EyeWorld Asia-Pacific June 2012 Issue

20 EWAP CATARACT/IOL June 2012 Getting up-close and personal with new accommodative IOLs by Maxine Lipner Senior EyeWorld Contributing Editor Profiling new rising accommodative stars T here’s a new group of accommodative lenses waiting in the wings to impress practitioners with their ability to offer near and intermediate acuity in addition to typical distance. EyeWorld had a heart-to-heart with practitioners already versed in the lenses to find out the intimate details of what gives these lenses their unique personalities. Fluid disposition With traits unlike any of its accommodative cousins, the FluidVision lens (PowerVision, Belmont, Calif., USA) closely emulates Mother Nature’s accommodative mechanism, according to Louis D. “Skip” Nichamin, MD , medical director, Laurel Eye Clinic, Brookville, Pa., USA. “The lens was designed with the intent of harnessing Mother Nature’s natural accommodative forces from the ciliary body expressed through the zonules and capsule to an artificial lens that would have shape changes that are similar and replicate our natural accommodative process,” Dr. Nichamin said. This, he noted, is in contrast to the NuLens (NuLens Ltd., Israel), which uses a reverse accommodative process, although it does appear to work. Dr. Nichamin views the way the fluid moves here as remarkable. “The annular peripheral haptics are the reservoirs for the fluid, and as the ciliary body and zonular apparatus contract and expand, that fluid in the peripheral annular haptics is forced radially through a channel into the center of the lens, causing it to increase its anterior posterior curvature,” he said. “The fluid moves back and forth naturally through this pliable system.” The channels in the lens are completely translucent. He finds that near vision with the lens is promising, offering an average of over 5 D of accommodation in the testing of sighted eyes. In some non-sighted eyes stimulated physiologically, results have been even better, indicating that even greater levels of accommodation are possible. In the next few months, the company will begin European studies. After receiving the CE mark, the company hopes to start FDA trials. Antithetical accommodative nature The NuLens is a two-piece accommodating IOL that is placed out of the bag, according to Steven G. Slade, MD , Slade & Baker Vision Center, Houston, Texas, USA. “The base unit is put in on top of the bag and then a second optic is put in with the haptics that fixate in the sulcus,” he said. “When the patient accommodates, the collapsed bag moves forward and AT A GLANCE • The FluidVision uses liquid channels to harness Mother Nature’s accommodative forces • With the NuLens, accommodation is counter to that of the patient’s natural lens • The two-piece Synchrony lens boasts movement of the front optic • With the Tetraflex lens, higher-order aberrations are the key to near and intermediate vision Danying ZHENG, MD Chief Physician, Zhongshan Ophthalmic Center, Sun Yat-Sen University 54 South Xianlie Road, Guangzhou, Guangdong 510060, China Tel. no. +13609702956 Fax no. +86-20-87333271 zhengdyy@163.com T here are three alternatives to correct presbyopia. These are monovision, multifocal intraocular lens, and accommodative intraocular lens (AIOL). The latter can restore true accommodative function to the aging eye for correction of presbyopia. Much ongoing research and clinical work in recent years showed its good ability to offer satisfied visual outcomes for patients. AIOL mainly includes single-optic shifting AIOL (Crystalens AT45, 1CU, Tetraflex), dual-optic shifting AIOL (Synchrony dual-optic) and deformation AIOL (Smart IOL, NuLens, FlexOptic, FluidVision lens). Patients after implantation of Crystalens AT45 showed good full-range vision 1 . Sanders 2 reported the encouraging outcomes of the Tetraflex. Ossma 3 reported the satisfying accommodative amplitude of the Synchrony dual-optic lens. But further study with a larger sample and longer time is needed. What’s more, the news from Dr. Nichamin is exciting that the near vision of the FluidVision lens is promising and offers an average of over 5 D of accommodation in the testing of sighted eyes. So is the result by the trial surgeon Dr. Slade that the NuLens accommodating IOL has been tested in 30 eyes so far and has attained between 4 to 7 D of accommodation. I believe AIOL, especially the dual-optic shifting AIOL and deformation AIOL, will become an increasingly prevalent method to correct presbyopia in the future. And more study on this topic is anticipated to be reported. In modern society, various working light conditions are needed and AIOLs have the advantage of not causing the decreased contrast sensitivity. New AIOLs providing perfect functional vision from far to near like multifocal intraocular lens while being free of the visual disturbances are expected to be developed and marketed. However, a number of challenges are needed for longitudinal studies to maintain the true accommodation and satisfied postoperative outcome for AIOL. Such as limitation of accommodative amplitude of certain AIOL, astigmatism induced by larger incision, the influence of posterior capsular opacification and aging vitreous body. Since sufficient capsular elasticity and incompressible vitreous body are the bedrock of the accommodation mechanism. Stable accommodative function and spectacle independence are anticipated in the future. Technology of AIOL design and surgery technique should be improved for achieving these ultimate goals. References 1. Cumming JS, Colvard M, Dell SJ, et al. Clinical evaluation of the Crystalens AT45 accommodating intraocular lens Results of the U.S. Food and Drug Administration clinical trial. J Cataract Refract Surg . 2006;32:812-825. 2. SandersDR, SandersML. Visual performanceResults after TetraflexAccommodating Intraocular Lens Implantation. Ophthalmology . 2007;114:167-168. 3. Ossma IL, Galvis A, Vargas LG, et al. Synchrony dual-optic accommodative intraocular lens Part 2: Pilot clinical evaluation. J Cataract Refract Surg . 2007;33:47-52. Editors’ note: Dr. Zheng has no financial interests related to her comments. Views from Asia-Pacific