Cataract Patients

By Ahmed Nasrullah, MD

Dulles Eye Associates

. http://www.dceyedr.com/

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Cataract Patients

Better Vision With Symfony Intraocular Lens Better Computer Vision, Less Night Glare, Treats Astigmatism

For many cataract patients, multifocal intraocular lenses have worked well and have afforded them a broader range of vision postoperatively. For others, though, the possibility of glare, halo and other qualitative vision problems has led them to shy away from multifocal lenses and stick with monofocal options. There are some lenses, however, that aim to bridge the gap between multifocals and monofocals and allow more vision at different distances while minimizing visual side effects. Here’s a look at the mechanism of action and current results of these devices.

Lenses in Use

There are a few intraocular lenses (IOLs) in use in the United States that may give increased depth of field without qualitative issues.

Abbott laboratories received FDA approval to market the Tecnis Symfony extended range of vision IOL in United States in July 2016. The Symfony takes a different approach to maximizing a patient’s range of vision by addressing the optical property known as chromatic aberration.

Because it tackles this chromatic aberration, the Symfony is an example of an emerging class of IOLs known as the extended-depth-of-focus lens (EDOF). Surgeons say the current hallmark of the EDOF lens is that it gives cataract patients a somewhat expanded depth of field (better computer range vision) so you get better reading with less distance glare.

Here is how the Symfony can give more depth of field. When we look up close, we experience the depth-of-field effect and our pupils constrict. That constriction ends up giving us the equivalent of about 0.75 to 1 D more near vision than we’d have when looking into the distance because of the pinhole effect.

Building on this natural accommodative effect, the Symfony uses diffractive optics to both improve the quality of vision from the lens and expand the range of distances at which the lens can adequately focus. It uses diffractive optics to do two things 1) it corrects chromatic aberration, and 2) it uses these optics to extend the range of quality vision.

The idea behind chromatic aberration correction is simply to get the colors of the spectrum focused at the same point. The different colors of the spectrum focus differently. Different materials have different dispersive properties with light; some focus colors closely together and some spread them out. The idea is that if you focus all of the colors together, you can have a higher quality of vision. The Symfony takes the acrylic that focuses colors well and improves on it.

In New Zealand and Europe, the Symfony gives 20/20 or better vision at distance and ninety-six percent of patients had 20/25 or better vision at intermediate (computer distance). At near (reading), 92 percent have 20/40 or better vision. In terms of quality of night vision, it’s comparable to a standard monofocal lens.

The Symfony lens may be a great new option for your cataract surgery, but only your ophthalmologist, after a full examination and consultation, can help determine if its right for you.