Surgeon predicts LASIK will be procedure of choice with excimer laser

Issue: November 1995

PANAMA CITY BEACH, Fla.—In spite of recent Food and Drug Administration approval of the excimer laser for photorefractive keratectomy (PRK), one ophthalmic surgeon predicts the excimer's true calling is for yet another refractive procedure, laser-assisted in situ keratomileusis (LASIK).

mugshot --- Albert Neumann.

"The excimer laser should be approved for use in combination with an ALK (automated lamellar keratoplasty) flap in LASIK," Albert C. Neumann, MD, told optometrists at the 12th Annual Bay Point Anterior Segment Symposium here. "It has great advantages over any other refractive surgical procedure currently available."

ALK, excimer synergistic

The excimer laser is better suited for LASIK than for PRK because of its potential for performing intracellular surgery, said Neumann, medical director of Neumann Eye Institute and Ambulatory Surgical Center, Deland, Florida. "The excimer light energy is projected onto the tissue and molecules are broken up and tissue is ablated," he said. "It is very accurate, and each pulse can remove a tenth of a micron, so potentially we have an instrument here that can do intracellular surgery in the future."

To complement the laser's accuracy is ALK, a version of keratomileusis that has been around for years. Luis A. Ruiz, MD, is credited with simplifying keratomileusis and shortening the length of the procedure from an hour and a half to about 10 minutes. In ALK, a microkeratome removes a layer of cornea, or cap, then a second pass of the instrument removes a precise amount of corneal tissue to correct high myopia. Hyperopia can also be corrected by a deeper microkeratome pass.

"Suddenly every surgeon could do ALK (following Ruiz's modifications) and the complications were minimized because no suturing was required," Neumann said. "So when you combine ALK with excimer, you have something synergistically beautiful because the accuracy is greatly enhanced and coexisting astigmatism can simultaneously be treated."

Bowman's membrane preserved

In patients undergoing LASIK, a corneal flap with a hinge is created with the pass of a microkeratome. The excimer energy is applied to the stromal bed, without violating Bowman's membrane, as with PRK.

"That is the key," Neumann said. "By preserving Bowman's you do not see any haze or significant regression. You only insult Bowman's at 8 mm of the para-central optical zone, i.e., the diameter of the cut (with the microkeratome). The rest of Bowman's is intact. Whenever you violate Bowman's by removing it with surface ablation you may get haze and regression of effect."

Since the cornea's response to surgical trauma will vary, Neumann advocates performing LASIK on the non-dominant eye before performing surgery on the fellow eye. "The valuable information you get by waiting is incredible. You can see some of the healing, even though it is early, and you know whether the patient is undercorrected or overcorrected."

Neumann currently performs LASIK in Orlando, Santo Domingo and Hamberg.

Neumann said LASIK gives surgeons and patients a procedure that can accommodate all ranges of myopia, hyperopia and astigmatism, from –30 D up to +5 D. In addition to preserving Bowman's membrane and preventing stromal haze, LASIK allows rapid recovery of vision and early refractive stability without postoperative pain and steroid management.

Neumann does agree, however, that the future also holds problems for LASIK, "but from my 15 years of experience, no other procedure has done this well this early," he said.