LASIK (laser in situ keratomileusis) is an outpatient surgical procedure used to treat nearsightedness, farsightedness and astigmatism. With LASIK, an ophthalmologist (Eye M.D.) uses a microsurgical instrument and a laser to reshape the cornea in the front of the eye. This improves the way the eye focuses light rays onto the retina at the back of the eye.

> Watch a video about LASIK (from EyeCare America)

It is important that anyone considering LASIK have realistic expectations. LASIK allows people to perform most of their everyday tasks without corrective lenses. However, people looking for perfect vision without glasses or contacts run the risk of being disappointed.

More than 90 percent of people who have LASIK achieve somewhere between 20/20 and 20/40 vision without glasses or contact lenses. If 20/20 vision is essential for your job or leisure activities, consider whether 20/40 vision would be good enough for you. You should be comfortable with the possibility that you may need a second surgery or that you might need to wear glasses for certain activities, such as reading or driving at night.

LASIK cannot correct presbyopia, the age-related loss of close-up focusing power.

How It Works

LASIK is performed while the patient reclines under the laser in an outpatient surgical suite. First, the eye is numbed with a few drops of topical anesthetic. An eyelid holder, called a speculum, is placed between the eyelids to keep them open and prevent the patient from blinking.

A suction ring placed on the eye lifts and flattens the cornea, and helps keep the eye from moving. The patient may feel pressure from the eyelid holder and suction ring, similar to a finger pressed firmly on the eyelid. From the time the suction ring is put on the eye until it is removed, vision appears dim or goes black.

Once the cornea is flattened, an automated microsurgical instrument called a microkeratome will move across it. The microkeratome creates a hinged flap of paper-thin corneal tissue. This flap is lifted and folded back. The laser, preprogrammed with measurements customized to the patient's eye, is then centered above the eye.

The patient looks at a special pinpoint light called a fixation light or target light while the laser sculpts the exposed corneal tissue. After the laser has reshaped the cornea, the surgeon places the flap back into position and smoothes the edges. Within two to three minutes, the flap sticks in position.

The patient should plan on going home and taking a nap or just relaxing after the procedure. To help protect the cornea as it heals, the ophthalmologist may place a transparent shield over the eye. The patient may just have to wear a shield at night. The ophthalmologist will provide eyedrops to help the eye to heal and to alleviate dryness.

It may take three to six months for vision to stabilize following LASIK surgery.

Risks

LASIK, like any surgery, has risks and complications that should be carefully considered. Most complications can be treated without any loss of vision. There is a chance, though extremely small, that vision will not be as good after the surgery as before, even with glasses or contacts.

> Questions to ask when considering LASIK

Some people experience temporary side effects after LASIK that usually disappear over time. These side effects may include discomfort or pain, hazy or blurry vision, scratchiness, dryness, glare, halos or starbursts around lights, light sensitivity or small pink or red patches on the white of the eye. In rare situations, these effects may be permanent.

Infection is a small possibility with any surgical procedure, including LASIK. Antibiotics can usually clear up such infections. Rarely, complications during surgery may cause irregularities in the corneal flap, requiring further treatment.

This information is used with permission from the EyeCare America Web site: www.eyecareamerica.org/eyecare/treatment/lasik/index.cfm. Accessed April 9, 2008.