Development of a chemical retinal prosthesis: Stimulation of rat retina with glutamate

Retinal degenerative diseases cause partial or total blindness and affect millions of people worldwide, yet currently have no treatment. Retinal prostheses using electrical stimulation are being developed but face significant problems moving forward. Here we propose using chemical stimulation, via the neurotransmitter glutamate, to modulate retinal ganglion cell (RGC) spike rates. Our results demonstrate that it is feasible to stimulate RGCs in an explanted retina using focal ejections of glutamate from either subretinal or epiretinal sides. Preliminary evidence suggests we are primarily activating RGCs as opposed to bipolar cells. This is an important first step in the development of a chemical retinal prosthesis based on microelectromechanical systems (MEMS) technology.