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PURPOSE: We evaluated four femtosecond laser intrastromal cutting procedures: creation of a corneal flap for laser in situ keratomileusis (LASIK), tunnel and entry cut for intracorneal ring, corneal flap and removable lens for keratomileusis, and intrastromal ablation for myopia and hyperopia. METHODS: A clinical trial using a femtosecond surgical laser (IntraLase Corporation) was performed in partially sighted eyes. Femto-LASIK treatment was performed on 46 eyes up to -14.00 D; 16 patients received intracorneal ring segments (Femto-ICRS); 5 patients each with one highly myopic eye had femtosecond laser keratomileusis (FLK), and 13 patients each with one myopic or hyperopic eye had intrastromal ablation (ISPRK). In Femto-LASIK, excimer laser ablation was done under the flap. In Femto-ICRS, ring segments were introduced into the laser-created channels. In femtosecond laser keratomileusis, a lens-shaped block of stroma was removed manually from under the flap. RESULTS: No difference was found between the results obtained with Femto-LASIK and a standard microkeratome. No refractive effects occurred when the created flap was not elevated. In cases of Femto-ICRS and conventional ICRS produced the same refractive results. With Femto-ICRS, no intraoperative complications occurred and visual acuity improved immediately after surgery. In femtosecond laser keratomileusis, high myopia was corrected without using excimer laser ablation; centralization of the treatment area was excellent. In intrastromal ablation, 1 to 2 hours after surgery the corneas were highly transparent; refractive results were stable. CONCLUSIONS: Femtosecond lasers can produce precise intrastromal cutting, offering significant safety and other advantages (no razor blades, corneal trauma, partial resections, or sterilization issues) over current techniques. [J Refract Surg 2003;19:94-103]

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We have performed excimer laser photorefractive keratectomy operations with a Schwind Keratom 2F to correct nearsightedness. 613 eyes of 348 patients were treated by this ablation method. We have selected 3 18 case, where the follow-up was at least 6 months long. The intended corrections were in the range of -1 .75 D to -9.0 D for myopia. The optical zones were 5.5 and 6.0 mm. We present various results ofthe treatments: change ofvisual acuity, residual spherical refractive error, time evaluation of healing, and ablation speed. We have found that the ablation speed of human cornea is depends on the age of patients. An equation is also presented to describe the relation between age and ablation speed.