EyeWorld India June 2015 Issue

June 2015 17 EWAP FEATURE in illumination and alters the refractive index of the material,” Dr. Packer explained. The technology 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 feasible, Dr. Packer said. Dr. Nichamin likewise sees the lens as intriguing. However, at the heart of this technology is a microbattery-powered electrical system triggered by the body’s accommodative 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 FluidVision 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 silicone oil that moves from the outer haptics into the optics and back out during accommodation and disaccommodation,” Dr. Nichamin explained. “That fluid movement causes the central optic to change its curvature—it gets thicker during accommodation and thinner during disaccommodation.” The outer shell of this lens is made of a proprietary hydrophobic acrylic, he noted, adding that the material inside is an index-matched silicone oil just like that used during retina surgery. As a result there are no optical interfaces, Dr. Nichamin said. “It acts like a homogenous single optical element, and it takes very little fluid volume- wise to create significant lens shape—hence, accommodation,” he said. “Pharmacologic and bench studies indicate one could get 5 D to 10 D of accommodation, which stimulated further development.” To date, dozens of sighted eyes have been implanted with the FluidVision, he said. Investigators are seeing a minimum of 2 D to 2.25 D of accommodation. “All patients have distance vision comparable to modern-day monofocal lenses,” Dr. Nichamin said, adding that this is in conjunction with 20/25 near vision. Dr. Packer pointed out that investigators have shown more than 3 D to 5 D of accommodation in most eyes with the FluidVision. The lens is currently being implanted through a 3.5 mm incision, so it is injectable into the capsular bag in a conventional manner, Dr. Nichamin said. “Now with additional experience gained both in South Africa and Europe, FDA trials are not far off,” he predicted. There is another interesting lens in the works, Dr. Packer said—a triplet optic, which Pablo Artal, PhD, discussed at the 2014 European Society of Cataract & Refractive Surgeons’ annual meeting in London. “It’s a sandwich with two convex lenses and a concave lens in the middle,” Dr. Packer explained, adding that this involves different materials with different refractive indexes. Initial work, at least on the optical bench, show the lens to be responsive. “If you compress it 1 µm, you get a diopter of true accommodation,” he said. With just a small amount of compression, 6 D of accommodation would be possible. Dr. Weinstock said some technologies being studied are examining where ultraviolet or femtosecond light can be applied to a lens material like an acrylic that can change the shape of the lens inside the eye. “All of these technologies are interesting, but our hands are still tied because there is nothing on the immediate horizon that is a viable physiologic replication of accommodation in an IOL,” Dr. Weinstock said. EWAP Editors’ note: Dr. Nichamin has financial interests with Bausch + Lomb and PowerVision. Dr. Weinstock has financial interests with Alcon (Fort Worth, Texas), Bausch + Lomb, STAAR Surgical (Monrovia, OCULUS Asia Ltd. Hong Kong Tel. +852 2987 1050 • Fax +852 2987 1090 www.oculus.de • info@oculus.hk 欧 洲 科 学 之 路 Highspeed Scheimpflug Imaging – the Future of Diagnostics OCULUS Corvis ® ST Highspeed Scheimpflug camera in combination with non-contact tonometer: • Precise measurement of IOP • Precise measurement of CCT • Potential to measure biomechanical properties • Screening for corneal ectasia Visit OCULUS at APACRS booth 45 Calif.), and Valeant Pharmaceuticals (Bridgewater, NJ). Dr. Packer has financial interests with Alcon, Bausch + Lomb, PowerVision, and STAAR Surgical. Contact information Nichamin: ldnichamin@gmail.com Packer: mark@markpackerconsulting.com Weinstock: rjweinstock@yahoo.com