Techniques for de-epithelialization for surface ablation. A, Scraping with a blade. B, 20% dilution of absolute ethanol in an optical zone marker well. C, Rotary brush debridement. D, “Laser scrape,” in which a broad-beam laser exposes the entire treatment zone to ablation pulses; these pulses remove most of the epithelium that is fluorescing brightly, after which the basal epithelial layer is removed by scraping with a blade. E, Epi-LASIK with a mechanical microkeratome (the epithelial flap may be removed or retained).