LASEK (laser epithelial keratomileusis) is a newer variation of PRK, a procedure in which laser energy is applied directly to the eye's outer surface for reshaping and vision correction.

To understand how LASEK works, you first must know the fundamental differences between LASIK, PRK and LASEK:

With LASIK, a thin flap is cut into the eye's surface and then lifted. Laser energy is applied to the eye for reshaping, and the flap is replaced to serve as a type of natural bandage for quicker healing.

An eye surgeon using PRK does not cut a thin flap into the eye's surface, as occurs with LASIK. Instead, laser energy is applied directly to the eye's surface. The ultra thin, outer layer of the eye (epithelium) is removed completely by laser energy during a PRK procedure, and eventually grows back.

A LASEK procedure involves preserving the extremely thin epithelial layer by lifting it from the eye's surface before laser energy is applied for reshaping. After the LASEK procedure, the epithelium is replaced on the eye's surface.

In LASIK, the thicker flap is created with a microkeratome cutting tool or a special laser. With LASEK, the ultra thin flap is created with a special cutting tool known as a trephine. LASEK is used mostly for people with corneas that are too thin or too steep for LASIK, when it may be difficult to create a thicker LASIK flap. LASEK was developed to reduce the chance of complications that occur when the flap created during LASIK does not have the ideal thickness or diameter.

The LASEK Procedure

During LASEK, your surgeon uses local anesthesia. Then he or she cuts the epithelium, or outer layer of the cornea, with a fine blade (trephine). Then the surgeon covers the eye with a diluted alcohol solution for approximately 30 seconds, which loosens the edges of the epithelium.

After sponging the alcohol solution from the eye, the surgeon uses a tiny hoe to lift the edge of the epithelial flap and gently fold it back out of the way.

Then the same excimer laser used for LASIK or PRK sculpts the corneal tissue underneath. Afterward, a type of spatula is used to place the epithelial flap back on the eye.

In a new variation of LASEK, the same plastic blade (epithelial separator) used in epi-LASIK creates the thin epithelial flap. But because alcohol is applied during the procedure as it is in straight LASEK, the procedure is called epi-LASEK with an "E" instead of an "I."

After LASEK

In many ways, LASEK vision recovery is slower than LASIK recovery, but there are some differences. According to doctors who perform LASEK, the flap edge heals in about a day, though patients usually wear a bandage contact lens for approximately four days to protect the eye.

Your eye may feel irritated during the first day or two afterward. Also, with LASEK compared with LASIK, it often takes longer to recover good vision up to four to seven days — but this can vary from one person to the next. You also may experience more pain with LASEK compared with LASIK.