Corneal epithelial changes after excimer laser photorefractive keratectomy.

We used the specular microscope to investigate corneal epithelial changes after excimer laser photorefractive keratectomy. Thirteen patients underwent photorefractive keratectomy on one eye to correct myopia. We observed the central corneal epithelium of each eye at postoperative periods from one to 15 months after photorefractive keratectomy. The fellow eye served as a control. In 11 eyes (85%) the central cornea showed normal epithelial patterns. Two eyes had an abnormal epithelial pattern that included elongated epithelial cells. There were no difference in the mean cell area or coefficient of variation of mean cell area between the treated eyes and the control eyes. These results suggest that permanent destruction of Bowman's membrane caused by photorefractive keratectomy does not affect the morphologic characteristics of the most superficial layer of the corneal epithelium in most eyes. However, the presence of abnormal epithelial cell patterns in two patients should be considered a risk factor for this procedure.