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Aspheric multifocal IOL showing better results than standard version
Clinical data have not yet been released, but one ophthalmologist is reporting superior laboratory results with the lens.
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 Con Moshegov |
HANOI – A multifocal IOL enhanced with an aspheric surface is demonstrating superiority over the standard version in laboratory experiments and early clinical results, according to one ophthalmologist.
Con Moshegov, FRANZCO, of Perfect Vision Laser Correction in Sydney, Australia, has been working with the new version of Alcon’s ReSTOR lens and discussed its benefits at the Asia-Pacific Association of Cataract and Refractive Surgeons meeting.
According to Dr. Moshegov, Alcon has put asphericity on the ReSTOR design to improve image quality. “I think it’s a good lens that has been made better, so it’s not a complete overhaul of the ReSTOR lens. It’s just a fine tuning,” he said.
Managing spherical aberrations
Although results have always been good with the standard ReSTOR, there is the problem of spherical aberration seen with any spherical lens. There is also the reduction in contrast seen with the diffractive component of the ReSTOR. The combination of these causes some loss of contrast sensitivity, Dr. Moshegov said.
“The quality of vision is slightly worse than a monofocal lens, so you trade absolute crispness, absolute quality, for range, and some people like that, some people don’t,” he said.
According to Dr. Moshegov, Alcon took note of a recent study conducted by researchers at Iladevi Cataract and IOL Research Center in India that analyzed and compared the effects of the AcrySof IQ and the SA60AT on contrast sensitivity.
The results of the study showed that contrast sensitivity was statistically significantly better with the AcrySof IQ at all spatial frequencies during mesopic testing with a 4-mm and 6-mm artificial pupil.
Recent data from the U.S. Food and Drug Administration also support these conclusions and show that spherical aberrations were statistically significantly less with the AcrySof IQ than with the SA60AT, according to Dr. Moshegov.
“We can extrapolate then that similar designs for the multifocal lens should be beneficial over the ordinary one,” he said.
Laboratory data
So far, Dr. Moshegov’s clinical data is limited to 12 eyes of six patients implanted with the new aspheric ReSTOR, or SN6AD3, but he said he intends to have contrast sensitivity data ready for this year’s American Society of Cataract and Refractive Surgery meeting.
“All six patients are happy,” he said. “Yes, they do see some haloing, but none have any regrets whatsoever.”
In the meantime, Dr. Moshegov said he and colleagues are making deductions about the efficacy of the lens based on promising laboratory results.
In a comparison of distance vision quality under mesopic conditions between the standard ReSTOR and the aspheric ReSTOR, modulated transfer function data showed twice the improvement of modulated transfer function performance at 100 line pairs per millimeter with the aspheric ReSTOR, according to Dr. Moshegov.
“We’re off to a good start because at least there is laboratory evidence that it’s better, and so it’s a matter of proving it,” he said.
Lens parameters
The aspheric ReSTOR has an overall length of 13 mm and an optic diameter of 6 mm. It is biconvex with an anterior aspheric optic, in addition to the anterior apodized diffractive optic, and is designed to be inserted through an undistorted 2.2-mm incision, according to Dr. Moshegov.
The ideal patient for the lens will be one who normally wears glasses for both distance and near and has “manageable” astigmatism, he said.
However, patients must still be aware that there will be some compromises involved, he said.
The wrong patient, according to Dr. Moshegov, is “someone who is particularly sensitive about aberrations, slightly high-strung, someone that will notice every little halo, every little reflection.”
Overall, he said there will be less sacrifice of quality of vision with this lens compared with the standard ReSTOR.
“I think that this will completely eliminate the need for a standard ReSTOR,” Dr. Moshegov said.
For more information:
- Con Moshegov, FRANZCO, can be reached at Perfect Vision Laser Correction, Suite 3, ‘The Madison’ 25-29 Hunter St., Hornsby NSW 2077, Australia or Level 2, ‘Park House’ 187 Macquarie St., Sydney NSW 2000, Australia; +61-9482-5155; fax: +61-9482-5166; e-mail: con@perfectvision.com.au. Dr. Moshegov has no direct financial interest in the products discussed in this article, nor is he a paid consultant for any companies mentioned.
- Alcon, the maker of the AcrySof ReSTOR aspheric IOL, can be reached at 6201 South Freeway, Fort Worth, TX 76134 U.S.A.; +1-817-293-0450; fax: +1-817-568-6142; Web site: www.alconlabs.com.
- Jared Schultz is an OSN Correspondent based in Philadelphia, U.S.A.