Corneal surface after deepithelialization using a sharp and a dull instrument.

Manual removal of the corneal epithelium currently precedes excimer laser photorefractive keratectomy. To assess the smoothness of the corneal surface following this procedure, six paired human eye-bank eyes (12 eyes) were manually deepithelialized using a blunt instrument (Paton spatula) on one eye and a sharp instrument (surgical blade) on the contralateral eye; all deepithelializations were done by the same surgeon. The 12 corneas were then resected and processed in an identical fashion for scanning electron microscopy. The microphotographs obtained showed that among the corneas deepithelialized with the blunt spatula, two had a smooth surface, and four had variable amounts of residual epithelial cells and basement membrane, confirmed by light microscopy. The surface of five corneas deepithelialized with the sharp instrument were slightly rougher than the former, with occasional linear scratches; one cornea retained a small amount of basement membrane. Removal of epithelium appears to be more complete when a sharp instrument is used. These findings may have clinical relevance, since residual epithelium and basement membrane after deepithelialization may influence the depth of ablation subsequently achieved with the excimer laser.