June 2017

 

COVER FEATURE

 

Rebirth of laser vision correction
New technologies in corneal refractive surgery poised to spur growth


by Liz Hillman EyeWorld Staff Writer

   

Dr. Wiley performs the femtosecond laser portion of SMILE with the VisuMax laser. This image shows the initial portion of the posterior “refractive cut,” which is the most posterior laser cut in SMILE. This is created in a circular pattern starting at the periphery and moving central.

Dr. Wiley performs topography-guided LASIK with the Nidek Quest excimer laser following a femtosecond laser-created flap.
Source (all): William Wiley, MD




“We can more specifically go after what patients’ eyes are presenting to us and what their desires are, and that’s the beauty of having all of these choices.”
—Vance Thompson, MD

New technologies are bringing patients in off the sidelines and expanding the possibility of laser vision correction to those who might not have been candidates before, physicians say

Driven by new technologies, techniques, better patient selection, and thus better outcomes, some practices have seen a resurgence in corneal refractive surgery, especially on the laser vision correction front, said William Wiley, MD, medical director, Cleveland Eye Clinic, Cleveland.
According to the 2016 ASCRS Clinical Survey, the average annual laser vision correction volume was 301 cases—relatively consistent with previous ASCRS Clinical Surveys. But respondents, on average, projected that in 3 years their annual laser vision correction volume would increase by nearly 80%, up to an average of 535 cases annually. Among U.S. respondents, on average, 86% said wavefront technology covered the majority of their current corneal refractive procedures, compared to 48% among international respondents. Conversely, international respondents were more likely to perform standard ablations, small incision lenticule extraction (SMILE, Carl Zeiss Meditec, Jena, Germany), and topography-guided procedures. In the next 3 years, 73% of U.S. respondents said they thought the majority of their corneal refractive procedures would be wavefront, but topography-customized in this group jumped to nearly 20%.
LASIK, now more than 25 years old, has come a long way, said Stephen Slade, MD, Slade & Baker Vision Center, Houston.
“LASIK is now modern LASIK—eye trackers, fast ablations, femtosecond laser keratomes, sophisticated aspheric ablations. It’s not at all the same procedure, and the results are wonderful,” Dr. Slade said. “Wavefront-optimized LASIK … is 94–95% 20/20. Topographically based ablations … are in the same range.”
While wavefront ablations, first approved by the U.S. Food and Drug Administration (FDA) in the early 2000s, measure aberrations or irregularities in the total eye and then fix them on the cornea, topographically based ablations, approved in 2013, make the cornea itself more regular. Thus, the latter procedure may be more suited for older patients potentially facing cataract surgery with multifocal IOLs in the next decade where a more regular cornea would be preferred, Dr. Slade said.
More recent advances in laser vision correction include the iDesign Advanced WaveScan Studio System (Johnson & Johnson Vision, Santa Ana, California)—FDA approved in May 2015—and SMILE—FDA approved in September 2016 for the VisuMax laser (Carl Zeiss Meditec).
“I think the increase in the volume of refractive surgery that we’re experiencing is because patient satisfaction levels are at an all-time high,” said Vance Thompson, MD, Vance Thompson Vision, Sioux Falls, South Dakota. “I think it’s because of the big companies out there continuing to do research and development to bring us technologies that fit various indications, which leads to high patient satisfaction. When patients are telling other people and their doctors about their joy after refractive surgery, that’s what drives the market. I think we work for the people and if we make them happy, [this] is what leads to a growth in refractive surgery.
“As far as new technologies, I think they’re playing a great role in increasing patient confidence, lessening the fear factor, and increasing patient satisfaction postoperatively. Having been an investigator in the PRK, LASIK, and SMILE trials in this country, and phakic IOLs, I’ve seen a lot of refractive surgery advancements,” Dr. Thompson continued, adding that he currently performs all of these corneal refractive procedures.

Topography-guided ablations

In his practice, Dr. Wiley credits topography-guided PRK and LASIK—first FDA approved for Contoura Vision (Alcon, Fort Worth, Texas) and later the Customized Aspheric Treatment Zone (CATz, Nidek, Fremont, California) technology—with bringing in patients who might have been on the sidelines of laser vision correction.
“We saw a bump in our procedure volume with that for virgin eyes,” Dr. Wiley said, adding that it has also started bringing in patients who might have had earlier refractive surgery and who experienced mild side effects or had irregularities in their eye to begin with. “We saw the ability to attract new patients with topography-guided [technology] but also maybe some patients who weren’t quite as excited with their original treatment years ago; it may be a therapeutic option to help them.”
A topographic approach to laser vision correction—which takes a highly detailed map of the entire cornea—Dr. Thompson said, revealed that there were more patients than previously realized who had elevations and depressions within their corneas that were not being addressed.
“Being able to do these ablations and deliver more energy to the elevations and less energy to the depressions has been something that we’ve been surprised at how many abnormal corneas can benefit from this in both PRK and LASIK,” he said.
Dr. Wiley treats all of his LASIK patients with topography-guided technology, provided he is able to obtain a good topography scan. However, he sees some physicians reserve the technology only for patients with more irregular corneas.
“Some people say, ‘Why use it if it’s a virgin eye with no problems?’ Yes, chances are it may not make a big difference in those eyes where the topography effect is so small that you might only be treating 1 to 2 microns of irregularity; however, there has been no demonstrated downside to treating even the slightest topographic irregularities. … To me, it self-limits the eyes that are more regular,” Dr. Wiley said. On the other hand, he added that research has shown that some wavefront-guided technologies are not necessarily better for all cases.

iDesign wavefront technology

Edward Manche, MD, director of cornea and refractive surgery, Byers Eye Institute, and professor of ophthalmology, Stanford University School of Medicine, Stanford, California, has used the iDesign aberrometer—which incorporates aberrometry, wavefront refraction, topography, keratometry, and pupillometry—for more than 5 years, participating in the FDA clinical trials that led to its approval.
“I have had outstanding results with the iDesign wavefront-guided treatments,” Dr. Manche said. “A higher percentage of patients achieve visual acuities of 20/20
and 20/16 compared to the older WaveScan wavefront-guided treatments. The technology can also be used in an off-label fashion to treat highly aberrated eyes that were previously untreatable.”
Similarly, Dr. Thompson mentioned how this technology could benefit those with higher-order aberrations, as well as those with low light image quality issues.
Dr. Manche went on to say that the current iDesign wavefront-guided technology has five times the resolution compared to the previous generation WaveScan system. “I have not found any disadvantages to the new system and use it nearly exclusively for all of my wavefront- guided treatments,” he said.
Dr. Wiley said that his practice has looked at iDesign but hasn’t brought on the technology yet. “It’s nice to see that the VISX platform [Johnson & Johnson Vision] is improving their technology,” he said.
A 2016 study published in the Journal of Refractive Surgery compared visual outcomes of wavefront-guided ablation using the iDesign aberrometer and STAR S4 IR excimer laser system (Johnson & Johnson Vision) and topography-guided ablations with the EC-5000 CXII excimer laser system (Nidek).1 Overall, the study authors concluded that both systems yielded “excellent results in predictability and visual function.” The wavefront-guided system showed some possible advantages in quality of vision, and selecting the appropriate system based on each patient’s eye conditions may be important, according to the study authors.

SMILE

As Dr. Slade put it, physicians are just starting to figure out who might be good SMILE candidates. In the U.S., SMILE is currently only approved to correct sphere, not astigmatism, limiting indications on that front. However, the data from the SMILE trial for astigmatism has been submitted to the FDA for approval and “that data is excellent,” Dr. Slade said, noting that he expects approval will come within the next year and a half.
Potential benefits to the SMILE procedure include biomechanical stability in the cornea, less inflammation, and fewer dry eye symptoms, though these have yet to be fully established, according to Moshirfar et al.2 SMILE has been shown to result in less corneal denervation, fewer higher-order aberrations, and faster corneal nerve healing compared to LASIK, the study authors wrote.
What’s more, as a flapless procedure, it could be an option for those whose lifestyle or hobbies would carry the risk of flap trauma, Dr. Wiley said.
“Some of the things that are more borderline—mild dryness or a slightly thinner cornea, a slightly higher prescription coupled with lifestyle—factor in to one procedure being a little better suited for a patient than another,” Dr. Wiley said. “At this point, it’s more of an art than a science, understanding the relative advantages versus disadvantages of these new procedures.”
SMILE, Dr. Wiley pointed out, can take longer compared to LASIK in some cases to get the “wow effect.” “In someone who has a small prescription, thick cornea, and doesn’t have lifestyle concerns, LASIK might get them to ‘wow’ quicker and be more straightforward,” he said.
There might also be patients who are worried about a flap in their cornea but who are reluctant to have PRK, due to discomfort and delayed visual recovery, Dr. Manche said. These patients, who Dr. Slade described as those psychologically worried about LASIK, might find SMILE a palatable alternative.

Not replacing but expanding the market

Dr. Thompson sees newer laser vision correction technologies as “additives to the menu.” With all of the options available, including traditional LASIK and PRK, Dr. Thompson said the patient consult can be lengthy, but it’s worth taking the time.
“We can more specifically go after what patients’ eyes are presenting to us and what their desires are, and that’s the beauty of having all of these choices,” he said.
Dr. Wiley said when you have more patients who are candidates for laser vision correction, thanks to more options expanding indications, the whole field benefits.
“Any time you take away a potential hurdle for one patient or classification of patients, it grows the market in a way that’s exponential where each patient who gets refractive surgery tells five or six other patients about their experience. The more patients going through that process, the larger the market gets across the board,” Dr. Wiley said. “… even within the scope [of the procedure] if you increase satisfaction among patients, let’s say you decrease even just a little bit of the dryness … that’s less negatives out there.”
Not only have treatment technologies improved, but diagnostics have improved to help physicians better match patients with the treatment that could yield the best outcome for them. Dr. Slade said a common problem is patients coming in not knowing what they’re a candidate for.
“People will spend years deciding what is best for them—PRK, LASIK, SMILE. They’ll get on the internet, compare the different procedures, and try to find out which is best, but they don’t know which is best for them,” Dr. Slade said. “We encourage people to come in and get a screening evaluation.”
From the physician side of it, Dr. Slade said you and your patients are better off if you stay up to date with technology.
“You need to know about SMILE and you need to be able to intelligently answer questions about it. … Just like how [laser vision correction] is an elective procedure, buying a new laser, learning a new technique is an elective procedure or purchase, and you get to do it whenever you want.”
Dr. Wiley cautioned colleagues and industry against pitting one technique against another. “We don’t want to get into a situation of pitting one technology against the other and saying, ‘LASIK is bad and I have SMILE, my competitor down the road doesn’t.’ … I think being careful with how we apply the new technology, educate the patients, and market the procedures, we’re better off if we market refractive surgery as a whole.”

References

1. Toda I, et al. Visual outcomes after LASIK using topography-guided vs. wavefront-guided customized ablation systems. J Refract Surg. 2016;32:727–32.
2. Moshirfar M, et al. Small-incision lenticule extraction. J Cataract Refract Surg. 2015;41:652–65.

Editors’ note: Dr. Manche has financial interests with Carl Zeiss Meditec and Johnson & Johnson Vision. Dr. Slade has financial interests with Alcon and Carl Zeiss Meditec. Dr. Thompson has financial interests with Alcon, Bausch + Lomb (Bridgewater, New Jersey), Carl Zeiss Meditec, and Johnson & Johnson Vision. Dr. Wiley has financial interests with AcuFocus (Irvine, California), Alcon, Carl Zeiss Meditec, Johnson & Johnson Vision, Revision Optics (Lake Forest, California), and STAAR Surgical (Monrovia, California).

Contact information

Manche
: edward.manche@stanford.edu
Slade: sgs@visiontexas.com
Thompson: vance.thompson@vancethompsonvision.com
Wiley: drwiley@clevelandeyeclinic.com

New technologies in corneal refractive surgery poised to spur growth New technologies in corneal refractive surgery poised to spur growth
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