Epithelial scraping a successful option to re-treat LASEK patients

The procedure is safer, more convenient and more cost-effective than repeat laser therapy.

Issue: August 2010

ByMaria E. Lim, BS

BySergul A. Erzurum, MD, FACS

LASEK is a safe and effective treatment to correct myopia, hyperopia and astigmatism, yet all refractive procedures can result in a residual refractive error. This requires the patient to return to the laser suite and undergo further stromal tissue removal. We describe a series of five eyes that showed regression after LASEK and were treated by scraping the epithelium in the clinic instead of resorting to additional laser treatment.

Patients and setting

The patients ranged from 52 to 69 years in age (mean: 56.8 years) at the time of their primary LASEK procedure. Four weeks after LASEK, the patients had some residual refractive error that prevented them from seeing comfortably without correction. They also reported reduced clarity of vision, even with best correction.

The primary LASEK procedure was performed bilaterally on all patients. A corneal epithelial flap was created with an alcohol solution (20%) applied for 30 seconds. Treatment was precalculated with the patients’ preoperative cycloplegic refraction, and the Visx Star S4 laser (Abbott Medical Optics) was used to ablate and reshape the cornea. The epithelium was replaced in all patients, and a bandage contact lens was applied to the eye. A regimen of Vigamox (moxifloxacin HCl ophthalmic solution, Alcon), Acular (ketorolac tromethamine ophthalmic solution, Allergan) and FML (fluorometholone ophthalmic suspension, Allergan) was used four times daily until the surface healed. The contact lens was removed after 5.8 days (range: 5 to 7 days).

When the patients showed signs of regression, epithelial scraping was offered as an alternative option to re-treatment with laser therapy. Topical anesthesia was applied, and the patient’s epithelium was visualized with a slit lamp. Smooth-tip forceps were used to completely remove the loose epithelium. Patients were fitted again with a bandage contact lens worn for 6.6 days on average (range: 6 to 8 days), until the cornea re-epithelialized. Moxifloxacin, ketorolac tromethamine and fluorometholone were used four times daily in a similar fashion as after the initial LASEK procedure, until the surface healed.

Results

The patients were seen at 1 day, 5 days and 1 month after the scraping. Uncorrected visual acuity, best corrected visual acuity and manifest refraction were studied before and 1 month after initial surgery, as well as after the scraping. Average total length of follow-up was 4.2 months (range: 1 to 10 months).

Before scraping the epithelium, UCVA ranged from 20/40 to 20/400, and BCVA was 20/20 in two eyes, 20/25 in two eyes and 20/60 in one eye. Pre-scrape spherical equivalent ranged from –1.75 D to +1.35 D. All but one patient was found to have an irregularity of the epithelium. After scraping the epithelium, UCVA ranged from 20/20 to 20/160, and BCVA was 20/20 in four of the five eyes. The spherical equivalents after scraping ranged from –2.125 D to +0.75 D. Three eyes were left with a myopic prescription to result in monovision. All patients were satisfied with their final visual acuity after scraping (Table).

Discussion

Typical management for undercorrection or overcorrection after refractive surgery is re-treatment with additional laser surgery. This is true of all of the present procedures, including LASIK, PRK and LASEK. The flap in LASIK surgery results in more stable outcomes but cannot be easily manipulated postoperatively. Therefore, postoperative LASIK patients who have a residual refractive error must undergo re-lifting of the flap in order to re-treat. Arshinoff et al reported that in patients with undercorrection after PRK, NSAID eye drops used with topical steroids and a bandage contact lens increased myopic regression. This method, however, does not completely eliminate undercorrection, which to our knowledge can only be re-treated surgically for best postoperative results. LASEK also results in surgical undercorrections and overcorrections. Contact lens wear and nonsteroidal treatment can be attempted as a conservative treatment for the postoperative hyperopic errors, but laser re-treatment is necessary for myopic regression and in more severe hyperopic outcomes.

In our series, most of the patients were older, and four of the five had very loose or irregular epithelium with little resistance to scraping. Although all of the patients were correctable to visual acuity better than 20/25 after LASEK, all complained that their uncorrected vision lacked quality. In this subset of patients, we found scraping the epithelium, as opposed to re-treatment with LASEK, to be a viable treatment option to improve uncorrected visual acuity. Epithelial scraping provides advantages over laser re-treatment because no stromal tissue is removed. This procedure is also more convenient for patients in that it precludes a revisit to the operating suite and avoids the cost of laser re-treatment. Patients also do not feel that their initial LASEK procedure “failed” them, resulting in a more positive outlook toward epithelial scraping.

The technique that we described manipulates epithelial healing to correct refractive errors. Corneal epithelium significantly affects clarity of vision as well as refractive error. Patient-specific differences in epithelial healing and compensatory epithelial hyperplasia contribute to postoperative refractive regression, as seen in the increased flap thickness after repeat laser therapy. By manipulating the epithelial healing pattern, postoperative refractive outcome can be adjusted. The epithelium of the patients in this study healed loosely after their initial LASEK procedure, and we attributed their reduced visual acuity to the irregular epithelium.

We believe epithelial scraping should be considered in all patients who have persistent refractive error following LASEK. Potential characteristics that lead to good outcomes after scraping include increased age of patient, reduced uncorrected and best corrected visual acuity, and irregular corneal epithelium. By scraping the epithelium and manipulating bandage contact lens wear with NSAID usage, these patients can achieve a better outcome that is safer, convenient and cost-effective.

References:

Anderson NJ, Beran RF, Schneider TL. Epi-LASEK for the correction of myopia and myopic astigmatism. J Cataract Refract Surg. 2002;28(8):1343-1347.

Autrata R, Rehurek J. Laser-assisted subepithelial keratectomy and photorefractive keratectomy for the correction of hyperopia. Results of a 2-year follow-up. J Cataract Refract Surg. 2003;29(11):2105-2114.

Arshinoff S, D’Addario D, Sadler C, Bilotta R, Johnson TM. Use of Topical Nonsteroidal Anti-Inflammatory drugs in excimer laser photorefractive keratectomy. J Cataract Refract Surg. 1994;20 Suppl:216-222.

Cagil N, Aydin B, Ozturk S, Hasiripi H. Effectiveness of laser-assisted subepithelial keratectomy to treat residual refractive errors after laser in situ keratomileusis. J Cataract Refract Surg. 2007;33(4)642-647.

Das S, Sullivan LJ. Comparison of residual stromal bed and flap thickness in primary and repeat laser in situ keratomileusis in myopic patients. J Cataract Refract Surg. 2006;32(12):2080-2083.

Maria E. Lim, BS, can be reached at mlim1@neoucom.edu.

Sergul A. Erzurum, MD, FACS, can be reached at Eye Care Associates, 1075 W. Western Reserve Road, Poland, OH 44514, U.S.A.; +1-330-746-7691; fax: +1-330-965-9288; e-mail: sergul@zoominternet.net.

Drs. Lim and Erzurum acknowledge the financial support of the Polena Trust for Ocular Research at the St. Elizabeth Development Foundation, Youngstown, Ohio, and manuscript assistance provided by David Gemmel, PhD. All statements are the sole responsibility of the authors. The authors have no financial conflict of interest associated with products described in the report.