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Study finds Summit Apex Plus/Infinity effective for hyperopic astigmatism
Half of patients achieve 20/20 or better uncorrected visual acuity at 9 months.
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DALLAS — Both the Summit Apex Plus excimer laser and its successor, the Infinity LS system, effectively treat hyperopic astigmatism, according to the results of a multicenter study.
“Unlike the Visx excimer laser, which uses a scanning slit for hyperopic treatment, both these systems from Alcon Summit Autonomous employ disc-in-the-rail technology for the correction of hyperopia. The blend is accomplished using the Axicon disc to extend the beam profile to 9.5 mm, with the ablation itself 6.5 mm,” said investigator Stephen F. Brint, MD, at the American Academy of Ophthalmology meeting here.
The disc is actually a PMMA button banded to a silica plate. Correcting spherical hyperopia with this platform is performed with an L-disc, and when correcting hyperopia with astigmatism uses a P-disc. The diameter of the affected treatment zone is 6.5 mm with both the L- and the P-disc. Once the disc treatment is completed, a non-disposable Axicon cassette is placed in the excimer laser, which deflects the beam out to 9.5 mm.
“Most of the beam energy of the Axicon is actually delivered adjacent to the edge of the 6.5-mm hyperopic ablation, and then tapers out to 9.5 mm with very little energy,” said Dr. Brint, a refractive surgeon in private group practice.
Study parameters
For the multicenter study, an L-disc was used for treating spherical hyperopia up to +6 D; the P-disc was used for correcting hyperopia with astigmatism up to +6 D (and up to 6 D of cylinder). The final ablation profile was extremely large and smooth.
Dr. Brint reported on 6-month results of about 300 eyes, as well as his personal experience with some eyes further out. After 6 months, re-treatments (including bilateral) were permitted.
Most eyes were treated with the P-disc to correct both hyperopia and astigmatism. “Some of the fellow eyes, however, did not have significant astigmatism, so they were treated only with the L-disc,” he said.
The mean SE treated was +2.6 D with both the L- and P-discs. In total, 74% of eyes had less than 2 D of cylinder to correct and 26% had greater than 2 D of cylinder.
Safe procedure
“The safety of the procedure is excellent,” Dr. Brint said. No patient lost two or more lines of best corrected visual acuity (BCVA). No patient had induction of 2 D or more of cylinder or BCVA worse than 20/40 if that patient was 20/20 or better preoperatively.
Uncorrected vision at 6 months in 292 eyes indicated that roughly 40% achieved 20/20 or better, about 62% were 20/25 or better and 90% were 20/40 or better. About 65% of patients were within 0.5 D of intended correction and 90% were within 1 D.
“Stability was also excellent. By 1 month, the slight amount of early postoperative myopia had regressed. This remained stable out through the 6-month period,” Dr. Brint said.
9-month data
Dr. Brint and Daniel S. Durrie, MD, of the Hunkeler Eye Centers in Kansas, enrolled patients earlier than the other investigators, so they had 9-month follow-up data on 79 patients. “In our own series, 50% of patients achieved 20/20 or better by 9 months, which sort of reflected what we had seen all along at 3, 6 and 9 months,” Dr. Brint said. Also at 9 months, 70% of patients were 20/25 or better and about 90% were 20/40 or better.
The percentage of patients who were within 0.5 D or 1 D of intended correction was slightly higher, too. “At 9 months, we had 70% that were within 0.5 D and about 93% within 1D,” he said.
“Treatment using the hyperopic disc method with the Apex Plus and Infinity platform has demonstrated good efficacy, safety and predictability. It appears to meet the FDA criteria for approval,” Dr. Brint said.
For Your Information:
- Stephen F. Brint , MD, can be reached at Brint Vision Correction Center, 3901 Veterans Blvd., Metairie, LA 70002; (504) 888-2020; fax: (504) 888-2929; e-mail: brintmd@aol.com. Dr. Brint has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
- Alcon Summit Autonomous, manufacturer of the Summit Apex Plus and the Infinity LS excimer laser systems, can be reached at 6201 South Freeway, Fort Worth, TX; (800) 862-5266; fax: (817) 241-0677.