Morphometric analysis of corneal endothelium following radial keratotomy.

We performed morphometric analysis of the central corneal endothelium on 24 eyes of 19 patients who had had anterior radial keratotomy. The endothelium was analyzed for a variety of parameters, including cell area, perimeter, side lengths, cell shape, and number of sides. Mean, standard deviation, and coefficient of variation were calculated for each parameter. The mean cell density decreased from 2,835 to 2,677 cells/mm2, mean cell perimeter increased from 71.4 micron to 74.3 micron, and mean side length increased from 11.8 micron to 12.3 micron following surgery. The changes in these three parameters were statistically significant (P less than 0.05). The coefficient of variation of cell area (polymegathism) changed from 0.319 to 0.307, the hexagonality changed from 62.5% to 59.6%, and the cell shape changed from 0.872 to 0.867. The changes in these parameters were not statistically different before and after surgery. The group of patients that had no reported microperforations showed only a small decrease of cell density (1.6%), while the group of patients that had microperforations showed a large decrease of cell density (14.3%). The cell perimeter and side lengths showed a similar pattern. The group of corneas with the optical zone diameter less than 3.5 mm showed a decrease in mean cell density from 2,994 to 2,725 cells/mm2, and the cell shape changed from 0.874 to 0.866 following surgery. The changes in these parameters were statistically significant (P less than 0.05) before and after surgery. Among all factors associated with radial keratotomy, microperforation and a small diameter of central optical zone appear to be the two greatest risk factors.