Regression and epithelial hyperplasia after myopic photorefractive keratectomy in a human cornea

We present the histology of a cornea of a woman who had excimer laser photo refractive keratectomy (PRK) for myopia 6 months before she died in an acci dent. Preoperative spherical refraction was -6.00 diopters (D) with an asti gmatism of -0.50 D. Six months postoperatively, refraction was -4.50 D. Sli ght corneal haze was noted at 1 and 3 months. The corneal histology showed marked epithelial hyperplasia in the center of the ablation zone without su bepithelial deposition of newly synthesized collagen, proteoglycans, or bot h. The epithelial thickness was 38 mu m in the untreated area and 93 mu m i n the center of the ablation. In conclusion, postoperative epithelial hyper plasia was responsible for regression after PRK in this eye. (C) 1999 ASCRS and ESCRS.