Expanded use of femtosecond lasers and wavefront technologies are at the forefront of corneal-based refractive surgery.

Individualized treatment is the goal of the latest technology in corneal refractive surgery, including the use of lasers and corneal inlays. However,

the economic downturn has hampered those innovations.

Private practice has also been affected by the recession, OSN Cornea/External Disease Board Member Francis W. Price Jr., MD, said in an interview with Ocular Surgery News. Dr. Price said the impact on private practice could lead to reduced research and development.

“There are a lot of things going on,” he said. “But everything is languishing right now. If someone wants you to pay half a million dollars for a laser, it’s kind of hard to justify that. It makes it tough.”

Although corneal-based refractive surgery has not escaped the effects of the recession, technology in the field continues to uncover ways to individualize treatment, offering the safest and most effective options for each patient, according to David R. Hardten, MD, OSN Cornea/External Disease Section Editor.

Dr. Hardten said physicians have debated wavefront-optimized vs. wavefront-guided LASIK techniques for some time, as they report the merits of each in practice. In addition, femtosecond lasers and corneal inlays are also being used more often in the clinical practice.

“The current hot topics are the expanded use of femtosecond flap creation in LASIK and the expanded use of wavefront-derived, but then also wavefront-optimized treatments or an optical zone or an ablation zone optimization with LASIK — [basically] the customization of the surgical procedure to the individual patient,” he said. “So we’re trying to, in the individual patient, achieve optimal outcomes.”

Wavefront technology

Since wavefront-optimized platforms first entered the market, there has been debate over whether it is better than wavefront-guided and which patients benefit from it most. Numerous companies have wavefront treatment platforms, including Alcon’s WaveLight, Abbott Medical Optic’s WaveScan WaveFront, Bausch and Lomb’s Zyoptix and Carl Zeiss Meditec’s WASCA Analyzer.

“Good results occur with each of the platforms, and the question is: Which one makes the most sense? A lot of that has to do with the machine that you own,” Dr. Price said.

He said he has found that only a small percentage of corneal refractive patients requires wavefront-guided treatments. Wavefront modification can optimize spherical aberration, which may be an added benefit of the treatment. Clinicians are not yet agreed if zero is the best spherical aberration or if presbyopic patients benefit from an increased depth of focus with degrees of positive or negative spherical aberration.

Dr. Price said an increased understanding of positive and negative spherical aberrations and when they can assist with depth of focus could result in improved applications.

“I think that we’ll be paying attention to the wavefront more to decide how we want to change it, perhaps, rather than just trying to zero it all out,” he said.

Wavefront-optimized treatments appear to provide the most benefit to refractive patients and could become the most commonly used technique. Those treatments are helpful in that they do not treat distortions that could be caused by changes in the crystalline lens or dry eye syndrome.

“The last thing that we want is to make permanent changes to the cornea based upon changes that we see in the lens or secondary to dry eye and things like that,” Dr. Price said.

The ultimate customized regimen would offer a choice of wavefront-guided, wavefront-optimized or a topography-guided treatment. That system could account for both a patient’s age and health of the corneal surface. Such a combination platform has not yet reached the market, he said.

Femtosecond lasers

The use of femtosecond lasers to create flaps in refractive surgery has been steadily gaining interest because of the safety and precision of the cuts, according to OSN Cornea/External Disease Board Member Roger F. Steinert, MD, but the economy has stalled the technology from reaching many private practices.

“Unfortunately, the economy and economics drive a lot of this,” Dr. Steinert said. “The therapeutic applications are extremely important for the industry because if we can take unhappy patients and make them happy and see better, it will be a positive thing for the industry as a whole. … When business slows down, so does development; it’s just the economics of it.”

Dr. Price said the latest version of the IntraLase femtosecond laser (AMO) was released just when the economic situation worsened.

“People are on the sidelines right now with what’s going on with some of the femtosecond lasers just because it’s such a huge cost outlay,” he said. “One of the big advantages that femtosecond laser has over mechanical microkeratome is in the flap design. Not only do you get a planar flap, which most of us think is better, but you get a vertical or near vertical incision on the side, so that should make it less likely to get endothelial ingrowth, especially on re-treatments.”

The new IntraLase technology can perform oval and back-beveled cuts, creating a flap that “snaps into place,” promoting the best possible healing, according to Dr. Price.

Another laser, the Femtec (20/10 Perfect Vision) alters the corneal biomechanics to multifocal, allowing near vision to correct for presbyopia, Dr. Steinert said.

Corneal inlays

Lasers will continue to play an important role in corneal-based refractive surgery in the near future, but corneal implants have also been gaining in popularity, Dr. Hardten said.

Intacs (Addition Technology), a corneal inlay, gained a humanitarian device exemption by the U.S. Food and Drug Administration in 2004 for use in keratoconus cases and is used frequently now, he said.

Other inlays for presbyopic use are in clinical trials in the U.S.

“It seems like there is increasing attention toward some corneal implants, things like Intacs or presbyopic corneal inlays, like AcuFocus [corneal inlay], for example. So I think we’ll see some continued attention to corneal inlays,” he said.

Author: Erin L. Boyle

Source: OCULAR SURGERY NEWS U.S. EDITION