Issue: March 2010
March 01, 2010
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Aspheric monofocal IOL shows positive results in FDA clinical trial

The single-piece lens compensated for spherical aberration, improved photopic and mesopic contrast sensitivity, surgeon says.

Issue: March 2010
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Y. Ralph Chu, MD
Y. Ralph Chu

A new aspheric single-piece IOL yielded positive visual outcomes and low complication rates in a U.S. Food and Drug Administration clinical trial, according to an investigator.

Y. Ralph Chu, MD, presented 1-year data for the Tecnis one-piece IOL (Abbott Medical Optics) at the American Society of Cataract and Refractive Surgery meeting in San Francisco.

“One thing that we noticed in this clinical trial was anecdotally a high percentage of patients that had a ‘wow’ factor from this monofocal IOL,” Dr. Chu said.

The clinical trial included 123 patients with a mean age of 71.9 years (range, 48 to 94 years). The patient group was 56.9% women and 43.1% men.

Investigators targeted refraction at emmetropia, ± 0.25 D, for all but three patients.

Study results showed that at 1-year postoperatively, 91.5% of patients had distance uncorrected visual acuity of 20/40 or better; 100% of patients had distance best corrected visual acuity of 20/40 or better.

“There is something more to just the platform itself,” Dr. Chu said. “If you look at the material in the optic design, then you’ll see why the quality of vision is so strong for this one-piece lens. And it was a safe lens, as we would expect.”

Results showed no lens-related complications. Four patients (3.3%) developed cystoid macular edema; one patient had persistent cystoid macular edema at 1 year. One patient had to undergo a lens exchange because of a torn haptic, and another patient underwent pars plana vitrectomy with an epiretinal membrane peel.

The IOLs hydrophobic acrylic material minimized glistening, calcification and chromatic aberration, Dr. Chu said.

“The … Tecnis acrylic material is not the same as the other acrylic material on the market, and it has the lowest … chromatic aberration,” he said. “If you couple spherical aberration improvement [with] minimal chromatic aberration, the two are synergistic to improving quality of vision.”

Contrast sensitivity, myopic shift

Dr. Chu also presented findings from international studies focusing on the Tecnis one-piece IOL.

In a prospective study of 50 patients with a mean age of 71.32 years who were implanted with the IOL, Peter Szurman, MD, and colleagues found virtually no spherical aberration, Dr. Chu said. The study was conducted at two sites, and outcomes were assessed at a mean 12.8 weeks.

Results also showed that the IOL improved contrast sensitivity.

“What they found is what we would expect, that the spherical aberration of the Tecnis one-piece is essentially zero across all pupil sizes,” he said. “And when you looked at a comparison to spherical IOLs, as the pupil increases, you can see an increasing amount of aberration that’s delivered through or a residual aberration through a spherical IOL compared to this aspheric-correcting IOL. That results in better contrast [sensitivity], as we have learned through the FDA clinical trial, and there’s better photopic and mesopic contrast.”

Results also showed no myopic shift, according to Dr. Chu.

“One of the concerns with asphericity is that we are causing a change in the refraction,” he said. “And with the spherical IOL, with the spherical aberration, you can see in larger pupil sizes that there is a slight myopic shift when you get to the larger pupil sizes, but there is no myopic shift with this Tecnis one-piece in the study they conducted.”

“The Tecnis one-piece platform … completely compensates for the spherical aberration inside the eye,” he said. “You can see that results in improved photopic, as well as mesopic contrast sensitivity. There is really no myopic shift in the refraction. These patients have excellent visual acuities.”

Drs. Mester and Kaymak also found that minimal tilt and decentration did not adversely affect quality of vision, Dr. Chu said. – by Matt Hasson

  • Y. Ralph Chu, MD, can be reached at Chu Vision Institute, 9117 Lyndale Ave. South, Bloomington, MN 55420, U.S.A.; +1-952-835-0965; fax: +1-952-835-1092; e-mail: yrchu@chuvision.com. Dr. Chu is a paid consultant to Abbott Medical Optics.

PERSPECTIVE

The U.S. Food and Drug Administration safety and effectiveness data for the spherical version of the AMO one-piece IOL demonstrate results that exceed the standards for approval of IOLs. Data from Peter Szurman’s study of 50 subjects in Tübingen, Germany, who were implanted with the aspheric Tecnis one-piece, reveal elimination of both spherical aberration and night myopia. The evaluation of Purkinje light reflex data by Ulrich Mester and Hakan Kaymak in Sulzbach, Germany, demonstrates that the decentration and tilt of the Tecnis one-piece are not significantly different from the natural decentration and tilt of the crystalline lens in healthy, young, phakic subjects. Together, these studies provide solid evidence for the enhanced functional vision already reported with the Tecnis optical platform in multiple peer-reviewed publications.

– Mark Packer, MD, FACS
Drs. Fine, Hoffman and Packer Ophthalmologists, Eugene, Ore.