January 2019

CATARACT

Research highlight
Close-up on extended depth of focus lenses


by Maxine Lipner EyeWorld Senior Contributing Writer








A patient with the Tecnis Symfony IOL
Source: Viral Juthani, MD

 

What these could mean for presbyopic patients

For presbyopic patients undergoing cataract surgery, a new option that may be attractive is the use of extended depth of focus (EDOF) lenses, according to Viral Juthani, MD, assistant professor of ophthalmology, Montefiore Medical Center, Albert Einstein College of Medicine, New York. Investigators took a look at EDOF lenses that are available worldwide in a review published in Current Opinion in Ophthalmology.1

Current backdrop

Before EDOF lenses, the options for spectacle independence after cataract surgery were monovision with monofocal lenses or use of multifocal or accommodative lenses, Dr. Juthani explained. He said there are three main disadvantages with multifocal lenses. “First is the loss of contrast sensitivity, and the second is the limitations associated with having fixed focal points because they result in fixed working distances. Patients would say they see well at a distance, intermediate, and near point, but in between, they had diminished visual quality.” Third, multifocal lens patients were reporting some photopsias such as halos, glare, and starbursts. The idea behind the lens was to improve the range of clear vision without fixed focal points while reducing photopsias and loss of contrast sensitivity.
The Crystalens (Bausch + Lomb, Bridgewater, New Jersey) was the main accommodative lens. “It has grown out of favor as studies have shown that the effects of accommodation tend to wear off over time,” Dr. Juthani said.

Emerging EDOF approaches

The early stage review that investigators undertook summarized the current EDOF lenses available worldwide. Dr. Juthani said it is a big picture look at studies describing visual outcomes and patient satisfaction.
Currently, there are three different types of EDOF lenses aimed at trying to provide more seamless near, intermediate, and distance vision. Only one, the Tecnis Symfony (Johnson & Johnson Vision, Santa Ana, California), is FDA approved. “Instead of creating fixed focal points, they create a single elongated focal point to enhance the depth of focus for improved range of vision, and they focus incoming waves in an extended longitudinal plane as opposed to fixed points using modified diffractive optics,” Dr. Juthani said. With the Symfony they tried to offset the limitations of having the elongated plane by correcting for chromatic aberration.
There was little in the literature on this because the technology is so new but investigators did manage to find one large trial2 by the Concerto Study Group, which included 411 patients who underwent bilateral implantation of the Symfony lens. The study included two groups, one in which micro-monovision was the aim in the non-dominant eye and the other in which emmetropia was the target. “They found that using micro-monovision improved independence and patient satisfaction,” Dr. Juthani said. “About 14% of patients required spectacles postoperatively. While generally 10% or fewer of those with multifocal lenses need spectacles after implantation, the side effect profile with the Symfony lens was slightly improved with the EDOF lens.”
The main disadvantage of these lenses compared to the multifocals is the quality of the uncorrected near vision, especially at the 12- to 14-inch distance, he explained, adding that it’s the nature of these lenses. “The longer you create the focal plane to be, the more blurring you get in that range,” he said.
Dr. Juthani finds that the Symfony lens is best suited for those with little or no astigmatism, who have otherwise healthy eyes and an active lifestyle. “Also, taller individuals who tend to have longer arms—and because of that have a longer working distance—might enjoy these more than people who have shorter arms and are holding a book closer to their face,” he said.
Other EDOF lenses rely on different technology. Dr. Juthani pointed to the small aperture lenses, which work by the pinhole effect, blocking unfocused rays of light that can degrade the image quality. These include the IC-8 lens (AcuFocus, Irvine, California) and the XtraFocus pinhole implant (Morcher, Stuttgart, Germany). Such lenses are not available in the United States and the data available on them are limited. “The application seems greatest in patients who have slightly greater amounts of astigmatism and other higher order corneal aberrations,” Dr. Juthani said.
Another approach is with a multifocal aspheric lens, such as the Mini Well Ready (SIFI Medtech, Catania, Italy), the first progressive aspheric intraocular lens, available in Europe, Dr. Juthani noted. “Instead of having discreet steps for correcting distance, intermediate, and near, it has more of a blended optic,” he said. “It’s similar to having a progressive lens in the eye.” While he finds that the initial results for this type of lens look good, there’s a need for longer and more formal prospective studies, he said.
In Dr. Juthani’s view, EDOF lenses are a valuable addition to the presbyopic armamentarium. “I think there is a group of patients who will be happy with these lenses, and we have to have the right conversations with people to determine what works best for them,” he said.
Going forward, he pointed out that there will be some new trials looking at a combination of EDOF lenses in one eye and either a multifocal or a trifocal lens in the other. “It will be interesting to see what these formal studies show,” he concluded.

References

1. Akella SS, Juthani VV. Extended depth of focus intraocular lenses for presbyopia. Curr Opin Ophthalmol. 2018;29:318–322.
2. Cochener B, et al. Clinical outcomes of a new extended range of vision intraocular lens: international multicenter Concerto Study. J Cataract Refract Surg. 2016:42:1268–1275.

Editors’ note: Dr. Juthani has no financial interests related to his comments.

Contact information

Juthani: VIRJUTH@montrfiore.org

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