EyeWorld Asia-Pacific September 2011 Issue

September 2011 13 EW FEATURE Next from page 11 A case with the Tetraflex accommodative IOL demonstrating an enhanced refractive range into myopia with near focus Source: Paul J. Dougherty, MD With the Tetraflex, patients get good functional near vision and superb distance vision without those side effects.” Dr. Dougherty has been unhappy with the Crystalens and has actually “abandoned” it because of Z syndrome occurrences, unsatisfactory 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, MD, Jules Stein Eye Institute, David Geffen School of Medicine, University of California, Los Angeles, Calif., USA, 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 for the Tetraflex yet, but did indicate it should be treated as a premium IOL and priced as such. Other lenses that are in the pipeline include the Synchrony (Abbott Medical Optics, AMO, Santa, Ana, Calif., USA), NuLens (NuLens Ltd., Israel), the AkkoLens (AkkoLens International, the Netherlands), and the Electro-active AutoFocal Intraocular Lens (Elenza, Roanoke, Va., USA). All have varying diopters of accommodation, with the NuLens expecting to have a 4 D to 8 D range and the Synchrony from 1.0 D to 1.5 D, depending on patient age, said Jorge Alió, MD, Instituto Oftalmologico de Alicante, Spain, and clinical investigator for the Synchrony, NuLens, and AkkoLens NuLens, and AkkoLens. “There is a range of variability and each lens behaves differently,” he said. “The variability reflects the complex condition of accommodation 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 intracapsular 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 created following the Alvarez principle,” 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 completely 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 issues.” All three of these lenses are years away from reaching US soil, but Synchrony, which AMO obtained when it acquired Visiogen in 2009, is currently in front of the FDA and could gain approval this year or next. Synchrony is a dual-optic accommodating IOL that uses a preloaded disposable injector allowing for controlled implantation into the bag. Currently, the incision needs to be around 3.8 mm, which does increase the chance of surgically induced astigmatism (SIA). Studies have shown that SIA stabilizes within 0.5 D by 3 months post-op. Furthermore, making a circular and centered capsulorhexis of less than 5 mm is crucial; if it’s too big the lens won’t be retained in the bag. “There is no question the Synchrony accommodates to a very acceptable degree,” said Dr. Hovanesian. “The challenge it will face is that not every surgeon is ready to implant a lens this mechanically complex. The company has done a brilliant job of creating an injector system that, at the time of approval, will probably go into an incision less than 3 mm in size, but you have to have some faith that the lens will unfold the way it’s designed to. Not all surgeons are ready for that. It will be well suited for femtosecond laser surgery.” Dr. Dougherty agreed. “From what I understand, it’s a much more difficult surgery. For the average surgeon, it’s going to be a much more challenging lens.” All of this, of course, is speculation. The technology is sure to develop and evolve between now and when most of these lenses are approved. “Right now we can only talk about these lenses conceptually and what we expect to see,” said Dr. Hovanesian. “The new lenses are more complicated in their design and implantation, but will probably deliver accommodation that is much closer to what nature did in a young, healthy eye.” EW Editors’ note: Dr. Dougherty has a financial interest with Lenstec. Dr. Hovanesi an has financial interests with AMO and Bausch & Lomb. Dr. Alió has financial interests with AMO, AkkoLens International, and NuLens Ltd. Contact information Alió: jlalio@vissum.com Dougherty: flapzap@gmail.com Hovanesian: drhovanesian@harvardeye.com