Recent Results from Second Sight’s Argus® II Retinal Prosthesis Study

Abstract

Purpose: To provide an update on performance outcomes in the Argus II Retinal Prosthesis Study.

Methods: Subjects had bare light perception or worse vision due to retinitis pigmentosa. All subjects were implanted with a Second Sight Argus II implant (clinicaltrials.gov NCT00407602). Visual function was evaluated by a grating visual acuity test as well as by assessing the ability to determine the direction of motion of a line and the location of a square on an LCD screen. Orientation and mobility (O&M) tests were also given, which involved following a line and finding a door. The Functional Low-vision Observer Rated Assessment was used by low-vision rehabilitation experts to evaluate subjects’ functional vision and well-being.

Results: As of December 1, 2012, 30 subjects have been implanted at 10 centers (in the main study). Subjects have been implanted an average of 4.2 ± 1.0 years (range of 1.2 - 5.5), and all have used or are using the System at home. In this report we are only mentioning what we have learned new over the last year. Over the past year, the Argus II continues to work in all subjects except for one device which had exhibited intermittent communication link which subsequently failed at 4 years post-implant. There was one additional case of presumed endophthalmitis (culture negative) associated with an area of conjunctival erosion which resolved using intravitreal and topical antibiotics and with repair of the conjunctiva and did not require device removal. Additional research has demonstrated GVAs as high as 1.0 logMAR (20/200) using image processing algorithms. Functional vision O&M tests continue to demonstrate that subjects are significantly better at performing visual tasks with the System ON vs. OFF. In September 2012, the Argus II retinal prosthesis received a unanimous approval by an advisory panel convened by the FDA ophthalmic device division.

Conclusions: With over 125 cumulative patient-years of follow-up on 30 subjects, this is the largest study of a visual prosthesis to date. This year results continue to confirm previous reports on the ability of the Argus II prosthesis to provide visual function and functional vision over several years. The Argus II Retinal Prosthesis System has been commercially available in Europe since 2011 and FDA approval in the US is now pending. Funding information: NIH 5R01EY012893-10

Keywords: 688 retina • 698 retinal development • 462 clinical (human) or epidemiologic studies: outcomes/complications