RECOVERY OF CORNEAL INNERVATION FOLLOWING PHOTOREFRACTIVE KERATOABLATION

Objective: To study the morphological recovery of rabbit corneal nerve s for up to 12 months after photorefractive keratoablation. Methods: T he histochemical acetylcholinesterase reaction was used to demonstrate morphological features in rabbit corneal nerves at 1 hour, at 6 weeks , and at 3, 6, or 12 months after photorefractive keratoablation. Resu lts: Photorefractive keratoablation ablated the subepithelial nerve pl exus, leaving sharply cut stromal nerves. Epithelial innervation was a lmost completely restored in 3 months, with innervation proceeding fro m the epithelial nerve plexuses at the wound margins, but the stromal nerves showed abnormal morphological features throughout the study. Ab normally coiled, regenerating axons emerged from the cut stromal nerve s. The first of them were observed to penetrate into the epithelium 3 months postoperatively. The acetylcholinesterase reaction of the epith elial cell membranes was weaker in the wound area, except in the speci mens that were observed at 12 months. Conclusions: Epithelial innervat ion was restored relatively quickly; otherwise, neural recovery was sl ow. The structure and architecture of the stromal nerves was abnormal even in the the specimens that were observed at 12 months. We hypothes ize that corneal nerve damage induced by deep photoablations may corre late with the predictability problems and haze.