Corneal refractive surgery, commonly known as LASIK (an acronym for Laser-Assisted in Situ Keratomileusis), is a type of eye surgery that is used to correct vision problems such as nearsightedness, farsightedness, and astigmatism. It involves reshaping the cornea, which is the clear outer layer of the eye, using a laser. The procedure is relatively quick and painless, and most patients experience improved vision within a few days.