LASIK and PRK are the two main techniques used. Both use the laser technique to remodel the stroma of the cornea (outer transparent layer) and change its curvature so that images are formed on the retina (fundus) of the eye.
LASIK: Laser Intrastromal keratomileusis
The surgeon creates a flap (thin layer) on the cornea like a cover and then pulls it back. The flap is created with a special precision instrument called a microkeratome. The laser ablates beneath the surface and above the stroma of the cornea, by reshaping it without causing injury. The flap is replaced and the surgery in over. The surgery is performed using anesthetic eye drops and is entirely painless. The laser application lasts less than 1 minute and the whole process does not last for more than 5 minutes for each eye. This is no need for protective lens or stitches and there is no post operative pain or discomfort. The patient leaves the operating room without bandages and without needing glasses.
PRK: Photo-refractive keratectomy
The technique does not provide for the creation of a flap. The corneal epithelium (surface layer) is removed with diluted alcohol and the laser is applied to the surface. Lastly, a therapeutic contact lens is placed and this remains until the healing of the epithelium is complete (a few days). Today, most surgeons use a special drug that minimizes the likelihood of postoperative opacity (haze) and pain that often exists with this technique use, prior to placing the lens. The surgery is performed using anesthetic eye drops and is entirely painless. The laser application lasts less than 1 minute and the whole process does not last for more than 5 minutes for each eye. With this technique also, the patient leaves the operating room without bandages and without needing glasses.
Newer LASIK techniques
The newer techniques concern the creation of the flap, which is not created using a mechanical microkeratome instrument, but with another special laser called the femtosecond laser. This laser that creates small air bubbles under the surface of the cornea at a depth chosen by the surgeon, the flap is then lifted and the excimer laser is used. This technique is also known as all-laser lasik.