Different Types of Corrective Eye Surgery

When light enters the eye, it passes through the lens and the cornea before falling onto the retina to produce a clear image. If there are irregularities in the shape of the cornea (refractive error), then the light does not fall on the retina correctly. Corrective eye surgery is performed to repair the abnormalities in the cornea that cause a refractive error. The types of eye problems associated with a refractive error include farsightedness, nearsightedness and astigmatism (blurred vision). People with these vision problems can choose from a number of corrective eye surgery options. Most of these procedures are outpatient and take no longer than 1 hour.

LASIK

• Laser in-situ keratomileusis (LASIK) surgery is reserved for the treatment of nearsightedness. Nearsightedness occurs when the cornea is too steep. In LASIK surgery, the surgeon creates a flap on the top of the cornea (with a blade or laser) to expose the tissue beneath. He then makes structural changes to the cornea (to reduce steepness) using an excimer laser. After the procedure, the flap is folded back into position and allowed to heal by itself. Recovery time for LASIK ranges from a few days to a week. LASIK surgery is by far the most popular corrective eye surgery for myopia.

Photorefractive Keratectomy (PRK)

• Photorefractive keratectomy (PRK) surgery is similar to LASIK and is used to treat mild to moderate myopia (nearsightedness). It makes use of the same computer-guided excimer laser used in LASIK to make structural changes to the surface of the cornea. According to the U.S. Food and Drug Administration, PRK has a success rate of 95 percent. The recovery time for PRK can extend to several weeks. For this reason, many people prefer LASIK to PRK.

Radial Keratotomy (RK)

• Radial keratotomy (RK) surgery was first introduced in the United States in 1978. It is another surgical option for people who suffer from a mild case of nearsightedness. A surgeon uses a diamond scalpel to create tiny spoke-shaped incisions in the cornea, which causes a flattening of the cornea's optical zone (center). The major drawback of RK surgery is the protracted recovery time, which can extend to several weeks.

Automated Lamellar Keratoplasty (ALK)

• Automated lamellar keratoplasty (ALK) is reserved generally for the treatment of farsightedness or some extreme cases of nearsightedness. Farsightedness occurs when the surface of the cornea is too flat. ALK for farsightedness involves the surgeon creating a flap by making a deep incision into the cornea. The pressure inside the eye causes the cornea to expand and thus the previously flat cornea becomes properly bulged. To treat nearsightedness, the surgeon creates a flap in the cornea and then removes a thin slice of tissue to reduce the steepness of the cornea.

Astigmatic Keratotomy (AK)

• Astigmatic keratotomy (AK) is used to treat astigmatism (blurred vision), which is caused by abnormalities in the shape of the cornea. AK is similar to RK in that it also involves making microscopic incisions in the cornea. AK differs from RK in that the incisions are of a curved pattern.