Eyeworld

EW FEATURE 110 Refractive options March 2015 by Maxine Lipner EyeWorld Senior Contributing Writer debt of gratitude for failing many times and going through about 12 different lens designs before he finally found one that was stable and functional enough to work and to provide the results to finally allow it to get approved—but it's still not perfect." In the wings There are currently other lenses in the wings that are beginning to draw attention. Dr. Nichamin pointed to a couple of lenses that go into the cili- ary sulcus—the AkkoLens (AkkoLens International, Breda, the Nether- lands) and the NuLens (NuLens Ltd., Herzliya Pituach, Israel). The AkkoLens design is 2 lenses that move perpendicular to the optical axis, Dr. Nichamin said. "In other words, they slide over each other as the ciliary body contracts and relaxes," he said. "The AkkoLens relies on accommodative forces to move 2 overriding cubic optical elements in opposite directions." Dr. Packer thinks this lens works in an interesting way. "It goes in the ciliary sulcus and when the muscle constricts, it compresses the lens and the lens has a variable curvature—as it gets compressed, it increases the accommodative power," Dr. Packer said. While the number of patients implanted with the AkkoLens is small, it shows promise "with vari- able amounts of accommodation to reportedly as high as 6 D," Dr. Nichamin said. The NuLens is also sulcus-based, but works in a contrary manner, he said. Normally in the human eye, as the ciliary body contracts, it causes accommodation; however, with the NuLens it is just the opposite, and despite the counterintuitive said, adding that the range tends to be from 20/20 to 20/80. Meanwhile, the TRULIGN lens garnered FDA approval but without the "accom- modative" label, Dr. Packer said. "The TRULIGN provides in- creased distance, intermediate, and near vision with reduced spectacle dependence or increased spectacle independence," he said. Functional- ly the TRULIGN provides about 1 D of accommodation, but this cannot be measured objectively, Dr. Packer said. Outside of the U.S., while the Crystalens has made some inroads, it is not as popular as it is in the U.S., said Robert J. Weinstock, MD, director of cataract and refractive surgery, The Eye Institute of West Florida. Likewise, the CE-marked Tetraflex accommodative lens (Len- stec, St. Petersburg, Fla.) is being used in some cases but is not a wide- spread solution, he said. "My under- standing in talking to colleagues is that there is not an accommodative IOL in the U.S. or outside the U.S. that is just booming," Dr. Weinstock said, adding that beyond the U.S. borders, multifocal technology is more favored than accommodative. "I think that's because there are many more multifocal IOL technol- ogies available and approved outside of the U.S.," he said. "It's much eas- ier to make a lens with multifocality than it is to design one that actually moves." Especially with the FDA climate today in the U.S., it is much more challenging to develop a lens that mimics natural accommodation, he noted. "Stuart Cummings [MD] basically poured his life's work into developing the Crystalens," Dr. Weinstock said. "We owe him a Eyeing new IOLs for improving near vision T he availability of a full-spectrum accommo- dative lens is among the greatest aims in all of anterior segment surgery, according to Louis D. "Skip" Nichamin, MD, Beaver Creek, Colo. Dr. Nichamin has often referred to this as the "Holy Grail" in anterior segment ophthalmology. "I believe it's even more so today than ever given the increased awareness and demand for refractive surgery and increased lifestyle treat- ments," he said. Mark Packer, MD, clinical asso- ciate professor, Oregon Health & Sci- ence University, and medical direc- tor of Boulder Eyes, Boulder, Colo., agreed, saying that a full-spectrum lens would be a huge winner. "If that existed, we would not have to bother with multifocals and extended depth of focus and pinhole implants," he said. "That would be the end if we had a reliable, effective, accommodative lens." Current course In the U.S., there are the options of the FDA-approved Crystalens (Bausch + Lomb, Bridgewater, N.J.) and TRULIGN toric intraocular lens (Bausch + Lomb) for those with astigmatism. But Dr. Packer finds that these patients are often not completely spectacle-free and need a low-powered pair of reading glasses. "If you have 20/20 distance vision [with the Crystalens], the av- erage near is going to be 20/40," he Joining the accommodative movement continued on page 112 AT A GLANCE • Making a lens that mimics accommodative movement continues to be extremely challenging. • Innovative approaches from fluid-filled lenses to a microbattery-powered electrical system are being considered. • Sulcus-based accommodative IOLs have also shown some success. The triplet optic involves 2 convex lenses sandwiching a concave lens and is designed to respond to a small amount of compression. Source: Mark Packer, MD mechanism, this approach has worked in some cases. "It seems to work in animals as well as in limited human studies," Dr. Nichamin said. Some other lenses being devel- oped are more traditionally slated for the capsular bag. Dr. Packer views the Sapphire AutoFocal IOL (ELENZA, Roanoke, Va.), in devel- opment, as a fascinating idea. He describes it as a glass photoelectrical device, based on the idea that as someone focuses at near, the pupil gets smaller. "The lens senses this change in illumination and alters the refractive index of the material," Dr. Packer explained. The technol- ogy was extrapolated from variable focal, electro-optical eyeglasses, he said. However, one challenge with the lens may be getting it into an eye in a way that is surgically feasi- ble, Dr. Packer said. Dr. Nichamin likewise sees the lens as intriguing. However, at the heart of this technology is a micro- battery-powered electrical system triggered by the body's accommo- dative stimuli that can change the lens' focus, he said. "It's fascinating, but one has to have some battery recharging system, whether it's in the form of occasionally wearing glasses while you sleep or implanting the power source somewhere else," Dr. Nichamin said. Also in the works is the Fluid- Vision Lens (PowerVision, Belmont, Calif.), which likewise resides in the capsular bag. "It has annular 3D haptics that communicate with the central optic, all of which are filled with sili- cone oil that moves from the outer haptics into the optics and back

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