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Promising results in multicenter trial led to Visx custom ablation approval
The CustomVue system was approved in May. In U.S. trials, 98% of patients achieved vision of 20/20 or better at 1 year.
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SAN FRANCISCO – The CustomVue laser vision correction system has been granted regulatory approval by the Food and Drug Administration, manufacturer Visx announced.
The Visx CustomVue system includes the WaveScan diagnostic system and the S4 excimer ablation system. The FDA granted approval for CustomVue treatment of patients with up to –6 D manifest refraction spherical equivalent and cylinder of up to –3 D.
Visx is the second company to have a wavefront-guided ablation system granted U.S. regulatory approval. The FDA approved Alcon’s CustomCornea system in October.
The CustomVue approval is based on results of a multicenter clinical trial of the Visx system at several centers across the United States. Colman R. Kraff, MD, of Chicago, presented the 1-year results of that trial here at the American Society of Cataract and Refractive Surgery meeting earlier this year.
One-year results
The FDA multicenter trial included 351 eyes of 189 patients at six centers. Enrolled patients had a mean age of 36 years.
Mean preoperative spherical error was –3.6 D, mean preop cylinder was 0.7 D with a range up to 3 D, and the mean refractive spherical equivalent was 3.2 D. All eyes were targeted for emmetropia.
“For the trial, a bilateral LASIK treatment was performed using three different microkeratomes,” Dr. Kraff said. “We used an 8-mm ablation zone, and the environmental conditions were tightly controlled.”
Dr. Kraff said that of 86 patients in the trial who reached the 1-year follow-up mark, 98% achieved uncorrected visual acuity (UCVA) of 20/20 or better, 70% were 20/16 or better and 23% were 20/12 or better.
Of 277 patients who reached the 6-month mark, 94% achieved a UCVA of 20/20 or better, 74% were 20/16 or better and 27% were 20/12 or better, he said.
Sixty-nine percent of patients at 6 months had the same or better postoperative UCVA compared to their preop best corrected visual acuity (BCVA). At 1 year, the percentage rose slightly to 71%, he said.
“And 90% of these eyes (at 6 months) were within 0.5 D of the intended correction, and 99% of the patients were within 1 D,” Dr. Kraff said. At 1 year, 93% were within 0.5 D of intended correction, and 100% of eyes were within 1 D.
The researchers found that the mean refractive spherical equivalent (MRSE) was stable over time postoperatively. Between the 3-month and 6-month visits, MRSE changed 0.5 D or less in 97% of eyes and 1 D or less in 99% of eyes.
In the safety data, at 6 months, 64% of eyes had a gain in BCVA compared to baseline. No eyes lost more than one line of BCVA, Dr. Kraff said.
Evaluation criteria
In addition to standard visual acuity measurements, Dr. Kraff and colleagues also analyzed the gains and losses in higher-order aberrations from preop to postop.
Researchers found less increase in higher-order aberrations generally postop in comparison to conventional treatments, and particularly much less increase in spherical aberration. The conventional treatment data for comparison was provided by Steve Schallhorn, MD.
With the CustomVue system, higher-order aberrations were less than with conventional treatment, as shown by the percentage of eyes with either a decrease or an increase of less than 0.1 µm of root mean square (RMS) in coma, trefoil and spherical aberration, Dr. Kraff said.
“Conventional treatments resulted in an increase from 0.29 µm RMS preoperatively to 0.47 µm RMS postop for overall higher-order aberrations. Spherical aberration increased from 0.07 µm RMS before surgery to 0.21 µm RMS after,” he said.
With CustomVue treatment, higher-order aberrations increased from 0.28 µm RMS preop to 0.31 µm RMS at 6 months. Spherical aberration increased from 0.11 µm RMS to 0.13 µm RMS. According to Visx, this difference was not statistically significant.
“Studying the histogram for higher-order RMS improvement at 6 months, we found that 67% of patients treated with the WavePrint system either had a decrease in RMS or an increase of less than 0.1 µm,” Dr. Kraff said.
Night vision satisfaction
Patients reported high levels of satisfaction with the results. When asked about their night vision, preoperatively 65% of patients were satisfied vs. 85% at 6 months. The percentage of patients who were dissatisfied with their night vision dropped from 10% preoperatively to 6%, and the percentage of patients who reported being somewhat or very dissatisfied was reduced from 24% before surgery to 7% at 6 months.
The patient-satisfaction results were also positive regarding the severity of halos and glare at night.
Dr. Kraff and colleagues found that contrast sensitivity results remained the same or were slightly improved following surgery.
“And if we look at the 6-month key effectiveness of the criteria compared to the FDA target, in every category the results were superior,” he said.
Adverse reactions were minor, Dr. Kraff said.
“Two patients experienced an epithelial defect, both of which healed. Five eyes experienced diffuse lamellar keratitis, and they were all 20/20 or better at 1 month after surgery,” he said.
The researchers found that no patient had a loss of one or more lines of best corrected visual acuity, and no patient had an increase of cylinder of 1 D or greater.
Visx executives noted that clinical trials are under way with the system for the correction of hyperopia, presbyopia and reduced acuity following refractive surgery.
For Your Information:
- Colman R. Kraff, MD, is in private multispecialty practice with a practice focus in anterior segment and refractive surgery. He can be reached at 25 E Washington St, Suite 606, Chicago, IL 60602; (312) 444-1111; fax: (312) 444-1953; e-mail: corkraff@goamerica.net.
- Visx Inc., manufacturer of the CustomVue laser vision correction system, can be reached at 3400 Central Expressway, Santa Clara, CA 95051-7122; (408) 733-2020; fax: (408) 773-7278.