EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
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March 2013 EW RETINA 75 Watch these videos on your smartphone or iPad using your QR code reader. (Scanner available for free at your app store.) rehab screening and will work with the patient postop. Some patients are thrilled with any amount of visual improvement, others consider the improved central vision as a compromise to increased loss of peripheral vision in the implanted eye, and for others still loss of any vision is unacceptable. "In the studies, the most successful groups were those that had the best low vision specialists, people who were enthusiastic," Dr. Kuppermann said. "Having the surgery, determining if a patient is a candidate, all that is barely half the battle. The real challenge is in teaching people how to use it." In development for RP There are currently two devices being developed for retinitis pigmentosa (RP), a genetic disorder that eventually results in blindness. The Argus II (Second Sight Medical Products, Sylmar, Calif.) takes an epiretinal approach, while the Retina Implant (Retina Implant, Reutlingen, Germany) takes a subretinal approach. With the Argus II, a 55-electrode chip is placed on top of the macular region, and requires the patient wear glasses that have a camera mounted on it. The device includes a wireless processor and a battery pack patients wear around their waist, said Brian Mech, Ph.D., vice president of business development. The Argus II received FDA approval in February. With the Retina Implant, the 1,500 electrode, 3x3 mm2 microchip is placed underneath the retina where photoreceptor cells exist in normally sighted people, said Walter G. Wrobel, Ph.D., president and chief executive officer. A wireless power supply is implanted subdermally behind the ear. The device is completely embedded in silicone for biocompatibility (except for the stimulating chip), with one half of the device implanted beneath the retina, the other half sewn onto the eye and covered by conjunctiva, Dr. Wrobel said. "Patients are able to distinguish between a fork and a spoon within days of the device being implanted," he said. "For them, it's really a miracle." Dr. Kuppermann said he tells "everyone who can benefit from the device" about the Argus II, but acknowledges it's very few people. "It's really the worst of the worst of the RP patients," he said. Unlike the IMT, "a cataract in these patients is not as much of a concern," Dr. Mech said. "We advocate removing the natural lens if present to eliminate the possibility of cataract formation (which is now higher because of the surgery)." Dr. Mech said Second Sight is considering the device for geographic atrophy, but notes the potential cost may be a barrier. "The device is $150,000 and in RP, that's likely spread out over 30 years so it's justifiable. But with AMD, patients are 80 so maybe there's five or 10 years' benefit, and it may not be as justifiable," Dr. Mech said. Dr. Kuppermann said, "If I was one of these patients with end-stage RP, I would give the electronic implant serious consideration, understanding all the risks. The potential to gain vision is better than the alternative." EW Editors' note: Dr. Colby has no financial interests related to this article. Dr. Kuppermann has financial interests with Second Sight. Dr. Mech and Dr. Wrobel are employees of Second Sight and Retina Implant, respectively. Contact information Colby: 617-573-5537, kacolby@meei.harvard.edu Kuppermann: 949-824-6256, bdkupper@uci.edu Mech: 818-833-5026 Wrobel: walter.wrobel@retina-implant.de An artist's rendering of the Retina Implant and how it works The Retina Implant (also shown at left) in a patient with retinitis pigmentosa Walter G. Wrobel, Ph.D., president and chief executive officer of Retina Implant, with an artist's rendering of the implant Source: Retina Implant