LASIK (Laser-Assisted In Situ Keratomileusis) is one of the surgeries that treat refractive errors of the eye. LASIK is a variant of excimer laser photorefractive keretectomy (PRK). Although LASIK is a newer procedure, it has become an increasingly common surgery which many people opt for to treat refractive errors.

LASIK improves the uncorrected vision for distance - one's visual capacity while not wearing corrective lenses - in most patients who have the procedure. Nearly all patients can expect to achieve 20/40 vision, which most states consider good enough to drive without having to wear contacts or glasses, and many can expect to achieve 20/20 vision or better. However, there are no guarantees that you will have perfect vision. People who are most satisfied with the results of laser correction clearly understand the potential risks and complications and possess realistic expectations of what their vision will be like after surgery.

LASIK combines the precision of the excimer laser that is used in PRK surgeries with the flap technique that characterizes ALK. Firstly, removal of the corneal surface tissue is not necessary and therefore, postoperative pain is substantially reduced compared to PRK. Secondly, postoperative visual acuity is restored within a few days rather than weeks. Finally, there is less corneal scarring in the long-term and greater stability of the correction.