Latest refractive lasers ‘changing the goal’ of surgery

The goal of refractive surgery is changing from doing away with glasses to providing better vision than glasses ever could, surgeon says. A review of recent trials.

The latest generation of refractive surgical lasers is achieving results that are “changing the goal” of refractive surgery, a leading refractive surgeon said.

“The latest versions of these lasers are getting very good results,” said Daniel S. Durrie, MD, Refractive Surgery Section Editor for Ocular Surgery News. “They’re all better than the lasers available 4 or 5 years ago.”

The newest lasers from a number of manufacturers are delivering faster pulses of low-temperature energy in wavefront-guided or wavefront-optimized patterns that provide excellent visual results, Dr. Durrie said. The technology is allowing surgeons to set a new goal for surgery, he said.

“If we look at refractive surgery 25 years ago to now, we have changed the reason for having the surgery. Until this latest group of lasers, [the goal] was trying to get rid of the inconvenience of glasses or contact lenses. The industry was established based on that goal. The goal now is that, with this new technology, we can achieve better vision than our patients ever had with their glasses or contact lenses,” Dr. Durrie said.

He noted that in several recent clinical studies, roughly 50% of patients achieved better vision without correction postoperatively than they had with their glasses preoperatively. The goal in the next 10 to 15 years, he said, will be to raise that number from 50% to 90% with a safe surgical procedure.

“That is going to tremendously affect the market,” Dr. Durrie said. “There was a certain number of people who would go through the expense and the risk of surgery just to get rid of the inconvenience, but with this new wave of technology, if we could tell patients they have a 90% chance of seeing better than they’ve ever seen with their glasses or contacts and they can get rid of the inconvenience, we’re going to go from having 2% to 5% of potential candidates having the surgery to 30% to 40%.”

In addition, many of the earlier problems with corneal haze and night vision have been addressed, Dr. Durrie said. Now the newest lasers are able to go back and correct adverse outcomes seen with the earlier lasers.

“We’re doing that all the time,” he said. “That’s probably the most exciting thing about my practice right now. We can take patients who were generally happy … but maybe have some halo or glare at night and use the new wavefront-guided technology to ‘upgrade’ their optics to have better quality of vision than they’ve ever had.”

Expanding indications

Recent studies show promising early results with the newest lasers and additional refinements or indications for existing lasers.

“We’re getting a broader range in the U.S. of excellent lasers,” Dr. Durrie said.

Excimer lasers currently approved by the Food and Drug Administration for wavefront-guided treatment include Alcon’s LADARVision with CustomCornea, which is approved for wavefront-guided LASIK for myopia and myopic astigmatism; Bausch & Lomb Surgical’s Technolas 217z, for Zyoptix wavefront-guided LASIK for myopia with or without astigmatism; and the Visx Star S4 with WaveScan, for CustomVue wavefront-guided LASIK for myopia and hyperopia with or without astigmatism.

Lasers that are FDA-approved for non-wavefront-guided treatment in the United States include Nidek’s EC-5000 laser, which is approved for LASIK for myopia with or without astigmatism, and the WaveLight Allegretto laser, which is approved for LASIK for myopia and hyperopia with or without astigmatism. The WaveLight laser uses what the manufacturer calls wavefront-optimized protocols, which take into account and correct for the spherical aberration in the average eye. WaveLight also has wavefront-guided and topography-guided protocols under study, Dr. Durrie said.

Currently undergoing clinical trials for FDA approval for non-wavefront-guided LASIK is Carl Zeiss Meditec’s MEL 80 excimer laser. Outside the United States, the MEL-80 is in use for wavefront-guided treatment. Dr. Durrie noted that lasers must be FDA-approved for conventional LASIK before they can be evaluated for wavefront-guided applications.

Another excimer laser in use internationally but not currently in U.S. clinical trials is the Schwind Esiris. According to Dr. Durrie, the manufacturers are contemplating undertaking the U.S. regulatory process.

Outside the realm of the excimer, the solid-state CustomVis 213 nm refractive laser is also in use internationally, he said.

“Each of these lasers has its own patented way to deliver [laser] pulses to the cornea. As clinical studies are done, each company fine-tunes their laser algorithms to improve their results,” Dr. Durrie told OSN.

Papers on many of the latest applications and refinements of these lasers were delivered at the American Society of Cataract and Refractive Surgery meeting in Washington. This article recaps some of the highlights of those ASCRS presentations.

Alcon LADARVision with CustomCornea

In a study, Alcon’s LADARVision with CustomCornea was successfully used for surface ablation. Ninety-eight patients successfully underwent surface ablation with the laser, but a longer follow-up is needed, said Michael J. Endl, MD.

One hundred eighty eyes of 98 patients achieved good visual acuity with manifest refraction, Dr. Endl said. Patients underwent PRK with CustomCornea. Forty-one eyes received an expanded range algorithm, and 139 had the original algorithm. The epithelium was debrided with 30% of alcohol. Follow-up was 6 to 8 weeks, which is standard for LASIK patients, he said.

At 6 weeks, 95% of patients were within 1 D of intended correction. However, there was a trend toward higher correction, Dr. Endl said. At this point, 70% achieved 20/40 or better, and 46% were 20/20 or better, he said.

“It is a little bit lower than what we expect with our LASIK patients, but at 3 to 6 months, I see some [patients achieve] 20/40 and 20/30, and they are happy,” he said.

Postoperative refraction remained stable with no statistically significant increase in higher-order aberrations or coma from preop to postop, Dr. Endl said. There was a significant decrease in spherical aberration and trefoil, he said.

“This study provides evidence that utilizing surface ablation with CustomCornea for the treatment of myopia with or without astigmatism appears safe and effective. Further follow-up is warranted to determine when postoperative uncorrected visual acuity continues to improve,” he said.

“It remains to be seen if in fact surface ablation provides a truer application of our complex preoperative wavefront measurements. Some surgeons have demonstrated a change in higher-order aberrations simply by creating a LASIK flap. These flap alterations may potentially decrease the accuracy of the laser ablation,” Dr. Endl said.

B&L Technolas with Zyoptix

Patients with high levels of hyperopia and mixed astigmatism had favorable outcomes in a small study with Bausch & Lomb’s Technolas 217z100 with Zyoptix.

Mariane M. Kairala, MD, performed LASIK with the Technolas laser and iris tracking system on 50 eyes. Thirty-one eyes had hyperopic astigmatism, and 19 eyes had mixed astigmatism. Patients had up to +6.5 D of sphere and up to –5.32 D of cylinder, she said.

Of the patients with hyperopic astigmatism, 29 of 31 eyes achieved 20/40 or better UCVA, Dr. Kairala said. Fifteen percent achieved 20/15 or better UCVA. All eyes maintained refractive stability during the 3-month postoperative follow-up, she said.

Eyes with mixed astigmatism had preop BCVA of 20/20 or better. Postop, they had 20/40 or better UCVA 1 week postop and again at 3 months, and 13.33% obtained UCVA of 20/15 or better at 3 months. No eyes lost more than two lines of vision, she said.

Carl Zeiss Meditec MEL 80

The MEL 80 wavefront-optimized excimer laser from Carl Zeiss Meditec is showing comparable results to other refractive lasers, and company investigators are “eagerly awaiting” final results from the laser’s clinical trials, said Steven J. Dell, MD.

Dr. Dell is an investigator in a U.S. clinical trial of the MEL 80; he and colleagues are evaluating the results of LASIK using the device in 360 eyes at five U.S. sites. Dr. Dell discussed preliminary results of the trial.

Enrolled patients have myopia up to –10 D and –3.8 D of astigmatism, Dr. Dell said. The wavefront-optimized procedure is fast, with ablation taking an average of 3 seconds per diopter of correction, he said.

Early results of the study show that 93% of eyes achieved 20/20 or better uncorrected visual acuity at 6 months, 63% achieved 20/16 or better UCVA, and 27% achieved 20/12 or better UCVA, Dr. Dell said.

In terms of safety, 34% of eyes gained one line of vision while 6% lost one line. No patients lost two or more lines of vision, he said.

CustomVis solid-state laser

Paul van Saarloos, MD, presented preliminary results of the CustomVis solid-state 213 nm laser. In a small study, patients with myopia with or without astigmatism had improved vision. Further studies are needed, however, to determine the long-term effects of the procedure with the laser.

“There are a number of advantages of solid state. It’s a lot more reliable than excimer lasers. The energy is extremely stable. Pulse-to-pulse stability is excellent. It’s easy to use, doesn’t use a lot of power,” Dr. van Saarloos said.

The laser has fast eye-tracking software and can track up to six dimensions. The system also tracks on the limbus, which gives the surgeon increased accuracy and good registration for custom surgery, he said.

Dr. van Saarloos performed LASIK on 19 eyes with the CustomVis Pulzar Z1 solid-state laser. The laser has a 0.6-mm flying beam spot, a pulse rate of 300 Hz to 400 Hz, the Crystal Scan scanning system and the ZCADTM surgical planning application, according to the study abstract.

One-month results showed that 87.5% of eyes achieved 20/20 or better, 93.8% were 20/25 or better, and 100% were 20/30 or better. Many cases (81.3%) were within +0.5 D of intended correction, and 93.8% were within +1 D. Refractive stability was maintained in 87.5% of eyes, and 12.5% lost one line of visual acuity, Dr. van Saarloos said.

Preoperatively, patients had up to 5 D of myopia with refractive cylinder less than 4.5 D, and manifest refraction spherical equivalent was less than 6 D, he said.

Nidek EC-5000

Patients with hyperopia saw well early after LASIK surgery with the Nidek EC-5000 excimer laser, said George O. Waring III, MD.

Dr. Waring performed LASIK on 300 eyes, 150 with hyperopia and 150 with hyperopic astigmatism. He said he treated up to 6 D of hyperopia and up to 3 D of astigmatism.

“You should cut off your laser ablations at +4 D and maybe +0.5 D or 2 D of astigmatism, but we went up to 6 D,” Dr. Waring said.

Two-thirds of eyes achieved 20/20 or better UCVA. One-fourth of eyes were 20/15 to 20/16, and 85% were at 20/25, according to Dr. Waring. Three percent of eyes lost visual acuity, which is within the normal range of other excimer lasers, he said.

“People who report only 20/25 are having their doubts, and that’s what we did. However, there are a lot of patients that are happy with 20/25 UCVA, and getting 85% here is quite OK,” he said.

Half of the eyes were 20/20 1 week after LASIK, and three-quarters were 20/25, Dr. Waring said.

“That’s a tribute to the nice profile that Nidek has allowed that rapid recovery,” he said.

Overall results, however, showed a tendency to undercorrect, he said. There was also a regression effect with time, which is common among other treatment modalities for hyperopia, he said.

Schwind Esiris

Patients with high myopia were successfully treated with LASEK and the Schwind Esiris laser.

J.W. Osbourne, MBChB, BSc, treated patients with myopia up to –11 D. He conducted a study on 74 eyes of 50 patients. Mean preoperative spherical equivalent was –7.6 D, and mean cylinder was –1.23 D. Seventy-one eyes had intact epithelial flaps, and three eyes had adherent flaps, Dr. Osbourne said in the study abstract.

Refractive outcomes were stable initially after the procedure and up to 1 year, he said. Seventy eyes were within ±1 D of the intended correction, and 59 eyes were within ±0.5 D, he said.

Mean spherical equivalent after 1 year was –0.09 D.

Postoperatively, mean cylinder was –0.59 D at 70°. Preoperatively, it was –1.37 D at 94°, he said.

At 1 week postop, best corrected visual acuity was 20/40 or better in 69 eyes, Dr. Osbourne said. From 6 months to 1 year, three eyes gained two lines of visual acuity, 12 eyes gained one line, 54 eyes did not change, and five eyes lost one line of vision. No eyes lost more than one line, he said. UCVA at 1 year was 20/20 or better for 27 eyes, 20/25 or better for 35 eyes and 20/40 or better for 44 eyes. Two eyes had more than +1 axial haze, Dr. Osbourne said.

Visx CustomVue Wavefront

Wavefront-guided surface ablation may be appropriate for use in patients with significant coma and trefoil due to keratoconus, according to Richard L. Lindstrom, MD.

Dr. Lindstrom and colleagues evaluated the effect of wavefront-guided surface refractive surgery with Visx CustomVue Wavefront laser in 56 patients with high coma or trefoil due to keratoconus.

Preoperatively, the average higher-order aberrations at a 6-mm optical zone were 0.37 µm. Coma ranged from 0.23 µm to 0.09 µm, trefoil ranged from 0.12 µm to 0.08 µm, average spherical equivalent was –3.15 D, and average astigmatism was 0.92 D. Mean physician adjustment to nomogram was –0.34 D, Dr. Lindstrom reported.

The preliminary results at 3 months postop showed that all patients had achieved 20/40 or better UCVA, 92% achieved 20/25 or better UCVA, and 80% achieved 20/20 or better UCVA. Average spherical equivalent was +0.09 D, he said.

Dr. Lindstrom said corneal ablation in keratoconus patients is a controversial topic. He said many surgeons would perform keratoplasty on patients with keratoconus who were at risk for ectasia.

WaveLight Allegretto

Patients with preoperative coma and higher-order aberrations were treated successfully with the wavefront-guided treatments of the WaveLight Allegretto laser.

The patient population was split into two groups. Group 1 received wavefront-optimized treatments based on phoropter refraction measurements. Group 2 underwent wavefront-guided treatments based on aberrometer measurements. Both groups achieved 20/20 or better UCVA with the WaveLight Allegretto laser, Guy M. Kezirian, MD, said in the study abstract.

The treatments yielded similar results in the absence of preoperative aberrations. In patients with existing coma or spherical aberrations, the wavefront-guided treatment appeared appropriate with good predictability, according to Dr. Kezirian.

For Your Information:

• Steven J. Dell, MD, can be reached at 1700 S. Mopac, Austin, TX 78746; 512- 327-5200; e-mail: sdell@austin.rr.com.
• Daniel S. Durrie, MD, can be reached at Durrie Vision, 5520 College Blvd., Suite 201, Overland Park, KS 66211; 913-491-3737; fax: 913-469-6686; e-mail: ddurrie@durrievision.com.
• Michael J. Endl, MD, can be reached at 2400 Pine Ave., P.O. Box 2087, Niagara Falls, NY 14301; 716-282-1114; fax: 716-282-0523; e-mail: mpderme@aol.com.
• Mariane M. Kairala, MD, can be reached at 60 Dinsmore Ave., Framingham, MA 01702-6013; 508-405-0816.
• Guy M. Kezirian, MD, can be reached at 4601 E. Mockingbird Lane, Paradise Valley, AZ 85253-2420; 480-348-9299; fax: 480-348-9288.
• Richard L. Lindstrom, MD, can be reached at Minnesota Eye Consultants, 710 E. 24th St., Suite 106, Minneapolis, MN 55404-3810; 612-813-3600; fax: 612-813-3660; e-mail: rllindstrom@mneye.com.
• J.W. Osbourne, MBChB, BSc, can be reached at St. Thomas’ Hospital, London, Lambeth Palace Rd, London SE 1 7E11, United Kingdom.
• Paul van Saarloos, PhD, can be reached at P.O. Box 518, Balcatta, WA-6914 Australia; 61-8-9273-4000; fax: 61-8-9273-4044; e-mail: info@customvis.com; Web site: www.customvis.com.
• George O. Waring III, MD, can be reached at InView, 301 Perimeter Center North, Suite 600, Atlanta, GA 30346; 678-222-5102; fax: 404-250-9006; e-mail: drgeorge@georgewaring.com.

• Alcon, maker of LADARVision with CustomCornea, can be reached at P.O. Box 6600, Fort Worth, TX 76115; 877-523-2784; Web site: www.alcon.com.
• Allegretto, maker of the WaveLight Allegretto laser, can be reached at 800-668-5236; Web site: www.allegretto.ca.
• Bausch & Lomb, maker of the Technolas with Zyoptix system, can be reached at 1400 N. Goodman St., P.O. Box 450, Rochester, NY 14609; 585-338-6000; fax: 585-338-6007; Web site: www.bausch.com.
• arl Zeiss Meditec, maker of the MEL 80, can be reached at 5760 Haciendo Drive, Dublin, CA 94568; 925-557-4100; fax: 925-557-4101; Web site: www.meditec.zeiss.com.
• CustomVis, maker of the CustomVis solid-state 213 nm laser, can be reached at P.O. Box 518, Balcatta, WA-6914 Australia; 61-8-9273-4000; fax: 61-8-9273-4044; e-mail: info@customvis.com; Web site: www.customvis.com.
• Nidek, maker of the EC-5000 excimer laser, can be reached at info@nidek.co.jp; Web site: www.nidek.com.
• Schwind eye-tech-solutions, maker of the Schwind Esiris Scaning Spot Excimer Laser, can be reached at Mainparkstrasse 6-10, D-63801 Kleinostheim, Germany; 49-6027-508-0; fax: 49-6027-508-208; e-mail: info@eye-tech-solutions.com; Web site: www.eye-tech-solutions.com.
• Visx, maker of CustomVue Wavefront, can be reached at 3400 Central Expressway, Santa Clara, CA 95051; 408-773-7321; Web site: www.visx.com.

• Jeanne Michelle Gonzalez is an OSN Staff Writer who covers all aspects of ophthalmology, specializing in practice management, regulatory and legislative issues. She focuses geographically on Latin America.