Epi-LASIK: Advanced surface ablation for the treatment of moderate to high myopia and myopic astigmatism

It has been reported that the surface ablation procedures are less invasive in terms of corneal biomechanics as compared to LASIK( Laser- insitu- keratomileusis) It is found that LASIK flap is associated with biomechanical problems wherein the hinge contributes to irregularity and may increase coma. There has been reported postoperative dryness with irregular healing along with loss of stretch effect by cutting collagen and increase in dermatan sulphate proteoglycan, thereby weakening the tensile strength of the cornea. Moreover the use of microkeratome in LASIK may have negative issues in the form of epithelial defect, epithelial ingrowth , persistent ocular dryness, flap related complications like free cap, button hole ,wrinkled flap, etc. Again the most commonly performed surface ablation procedure , Photo Refractive Keratectomy (PRK) has been reported to induce biochemical problem in the corneal tissue leading to apoptosis with irregular collagen formation and slower healing characterized by pain and early poor acuity. Moreover disruption of Bowman membrane and release of cytokines and inflammatory mediators initiates myofibroblast proliferation in PRK leading to development of haze and regression.