To examine the morphological characteristics of the transplanted cornea in patients who received penetrating keratoplasty at least 10 years previously prior.

Each layer of the transplanted cornea of patients who received penetrating keratoplasty 10 years previously prior was examined with a confocal microscope (ConfoScan 4.1, Fortune Technology, Italy). Cross-sectioned corneal images of the corneal epithelium, Bowman's layer, stromal layer, Descement's membrane, and endothelium were evaluated and compared with the normal fellow other eye. A total of three eyes from three subjects between the ages of 60 and 70 years were examined. The epithelial cells had large cell borders, and a spindle shaped, and a highly reflective nucleus. The keratocytes were highly reflective and the density of keratocytes was lower than that in the normal cornea. The regenerated nerve fibers were markedly altered, as characterized by increased nerve tortuosity, reduced branching patterns, and shorter nerve lengths. In the endothelial cell layer, a bright nucleus, a reduced ratio of hexagonal cells, and several multinuclear cells were observed.

Even 10 years after penetrating keratoplasty, the entire transplanted cornea is morphologically different from the normal cornea.