Prognosis
In order to interpret a successful result, the following information is given on Lasik results that differ from the desired value by either half a diopter or a whole diopter. In the correction of short-sightedness (myopia), Lasik has a success rate of approximately 84% with a deviation of 0.5 dopters from the desired visual acuity. If the range is extended to a deviation from a doptre, a successful result is even present in 95% of the cases treated with Lasik.
Lower success rates are achieved in the treatment of farsightedness. A maximum deviation from the desired result is achieved at about 70%, whereas the success rate for visual acuity deviating by one diopter is 91%. The result of Lasik depends both on the conditions of the operation and the instruments used, as well as on the individual conditions of the patient. The post-laserization rate after Lasik is 10-20%.
Alternative methods to Lasik
There are other procedures of refractive surgery which are used to treat the cornea. These include photorefractive keratectomy (PRK), laser-epithelial keratomileusis (Lasek) and epithelial laser in situ keratomileusis (Epi-Lasik). All of these procedures also use a laser to modify the cornea and make use of the principle of so-called surface ablation, which is an ablation of the corneal surface.
The keratectomy used in photorefractive keratectomy means, for example, “cutting out the cornea”. The laser is used to ablate the cornea on the surface, but without cutting the flap typical of Lasik. In Lasek, the uppermost corneal layer, the epithelium, is detached with the help of alcohol, then the underlying tissue is lasered and finally the detached epithelium is placed back on the defect.
In epi-Lasik, too, the epithelium of the cornea is first detached and, after ablation of the cornea, is reattached to its former location. The device used for cutting the cornea is more blunt compared to the Lasik device. In contrast to Lasik, the other mentioned procedures cause considerably more pain after the operation, which gives Lasik an advantage in this respect.
