Optobionics’ Artificial Silicon Retina ™ microchip

Optobionics describes the technology of the silicon chip that it has designed:

Optobionics’ Artificial Silicon Retina™ microchip is designed to stimulate damaged retinal cells, allowing them to send visual signals again to the brain. This may be possible in patients with retinitis pigmentosa (RP), age-related macular degeneration (AMD) and possibly other retinal conditions.
The ASR microchip is a silicon chip 2mm in diameter and 25 microns thick, less than the thickness of a human hair. It contains approximately 5,000 microscopic solar cells called “microphotodiodes,” each with its own stimulating electrode. These microphotodiodes are designed to convert the light energy from images into electricalchemical impulses that stimulate the remaining functional cells of the retina in patients with AMD and RP types of conditions.
The ASR microchip is powered solely by incident light and does not require the use of external wires or batteries. When surgically implanted under the retina – in a location known as “subretinal space” – the ASR chip is designed to produce visual signals similar to those produced by the photoreceptor layer. From their subretinal location, these artificial “photoelectric” signals from the ASR microchip are in a position to induce biological visual signals in the remaining functional retinal cells which may be processed and sent via the optic nerve to the brain.

According to BusinessWeek (Feb.7, 2005), ASR chips have already been implanted into legally blind volunteers in three hospitals across the country (USA).
Additional info at Optobionics…