Eyeworld

EW FEATURE 36 by Faith A. Hayden EyeWorld Staff Writer Next-generation accommodating IOLs: A status update Tetraflex, Synchrony to be approved soon T his year may finally be the year the Crystalens (Bausch & Lomb, Rochester, N.Y.), a silicone, hinge design, ac- commodating IOL, has some competition. The long-awaited Tetraflex (Lenstec, St. Petersburg, Fla.) should garner the coveted FDA stamp of approval soon, becoming a serious market rival. "The company thought it might get FDA approval before the ASCRS Annual Meeting [in March], but it still hasn't heard," said Paul J. Dougherty, M.D., clinical instructor of ophthalmology at the Jules Stein Eye Institute, UCLA, medical direc- tor of Dougherty Laser Vision, Los Angeles, and clinical investigator of the lens. "I look forward to having access to this technology for my pa- tients because my clinical trial pa- tients were so happy with their results." The Tetraflex has a 2.2-millime- ter injector allowing surgeons to make a 2.5-mm or 3.0-mm incision. The lens itself is made of hy- drophilic acrylic with closed loop haptics and a 5-degree anterior an- gulation. "This is like any other IOL im- plantation," said Dr. Dougherty. "It's an extremely easy lens to put in. When it comes out, it will be the most accurate premium lens in the U.S. in terms of refractive outcomes. It is manufactured to a tenth of a diopter tolerance, which is better than any other premium IOL in the world. It's going to come out in quarter diopter steps between 15 and 25." Dr. Dougherty acknowledged that it is critical that the lens haptics be positioned properly at the time of implantation. He suggested using a lens hook to move the Tetraflex nasally and temporally to make sure the haptics fully unfold in the cap- sular bag. In terms of quality of vision, in the clinical trial Dr. Dougherty found that 75% of patients were completely reading glasses inde- pendent or only minimally depend- ent in low lights or for fine print. His patients are currently achieving about 0.5-1.0 D of accommodation with the Crystalens, but it is esti- mated that patients will achieve approximately 1.5 D of accommoda- tion with the Tetraflex. "The main upside of this accom- modating lens is the quality of vi- sion; it's spectacular," he said. "There are less glare, halos, and con- trast sensitivity issues than with multifocals. The downside is the per- centages of patients reading at the 20/20 or 20/25 levels are not as high. The multifocals give crisper near vision, but there are visual side effects. With the Tetraflex, patients get good functional near vision and superb distance vision without those side effects." Dr. Dougherty has been un- happy with the Crystalens and has actually "abandoned" it because of Z syndrome occurrences, unsatisfac- tory accommodation, and issues with refractive errors. "With hinges, you don't know where the lens is going to end up with respect to the nodal point," he explained. "The Tetraflex doesn't have hinges." John A. Hovanesian, M.D., Jules Stein Eye Institute, David Gef- fen School of Medicine, University of California, Los Angeles, however, uses the Crystalens for the majority of his presbyopia-correcting IOLs. "I feel very safe in using it," he said. "It's a safe lens to use, and it most closely mimics the way the eye was designed to work." Dr. Dougherty couldn't reveal a price of the Tetraflex yet, but did in- dicate it should be treated as a pre- mium IOL and priced as such. Other lenses that are in the pipeline include the Synchrony (Abbott Medical Optics, AMO, Santa, Ana, Calif.), NuLens (NuLens Ltd., Israel), the AkkoLens (AkkoLens In- ternational, the Netherlands), and the Electro-active AutoFocal Intraoc- ular Lens (Elenza, Roanoke, Va.). All have varying diopters of accommo- dation, with the NuLens expecting to have a 4 D to 8 D range and the Synchrony from 1.0 D to 1.5 D, de- pending on patient age, said Jorge Alió, M.D., Instituto Oftalmologico de Alicante, Spain, and clinical in- vestigator for the Synchrony, NuLens, and AkkoLens. "There is a range of variability and each lens behaves differently," he said. "The variability reflects the complex condition of accommoda- tion whose mechanism is partially by these lenses. Variability is related to ciliary body action, age, anatomic issues related to the capsule, and capsular bag fibrosis." Whereas the Synchrony, Crystalens, and Tetraflex are intra- capsular accommodating lenses, the NuLens and AkkoLens are sulcus placed lenses. The AkkoLens has been used in a handful of European patients with "very promising" but confidential outcomes thus far, said Dr. Alió. "The AkkoLens is implanted in the sulcus and takes advantage of the forces generated in the capsular zonular fiber system to induce changes in the displacement of two sinusoidal surfaces, which are cre- ated following the Alvarez princi- ple," he said. "The clinical application of the lens is already a fact as they are being implanted in Alicante." For truly unique technology, look no further than the Elenza lens, the first electrically activated IOL. The lens is purely experimental so far and will stay that way for some time, but still provides a fascinating glimpse into the future. "The activation of the lens leads to a change in its power based on changes induced in the physical characteristics of the optics," said Dr. Alió. "Elenza may create a com- pletely new concept in intraocular devices. It's not only about the lens, but the technology being used; it is so sophisticated that it might lead to a cascade of intraocular devices, which would be perfect to measure variations in intraocular disease, IOP on a real basis, and many other is- sues." All three of these lenses are years away from reaching U.S. soil, February 2011 PRESBYOPIA June 2011 AT A GLANCE • Tetraflex and Synchrony will be the next near-enhancing IOLs to come to the U.S. market • These new lenses might deliver near vision that is closer to what nature did in a young, healthy eye • The first electronic autofocus lens is currently in experimental use The Tetraflex Source: Paul J. Dougherty, M.D. A case with the Tetraflex accommodative IOL demonstrating an enhanced refractive range into myopia with near focus Source: Paul J. Dougherty, M.D. continued on page 38

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