Five-year data from the Argus II Retinal Prosthesis System Clinical Tria

Abstract

Purpose: To present five-year results from the Argus II Retinal Prosthesis Study (clinicaltrials.gov NCT00407602) and update on the commercial implant program.

Methods: All subjects implanted with a Second Sight Argus II implant were blind from retinitis pigmentosa or similar disorders. In the clinical trial, visual function was evaluated by visual function tests such as 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 October 15, 2014, 30 subjects have been implanted at 10 centers in the clinical trial. Subjects (excluding three who have been explanted) have been implanted an average of 6.2 ± 0.9 years (range of 5.2 - 7.4). The Argus II remains implanted and functioning in 24 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.<br /> As of October 15, 2014, there have been 54 additional implants of the Argus II commercially in Europe, the U.S., Canada, and the Middle East.

Conclusions: With 176 cumulative subject-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. Current research efforts are directed toward a feasibility study for age-related macular degeneration, and the development of a prosthesis for the primary visual cortex.