Refractive Surgery
The cornea is the foremost part of the eye, the outermost covering, is transparent, and has an optical function.
In corneal surgery, refractive surgery is an important part of it. This surgery removes refractive errors (myopia, farsightedness and astigmatism) in order to achieve optimal vision without the dependence on glasses or contact lenses.
Laser eye surgery is a quick, painless and highly personalized technique that is always performed with topical anesthesia with drops. LASIK is the technique used by the excimer laser, and involves removing diopters from the eye by shaping the middle layer of the cornea so that objects focus on the appropriate area of the retina.

Myopia
The myopia is a refractive defect of the eye that causes light rays coming from distant objects converge before reaching the retina, the eye is more nearsighted long (for the back) that an eye sa (emmetrop); in this way myopia causes poor vision from afar and usually stabilizes around the age of 20.
Hyperopia
In hyperopia, unlike myopia, the eyeball is shorter than usual; this causes the objects to be focused behind the retina. All children at birth are farsighted, but with growth farsightedness decreases to disappear in most cases.
Astigmatism
The astigmatism is a refraction defect in which the cornea is more curved in one of its axes. In order to have good vision, the cornea should be transparent, smooth, and with a uniform curvature in all directions. Astigmatism usually causes blurred or distorted vision.