Purpose: The aim of this study was to examine the human corneal endothelium of the transplant donor, wound, and adjacent host to determine the fate of the endothelial cells after penetrating keratoplasty.
Methods: We performed dissecting microscopic overviews and light and scanning electron microscopy on clear corneal transplant specimens obtained 1 month to 47 years after transplantation. The indications for the primary keratoplasty were keratoconus (11), Fuchs endothelial dystrophy (7), bullous keratopathy (6), others (5), and 8 cases without clinical data.
Results: We were able to visualize the wound and perform relative endothelial cell counts in 17 of 37 specimens. The wounds were of 4 shapes: smooth, anterior and/or posterior gaping, and anterior or posterior overriding. Any combination could be seen in the same specimen. Cells migrated from the center of the donor across the donor-host wound toward the host, but in all cases, the cells spread out, enlarged, and were ultimately lost. One case of Fuchs endothelial dystrophy may have had cell migration from the host across the wound to the donor.
Conclusions: We confirmed that donor cells migrate from higher density to lower density across the transplant wound over time. Wound configuration, donor cell health, recipient endothelial health, and probable cell-to-cell contact inhibition are involved in this process.