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Improving Retinal Implants with Safe Electronics

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Article Posted On 6/3/2014

Macular degeneration and retinitis pigmentosa are two diseases that both cause severe vision impairment and often blindness. In both instances, these diseases cause the deterioration of the rods and cones. It is these rods and cones within the retina that convert light signals into electrical signals that are then sent to neural cells, which communicate the information to the brain via the optic nerve.

Shawn Kelly, ICES senior systems scientist, and Ashwati Krishnan, a doctoral student in electrical and computer engineering, have been taking an original approach to this problem by applying an electrode directly below the retina to artificially stimulate the retinal neural cells in order to improve vision. In their approach, a microchip is placed on the eyeball and is connected to the stimulating electrode positioned just underneath the white wall of the eye.

Given the proximity of the electrode to the delicate retinal cells, they are working to develop a microchip that can safely deliver stimulating currents to the tissues of the retina without causing dangerous chemical reactions. They are also developing an improved wireless system to efficiently transmit sufficient power and image information to the microchip to support a large number of stimulation channels. This will allow for more pixels in the image that can be seen and thus, a clearer image.

The research that Kelly and Krishnan have been advancing in the area of retinal implants was furthered, in part, by funding from a Pennsylvania Infrastructure Technology Alliance (PITA) grant. PITA funding allowed this research team to design and have fabricated two versions of a safe, stimulating microchip. The project has already received funding from the Department of Veterans Affairs to develop the advanced telemetry system and The MOSIS Service, which provided chip fabrication.