Refractive surgery: which way now?

June 1, 2006

Advanced surface ablation, such as LASEK and Epi-LASIK, defined as a refractive laser technique that does not create a lamellar flap, is the wave of the future, according to Richard Yee, MD. He said that advanced surface ablations are ideal procedures for problem cases, such as those with thin corneas and high myopia and is even better for routine cases.

Yee's theory

"Advanced surface ablation has short-term complications such as pain and haze compared with the long-term complications of LASIK that are flap-related, such as thin flaps or button holes," he explained. Yee is professor and Joe M. Green Chair of the department of ophthalmology and visual science at the University of Texas Health Science Center of Houston Medical School, Houston, USA.

Other considerations are that the incidence of dry eye is more severe in LASIK and even higher in patients who undergo LASIK and use computers. Creation of flaps in LASIK increases higher-order aberrations. In addition, keratocytes decrease over the long term. "The safety profile and physiological optics are much better in patients who undergo advanced surface ablations," he said.

"Surface ablation will prevail because we have a better understanding of wound healing," he said. "When the basement membrane is left on, there is not as much scarring; the key factor in the early reports on LASEK is that the basement membrane was present.

"We can minimize the risk of haze, we can predict the patients who will develop haze, such as those who are younger and are darkly pigmented, and we can modulate haze and pain using autologous serum to less than half. We can re-treat haze; haze can be consolidated," he concluded.

Waring says...

The debate over which type of refractive procedure will prevail continues and, according to George Waring III, MD, the future belongs to lamellar surgery.

His rationale is based on a number of factors. "Refractive surgery is a patient-driven enterprise, it is elective, paid for by the patient and the number of procedures performed follows the consumer confidence index," he said.

LASIK has greater recognition than IOL implantation, and patients prefer a surface procedure rather than one done intraocularly.

"The perception on the part of patients is that a lamellar procedure is great," he said. Waring is the founder of InView Vision, Atlanta, USA.

Another argument that supports his thesis is that the results of LASIK in the vast majority of patients treated to correct myopia are near emmetropia and high numbers of patients with hyperopia achieve good visual acuity levels. The selection of appropriate patients for LASIK is improving with the avoidance of thin corneas, keratoconus suspects, extremes of steep and flat corneas and perfectionist patients.

"The use of lamellar surgery is what really makes it exciting. The reason it will survive into the future is that it covers the spectrum of patient needs: primary treatment, secondary treatment and finally it can be used as a rescue procedure following the failure of other types of refractive procedures," Waring stated.

The number of re-treatments that can be performed is unlimited as long as the patient has a sufficiently thick stromal bed and the flap is healthy, he added, and attributes the ability to re-treat to the manner in which the wound heals. In addition, surgeons have become more skilled at avoiding complications and microkeratomes cut flaps that are closer to the desired thickness.

The long-term challenges include acquiring long-term follow-up data; surgeons still need to determine if there is progressive corneal steepening over the long term. Others are developing faster lasers and even more accurate microkeratomes.