Boulder Eye Surgeons

Donald Keller MD, Brian Nichols MD PhD and Kevin Cuevas MD


How does LASIK or PRK work? How are they different?
In both procedures, a specialized laser (excimer laser) is used to reshape the front surface of the cornea to change where the eye is focused when it is in a relaxed state (i.e. not squinting or trying to focus up close). This puts the image onto the retina, and you see a sharp image.


Laser in-situ keratomileusis (LASIK): In LASIK, a specialized laser (femtosecond laser) creates a thin flap, which is lifted out of the way and the underlying tissue (stroma) is reshaped by the laser. When the treatment is complete, the flap is carefully laid back down and allowed to heal into place. This small flap acts as a bandage of sorts and protects the newly treated area and helps reduce discomfort. The initial healing process is often very quick – within 24-48 hours — and allows for fast visual recovery and reduced pain.

Photorefractive Keratectomy (PRK): Unlike LASIK, this is a flap-free technique. In order to reach the stroma, where the excimer laser performs the treatment, a special solution of alcohol is used to remove the outer layer completely. This layer grows back in three to five days, and you will wear a “bandage contact lens” for a few days to shield the exposed area, keep it safe and reduce pain.