Facts for Consumers produced in cooperation with the American Academy of Ophthalmology (AAO).
If you're tired of wearing glasses or contact lenses, you may be considering Lasik eye surgery - one of the newest procedures to correct vision problems. Before you sign up for the surgery, get a clear picture of what you can expect.

The Facts:

• Lasik is surgery to a very delicate part of the eye.

• Hundreds of thousands of people have had Lasik, most very successfully.

• As with any surgery, there are risks and possible complications.

• Lasik may not give you perfect vision. The American Academy of Ophthalmology (AAO) reports that seven out of 10 patients achieve 20/20 vision, but 20/20 does not always mean perfect vision.

• If you have Lasik to correct your distance vision, you'll still need reading glasses around age 45.

• Lasik surgery is too new to know if there are any long-term ill effects beyond five years after surgery.

• Lasik surgery cannot be reversed.

• Most insurance does not cover the surgery.

• You may need additional surgery - called "enhancements" - to get the best possible vision after Lasik.

Understanding Your Eyes

To see clearly, the cornea and the lens must bend - or refract - light rays so they focus on the retina - a layer of light-sensing cells that line the back of the eye. The retina converts the light rays into impulses that are sent to the brain, where they are recognized as images. If the light rays don't focus on the retina, the image you see is blurry. This is called a refractive error. Glasses, contacts and refractive surgery attempt to reduce these errors by making light rays focus on the retina.

Refractive errors are caused by an imperfectly shaped eyeball, cornea or lens, and are of three basic types:

• myopia - nearsightedness; only nearby objects are clear.

• hyperopia - farsightedness; only objects far away are clear.

• astigmatism - images are blurred at a distance and near.
  

There's also presbyopia - "aging eye." The condition usually occurs between ages 40 and 50, and can be corrected with bifocals or reading glasses.
Are You A Good Candidate for Lasik?

Lasik is not for everyone.

• You should be at least 18 years old (21 for some lasers), since the vision of people younger than 18 usually continues to change.

• You should not be pregnant or nursing as these conditions might change the measured refraction of the eye.

• You should not be taking certain prescription drugs, such as Accutane or oral prednisone.

• Your eyes must be healthy and your prescription stable. If you're myopic, you should postpone Lasik until your refraction has stabilized, as myopia may continue to increase in some patients until their mid- to late 20s.

• You should be in good general health. Lasik may not be recommended for patients with diabetes, rheumatoid arthritis, lupus, glaucoma, herpes infections of the eye, or cataracts. You should discuss this with your surgeon.

• Weigh the risks and rewards. If you're happy wearing contacts or glasses, you may want to forego the surgery.

• Understand your expectations from the surgery. Are they realistic?

• Ask your doctor if you're a candidate for monovision - correcting one eye for distance vision and the other eye for near vision. Lasik cannot correct presbyopia so that one eye can see at both distance and near. However, Lasik can be used to correct one eye for distance and the other for near. If you can adjust to this correction, it may eliminate or reduce your need for reading glasses. In some instances, surgery on only one eye is required. If your doctor thinks you're a candidate, ask about the pros and cons.
  

Surgery: What to Expect Before, During and After Before

You'll need a complete eye examination by your refractive surgeon. A preliminary eye exam may be performed by a referring doctor (Eye MD or optometrist). Take your eye prescription records with you to the exams. Your doctor should:

• Dilate your pupils to fine-tune your prescription.
  

• Examine your eyes to make sure they're healthy. This includes a glaucoma test and a retina exam.
  

• Take the following measurements:
  

• The curvature of your cornea and your pupils. You may be rejected if your pupils are too large.
  

• The topography of your eyes to make sure you don't have an irregular astigmatism or a cone-shaped cornea - a condition called Keratoconus.
  

• The pachymetry - or thickness - of your cornea. You need to have enough tissue left after your corneas have been cut and reshaped.
  

• Ask you to sign an informed consent form after a thorough discussion of the risks, benefits, alternative options and possible complications. Review the form carefully. Don't sign until you understand everything in the form.
  

• If your doctor doesn't think Lasik is right for you, you might consider getting a second opinion; however, if the opinion is the same, believe it.

Alternatives to Lasik
You may want to discuss some surgical alternatives to Lasik with your eye doctor:

• Photorefractive keratectomy (PRK) is a laser procedure used to reduce myopia, hyperopia and astigmatism without creating a corneal flap.
  

• Astigmatic keratotomy (AK) is an incisional procedure to reduce astigmatism.
  

• Intrastromal corneal rings are clear, thin, polymer inlays placed on the eye to correct low myopia only.