THE EFFECT OF 193 NM EXCIMER-LASER RADIATION ON THE HUMAN CORNEAL ENDOTHELIAL-CELL DENSITY

The effect of 193 nm excimer laser radiation on human corneal endothel ial cell density was examined. Fifty-five eyes from 35 patients underw ent photorefractive keratectomy for myopia. Photomicrographs of the en dothelium were taken a short time before the operation and on an avera ge of 7 months postoperatively with a specular microscope. The average endothelial cell densities were preoperatively 3375 +/- 266 cells/mm( 2) (mean +/- SD) and postoperatively 3348 +/- 287 cells/mm(2), corresp onding to a fall of 27 cells/mm(2) (N = 55). This fall in endothelial cell density was not statistically significant. A significant correlat ion between the change in cell density and age of the patient was foun d, with older patients losing more cells (N = 35, 2p < 0.05). The magn ification of the specular microscope was found to change with corneal thickness, The importance of correcting the endothelial cell densities for corneal thickness is discussed.