The so-called LASIK surgery, or “laser excimer in situ keratomileusis”, is performed on the human cornea. Ideally, the eye focuses the incident light onto the retina and we can see clearly. However, in myopia, the focus is before the retina. By wearing myopia glasses, concave lenses can divert the light and move the focus back to the retina, thus correcting myopia. Surgical correction of myopia is achieved by changing the refractive structure of the eye to adjust the focus of light. The cornea provides about 2/3 of the refractive power of the entire eye, and it is by changing the corneal refractive index that LASIK surgery is able to correct myopia. The procedure is not complicated to say the least: first, a flap with a tip about 100-180 microns thick is cut on the surface of the central area of the cornea and flipped up, exposing the corneal stroma under the flap, then a high-energy excimer pulsed laser is used to cauterize a certain thickness of the corneal stroma, and finally the flap is capped back to its original position without any need for suturing. The corneal epithelial cells will be completely repaired within 24-48 hours. Immediately afterward their basement membrane, the anterior elastic lamina, will also gradually repair.