Safety, outcomes of surface ablation versus lamellar surgery debated

June 1, 2008

In a debate at the American Academy of Ophthalmology annual meeting, one surgeon contended that surface ablation is safer and more effective than LASIK because of complications associated with flap creation in lamellar procedures. His counterpart, however, suggested that LASIK is preferable because of risks associated with surface procedures, including ectasia, infections, and haze.

Key Points

New Orleans-Surface ablation is safer and produces better visual outcomes than lamellar surgery, said Vincent P. de Luise, MD, FACS, whereas Minas T. Coroneo, MD, MS, FRANZCO, FRACS, countered that LASIK is preferable if patients must choose between the two procedures. They offered their views during a point-counterpoint debate at the American Academy of Ophthalmology annual meeting.

PRK, LASEK, and epi-LASIK are surface ablation procedures, whereas LASIK is a lamellar procedure, regardless of whether it is performed with a thin flap, thick flap, or a femtosecond laser in sub-Bowman's keratomileusis.

Speaking first, Dr. de Luise argued that techniques in which a flap is created are more risky than surface procedures. "With apologies to Gertrude Stein, in terms of surface ablation versus LASIK, a flap is a flap is a flap. Not making a flap is safer than making a flap, regardless of the method employed. True, the femtosecond laser creates a safer flap than a mechanical microkeratome, but it's still a flap no matter how you slice it."

Infection is not unique to either surface or lamellar procedures. In surface procedures, however, infections usually involve gram-positive organisms and can be treated at the surface with topical antibiotics because the infectious agents are accessible.

The unique risks of lamellar procedures include striae, buttonholes, epithelial ingrowth, incomplete flaps, diffuse lamellar keratitis (DLK), transient light-sensitivity syndrome (TLSS), and glare. The growing use of the femtosecond laser to perform surgery has dramatically reduced the incidence of complications such as buttonholes, striae, and incomplete flaps. A surface procedure, however, would lessen the risk of glare, ingrowth, or DLK, Dr. de Luise said. He added that infections typically are more difficult to eradicate when they occur under the flap.

He acknowledged that surface ablation procedures have a prolonged recovery time compared with LASIK but noted that newer advanced surface ablation techniques such as epi-LASIK are closing the gap. Overall, no difference exists in contrast sensitivity between surface and lamellar procedures, although one study showed that surface ablation is associated with better sensitivity than LASIK and another suggested that contrast sensitivity increased with LASEK and did not change with LASIK, Dr. de Luise said.

"Surface ablation is safer than LASIK," he said. "It's easier to perform. There's no flap, ergo no buttonholes. There's no flap, ergo no striae. There's no flap, ergo no ingrowth. There's no flap, ergo no DLK, TLSS, or rainbow glare."

Surface ablation also results in less ectasia and fewer medico-legal problems, said Dr. de Luise. LASIK-induced neurotrophic epitheliopathy (LNE) is a risk with both types of procedures; although LNE is transient, return of sensation can take up to 2 years following PRK and up to 5 years following LASIK.

"If you do these procedures, choose wisely. Choose the appropriate procedure for the appropriate patient, and you will go to the stars," Dr. de Luise concluded.