John S. Pollack, MD (Joliet, IL),* Kirk H. Packo, MD (Chicago, IL),* Gislin Dagnelie, PhD (Baltimore, MD), Ron A. Schuchard, PhD (Atlanta, GA), Julia A. Haller, MD (Baltimore, MD), Thomas M. Aaberg, MD (Atlanta, GA), Mathew W. MacCumber, MD, PhD (Chicago, IL), Pauline T. Merrill, MD (Oak Park, IL), Jennifer Yan, MD (Atlanta, GA), Alan Y. Chow, MD (Naperville, IL)*


To evaluate the safety and preliminary effectiveness of a subretinal Artificial Silicon Retina (ASR®) device for treatment of vision loss from retinitis pigmentosa in an expanded 20- patient, multicenter, phase II study.


A light-powered photovoltaic ASR microchip, 2-mm in diameter was implanted into the superiortemporal subretinal space of 20 patients with retinitis pigmentosa. The eye to be implanted was randomized. Patients had ETDRS Snellen equivalent of 20/200 or worse, or visual fields of 15 degrees radius centrally or less in any quadrant of both eyes. Masked and unmasked testers performed pre- and postoperative assessment of visual function employing a forced choice paradigm whenever possible using ETDRS letters, grating acuity, automated visual fields, functional MRIs, ERGs, orientation and mobility testing, and subjective questionnaires.


35% of implanted eyes show some ETDRS visual acuity improvement with 20% achieving at least a 2 line improvement at 9-12 months post-op. 70% of patients are indicating “lifeimpacting” changes in vision at 9-12 months post-operatively. Subjective, independent mobility questionnaire results demonstrate 35% achieve significance at 6 months post-op. The ASR devices have been well tolerated to date. A large intra-operative retinal bleb may allow the microchip to migrate inferiorly in some patients. 9-12 month data suggests possible visual function improvements in many of the patients.


In this expanded phase II study, subretinal ASR chips were successfully implanted at multiple centers and by multiple surgeons in patients with retinitis pigmentosa. A positive effect on visual function, reported in an earlier pilot study, is also being suggested in patients in this study.
* Financial interest disclosed