Study shows that epi-LASIK is more advantageous than mechanical photorefractive keratectomy

October 15, 2008

According to a prospective study, epi-LASIK seems to have two advantages compared with PRK performed with a mechanical microkeratome: faster visual recovery and less postoperative pain.

Key Points

Budapest, Hungary-Epi-LASIK seems to have two advantages compared with mechanical PRK: faster visual recovery and less postoperative pain, according to Zoltan Z. Nagy, MD, who is affiliated with the 1st Department of Ophthalmology, Semmelweis University, Budapest, Hungary.

LASIK is associated with biomechanical problems such as hinge issues, increased higher-order aberrations, postoperative dry eye, irregular healing, and loss of stretch effect from the cutting of collagen. With surface treatments, some apoptosis occurs with scarring and irregular collagen forms; slow healing postoperatively is characterized by pain and early poor visual acuity, Dr. Nagy said.

"Compared with other surface procedures, epi-LASIK and epi-LASIK in which the flap is discarded may decrease postoperative pain, restore the early postoperative uncorrected visual acuity [UCVA] to a good level, and decrease the formation of epithelial haze," he said.

Study population

One study group included 20 eyes of 10 patients who underwent epi-LASIK; those eyes had a mean preoperative spherical equivalent (SE) and cylinder, respectively, of –3.79 and –0.83 D.

The second study group included 20 eyes of 10 patients treated with PRK with mechanical debridement; those eyes had a mean SE and cylinder, respectively, of –3.68 and –0.68 D. The patients in both groups also were similar in age.

An excimer laser (MEL 80, Carl Zeiss Meditec) was used to perform all ablations. No mitomycin C was used in any of the cases; a bandage contact lens was applied in all cases. All procedures were performed by Dr. Nagy in the same surgical setting; the depths of the ablations were similar in both groups.

The findings

The UCVA and the level of postoperative pain were evaluated on days 1, 2, 3, and 4, week 1, and month 1 after the treatment.

He reported that on postoperative day 1, the eyes that underwent epi-LASIK had better UCVA than that of those eyes that underwent PRK. The pain scores were similar for the two groups.

On postoperative day 2, 40% and 15% of eyes had UCVA levels of 20/40 or better with epi-LASIK and PRK, respectively; the respective pain scores were 1.95 and 2.92.

On postoperative day 3, 90% and 70% had UCVA level of 20/40 or better; the pain scores were 0.5 and 1.2, respectively.

On postoperative day 4, 100% and 90% had UCVA level of 20/30 or better; no pain was reported.

One week postoperatively, 100% and 85% had UCVA level of 20/25 or better.

By 1 month postoperatively, 100% and 95% had UCVA level of 20/20 or better.

"Epi-LASIK with the flap discarded resulted in faster recovery of the UCVA compared with mechanical PRK. There were similar pain scores initially, but thereafter the eyes treated with epi-LASIK did substantially better than the eyes treated with PRK," Dr. Nagy said. "We believe that epi-LASIK should be the surface ablation of choice because of the visual acuity outcomes and the decreased level of pain compared with PRK."

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