Am I a Good Candidate?

By George W. Tate, Jr., MD

Published on July 20, 2006

Having specialized in refractive surgery since 1980, I truly feel that LASIK is the best in a long line of laser-assisted procedures that aim to correct myopia, hyperopia, and astigmatism. With LASIK, the risk of a serious complication is low (under 1% with an experienced surgeon), and the outcomes and results are predictable and long lasting. It has done wonders for my wife, many of my patients, and myself, and I would not hesitate to perform LASIK for any family member who could benefit from the procedure.

Having said this, LASIK is not for everyone. Although many ads seem to suggest that LASIK is the perfect solution for anyone's vision needs, it is surgery and some people are not well suited for the procedure. The keys to a successful result are forethought and patient selection.

A thorough LASIK consultation should include:

• a complete dilated exam to check for ocular abnormality,
• refraction (to establish the level and stability of the correction required),
• scotopic pupil and corneal thickness measurement,
• corneal topography mapping,
• tear function analysis,
• and most importantly, extensive time discussing the patient's medical history, lifestyle, vision requirements, and expectations.

If any of these areas sound confusing, do your research before making an appointment with a refractive surgeon.

Are You a Bad Candidate?

There are several existing medical conditions that would create poor results. Some of these include rheumatoid arthritis, advanced glaucoma, pregnancy or the likelihood of becoming pregnant soon after the procedure, breastfeeding, and autoimmune diseases.

Age and stability of one's prescription are also important factors when considering LASIK. Typically, near-sightedness does not stabilize until the early twenties. Therefore, teenage patients should wait until their vision has stopped changing in order to avoid needing a second procedure.

A common concern for patients over forty is the need for reading glasses. Those of us who are deep into middle age realize that even if we see perfectly at a distance, we cannot see close up without glasses. Many people who could only see up close for most of their lives cannot truly grasp what it means to lose their near vision. They have always handled this by taking off their glasses to read. But, that solution won't work after LASIK. There are options, such as monovision, in which one eye is corrected for distance and the other for near. This can greatly reduce a patient's need for reading glasses. Monovision should be discussed with your doctor in detail and tested in contact lenses for at least one month before your procedure.

Planning for a Good Result

Once you decide that LASIK is right for you, you need to know if it can be accomplished safely and effectively. LASIK works by removing a small amount of tissue to change the curvature of the front of the eye, and the resultant curve must lie between set limits or the result will be an increased risk of tear problems and unstable vision. It is for this reason that the tear function, corneal topography, and corneal thickness measurements are important. Also, only so much tissue can be removed without weakening the cornea. Thus there is an upper limit on the amount of correction that can be safely achieved. Bear in mind that it may not be wise to have LASIK if your test results indicate you just barely squeaked into the acceptable range. Regression --loss of effect--is common after LASIK and is normally handled by an enhancement (secondary procedure). However, if there is not sufficient corneal tissue remaining to work with, you may be left with a sub-optimal result.

Another major consideration, and one that is often discussed in the media, is the chance of experiencing glare. In order to avoid glare, the area of the correction must be larger than the pupil, much as a platter must be larger than the food it contains. If the pupil can dilate larger than the correction placed on the eye, unfocused light enters through the pupil, causing haloes and glare, particularly at night. In order to avoid this condition, I use a Colvard Pupillometer, essentially a night vision scope, to measure the size of the pupil in the dark. This information is critical when deciding which laser or lasers to use. The surgeon must have a laser capable of making a large diameter correction. Not every laser can cover a large pupil, and those that do may remove more tissue than the eye will safely permit. Sometimes, it may be advisable for a surgeon to perform a multi-zone correction; accomplishing this goal requires the use of two lasers. Other times, I simply tell the patient that I cannot do a satisfactory correction.

Dry Eyes is another common concern. As we age, our tear production naturally decreases and some medical conditions aggravate dryness. LASIK always causes temporary dryness because the sensory nerves to the cornea that stimulate tear secretion must regenerate after the procedure. In some, the dryness can be permanent. It is hypothesized that in such cases people are borderline tear deficient, and LASIK 'pushes them over the edge,' so to speak. Using tear plugs and vitamin A are effective ways of combating dry eye symptoms for many patients. To be sure, people with mild dryness can have LASIK, but there is more risk, more regression, and more need for postoperative care.

Finally, you should not have the procedure if you are shopping around to find the lowest price. There are facilities offering surgeons $75.00 per eye, with a guaranteed gross salary of $1,000,000 a year! This equates to a surgical load of 13,000 eyes a year or 53 eyes a day, 5 days per week. One wonders how much time is left for thoughtful evaluation or for the care of the patient's problem. One can also speculate how willing a provider under such financial pressure would be to turn down a case.

For the right patient, LASIK can be a joy. Just be sure that you're the right patient!

Dr. George W. Tate, Jr., M.D., is Medical Director at the TLC Laser Center in Charlotte, North Carolina.

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