Long-term changes in corneal endothelial morphology following wounding in the cat

The cat eye was used to determine the long-term morphological changes in the corneal endothelium that occur after central endothelial wounding. Central corneal thickness was measured using ultrasonic pachometry. Specular microscopy and computer-assisted morphometry was used to quantify central and peripheral endothelial cell density (ECD), coefficient of variation (COV) and the mean and standard deviation of the shape factor (S) over an 18-month period. After endothelial wounding, there was a rapid increase in corneal thickness followed by a rapid nonlinear decline, reaching presurgical levels 35 days after wounding. Central cell density had decreased by 25% at 4 weeks after wounding. During the following 18 months, endothelial cell density in the central cornea increased slightly. The coefficient of variation had increased by 60% at 4 weeks after wounding. This recovered slowly and had reached control levels by 18 months. The mean shape factor was higher in the wounded eye throughout the 18 months, whereas the standard deviation of the shape factor recovered after 12 months. Peripheral ECD had decreased significantly by 12 months after wounding, while COV and the mean shape factor was not significantly affected. The standard deviation of the shape factor had also increased significantly in the peripheral cornea after 18 months. These findings suggest that following endothelial wounding in the cat, changes in endothelial morphology occur over the entire cornea. Endothelial cell density and the shape factor have not recovered to control values, even 18 months after wounding. This pattern of endothelial repair supports the mechanisms of cell movement suggested by Honda et al and confirm the similarities in endothelial response between cat and man.