Both procedures use the excimer laser to reshape the cornea and correct nearsightedness, farsightedness, and astigmatism. The difference is that, with ASA, the epithelial layer of your cornea is gently removed before using the excimer laser and a bandage contact lens is placed on the eye for comfort while your cornea grows back over the treated area. In comparison, an additional laser called a femtosecond laser is used during LASIK to create a thin, protective corneal flap before using the excimer laser and then the flap is replaced, eliminating the need for a bandage contact lens. The long-term results of both procedures are the same but visual recovery with LASIK is usually faster, with less discomfort.