients were randomized into two groups comparing the postoperative therapy with topical steroids. During follow-up (median: ST: 13.5 months; LT: 12.5 months, maximum 25.3 months) episodes of endothelial graft rejection (3 chronic focal, 8 acute diffuse) showed 11 eyes of 11 patients. Five patients each had short-term and long-term topical steroid treatment. In 1 patient the graft rejection occurred before randomization at 6 months. Six patients with graft rejection episodes underwent a PK only (54% of graft rejections, 4.4% of all patients). In the remaining 5 patients, PK was combined with a lens surgery (46% of graft rejections, 6.9% of all patients). Ten of 11 corneal grafts regained their full function under treatment with systemic and local steroids.

The frequency of episodes of graft rejection in our study was lower than usually reported in the literature. A good compliance of patients appears to be a major factor for improved prognosis of the graft after PK and in case of graft rejection. Until now no significant differences between short-term or long-term postoperative topical steroid therapy could be detected regarding the incidence of corneal graft rejection.