Tecnis Symfony First with Extended Range of Vision
The future of cataract surgery has become much clearer thanks to a new category of lenses recently approved by the FDA. The Tecnis Symfony Intraocular Lens is the first and only presbyopia correcting extended range of vision lens, meaning it also allows patients to focus on objects up close. Presbyopia affects most people over age 40 and has long posed a challenge in the surgical treatment of cataracts.
Cataracts 101
A cataract is a clouding of the lens in the eye, which leads to decreased vision loss. By age 80, more than half of all Americans either have a cataract or have had cataract surgery, which is performed more than 4 million times a year.
In cataract surgery, the lens is removed and replaced with a 6 mm acrylic or silicon intraocular lens, inserted through a 2.5 mm or smaller incision. The IOL most commonly used in cataract surgery is a monofocal lens, which only allows the person to see at a distance, with closer objects being out of focus. "This is true microsurgery," said ophthalmologist James Loden, MD, founder and president of Loden iVision Centers.
Quick History of Cataract Surgery
While cataract surgery has been performed since the 1950s, it didn't gain popularity until the late '70s and early '80s, when advances allowed for more significant benefits. "They used to wait until patients could no longer function because it wasn't microsurgery," Loden said of the original procedure, which involved a 7 mm incision, unfoldable lenses and variable outcomes.
James Loden, MD
And while today's cataract surgery is quicker and more accurate than the surgery of the 1980s, Loden said there had been relatively little change in outcomes because the monofocal lens used for decades didn't offer clarity of all three zones - near, intermediate, and far. A decade ago, the crystal lens was unveiled and touted as an accommodating lens that allowed for intermediate vision (seeing a car dashboard or reading a computer screen), but it didn't work in 20-30 percent of patients.
"Early multi-focal lenses looked good on paper, but there were still a lot of problems," Loden explained. Intermediate vision was still subpar, and nearly 20 percent of patients experienced severe halos at night. "Abbott went back to research to look at new ways to produce lenses from the optic standpoint, using the same materials and concept but looking at the way implant optics were designed," Loden said. The once promising crystal lenses split light into two completely different focal points, meaning 18 percent of the light was lost and patients experienced halos.
The Symfony Difference
In contrast, the Tecnis Symfony IOLs are similar to camera lenses, which actually manipulate colors of light through chromatic aberration. "Blue light is bent more than red light. They manipulated the way different colors are bent to provide extended depth of focus, which gives high quality distant vision, low glare and less halos at night," Loden explained. In FDA trials, the percentage of halo and glares experienced by patients was almost identical to that of the monofocal lenses, considered the gold standard.
"The Symfony lens gives excellent distance vision and high quality interim vision for a person who wants more freedom with their lifestyle and younger feeling eyes," said Loden. "I've been coaching patients on the fact that they're going to be able to read fairly well without reading glasses but may want a pair of dime store reading glasses for needle point or checking stock quotes."
While the lens didn't receive FDA approval until mid-July and has just become commercially available, Loden participated in the U.S. clinical trial and saw results consistent with those reported nationwide. "Our study coordinator commented on the fact that everyone was able to fill out their exit studies with no spectacle correction, which is fairly impressive," he said. Though still new in the U.S., the lens has already been approved in 50 countries and been implanted in more than 2,000 eyes.
The FDA approval also included a version of the lens for people with astigmatism, the Tecnis Symfony Toric IOL. It's the first extended depth of focus lens with anti-astigmatism properties. "There are multiple ways of treating an astigmatism, but this is the first time we've been able to correct it with presbyopia correcting implants," Loden said. "This is a really big deal within the industry, and I predict it'll be a game changer."
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