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What Is Epi-LASIK Eye Surgery?

By Michael LoRe
Medically Reviewed by Kerry D. Solomon, MD, and member of the Refractive Surgery Council editorial advisory board on December 10, 2020
Epi-LASIK vs. LASIK: here's everything you need to know.

Before deciding on epi-LASIK surgery, it's important to understand the difference between LASIK and LASEK.

LASIK vs. LASEK

LASIK (laser-assisted in situ keratomileusis) is a popular eye surgery that corrects vision in people who are dealing with farsightedness, nearsightedness or astigmatism. LASEK (laser epithelial keratomileusis) is a similar procedure that combines the benefits of LASIK and PRK (photorefractive keratectomy).

The difference between LASIK and LASEK is how deep the cut is — in LASIK, a laser is used to reshape your cornea by cutting deep into the outer layer of your eyeball, while LASEK only cuts as deep as the outer layer of the cornea (epithelium).

With LASEK, the surgeon applies an alcohol solution after the initial cut to loosen up the epithelial layer, allowing it to be lifted and folded. After a laser is applied to the stroma — the thicker middle layer of the cornea — the surgeon folds the epithelial layer back down on top of the newly shaped tissue.

What is Epi-LASIK?

Epi-LASIK (epithelial laser in-situ keratomileusis) is an eye surgery that is similar to LASEK in that it preserves the epithelium. While the two procedures are similar in concept, they vary in how the flaps are produced.

With epi-LASIK, the surface layer over the cornea is fashioned with a precision surgical instrument called a microkeratome. The microkeratome is equipped with an applanation plate that flattens the cornea in advance of a modified dull blade.

So while the epithelial layer is lifted during epi-LASIK, it is loosened up and pushed to the side during LASEK. There is no alcohol solution used during epi-LASIK either. Because of this difference more epithelial cells are preserved during epi-LASIK, which may improve results compared to LASEK, and explain why epi-LASIK is being utilized more frequently than LASEK.

The goal of both epi-LASIK and LASEK is to reduce pain after the procedure, while increasing the speed of visual accuracy though results vary. As with any eye procedure, there is a risk of clouded vision, often called haze.

One study by the American Academy of Ophthalmology cites that one year after epi-LASIK treatment, all 138 patients tested had 20/40 vision or better, while more than three out of four eyes had 20/20 vision or better. Because of these findings, epi-LASIK was deemed "a safe and efficient method for the correction of low-to-moderate myopia and myopic astigmatism."

As with any procedure or medical treatment, it's important to speak to your doctor and see which is right for you. For example, if you suffer from high degrees of nearsightedness, LASIK is typically preferred to LASEK, epi-LASIK and PRK because of the risk of clouding associated with the latter three procedures.