What is LASEK?

By Sanford Moretsky, MD

Published on July 20, 2006

LASEK is an abbreviation for Laser Assisted Subepithelial Keratectomy. LASEK is a hybrid of FDA approved PRK (Photorefractive Keratectomy) and LASIK (Laser Assisted In Situ Keratomileusis). In this procedure, the surface of the cornea is peeled back, the laser is applied, and the surface layer is then replaced into position.

Technically, LASEK is a procedure that falls under the heading of neither LASIK nor PRK and, therefore, is performed as an “off-label” application. Up until last year, LASIK too was considered off-label.

PRK and LASIK – comparing the two components of LASEK

PRK and LASIK have some very important differences. The benefits of PRK are that it can be performed on patients whose corneas are too thin to allow both the necessary removal of tissue to achieve refractive correction and the creation of a protective corneal flap. Compared to LASIK, however, in PRK there are a number of downsides. Overall, most refractive surgeons have now evolved almost entirely toward LASIK.

One downfall of PRK is that healing tends to be more prolonged compared to LASIK because the tissue removed has to re-heal from the edges in. This occurs because, with PRK, the surface layer of the eye's epithelium is removed in order to apply the laser to the surface of the cornea and change its shape. In contrast, with LASIK, a hinged flap of the cornea is created with an instrument called a microkeratome, allowing the surface to be reapplied immediately after the laser application, much like closing a door. The only area that has to heal in order to complete the surface closure is the seam along the edge of the “door.”

Other downsides of PRK include a delay in both quality of vision and in the healing of the surface area, more discomfort, and the need to use various medicated eye drops over longer intervals. What's more, despite the fact that PRK actually preceded LASIK both in the FDA approval process and in practice in the U.S., PRK has limitations for higher ranges of correction due to haze of the cornea that may occur from the increased healing response of the surface tissue. (Typically, this haze is not visually significant.) LASIK eliminates many of the problems that PRK presents and has gained a rapid and almost universally higher acceptance among laser vision correction surgeons and patients alike.

LASEK

Some patients are not good candidates for LASIK because their corneas are too thin to treat or retreat if they should have regression. Other patients are hesitant because they have known someone who has had a “flap” complication or are just concerned about having a flap created with the application of the microkeratome. For these patients, the LASEK alternative is available.

In LASEK, while the eye is numbed with eyedrops, a diluted solution of alcohol is applied to the cornea for a sufficient period of time to allow softening of the corneal epithelium or surface layer of the cornea. It can then be surgically peeled back. The laser is applied, and the surface tissue is then re-attached. During the LASEK procedure, there is no need to apply the microkeratome. After the procedure, a high water content bandage soft contact lens is applied. In my experience, compared to PRK, the patient's discomfort level is reduced, visual recovery is accelerated, and the incidence of haze is less. It is sometimes necessary to perform LASEK on consecutive days rather than correcting both eyes on the same day.

LASEK is a suitable alternative to LASIK when corneal thickness or concern regarding the corneal flap is an issue. Compared to LASIK, there is also less risk since there is no flap created, but there is a slightly longer healing and visual recovery period. Compared to PRK, LASEK provides more rapid recovery and less discomfort.

LASEK is new and is only performed by select laser vision correction surgeons.

Dr. Sanford L. Moretsky, of Moretsky Cassidy Laser Vision Correction, has performed refractive surgery for over 20 years. Dr. Moretsky is Past President of the American Osteopathic College of Ophthalmology. Locally, he is Past President of the Phoenix Ophthalmological Society and is a member of the Board of Trustees of the Arizona Osteopathic Medical Association. He has been in practice in Arizona since 1978.

For more information on the author, please visit www.arizonalaservision.com

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