Article
Argus® II Retinal Prosthesis System: clinical trial results update (I)
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Authors
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Robert J. Greenberg
- Second Sight Medical Products, Inc, Sylmar, USA
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José-Alain Sahel
- Center Hospitalier National d’Ophtalmologie des Quinze-Vingt, Paris, France
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Lyndon da Cruz
- Moorfields Eye Hospital, London, United Kingdom
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Paulo Stanga
- Manchester Royal Eye Hospital, Manchester, United Kingdom
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Grégoire Cosendai
- Second Sight Medical Products, Sàrl, EPFL-PSE A, Lausanne, Switzerland
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Study Group Argus II
- Second Sight Medical Products, Inc, Sylmar, USA
| Published: | October 18, 2013 |
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Outline
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Purpose: The Argus II is intended to provide electrical stimulation of the retina to induce visual perception in blind individuals with severe to profound Retinitis Pigmentosa. It consists of internal components (6x10 epiretinal electrode array, receiving coil, electronics case) and external components (glasses mounted with a miniature video camera, small wearable computer). This clinical trial has demonstrated the safety and probable benefit of the System and has supported regulatory approval in the U.S. and Europe.
Methods: 30 subjects were enrolled in the clinical trial (clinicaltrials.gov NCT00407602); all had BLP or worse in both eyes at the time of implant. Visual function was assessed by high-contrast computer-based tests (SL, DoM, GVA). Functional vision was assessed with objective orientation and mobility (O&M) tests (finding a door, following a line), self-reported questionnaires (Massof Activity Inventory and the Visual Quality of Life index), and the Functional Low-vision Observer Rated Assessment (FLORA), which evaluated subjects’ functional vision and well-being in their home environment.
Results: As of April 11, 2013, 30 subjects have been implanted at 10 centers (in the main study). Subjects have been implanted an average of 4.5 ± 1.0 years (range of 1.2–5.8), and all have used or are using the System at home. Over the past year, the Argus II continued to work in all subjects except for one device which failed at 4 years post-implant. Functional vision O&M tests continue to demonstrate that subjects are significantly better at performing visual tasks with the System ON vs. OFF. Additional research has demonstrated visual acuity as high as 1.0 logMAR (20/200) using image processing (zoom); color perception has also been shown in research experiments. A total of 54 people (clinical trial subjects and commercial patients) worldwide have received the Argus II implant.
Conclusions: With over 134 cumulative patient-years of follow-up on 30 subjects, this is the largest study of a visual prosthesis to date. The results confirm previous reports on the ability of the Argus II to provide visual function and functional vision to blind patients, and to reliably function for several years. The Argus II Retinal Prosthesis System has been commercially available in Europe since 2011 and FDA approval in the US was received in 2013. Future software upgrades may extend the capabilities of the Argus II, for example by providing the ability to zoom in or out, or detect salient features of the image (e.g., faces).
Funding information: NIH 1RC3EY020778-01
