The Argus II epiretinal prosthesis system allows letter and word reading and long-term function in patients with profound vision loss.

Background: Retinal prosthesis systems (RPS) are a novel treatment for profound vision loss in outer retinal dystrophies. Ideal prostheses would offer stable, long-term retinal stimulation and reproducible spatial resolution in a portable form appropriate for daily life.

Methods: We report a prospective, internally controlled, multicentre trial of the Argus II system.