A new intraocular lens for cataract surgery, called the Symfony Lens, has just been FDA approved, and it is quickly becoming very popular. It is a new optical technology that is being described as providing “Extended Range of Vision.” Extended Range of Vision, essentially means giving good distance vision, but also allowing patients to see well at mid-range (computer, cooking, piano), and even have some reading vision.
Previous Technologies
Before the Symfony lens was available, there were several different options available to try to give patients vision at different distances. Multifocal lenses use diffractive technology to give simultaneous vision by splitting light into multiple distinct foci. The benefits of these lenses are that they give pretty good distance and reading vision, but the main limitation was that mid-range vision was somewhat limited, and some patients described seeing significant halos.
Accommodative lenses, such as the Crystalens or Trulign Toric, work by moving the lens forward and backward to change the focal length of the lens. This is done by flexing the ciliary muscles to move the hinges on these flexible lenses. The main limitation is the amount of movement each patient gets is variable, so most patients use reading glasses for fine print or extended reading. Also, as the capsule that holds the lens in place heals, it can contract and limit the movement of the lens, or move the lens out of position. This can be often be improved with a YAG laser capsulotomy if needed.
The goal of the Symfony lens is to give a larger, more continuous range of vision from distance to near, although patients do describe needing glasses to read fine print and/or extended reading. The new technology also decreases the incidence of significant halos and glare to a comparable rate as is seen in monofocal lenses.
How Does it Work?
The Symfony lens merges two technologies to achieve these goals. The first is the proprietary echelette design, which elongates the focus of the eye, in order to give the extended vision. A monofocal lens has one distinct focal point at distance or near, while a multifocal lens has two distinct foci at distance and near. The Symfony lens has one elongated focal point to allow distance, mid-range, and some near. Since this design is proprietary, the manufacturer will not go into more detail as to how this elongated focal point is achieved.
The second is also proprietary, and is described as achromatic technology, which increased contrast sensitivity. It essentially manipulates the colors of the visual spectrum, which all have different wavelengths, to be focused at the same point. This helps to correct for the normal aberrations in the visual system, and give better contrast and vision.
Is It the Right Lens for You?
Patients that I have implanted the Symfony lens in have been very happy. Some limitations may include severe dry eyes, macular degeneration, or other limitation of vision on top of your cataracts. I am happy to provide further discussion at your pre-operative visit to make sure I know your goals for your cataract surgery, and that you understand all of the choices available.
Ken Kreidl, MD