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Up Front | Nov 2003

Reoperation After LASIK and PRK

Surgeons need to understand the causes and accept retreatments as routine.

To view the figure related to this article, please refer to the print version of our November/December issue, page 17.
A surgeon's philosophy concerning reoperation after LASIK and PRK can profoundly affect a patient's psyche as well as the financial health of a practice. Patients often ask about their chances of needing a reoperation, and physicians cannot provide a meaningful response unless they have determined two parameters: (1) the timeframe in question and (2) the loss of visual acuity that will prompt a reoperation. For example, if a surgeon targets a UCVA of 20/25 for all patients, then the reoperation rate within 2 years may be in the range of 15%. If patients tolerate a UCVA of 20/40, then the reoperation rate may be only 5% within the same time frame.

FACTORS AFFECTING REGRESSION

Preoperative Refractive Error
A loss of visual acuity due to regression generally requires a reoperation. The dominant factor determining regression is the patient's preoperative refractive error. Based upon their experience, most keratorefractive surgeons accept that, the higher the patient's preoperative refractive error, the greater the degree of regression. Hyperopes regress more often than myopes.

A 20-year-old patient with a -10.00-D preoperative refractive error will probably experience a slight myopic drift during the subsequent 3 years, regardless of whether or not he undergoes LASIK. The cause is most likely an ever-increasing axial length rather than a change in corneal shape. Although a true regression of the corneal surgery may not cause this increase in refractive error, the new ametropia will likely lead to a reoperation and be classified as a regression.

Accommodative Change
During my ophthalmic training, I learned that a patient's refractive error stabilized in his late teens or early 20s and that the average patient frequently became more myopic due to incipient nuclear sclerosis during his late 50s. In my clinical experience, however, a significant number of my emmetropic patients have become mildly hyperopic in their late 30s. Undoubtedly, this shift is due to a loss of latent and manifest accommodation.

I have used hyperopic PRK to treat approximately 800 eyes (mostly bilateral cases) of patients who had undergone RK 15 years ago when they were 20 to 25 years old. These patients all had a successful postoperative course for 10 to 15 years but invariably returned when they were 38 to 40 years old with a refractive error of +1.50 D. I doubt that their corneas changed shape after 12 years of excellent, stable visual acuity. Regression or overcorrection would surely have occurred during the decade preceding the onset of this new hyperopia. Instead, their accommodative status changed.

Hard Contact Lens Wearers
Wearers of hard contact lenses typically discontinue lens wear for 2 weeks before undergoing refraction and LASIK. If they have worn their lenses for 30 years, then a significant amount of astigmatism is often masked. Such corneas will continue to change slightly for 4 to 6 months after the removal of hard lenses, often with an increasing degree of astigmatism.

I believe that it is both appropriate and practical to operate on these patients' existing refractive error after they have discontinued lens wear for several weeks (assuming no irregular astigmatism), and to inform them that they will likely require a reoperation in 3 to 6 months when their eyes have totally stabilized.

Oftentimes, such patients' changes in refractive error after LASIK or PRK are due to a combination of the factors mentioned earlier. The only certainty is that they will blame the keratorefractive procedure and/or surgeon for their need of a second procedure. The truth is that the necessity of a reoperation 2 years after achieving a stable and excellent result may have nothing to do with a change in corneal shape. Unfortunately, the keratometry of a cornea after refractive surgery does not match the change in refractive error, so the stability of an aspheric cornea can be difficult to determine. This fact is essentially irrelevant, however, because patients believe their visual acuity should be improved by their surgeons.

REOPERATION'S IMPACT ON THE PRACTICE
In Figure 1, the surgeon performs 1,000 quality LASIK and PRK procedures yearly and has a reoperation rate of 15%. Within 3 years, this physician will perform approximately 1,000 primary cases and 200 reoperations each year, due to the cumulative effect of any necessary reoperations from all previous years. For me, certain corollaries flow from this scenario. I suggest that all surgeons:

1. Not include reoperations “for life” within a global fee. Otherwise, they will perform 20% of yearly procedures for free;
2. Establish a sliding-scale reoperation fee that is based on the amount of time that has elapsed since the primary surgery;
3. Document for all patients the approximate chance that they will need a reoperation over a given time period, as well as the cost of a reoperation. They should have patients sign this documentation in order to avoid future disputes;
4. Accept reoperations as a routine part of their practice and not attribute them to inferior surgical care on their part; and
5. Recognize that the factors necessitating reoperations for patients who underwent LASIK or PRK will also apply to those who receive phakic IOLs. Keratorefractive surgery will play an important role in correcting lower degrees of ametropia after phakic IOL implantation.

ATTITUDE AND EXPECTATIONS
The future need for a reoperation is obvious preoperatively in some cases and should be documented prior to surgery. For example, a patient with a preoperative refraction of -8.00 -4.00 X 180 will likely require a reoperation for either sphere or cylinder 6 months after the primary procedure if the goal of best UCVA is 20/25. A patient who has mild irregular astigmatism may require a second PRK procedure. All refractive surgery patients should be aware that they may need a second procedure.

The goal of refractive surgery is excellent uncorrected visual function, and achieving this aim may entail two or more operations. Surgeons should view reoperations as tools for achieving better results, rather than as a failure of their own technique or ability. Enhancements and touchups are just different names for reoperations, which are simply a reality with which patients, surgeons, and the staff must deal. They are a necessary part of the process involved in achieving the best UCVA.

Lee T. Nordan, MD, is the director of Nordan Eye Laser Medical Group in Carlsbad, California. He holds no financial interest in the products and companies mentioned herein. Dr. Nordan may be reached at (760) 930-9696; laserltn@aol.com.

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