LASIK surgery may reduce or eliminate the need for corrective lenses — but for some people, the surgery is too risky. Find out whether you're a good candidate for LASIK surgery.

By Mayo Clinic Staff

If you're tired of wearing eyeglasses or contact lenses, you may wonder whether laser-assisted in-situ keratomileusis (LASIK) surgery is right for you. After all, LASIK surgery has a good track record and most people are satisfied with the results.

But LASIK surgery isn't the most appropriate vision-correction option for everyone, and it does have some risk. Read on to determine whether you're a good candidate for LASIK surgery.

LASIK surgery is a type of refractive eye surgery. During the procedure, an eye surgeon creates a flap in the cornea and then uses a laser to reshape the cornea and correct refractive error problems in the eye. LASIK surgery is most appropriate for people who have a moderate degree of refractive error, causing:

  • Nearsightedness (myopia), in which you see nearby objects clearly, but distant objects are blurry
  • Farsightedness (hyperopia), in which you can see far objects clearly, but nearby objects are blurry
  • Astigmatism, which causes overall blurry vision

A good surgical outcome depends on careful evaluation of your eyes before the surgery.

By the early to mid-40s, most adults have lost some ability to focus on nearby objects (presbyopia), which results in difficulty reading small print or doing close-up tasks. The condition may continue to worsen until about age 65.

If you have presbyopia, LASIK surgery may give you clear distance vision, but it can actually worsen your ability to see objects close up.

To maintain your ability to see close objects, you might choose to have your vision corrected for monovision. With monovision, one eye is corrected for distant vision, and the other eye is corrected for near vision. Not everyone is able to adjust to or tolerate monovision. It's best to do a trial with contact lenses before having a permanent surgical procedure.

As with any surgery, LASIK surgery carries risks, including:

  • Undercorrection, overcorrection, or new or additional astigmatism. If the laser removes too little or too much tissue from your eye, you won't get the clearer vision you wanted. Similarly, uneven tissue removal can result in astigmatism.
  • Vision disturbances. After surgery you may have difficulty seeing at night. You might notice glare, halos around bright lights or double vision.
  • Dry eyes. LASIK surgery causes a temporary decrease in tear production. As your eyes heal, they may feel unusually dry. Even after healing, you may experience an increase in dry eye.
  • Vision loss. In rare situations, you may have a decrease in the best corrected vision.
  • Flap problems. Folding back or removing the flap from the front of your eye during surgery can cause complications, including infection and excess tears.

You're more likely to experience complications from LASIK surgery if you:

  • Have a condition that may impair your ability to heal. Diseases that affect your immune system increase the risk of incomplete healing, infection and other complications. These diseases include rheumatoid arthritis, lupus and HIV.

    Taking an immunosuppressive medication may make you ineligible for LASIK surgery.

  • Have persistent dry eyes. If you have dry eyes, LASIK surgery may make the condition worse.
  • Have anatomic concerns. LASIK surgery may be inappropriate if your corneas are too thin, your corneal surface is extremely irregular or you have a condition in which the cornea thins and gradually bulges outward into a cone shape (keratoconus).

    You may not be eligible for LASIK surgery if you have an abnormal lid position or deep-set eyes.

    If your pupils are large, especially in dim light, LASIK may not be appropriate. Surgery may result in debilitating symptoms such as glare, halos, star bursts and ghost images.

  • Have unstable vision. You may not be eligible for LASIK surgery if the quality of your vision is fluctuating or getting worse.
  • Are pregnant or breast-feeding. Vision can fluctuate during pregnancy and breast-feeding, making the outcome of LASIK surgery less certain.
  • Have glaucoma. The surgical procedure can raise your eye pressure, which can make glaucoma worse.

You might also rethink having LASIK surgery if:

  • You have severe nearsightedness. If you're nearsighted and have been diagnosed with a high refractive error, the possible benefits of LASIK surgery may not justify the risks.
  • You have fairly good vision. If you see well enough to need contacts or glasses only part of the time, improvement from the surgery may not be worth the risks.
  • You actively participate in contact sports. If you regularly receive blows to the face and eyes, such as during martial arts or boxing, LASIK surgery may not be a good choice for you.
  • Cost is an issue. Most insurance plans don't cover the cost of vision-correction surgery.

If you're not a good candidate for LASIK surgery but you're still interested in vision-correction surgery, alternatives may include:

  • Photorefractive keratectomy (PRK). PRK is sometimes used for people who have a low to moderate degree of nearsightedness or farsightedness, those who have nearsightedness with astigmatism, or those who have farsightedness without astigmatism.

    PRK removes the thin surface layer of the cornea (epithelium). The surgeon then uses a laser to flatten the cornea or make its curve steeper. It may take three to six months to reach peak visual improvement.

  • Laser epithelial keratomileusis (LASEK). LASEK is similar to LASIK surgery, but the procedure allows the surgeon to remove less of the cornea, making it a good option for people who have thin corneas.

    People who play sports or have jobs that carry a high risk of eye injuries might also prefer LASEK because a thinner flap in the cornea means the cornea will be less vulnerable to serious damage should the flap be torn before it can heal.

  • Epithelial laser-assisted in-situ keratomileusis (epi-LASIK). In an epi-LASIK procedure, your surgeon separates the epithelium from the eye and uses a laser to reshape the cornea. This procedure is similar to LASEK.
  • Implantable lenses. Special corrective lenses (phakic intraocular lenses) are surgically inserted in front of the natural lens to improve vision.

    Implantable lenses can correct high degrees of nearsightedness not easily corrected by other surgical procedures. Possible complications include cataracts, increased pressure within the eye and damage to the cornea over time.

  • Bioptics. Bioptics combines one or more techniques, such as implantable lenses and LASIK, to treat nearsightedness or farsightedness.
  • Intracorneal ring segments. Intracorneal ring segments may sometimes be used to treat mild nearsightedness but the technique is more often used to treat keratoconus.

    During the procedure, a small incision is made in the cornea, and two crescent-shaped plastic rings are placed on the cornea's outer edge. The rings can flatten the cornea so that light rays focus more properly on the retina. If necessary, the rings can later be removed.

To make the most appropriate choice about refractive surgery, weigh the options, including the benefits and risks, with your eye doctor. Good results depend on careful evaluation of your eyes before the surgery as well as a clear understanding of the limitations of each procedure.

May 06, 2016