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Manage overcorrected LASIK with CLAPIKS
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Overcorrection in a myopic LASIK case can be very troublesome for the physician and the patient. These overcorrected cases require an extensive amount of the doctor’s chair time and optical rehabilitation, especially if the patient is presbyopic. Prevention is the best way to avoid overcorrection.
However, if a myopic patient results with overcorrection after LASIK, it is important to do the following:
- Re-evaluate the preoperative refractive data.
- Recheck the planned programmed ablation amount.
- Review and compare preoperative and postoperative topography.
- Check for any errors in the laser engineer’s transposition.
- Review all possibilities as to the etiology of the overcorrection.
- Carefully review the patient’s history, especially as it relates to pregnancy, nursing and signs of diabetes and collagen disease.
- Systematically evaluate and compare the dry manifest refraction with the cyclorefraction.
- Double-check your nomogram data entry and calculations.
Non-surgical postop approach
Despite our best efforts, overcorrections do occur, but a nonsurgical postoperative method exists to help treat these patients. J.E. McDonald, MD, and I have successfully managed such patients with the use of Acular (ketorolac tromethamine, Allergan) and a soft contact lens. Acular reduces prostaglandin production by inhibiting the prostaglandin synthetic enzyme, cyclo-oxygenase.
Prostaglandins are a part of the inflammatory cascade and amplify the immunological response to cellular injury. They are indirect mediators of pain, and Acular is an excellent agent for controlling pain. Acular is approved for treating itching associated with allergies. However, it can also help prevent cystoid macular edema and manage postop pain after photorefractive keratectomy (PRK), pain associated with corneal abrasions, episcleritis and other mild ocular inflammatory conditions.
One of Acular’s theoretical potential side effects is epithelial proliferation and thickening of the anterior stroma from the action on the proteoglycans. It is this theoretical side effect that may benefit the overcorrected patient.
Remember, 12 to 14 µm of change in thickness over a 6-mm zone equals 1 D of refractive change, so small amounts of epithelial thickening can cause some beneficial results. The use of the soft contact lens will promote hypoxia in the cornea, cause mechanical stress to the cornea and increase Acular contact time to the cornea. Clinically, the corneal epithelium will thicken. It is interesting to note that long-term wear of soft contact lenses would result in epithelial thinning.
Increasing corneal thickness
Hence, the corneal thickness is increasing for two reasons: hypoxia/ mechanical stimulation from the soft contact lens and epithelial thickening from Acular. Clinically, it is important when using this pharmacological method to take into account the amount of ablation and the amount of time since surgery. Remember, the higher the preop myopia, the more the postop regression. In fact, you want the high myope to be overcorrected for the first few weeks.
For example, an 8.50-D myope should be +2.00 D at 1 day, +1.50 at 1 week and a +1.00 at 1 month. At 3 months, he or she will be +0.5 D, and at 1 year, he or she will be plano. One needs to be cautious when pursuing this Acular strategy, because this method can induce the patient back into myopia, resulting in an unplanned enhancement.
At last year’s American Society of Cataract and Refractive Surgery meeting, Tal Raviv, MD, of the New York Eye and Ear Infirmary reported the results of a series of 14 patients who had overcorrections on one eye after myopic bilateral LASIK with a mean spherical equivalent of + 1.00 D at 1 week postop. The patients received Acular in one of their eyes, and the other eye served as a control. Dr. Raviv found that the eyes using Acular had a mean regression of 1.1 D, and the control eyes had a change of only 0.25 D, a statistically significant difference, with the Acular on average inducing 0.85 D of regression more than in the control eye. There were no side effects or complications noted from Acular in any of the patients.
Over the past 6 months, we were able to follow a series of 28 patients who were overcorrected in one or both eyes after myopic bilateral LASIK. The patient received Acular based on his or her preoperative myopia according to the protocol explained in the accompanying charts. All patients were started on Acular 1 week postoperatively.
Earlier in the study, we tried starting Acular later (i.e., 6 weeks postop), but found it had minimal effect. Earlier is better because most of the corneal healing response occurs in the first month. We also found that combining both Acular and extended soft contact lenses postoperatively has a greater effect on regression than Acular alone. This is due to the mechanical stimulation from the contact lens.
CLAPIKS
Dr. McDonald named this therapy contact lens-assisted, pharmacologically induced keratosteepening, or CLAPIKS.
The average spherical equivalent of the 28 patients at 1 week postop was +1.25 D with the use of Acular and the soft contact lens. The average postop spherical equivalent at 1 month postop was +0.75 D. The mean regression with the use of Acular was +0.50 D. No side effects or complications were noted with the use of Acular.
We concluded that the use of Acular and soft contact lenses appears to be safe and effective for reducing small amounts of hyperopia in the postop myopic LASIK patient. CLAPIKS may be used clinically to avoid additional surgery for overcorrection.
The use of Acular should be discontinued after the desired result is achieved or after 1 month. If the soft contact lens and Acular do not show any refractive error change after 4 weeks of treatment, discontinue and consider surgical or optical options. It is also important to remember that a non-contact lens wearer will not be comfortable with insertion and removal.
For Your Information:
- Jeffrey M. Augustine, OD, is center director of Clear Choice Laser Centers in Brecksville, Ohio.
- Kathy Gonzalez, OD, is on staff at Clear Choice Laser Centers. They can both be reached there at 6255 Old Royalton Rd., Suite 1912, Brecksville, OH 44147; (440) 740-0400; fax: (440) 740-0660; e-mail: JMAORSS@aol.com.
- Neither Dr. Augustine nor Dr. Gonzalez has a direct financial interest in the products mentioned in this article, nor is either a paid consultant for any companies mentioned.