Lasik, which stands for "laser-assisted in situ keratomileusis," is a kind of laser treatment or refractive laser eye surgery for individuals with a high degree of myopia, that is greater than 5 diopters. It is also known by alternate names like "Laser Vision Correction". The theory of Lasik surgery was developed by Dr. Jose Barraquer, who in 1970 introduced the first microkeratome, which is the instrument used for carrying out Lasik surgery. This procedure is called "keratomileusis", in which thin corneal flaps are cut and the corneal shape is altered. The first Lasik was performed in the USA in 1991.

Lasik is similar to PRK (photorefractive keratectomy) except that Lasik is a much more complex procedure, since it is executed for all degrees of shortsightedness.

Lasik is a beneficial procedure for a person, since it can help him reduce the need of glasses or contact lenses by lastingly changing the shape of his cornea. Sometimes, the images that we see appear blurry. This blurriness is called "refractive error", the cause of which is an imperfectly shaped eyeball or cornea. Lasik basically uses an Excimer Laser, which is an ultraviolet laser, to accurately remove the corneal tissue in order to correct the shape to achieve better focusing.

Today, Lasik surgery has reached the point where some special vision correction results can be achieved which would be otherwise impossible with the conventional Lasik surgery. This surgery, known as "Custom Lasik surgery", makes use of 3-dimensional measurements of the way our eyes process images to direct the laser in shaping the front part of our eye. This surgery, also known as the "Wavefront Technology", is better than the traditional Lasik surgery, as there is a better chance of achieving 20/20 vision.