Refractive eye surgery, also known as LASIK (Laser-Assisted in Situ Keratomileusis), is a surgical procedure used to correct vision problems such as nearsightedness, farsightedness, and astigmatism. It involves reshaping the cornea with a laser to improve the way light is focused on the retina. The procedure is relatively quick and painless, and most patients experience improved vision within 24 hours of the surgery.