An Update on the Argus II Epiretinal Implant

Abstract

Purpose: To present updated results from the Argus II Retinal Prosthesis Study (clinicaltrials.gov NCT00407602) and new results from post market/commercial patients

Methods: All subjects implanted with a Second Sight Argus II implant had severe outer retinal degenerations. In the clinical trial, visual function was evaluated by visual function tests presented on an LCD screen, including Square Localization, Direction of Motion, and Grating Visual Acuity. Assessments of functional vision included controlled Orientation and Mobility (O&M) tasks, and the Functional Low-Vision Observer Rated Assessment (FLORA).

Results: As of September 30, 2013, 30 subjects have been implanted at 10 centers in the clinical trial. Subjects (excluding one who was explanted at 1.2 years) have been implanted an average of 4.9 ± 0.6 years (range of 4.2 - 6.3). The Argus II remains implanted and functioning in 26 subjects. The safety profile remains acceptable. Performance has remained better with the System ON than OFF on all visual tests, with these results sustained out beyond 5 years of chronic use. As of September 30, 2013, 30 additional patients have been implanted with the Argus II in the post-market setting in Europe. In the first year, only two subjects experienced a serious adverse event (12.5%), compared to 36.7% at 1-year post-op in the clinical trial. Surgical time was reduced in the commercial patients compared to the clinical trial subjects.

Conclusions: With 150 cumulative patient-years of clinical trial follow-up on 30 clinical trial subjects, this is the largest study of a visual prosthesis to date. The results confirm previous reports on the ability of the Argus II prosthesis to provide visual function and functional vision over several years of chronic device use. The Argus II Retinal Prosthesis System is commercially available in the US and Europe, and in the post-market setting has shown improved safety and required shorter surgical implantation time.

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