Eyeworld

EW MEETING REPORTER June 2011 65 ness, face recognition, and finding signs worsened with worse visual acuity and with larger GA area at baseline. Longitudinally, reading and face recognition deteriorated significantly. Editors' note: None of the physicians mentioned reported a financial interest related to their comments or studies. by Michelle Dalton EyeWorld Contributing Editor Retinal prosthesis system offers hope for those with RP An implantable device has shown safety, high performance over more than 70 cumulative patient- years of follow-up on 30 subjects A retinal prosthesis system (Argus II, Second Sight, Lausanne, Switzerland) has provided "significant improvements in vision for the blind subjects who are suffer- ing from profound retinitis pigmen- tosa (RP)," said Gregoire Cosendai, Ph.D., vice president, Europe for Sec- ond Sight. He told EyeWorld most patients notice benefits as early as 2- 3 months, with a constant improve- ment through month 24. The device obtained the Euro- pean Conformity (CE) mark in Feb- ruary and will be submitted to the FDA this quarter, Dr. Cosendai said. "Currently in the U.S. the device was implanted under an Investiga- tional Device Exemption," he added. The system is approved for use in Europe with an indication of use for the following: people more than 25 years old with severe to profound outer retinal degeneration, some residual light perception, and a pre- vious history of useful form vision, according to Second Sight. "One of the most exciting thing we've found is that some subjects fitted with the device were able to consistently see colors, while a large majority were able to recognize large letters" Dr. Cosendai said. Paulo E. Stanga, M.D., consult- ant ophthalmologist, Manchester Royal Eye Hospital, England, found Highlights continued from page 64 "nine participants were able to reli- ably and repeatedly perceive up to eight different colors using Argus II," he said. "Color perception could be achieved by precisely controlling as- pects of the electrical stimulation. Color vision obtained in this man- ner represents a unique feature of an epi-retinal approach employing an external camera and processor." Thirty patients are enrolled in Second Sight's study. Some have had a similar device implanted for more than 6 years, Dr. Cosendai said. Functional vision orientation and mobility tests demonstrate that sub- jects were significantly better at per- forming visual tasks, such as following a line or finding a door, with the system on versus off. What it is Argus II is Second Sight's second- generation implantable device in- tended to treat people who have gone blind because of degenerative diseases such as RP. The system works by converting video images captured from a miniature camera, housed in the patient's glasses, into a series of small electrical pulses that are transmitted wirelessly to an array of electrodes on the surface of the retina (epi-retinal). These pulses are intended to stimulate the retina's re- maining cells, resulting in the corre- sponding perception of patterns of light in the brain. Patients can learn to interpret these visual patterns, thereby gaining some functional vi- sion. "This system is for people with much more advanced retinal dis- ease," Dr. Cosendai said. "This sys- tem is allowing patients to get some useful visual back." When the pho- toreceptors no longer function, it is impossible for the visual system to transform light into images, he ex- plained. At the recent Association for Research in Vision and Ophthalmol- ogy (ARVO) meeting, Mark S. Humayun, M.D., professor of oph- thalmology, University of Southern California, Los Angeles, presented the interim performance results on the latest study of implants in 30 pa- tients at 10 centers around the world (four in Europe and six in the U.S.). "All subjects implanted with a Second Sight Argus II Retinal Pros- thesis System previously had only bare light perception or worse vision due to RP or related outer retinal de- generative disease," he said. "During the clinical trial we were pleased to observe the promising results of the system that revealed that all 30 sub- jects in the trial obtained visual per- ceptions from the device. A large majority of them experienced bene- fit from the system in terms of visual function tests that ranged from lo- calizing and identifying an object to grating visual acuity." Dr. Humayun said during ARVO that 28 out of 30 devices are intact and functioning—one device was explanted around 14 months post- implant; a second remains im- planted but functions intermittently due to partial loss of the RF link that provides power and data to the array. Dr. Humayun said the adverse events "were similar to what's seen in other vitreoretinal procedures," and included lowered intraocular pressure, three cases of endoph- thalmitis (those were attributed to a hospital contamination rather than to the device), one case of conjuncti- val erosion that led to one explanta- tion, and two retinal detachments. "Even after repair of retinal detach- ment, the retina underneath the device remained attached and, therefore, the device still functioned as intended despite the presence of a detachment," Dr. Humayun said. Argus II is the first retinal pros- thesis in which the feasibility of reading sentences with prosthetic vi- sion has been demonstrated, Second Sight said. Two patients from the Paris center were able to correctly read four-word sentences, according to the company. Reading speeds in- creased quickly for the patients, and one was able to read at speeds of up to 10 words per minute. Editors' note: Drs. Cosendai and Humayun have financial interests with Second Sight. Dr. Stanga has no finan- cial interests related to his comments. Contact information Cosendai: +41 79 242 05 42, gcosendai@2-sight.com Humayun: 323-442-6522, humayun@usc.edu Stanga: +44 161 276 1234, info@retina.co.uk An illustration of Argus II Source: Second Sight A patient tests Argus II by reading the French phrase on the screen. In English the phrase is: He runs very fast Source: Second Sight

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