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WHAT'S NEW IN REFRACTIVE SURGERY?
Improvements and new products expand possibilities for a larger patient population.
BY RACHEL M. RENSHAW, EXECUTIVE EDITOR

The IntraLase Femtosecond Laser.

Refractive surgery has never been more dynamic, thanks to relatively recent advances in technology such as wavefront ablation, precision lasers, surface techniques and, most recently, phakic refractive and presbyopia-correcting IOLs.

But of all the changes in refractive surgery that have taken place over the past decade, perhaps the most significant and exciting development has been the evolving — and expanding — profile of the patient who is a candidate for refractive procedure. The days of the 30-something patient with myopia and possibly some astigmatism being the prototypical refractive candidate are long gone, as the tools in the refractive surgeon's armamentarium have increased and evolved. Today's refractive candidate can be a young adult, an octogenarian or anyone in between. Clearly, the rapid expansion of refractive procedures across the age spectrum is creating new opportunities for forward-looking practices.

This article will focus on the changes in refractive surgery that have most affected surgeons' practices, as well as how these changes are bringing benefits to a much broader patient base than ever before.

Laser Technology

Since the introduction of wavefront technology, surgeons have been able to customize the laser treatments that they are delivering to their patients, producing better results and fewer induced aberrations to the cornea in the process. How this technology is used is the differentiating factor in each platform that is available in the United States, among them being CustomVue (AMO/VISX, Santa Clara, Calif.), LADARVision with CustomCornea (Alcon, Fort Worth, Texas), Zyoptix (Bausch & Lomb, Rochester, N.Y.) and Allegretto Wave (WaveLight, Erlangen, Germany). However, whether surgeons are using a wavefront-guided or wavefront-optimized treatment, the results have been shown to be more precise with fewer induced aberrations and reduced retreatment rates. (For more on wavefront-guided vs. wavefront-optimized see page 33.)

Daniel S. Durrie, M.D., principal of Durrie Vision in Overland Park, Kan., says that most of the developments in lasers for refractive surgery have revolved around maturation of the technology, rather than new inventions. "What that means to me is that the laser procedure is safe, accurate and consistent, and patients are seeing that now is a good time to have surgery," he says. "We don't have a new wavelength laser, a new spot size or a new general concept. There's some discussion on topography-guided ablation but not anything that's gotten very far down the pipe."

The Verisyse phakic IOL.

The Visian ICL.

The interest in lasers for refractive surgery seems to revolve increasingly around flap creation. The IntraLase Femtosecond Laser (IntraLase, Irvine, Calif.) has changed the way many surgeons are performing LASIK. Eric Donnenfeld, M.D., medical director of TLC Laser Center in New York and a partner with Ophthalmic Consultants of Long Island and Connecticut, says that while the newer microkeratomes that are available provide reproducibility, reliability and safety, laser flap creation represents a more significant continuum in the charge toward higher technology.

"I have been impressed by the improvement in the IntraLase, which provides smoother beds with less irregularity, less inflammation and lower energy readings [than previous generations of the laser]. As femtosecond laser technology continues to improve, this will largely replace keratomes in flap formation for patients undergoing LASIK," says Dr. Donnenfeld.

Brian Will, M.D., president and medical director of Will Vision and Laser Centers in Vancouver, Wash., cites complications and medicolegal issues associated with blade flaps as the main reason why he prefers the IntraLase for LASIK. "Nothing ruins the day faster than a flap complication from a microkeratome, and the frustration and medical-legal exposure they provide is rapidly becoming unacceptable in modern refractive surgery," he says.

According to Dr. Will, the latest generation of the IntraLase can be run at 60 kHz and higher, allowing for more precision and better safety. He adds that the femtosecond laser provides rapid visual recovery and reduces the incidence of minor complications such as epithelial sloughing or ingrowth.

Dr. Will cites other applications for the IntraLase also. "With the ability of this technology to create intrastromal channels for Intacs (Addition Technology, Des Plaines, Ill.) and provide unlimited choices on graft and host tissue architecture, therapeutic applications of this device will rapidly revolutionize the field of corneal transplantation," he says.

The crystalens accommodative IOL.

Two companies in Europe currently have femtosecond technology, but when and if they will be marketed in the United States remains uncertain. The DaVinci Femtosecond Laser, from Zeimer Ophthalmic Systems (Port, Switzerland) received a CE mark and was cleared by the FDA in March, but is not available in the United States. The Femtec, from 20/10 Perfect Vision (Heidelberg, Germany) is only available in Europe.

The Resurgence and Improvement of Surface Procedures

While LASIK remains the laser refractive procedure of choice, there has been much talk about advanced surface ablation in that it eliminates concerns about flap complications, and some claim that vision is more stable in the long term. Why the shift?

Dr. Donnenfeld says that it is more of an additional tool, rather than a true shift from one procedure to another. "I don't see surface ablation as a panacea or a procedure that competes against LASIK but one that can be used to improve quality of vision and safety for some patients," he says. Among the patients for whom he uses surface ablation are those with an increased risk of ectasia, and those who require a smoother surface on which to perform ablation.

The debate continues as to how much surgeons should be utilizing surface procedures vs. LASIK. Dr. Durrie says he is using surface ablation approximately 25% of the time for his patients undergoing laser refractive surgery.

"If someone has had previous surgery, an RK that I'm upgrading or a small LASIK flap in the past that's causing coma or other problems, I have a tendency to use surface ablation," says Dr. Durrie. "I will also use surface ablation for more complicated cases, such as post-transplant, or in other situations where I don't want to make a flap on the cornea."

Dr. Durrie warns against the notion that patients with dry eye are automatically good candidates for surface ablation. "I caution that it's important to control the dry eye and any blepharitis ahead of time, because those patients have trouble healing, even with surface ablation," he says.

For more on surface ablation procedures, see "Fine-Tuning the epi-LASIK Procedure" on page 27.

The ReZoom multifocal IOL.

The ReStor multifocal IOL.

Phakic IOLs

Phakic IOLs have also expanded the possibilities in the refractive arena. Patients who were previously outliers for refractive surgical correction now can have these lenses implanted to correct higher ranges of myopia. The response to the Verisyse (AMO) and Visian ICL (STAAR Surgical, Monrovia, Calif.) has been positive but limited, and they are only approved for myopia, and not hyperopia and astigmatism. Staar Surgical is currently awaiting premarket approval from the FDA for its toric version of the ICL, the TICL for hyperopia and astigmatism.

David C. Brown, M.D., F.A.C.S., medical director and founder of the Eye Centers of Florida in Fort Myers, implanted the first Visian ICL in a patient with myopia during the U.S. clinical trials. He says the results with the ICL are "universally outstanding."

Dr. Brown recommends the ICL for all of his patients in the approved range of treatment, from -3 D to -16 D for correction, and above -16 D for reduction. While many surgeons may reserve the ICL for the higher ranges of myopia, Dr. Brown prefers the ICL for more patients because he says that the quality of vision is excellent and often exceeds that offered with LASIK. Additionally, there is no risk for ectasia with the lens implant and the procedure is reversible.

Refractive Results for the Presbyope

Perhaps the hottest news in refractive surgery is presbyopia-correcting IOLs. This technology has been practice-changing, because it not only redefines who is a candidate for refractive surgery, it also changes who is a refractive surgeon. The lines are blurred, with cataract surgeons having the ability to provide their patients with excellent near, intermediate and distance vision. The three IOLs that are currently FDA-approved for treating presbyopia include the accommodative crystalens (eyeonics, Aliso Viejo, Calif.) and the multifocal IOLs, ReZoom and ReStor.

"Presbyopia-correcting IOL technology has allowed our patients to break the constraints of presbyopia and pseudophakia following cataract surgery, allowing our patients to function better than normally after they have become presbyopic," Dr. Donnenfeld says. "What I've noticed is a continued response from ophthalmologists as they have adopted this new technology. We now understand and have a real appreciation for the importance of quality of vision not only for our multifocal patients but for all of our cataract patients."

Dr. Donnenfeld also suggests that accommodative IOL technology may be the trend that overtakes the market in the future. "There are a variety of new accommodating IOLs that are entering trials now and while they may be several years away, there's no doubt that these lenses will become more and more important," he says. Such accommodative technology includes the Synchrony A-IOL (Visiogen, Irvine, Calif.), which has recently received its CE mark in Europe. The Sychrony is a dual-optic injectable IOL that accommodates via a spring mechanism between the anterior and posterior optics, switching the focus from near to far.

Dr. Will agrees that IOLs have had a significant impact on refractive surgery. "Without question, the introduction of presbyopia-correcting IOLs has opened the door to an entirely new vista in vision correction" he says.

He adds that while the technology is currently primarily aimed at patients undergoing cataract extraction, the application of these IOLs includes clear lens exchange procedures for younger patients with presbyopia who are motivated to have better multifocal vision. "Current phacoemulsification techniques are capable of delivering both stellar surgical results and a very low incidence of vision-threatening complications — both critical factors for widespread market acceptance outside of cataract surgery. As future market forces broaden the acceptability of clear lens exchange, an additional critical factor for existing laser vision providers will be access to ophthalmic outpatient ambulatory surgery facilities so that these procedures can be delivered in a cost-effective manner," Dr. Wills says.

Conductive keratoplasty (CK) is another option for patients with presbyopia and is being used in more ways than previously, such as after LASIK or following implantation with a multifocal, accommodative or a phakic IOL. While the regression rate is similar to that of hyperopic LASIK and PRK, patients should be counseled that the gains in near vision will regress and that retreatment may be necessary. (For more on CK see page 51.)

Mutlifocal Ablations for Presbyopic Correction

More exciting developments for correcting presbyopia loom on the horizon. Sondra Black, O.D., clinical director for TLC Toronto, performs pre- and postoperative examinations and counseling for patients participating in the FDA clinical trials for multifocal ablation with the VISX Star4 using the CustomVue platform. The international multifocal LASIK trial is led by W. Bruce Jackson, M.D., chair of the University of Ottawa Eye Institute in Canada.

"The ablation is a central-near pattern derived from a patient's wavefront. Sixty percent of the patient's scotopic pupil has reading vision and then it blends out. There's some intermediate and then some distance on the periphery," says Dr. Black.

Of the patients in the Canadian trial, Dr. Black reports that approximately 96% treated binocularly with the multifocal ablation pattern have achieved 20/25 and are able to read at J3.

The postop visual recovery lacks the "Wow" effect that patients get from LASIK, but Dr. Black says that with counseling, patients are able to understand the visual benefits. "I tell patients that it is going to take 3 months before they're comfortable with reading. I've seen an improvement in my patients from 9 months to 12 months on the eye chart," she says, "so it's not just their own adaptation but the numbers that show it's improving."

Dr. Black says that multifocal ablations have the potential to further change the refractive market. "Everyone is talking about the multifocal IOLs and, yes, they're a great option for a cataract patient, but if you had a choice of doing a corneal ablation or going inside the eye to treat presbyopia, what are you going to do?" she asks.

Another possible solution for presbyopia currently in clinical trials is one that employs a "pinhole" effect to improve depth of field and reading vision. According to Dr. Donnenfeld, Acufocus (Irvine, Calif.) has just finished phase 1 clinical trials for this corneal inlay device and is enrolling patients in its next phase.

Patients Expect the Best

While all of the doctors interviewed for this article stated that major innovations may be far in the future, all agree that, as a result of the advances in technology and technique, patients have never been more demanding. The need for better quality outcomes will only increase as those same patients who sought LASIK begin to come of age as presbyopes and, subsequently, cataract patients.

"It's a statement of fact that refractive surgery will continue to improve as technology expands our horizons and refractive surgery has never been safer or provided better quality of vision than today," says Dr. Donnenfeld. "There's no doubt that it will continue to improve in the immediate future, providing a tremendous boon of quality and safety for our patients."