RT Journal Article
SR Electronic
T1 The Argus II epiretinal prosthesis system allows letter and word reading and long-term function in patients with profound vision loss
JF British Journal of Ophthalmology
JO Br J Ophthalmol
FD BMJ Publishing Group Ltd.
SP 632
OP 636
DO 10.1136/bjophthalmol-2012-301525
VO 97
IS 5
A1 Lyndon da Cruz
A1 Brian F Coley
A1 Jessy Dorn
A1 Francesco Merlini
A1 Eugene Filley
A1 Punita Christopher
A1 Fred K Chen
A1 Varalakshmi Wuyyuru
A1 Jose Sahel
A1 Paulo Stanga
A1 Mark Humayun
A1 Robert J Greenberg
A1 Gislin Dagnelie
A1 for the Argus II Study Group
YR 2013
UL http://bjo.bmj.com/content/97/5/632.abstract
AB 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. Twenty-eight subjects with light perception vision received a retinal implant. Controlled, closed-group, forced-choice letter identification, and, open-choice two-, three- and four-letter word identification tests were carried out. Results The mean±SD percentage correct letter identification for 21 subjects tested were: letters L, T, E, J, F, H, I, U, 72.3±24.6% system on and 17.7±12.9% system off; letters A, Z, Q, V, N, W, O, C, D, M, 55.0±27.4% system on and 11.8%±10.7% system off, and letters K, R, G, X, B, Y, S, P, 51.7±28.9% system on and 15.3±7.4% system off. (p<0.001 for all groups). A subgroup of six subjects was able to consistently read letters of reduced size, the smallest measuring 0.9 cm (1.7°) at 30 cm, and four subjects correctly identify unrehearsed two-, three- and four-letter words. Average implant duration was 19.9 months. Conclusions Multiple blind subjects fitted with the Argus II system consistently identified letters and words using the device, indicating reproducible spatial resolution. This, in combination with stable, long-term function, represents significant progress in the evolution of artificial sight.