Argus® II Retinal Prosthesis System

The Argus® II epiretinal prosthesis was the first retinal implant to receive commercial approval in Europe and in the United States. To date, it is the most widely used prosthesis worldwide with over 100 implanted patients in several countries, including the United States, United Kingdom, France, Germany, Switzerland, Mexico and Saudi Arabia. The device is used as a treatment for patients with profound vision loss due to end-stage photoreceptor degenerative diseases. Argus II works by electrical stimulation of the inner retina, retinal ganglion cells and/or bipolar cells that remain partially functional in these patients. The system is an epiretinal prosthesis, meaning that the microelectrode array is surgically implanted on the retinal surface nearest to the nerve fiber layer. Video signals are acquired by a glasses-mounted video camera and transformed into electrical pulses that are finally transmitted via the microelectrode array to the inner retina. The device is capable of eliciting visual perception in a reliable and controllable fashion through video processing and manipulation of stimulation parameters. Argus II and its predecessor, Argus I, were the first devices tested in humans to pass safety and efficacy assessments. This chapter will summarize the history of device development, initial preclinical studies and results from clinical trials. It will also discuss several future advances needed to improve the device in order to provide a more informative visual perception to blind patients.