Mild to moderate myopia successfully treated with Epi-LASIK

May 15, 2006

Mild haze (graded as 1.5 on a scale of 0 to 4 with higher scoresindicating more haze) was present the first day after surgery,which decreased by the fourth postoperative day to 0.5.

New Orleans-Mild to moderate myopia can be treated successfully using the EyeCare Epikeratome for Epi-LASIK (Norwood EyeCare). The uncorrected visual acuity (UCVA) improved significantly at 3 months postoperatively compared with preoperatively, according to Marguerite McDonald, MD, who reported the results of the Multicenter U.S. Prospective Study of the Safety and Efficacy of Epi-LASIK.

The study was a 3-month evaluation of the postoperative discomfort reported by patients, visual recovery, and wavefront-guided custom ablation using the Norwood instrument to correct myopia surgically. All patients were treated with the VISX S4 excimer laser (Advanced Medical Optics).

Other U.S. investigators were Daniel D. Durrie, MD, of Overland Park, KS; Mark Volpicelli, MD, Daniel Beers, MD, and Lee Shahinian, MD, all of Mountain View, CA; and Robert L. Kantor, MD, of Sarasota, FL.

The procedure with which each patient was treated is as follows. One drop of brimonidine tartrate ophthalmic solution, 0.15% (Alphagan P, Allergan) and a topical anesthetic were instilled into the eye undergoing treatment. With patients reclining under the excimer laser, a lid speculum was inserted. The epikeratome was used to lift the epithelial sheet; the sheet was then moved to the side. The laser energy was delivered to the cornea and the epithelial sheet was moved back to its original position. A Softlens 66 contact lens (Bausch & Lomb) was positioned on the eyes that were treated. The patients were followed up on 1, 4, and 6 days and 1 and 3 months after the procedure.

"Postoperatively, the mean manifest refraction was 0.04 X –0.08, and the spherical equivalent was 0.00 D. The mean UCVA and the mean BCVA were both 20/16. The mean pachymetry value was 466 μm (range, 388 to 518 μm)," Dr. McDonald reported. She is clinical professor of ophthalmology, Tulane University School of Medicine, New Orleans.

The procedure appears to be very accurate. Dr. McDonald reported that of the 71 study eyes, 38 eyes (53%) reached plano, 26 eyes (37%) were within 0.25 D of the intended correction, and seven eyes (10%) were within 0.5 D of the intended correction.

"The UCVA improved from a mean of 20/200 preoperatively to a mean of 20/16 postoperatively 3 months after treatment. The average spherical equivalent decreased from –2.88 D preoperatively to –0.11 D 1 month after treatment and 0.00 D 3 months after treatment," she said.

More specifically, at 3 months 16 eyes (23%) had an UCVA of 20/12.5 or better, 45 eyes (63%) had 20/16 or better, 58 eyes (87%) had 20/20 or better, and all eyes had 20/32 or better.

What must be recognized about the procedure is that the improvement in visual acuity is slower than the improvement after LASIK.

As Dr. McDonald reported, at 1 month after Epi-LASIK, no eyes had 20/12.5 or better, 19 eyes (27%) had 20/16 or better, 69 eyes (97%) had 20/20 or better, and 100% had 20/32 or better.

Regarding the BCVA 3 months after treatment, 23 eyes (33%) had 20/12.5 or better, 53 eyes (75%) had 20/16 or better, and 68 eyes (96%) had 20/20 or better.

Most aberrations decreased 3 months after treatment.