Patient Management
A Look at LASEK
Surgeons continue to fine-tune what they believe is a promising new procedure.
By Ophthalmology Management Staff

Dr. Massimo Camellin of Italy first described LASEK about 2 years ago. While some have dismissed the technique, which is a stromal laser ablation under an epithelial flap, as nothing more than a repackaging of PRK, others have embraced it as an important step in the evolution of refractive surgery.

ADVANTAGES AND DISADVANTAGES

Surgeons who are performing the procedure have been able to achieve results similar to or better than the typical results of LASIK, particularly in regard to induced spherical aberrations and post-op glare. Another reason the procedure is appealing is because the flap isn't created with a microkeratome; therefore, the potential complications associated with the stromal flap in LASIK are eliminated.

LASEK has some advantages in patient selection as well. In cases where LASIK might be problematic, such as very steep or very flat corneas, epithelial basement membrane disease, filtering blebs, asymmetric astigmatism or thin corneas, LASEK can be performed without difficulty. Similiarly, LASEK surgeons generally consider the procedure a better choice for patients with high myopia, large pupils, deep-set eyes, scleral buckles, previous vitrectomy, optic nerve drusen or those taking Coumadin.

Some preliminary evidence suggests that LASEK, like PRK, may be a better procedure than LASIK for customized wavefront ablations. Because there's no stromal flap that has to be precisely replaced over the ablation, the full benefit of the ablation can be realized.

In addition, several surgeons who've been performing LASEK have found that enhancements work well, usually with no more difficulty than the original procedure.

On the other hand, postoperatively, LASEK requires more intense management. Patients can have variable post-op pain for the first 24 to 48 hours. A bandage contact lens has to be worn, usually for 4 days. Vision is typically blurry for the first week. And, in many cases, steroid eye drops are used for 1 to 3 months.

Because his LASEK results and complication rate were much better than with LASIK, LASEK is now the sole refractive procedure that Thomas V. Claringbold, D.O., performs in his Michigan practice. He explained that another concern with LASEK is the haze that it might induce. With the more than 400 patients that he's operated on, he's noted fine reticular opacities in some patients at 3 months post-op. But "At 6 months, they're gone," he said. In his retrospective study of 222 eyes treated for myopia, at 12 months, none of the 84 eyes available for follow-up demonstrated reticular opacities or any appreciative haze.

In addition, he noted no epithelial problems, such as recurrent erosions, postoperatively. No severe dry eye problems were noted, and none of the patients required punctal occlusion. To date, none of the 222 eyes has needed an enhancement.

Dr. Claringbold began performing LASEK monocularly for each patient, usually 1 month apart. Now, barring special circumstances, he performs every case bilaterally, on the same day.

THE BASIC TECHNIQUE

During this year's meeting of the American Society of Cataract and Refractive Surgery, Lee Shahinian Jr., M.D., of California, described the LASEK technique:

"After topical anesthesia, an 8-mm, 270-degree trephine is centered on the pupil. Moderate downward pressure is applied to cut the corneal epithelium. The trephine can also be slightly rotated. Because the blade extends only 270 degrees, a hinge is created at 12 o'clock.

"Next, an 8.5-mm well is positioned on the cornea and filled with a 20% alcohol solution. This solution is prepared by mixing 1 cc of dehydrated ethanol and 4 CCs of distilled water and passing the solution through a .22-micron filter. The dilute alcohol is usually left on the cornea for 30 seconds, but this timing may be altered depending on patient age, contact lens history and experience with the fellow eye.

"The alcohol is removed with a merocel sponge. The corneal surface is then rinsed with balanced salt solution. The cornea is dried with a merocel sponge to expose the epithelial trephine mark. A micro hoe creates the edges of the epithelial flap. Next, an epithelial detaching spatula is used to peel the epithelium, with its basal lamina, away from Bowman's membrane. The epithelial flap is gathered on its hinge at 12 o'clock, exposing a glassy smooth Bowman's membrane.

"For the myopic laser ablation, I typically subtract about 10% from the spherical component of the PRK nomogram. The amount subtracted is reduced for very young patients and increased for very high myopia.

"Following the laser treatment, chilled balanced salt solution is applied to the cornea. The epithelial flap is returned to its original position with a smooth spatula. Unlike with traditional LASIK, flap alignment isn't critical. The flap usually overlaps the edges of its bed, but that also is not a problem. Typically, the flap edge is well healed by the following day.

"A bandage soft contact lens is applied to the cornea. This lens is typically removed on the fourth postoperative day. Nonsteroidal anti-inflammatory drops and antibiotic drops are instilled at the end of the case."

Some surgeons also employ a smoothing technique before the ablation. To even the operative surface, they brush on a viscoelastic-like substance, which settles into the microscopic "valleys" in the tissue. It appears that smoothing may further reduce the incidence of induced aberrations.