EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
Issue link: https://digital.eyeworld.org/i/78719
February 2012 IOLs Visit Us at the ASCRS 19 it t U at the e AS Booth 419 E pithe i a l remo vall i C mented to move, according to Mark Packer, M.D., clinical associate pro- fessor of ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland. Specifically, it is the anterior component that moves. "When we try and focus up close, the ciliary muscle contracts, releasing tension on the zonular fibers; the spring that is inside the structure of the Synchrony actually has memory," Dr. Packer said. "Then when the ciliary muscle relaxes and pulls peripherally on the zonular fibers, it is squeezing the capsule so that the lens is squeezed together and that front optic moves back." One of the things that Dr. Packer sees as setting the dual-optic lens apart is the fact that it keeps the capsule open and allows circulation of aqueous there. He pointed out that other lenses like the FluidVision have an open capsule but are too thick to allow free aqueous circula- tion. "But this has a design where there are channels around the front of the optic that allow aqueous to circulate into the capsule so that it is kept open," he said. "As a result of that, these capsules stay remarkably clear—there is virtually no capsular opacification." During the study no touchup procedures were allowed and due to the larger incision needed here, more astigmatism was induced. Even so, Dr. Packer found that approxi- mately 80% of patients were free of glasses. Currently the Synchrony lens is CE marked. FDA studies were completed in the U.S., where it is awaiting approval. Tightly titrated characteristics With the Tetraflex lens (Lenstec, St. Petersburg, Fla.), the theory is that accommodation results from an in- crease in higher-order aberrations, according to Paul J. Dougherty, M.D., clinical instructor of ophthal- mology, Jules Stein Eye Institute, University of California, Los Ange- les, and medical director, Dougherty Laser Vision, Los Angeles. "The way we think it works is that during the accommodative effort, ciliary muscle contraction and/or increased vitre- ous pressure deforms the lens and causes higher-order aberrations, which are one of the natural mecha- nisms of accommodation," Dr. Dougherty said. "There may be some Editors' note: Dr. Dougherty has finan- cial interests with Lenstec. Dr. Koch is on the advisory board of NuLens, but he has no financial interests related to this article. Dr. Nichamin has financial interests with PowerVision. Dr. Packer has financial interests with AMO. Dr. Slade has financial interests with NuLens. Contact information Dougherty: flapzap@gmail.com Koch: 713-798-6443, dkoch@bcm.edu Nichamin: 814-849-8344, nichamin@laureleye.com Packer: 541-687-2110, mpacker@finemd.com Slade: 713-626-5544, sgs@visiontexas.com small effect of movement of the lens, but we know that doesn't ac- count for all the effect of the lens." When investigators looked at higher-order aberrations in a sub- study of the FDA trial, they found a jump in these after implantation of the Tetraflex. "There was a 34% in- crease in total higher-order aberra- tions compared to a monofocal control," Dr. Dougherty said. An FDA study comparing read- ing speed with the Tetraflex to the Crystalens (Bausch + Lomb, Rochester, N.Y.) showed statistically significant improvement for patients with the Tetraflex. "I think that it offers better near vision," Dr. Dougherty said. Another feature that is unique about the Tetraflex is that it is very tightly titrated. "It's manufactured to 1/8 of a diopter tolerance, whereas ANSI [American National Standards Institute] standards allow up to 1 D of variation depending on lens power," Dr. Dougherty said. With the lens the majority of patients enjoy good social reading. "In the FDA study binocular accom- modative amplitude at 1 year showed that 9% of patients had 1 D or more of accommodation, and 68% had 2 D or more of accommo- dation," Dr. Dougherty said. He esti- mated that about 75% of patients never or only occasionally need reading glasses. The FDA trials in the U.S. have been completed, and the Tetraflex has received CE mark approval. "I can't wait for it to be FDA approved so that I can offer it to my patients," Dr. Dougherty said. EW Xli Xlinkn kin , PR & A ingg , PRK Addvan edancced Su face A at on ve the SurfrfaceAbllatiion. Remoov Epithe ium Pr omottes Con istentonssiste n ResultsResults! ntt + Mini n mize total pr + Esseential in r + Unifor + No n need f e total pr oced edu e time dure tim Essential in re-treatmeent Unifo m epithelium rem e ments emo amovall No need f or subsequent scraping pitheliuml in 5 to 7 secondseconds . pitheliall al inn Corneal Su p rior Results upere iorResult s T. 800.46 61.1200 800.461.1200 | www..ininno no vativexcimer .com