PURPOSE: To report on clinical corneal topography, histopathologic analysis, and fine structure findings in failed grafts after penetrating keratoplasty (PK) for keratoconus (KC).
DESIGN: Retrospective, consecutive, interventional case series with histologic and clinical correlation.
PARTICIPANTS: Twelve corneal buttons were obtained from consecutive patients undergoing repeated PK 10 to 28 years after the initial PK for KC. The indication for regrafting was endothelial deficiency in seven cases, irreversible immune graft rejection in two cases, and corneal ectasia in three cases.
METHODS: Removed corneal buttons were examined by light and transmission electron microscopy. A potential correlation between the clinical and videokeratoscopic findings and the microscopic structural observations was analyzed.
RESULTS: Preoperative simulated keratometry measured by TMS-1 (Tomey, New York, NY) or EyeSys CAS (EyeSys Technology, Houston, TX) ranged from 49.8 to 66.1 diopters. A pattern compatible with KC characteristics was observed in all cases. Fine structure analysis revealed Bowman's layer disruption or folds and stromal deposits in all corneal buttons. However, central corneal thinning was not present in any of the removed buttons.
CONCLUSIONS: Structure changes compatible with the diagnosis of KC were observed in all donor buttons many years after PK on KC recipients. Recurrence of the KC characteristics may result from graft repopulation by recipients' keratocytes, aging of the grafted tissue, or both.