Better barrier protection with epi-LASIK

CLEVELAND — Epi-LASIK has gained recent attention for its advantages over alcohol-assisted laser epithelial keratomileusis, said Marguerite B. McDonald, MD, FACS, speaking here at The Cole Eye Institute’s Cornea and Refractive Surgery Summit.

Unlike LASEK, epi-LASIK does not entail the use of alcohol in the removal of the epithelial sheet, which eliminates alcohol toxicity, Dr. McDonald said. Patients report good visual acuity in the first few days after epi-LASIK, she said.

In epi-LASIK, an epikeratome with a non-sharp “separator” is used, putting less pressure on the eye than is used in LASEK. The device is moved along the path of least resistance over the cornea, just under the basement membrane and above Bowman’s layer, Dr. McDonald said.

“These cells are alive for a few days, though they are fatally injured and will die,” she said. “But by the time they die, the stroma is no longer as vulnerable to their adverse effects. This is our theory as to why patients seem to have less pain.”

The epithelial sheet also acts as a natural barrier against inflammatory cells, Dr. McDonald said.

“We think there’s less haze and regression with epi-LASIK compared to PRK because the still-vital epithelial sheet acts as a barrier to inflammatory agents immediately after the surgery,” she said. The difference, she noted, is that after epi-LASIK, the agents have no pathway into the stroma because of the epithelial sheet; in PRK the pathway is open.

“The still-living epithelial sheet acts as a filter to inflammatory cells coming from the tears, which is why we think there’s faster recovery, less postoperative pain and less haze,” she said.