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The Limitations of LASIK and PRK Surgery for Eyes

By Dr. Donald McCormack, MD
Ophthalmologist at Boulder Medical Center

If you have a refractive error, such as nearsightedness (myopia)farsightedness (hyperopia)astigmatism, or presbyopia, refractive surgery is a method correcting or improving your vision. Refractive surgeries like LASIK and PRK can be quite successful for the right patient. I performed this type of surgery for 15 years and had excellent results. I stopped only when there was no longer a laser device available in Boulder. But part of my success was due to limiting the surgical procedures to only those who were excellent candidates.

Are these types of surgeries right for you? Here a few things to consider.

First, LASIK and PRK are elective surgeries. They won’t make your vision better than contacts or glasses do. Also, there are risks inherent in any surgery. So the surgery shouldn’t be done unless there is an excellent chance of a great outcome. I have seen many patients who had procedures by other surgeons who may never have clear vision again. They wished they had not chosen to have surgery.

If you are not a perfect candidate, do not risk surgery. It’s that simple.

Characteristics of a good Lasik or PRK candidate

So, what makes a good candidate, and why did I turn away more than 75 percent of the patients who asked me about having the surgery? Here a few characteristics of an ideal refractive surgery candidate:

  • Stable Vision is essential. If your optical prescription is changing — if you need to get new lenses each year to keep your vision crisp — LASIK and PRK will not stop that change. You should have a stable prescription for at least a year before having refractive surgery. If you don’t, you might be back in glasses within a year or two.
  • Small Pupils work best. If your pupils are large or dilate a lot in the dark, this can cause glare after surgery. This has to do with the way the laser shapes the cornea. The bottom line is that you should not have surgery if you have big pupils.
  • Not So Near-Sighted folks have the best result. The procedure works best if the ophthalmologist does not need to correct a lot for near-sightedness. With this said, the results are better for near-sighted than for far-sighted patients. The thickness of the cornea is one limitation in how much correction can be achieved.
  • Younger Patients can enjoy the most years from a successful surgery, but LASIK and PRK can’t get rid of glasses forever. As the lens inside the eye (behind the pupil) ages, the ability to read up close diminishes. Even if you have a perfect surgery outcome, you will need reading glasses in your early 40’s. While there are some options for older patients, such as correcting one eye for far vision and the other for near, this isn’t optimal for most people. If you’re already over 40, you can still have a successful surgery, but you must understand that you’ll need glasses to see things up close.
  • No Presence of Eye Disease is an absolute must for a LASIK or PRK candidate. The surgery can make dry eyes worse, for example. Irregularly shaped corneas can lead to poor and unstable vision after surgery.

Finally, if you have had a complete eye exam with your ophthalmologist and find that you are a good potential candidate for surgery, carefully consider which eye surgeon will care for you. I recommend considering these criteria:

  • Choose an ophthalmologist with a lot of experience;
  • Find a practitioner whose income does not depend solely on doing more LASIK and/or PRK cases. In other words, avoid the big discount LASIK centers;
  • Decide on someone who will spend time with you personally and do most of the critical pre-operative measurements and post-operative follow-up themselves (instead of technicians).

About Dr. Donald McCormack

As an ophthalmologist, Dr. McCormack diagnoses and treats all eye diseases, prescribes eyeglasses and contact lenses to correct vision problems, and performs a wide range of clinical procedures and more complicated eye surgeries. He has special interests in treatments for dry eyes and glaucoma and has been a principal investigator in numerous clinical research trials for these conditions.


This article is not intended to substitute for professional advice, diagnosis, or treatment. Always seek the advice of your physician.

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