Design and preliminary results of the Erlangen non-high-risk penetrating-keratoplasty study

Purpose The purpose of this prospective study is to examine the non-high-risk penetrating keratoplasty clinically, tyndallometrically and immunological-serologically in order to learn more about the pathogenesis, early symptoms and therapy monitoring of corneal graft rejection. Patients and Methods Since february 1997, patients undergoing non-high-risk-PK have been enrolled in this prospective study. Examinations are done preoperatively and in well-defined postoperative gates (6 weeks, 3 months, 6 months, etc.) and include clinical assessments, corneal topography, laser-tyndallometry, corneal endothelial cell count and corneal pachymetry. Preoperatively as well as at each postoperative examination, 10 mi serum and perioperatively corneoscleral donor tissue are collected and frozen (- 80 degrees C) to allow immunological and serological examinations in case of graft rejection later. A relational data base (MS Access) guarantees complete and homogenous standardized clinical and serological data. We randomised our patients with respect to duration of topical steroid therapy in standard situations (short-time vs, long-time) as well as for systemic steroid therapy (bolus group vs. tapering group) in case of a graft rejection in 2 treatment groups. Results Up to March 1998, 99 patients have been enrolled in this prospective study. Our report includes the first consecutive 55 patients (25 female, 30 male, recipient age 56.9 +/- 19.4 years, donor age 57.0 +/- 19.9 years). Up to now (follow-up 2.5 +/- 2.1,maximum of 7.3 months) we did not observe immunologic graft rejections. In one patient a primary graft failure occurred. Laser tyndallometry showed a reduction of blood-aqueous barrier breakdown from 6 weeks postoperatively (9.3 +/- 5.7 photon counts/msec) to 3 months post operatively (6.8 +/- 3.5 photon counts/msec). Conclusion This prospective randomized clinical and immunological study after non-high-risk-PK is supposed to give more information about pathogenesis, early symptoms and therapy monitoring of graft rejection after elective PK. The concept and design of this study are described. Preliminary data may give significant results in a few years.