Cornea Donor Study: The Effect of Donor Age on Penetrating Keratoplasty for Endothelial Disease

The study enrolled 1101 subjects with a corneal disease considered to be at moderate risk for failure (principally Fuchs' dystrophy and pseudophakic corneal edema). A donor cornea meeting the following criteria was assigned to the subject by one of 43 participating eye banks:

• donor age 10 to 75 years
• endothelial cell count 2300 to 3300
• tissue quality very good to excellent
• death to preservation time <12 hrs if body refrigerated or eyes on ice and <8 hrs if not
• death to surgery time <5 days

The cornea surgeon (investigator) and patient were masked to donor age and characteristics of the donor cornea. Preoperative management, surgical technique, and postoperative care, including prescription of medications, were provided according to each investigator's customary routine. The follow-up visit schedule for the initial six months was left to each investigator's discretion and after this time the minimum follow-up visit schedule included a visit between six and 12 months and then one visit every 12 months through five years. The primary study outcome was graft survival at five years. The definition of graft failure, based on the definition used in Collaborative Corneal Transplantation Studies, was a regraft or, in the absence of regraft, a cloudy cornea in which there was loss of central graft clarity sufficient to compromise vision for a minimum of three consecutive months. Follow-up in the initial phase of the study continued for five years unless the patient had a regraft of the study eye.

For the ABO compatibility study, the ABO blood type of both the donor and recipient were determined in order to compare the rate of graft failure for ABO-compatible cases with the rate for ABO-incompatible cases.

For the Specular Microscopy Ancillary Study, endothelial cell counts were determined from specular images by a central reading center, and the relationship of the cell counts to donor age were assessed. In the initial phase of the study, specular images were obtained at 6 months, and then annually through five years post-transplant.