spotlight on technology & technique
Faster Recovery and Less Pain with Surface Ablation
Moria's Epi-K is jumping into the epi-LASIK marketplace.
By John Parkinson, Associate Editor

As the old expression goes, there is more than one way to skin a cat. A similar sentiment applies in the field of laser vision correction with regard to the types of procedures available for surgeons to use. With each of the methods come different side effects and various recovery times.

The newest surface ablation procedure, which promises less pain and faster visual recovery than other surface ablation procedures, is epi-LASIK. Such attributes would allow this surface ablation approach to compete more effectively with LASIK.

New epikeratome products are gradually being released into this small but growing segment of the U.S. refractive market. The Epi-K from Moria is one such epikeratome, which is currently undergoing clinical trials.

This instrument works on a platform based on the company's One Use-Plus microkeratome. Specifically, the Epi-K system consists of the Evolution Three control unit, a handpiece that has two separate motors -- one for blade oscillation and the other for translation -- and a disposable system that consists of tubing, rings, and a head.

Disposable parts of the Epi-K make it more convenient and sanitary for epi-LASIK procedures.

The Procedure

As is standard practice, the ring is placed over the eye, and dual suction ports maintain the eyelid position. The surgeon guides the blunt metal edge -- located in the head -- mechanically cleaving the epithelial layer and separating it between the basement and Bowman's membranes. The angle of the blunt edge follows along the plane of least resistance, separating and rupturing the plane.

The Epi-K instrument separates the epithelial sheet but preserves the structural integrity of the stroma. With a successful separation, the epithelium and basement membrane will be lifted, but all of Bowman's layer and the stroma will remain intact.

The epithelial flap is folded back prior to laser ablation of the exposed surface. There have been suggestions to hydrate the flap at this point in the procedure, but the surgeons who have been working with the Epi-K -- Barrie D. Soloway, M.D., F.A.C.S., director of Vision Correction, The New York Eye and Ear Infirmary, and assistant professor of ophthalmology, The New York Medical College, and Mark Swanson, M.D., director of the Swann Laser Institute, Agua Prieta, Sonora, Mexico -- prefer to leave the sheet alone at this point after separation.

Upon completion of laser ablation, the flap is hydrated with saline solution and then placed back over the cornea with a metal irrigation cannula. Then, a contact lens is applied over the sheet. The contact lens is kept on for approximately 4 or 5 days to assist in the healing process.

Patient Upsides

For those patients who might be pain averse or are apprehensive about use of a microkeratome blade or having alcohol placed on their eyes, epi-LASIK offers a less invasive method. By avoiding the use of a blade or alcohol, patients may experience less discomfort. Both doctors who have been participating in the clinical trials are reporting that epi-LASIK causes less patient pain than other surface ablation procedures. The doctors are still using medications for postoperative pain management, but say the severity and duration of pain is significantly less than with LASEK and PRK.

Dr. Soloway has been using aspirin and ketorolac tromethamine (Acular) eye drops for post-op pain. Dr. Swanson has been using diclofenac sodium (Voltaren Ophthalmic) for his patients' pain.

Dr. Soloway discusses the advantages of not using a microkeratome blade or alcohol. "Ultimately, the surface procedure is safer simply because we are not cutting the flap and whatever kind of biomechanical problems that can occur with that."

He also acknowledges that by not using chemicals, this surface ablation allows patients to get back to their normal lives quicker.

Dr. Soloway has been seeing the greatest changes in patients' comfort levels and visual acuity on day three; however, he was impressed and a bit surprised by the rate of patients' recovery on the first day after surgery. "[Post-op] day one, patients typically looked hard-to-believe good," states Dr. Soloway.

Speeding up patients' recovery can be partially attributed to repositioning the epithelial sheet on the cornea as an atypical bandage. Dr. Swanson explains the effect. "With this type of procedure [epi-LASIK], you mimic the physiological reproduction of cells."

	Dual suction ports maintain a steady eyelid position.

Features of Epi-K

One feature that separates the Epi-K from other similar products is its disposable aspect. By utilizing disposable tubing, rings, and heads, the Epi-K alleviates infection problems that can be associated with reusable devices. More importantly, by encasing the edge in a disposable plastic head, Moria has eliminated the risk that the blunt edge might be inadvertently sharpened by contact with another surface and potentially cut into the stroma.

Along with disposable parts that aid in safety and convenience, the product has shown consistency in producing viable epithelial sheets. Dr. Soloway has performed 40 epi-LASIK surgeries thus far using the Epi-K, and in all the surgeries except one he has been able to create a viable epithelial sheet. "We had one eye where we had some epithelium retained on the stromal bed. We got the flap, but there was a piece of retained epithelium on the bed that needed to be scraped away. Other than that, we were getting great flaps. 39 out of 40 [procedures], we got great flaps," states Dr. Soloway.

Dr. Swanson doesn't believe epikeratomes will dominate laser refractive procedures, but rather that they will work as a complementary instrument to LASIK keratomes, giving doctors and patients greater options and flexibility. "It's not going to replace the whole technology but it will be another instrument we have available," states Dr. Swanson.

He adds that an additional option will help patients who have special needs. For example, patients who might be at greater risk of developing dry eye would be good candidates for epi-LASIK due to the procedure's less invasive technique.

Challenges

Trying to perfect the angle at which the metal edge cleaves and securing the proper translation speed for movement of the head across the corneal surface were two challenges Moria encountered during the development process. The company also indicates that it was quite a challenge to create a consistently blunt edge as opposed to a sharp edge.

The Epi-K is in the final stages of clinical trials in pursuit of 510K FDA approval. Moria's goal is to release the device in the fourth quarter of this year in selected international markets and in the United States by early next year.

For more information on Epi-K, contact Moria by phone at (800) 441-1314 or visit its Web site at www.moria-surgical.com.