The excimer laser reshapes the cornea, reducing nearsightedness, farsightedness and astigmatism and has been used to correct nearsightedness since 1989. The FDA approved the excimer laser for use in the United States in 1995. A light is presented for fixation and in less than 60 seconds the light pulses to remove a microscopic amount of tissue, flattening the cornea, allowing images to focus on the retina. After PRK, vision is blurred for three to five days because the epithelium was removed. A bandage contact lens is placed on the eye to minimize discomfort and aid in healing.
Some patients experience the sensation of sand in the eye and sensitivity to light.
Final visual results are apparent anywhere from a week to a few months since the corneal heals differently for everyone. An instrument called a microkeratome allows the doctor to fold back a thin layer of the cornea and then the excimer laser gently removes the proper amount of tissue. The thin layer is folded back to the original position and bonds within minutes. The eye is not patched after the procedure. There is little or no pain after the procedure since the epithelium is left intact.