Morphological Aspect of LASEK. Lasek & Asa History Technique Long-term Results.

The quality of the results of a photoablative refractive surgery procedure is determined by a number of factors. From amongst these, two anatomo-physiological factors play a critical role in influencing firstly the action of the laser beam and secondly, the repair reaction started up by the stromal- epithelial complex, as a response to the wound. These factors reside in the degree of smoothness of the surface on which the laser is applied and in the protective system of the post-photoablation residual stroma. The connecting link between these two aspects is the method used for preparing the stromal bed to be treated, which represents the first stage of the keratorefractive operation with the laser. There are two basic procedures for preparing the stromal bed: the creation of an epithelialstromal flap (LASIK technique) and the corneal disepithelialization (PRK technique). The LASEK technique was proposed with the goal of combining the advantages of both methods and of eliminating the possible risks associated with them at the same time. It provides for the removal of the epithelium, as an integral epithelial flap, to be repositioned on the treated stroma at the end of the laser treatment. With the aim of ascertaining the efficacy of the LASEK method, a large number of pre-clinical and clinical studies have been conducted to evaluate the two critical factors cited at the beginning, i.e. the surface on which the laser is applied and the consequent repair reaction of the stromal-epithelial complex.