Enhancement: The Laser-Assisted Refractive Surgery Redo

Written by John Taylor

While laser-assisted refractive surgery is a remarkably effective and successful means of correcting corneal defects to improve vision, occasionally a retreatment is required.

Although more than 90 percent of laser-assisted refractive surgeries result in markedly improved vision for patients, some patients will require a retreatment after surgery. Also, sometimes the gains in vision achieved diminish over time, also necessitating a retreatment. This is especially true for older patients.

New technology like wavefront imaging has greatly improved the success rates of laser-assisted refractive surgery, but the fact remains that it is subject to human error and other variables. Also, the complexity of the procedure may influence the results, for example, hyperopia is more difficult than myopia to correct, and if astigmatism is added to either condition the procedure becomes more complicated.

Older patients and patients who started out with severe myopia have a tendency to regress over time. It's highly unlikely that the patient's vision will backslide to where their vision was prior to their surgery, but it is possible that they could regress from 10 to 30 percent. Because of this, some doctors will actually overcorrect a severely myopic patient, causing hyperopia, with the expectation that their vision will eventually regress to plano.

In general, over 10 years about 20 percent of all LASIK patients will need a retreatment. For PRK patients, over the same 10 year period, about 42 percent of all patients will need retreatment. These statistics were compiled by the American Journal of Ophthalmology.

In most cases it will likely take several months before you are able to ascertain whether you will need an enhancement surgery after your initial laser-assisted refractive surgery. This is because your vision may fluctuate for several months following your procedure. The average enhancement surgery takes place about three to six months following the original procedure, but it can be done years after the original surgery.

If you feel that you need an enhancement surgery, consult with your doctor. However, some doctors shy away from enhancement surgeries, charging higher prices for them or outright refusing to perform a procedure on patients who have achieved at least 20/40 vision, the minimum required to drive without the use of contact lenses or glasses. Doctors may shy away from these surgeries for safety reasons, but others avoid them because they may skew their success rate numbers. Seeking a second opinion is advisable for patients considering an enhancement procedure.

What enhancement surgery you receive will depend upon what type of laser-assisted refractive surgery you used for your initial procedure. If you used LASIK, your doctor will most likely just lift the existing flap that was cut into your cornea and apply the excimer laser again. Your doctor is able to lift the flap, even several years after your initial surgery, because although the flap heals over time, it is relatively easy for your doctor to separate it from the cornea at the point of incision.

However, if you had Epi-LASIK for your initial procedure, you will be unable to use the same procedure for your enhancement surgery. This is because in Epi-LASIK, the Bowman's layer which was used for stability in the initial phase of the procedure is ablated by the excimer laser. Chances are that if you had Epi-LASIK and need an enhancement, your doctor will recommend PRK or LASEK.

If you had PRK or LASEK, your surgeon will lift or remove your epithelium just like he or she did during your initial surgery.

Prior to undergoing an enhancement surgery, you should discuss a technique known as CLAPIKS with your physician. This technique involves using eye drops to make your cornea easier to manipulate and reshape to fix mild degrees of overcorrection and undercorrection.

It's important to remember, that an enhancement procedure is a second surgery and carries all of the risks of the initial surgery. If your vision is only a little less than perfect, you should consider not having the surgery, especially if you are a high risk patient. Following your enhancement surgery, you'll have to follow all of the same aftercare guidelines that you did after your original procedure to avoid infection and problems with your flap, if you received LASIK or LASEK treatment. You'll also likely experience the same level of discomfort you did in your original surgery as well.

Enhancement procedures have a success rate comparable to that of initial procedures. While they may not be necessary for most patients, those who have experienced regression or unsatisfactory results from their initial procedure can consider it a viable option for improving their vision, again.