RT Journal Article
SR Electronic
T1 Minimizing Iridium Oxide Electrodes for High Visual Acuity Subretinal Stimulation
JF eneuro
JO eNeuro
FD Society for Neuroscience
SP ENEURO.0506-20.2021
DO 10.1523/ENEURO.0506-20.2021
VO 8
IS 6
A1 Samir Damle
A1 Maya Carleton
A1 Theodoros Kapogianis
A1 Shaurya Arya
A1 Melina Cavichini-Corderio
A1 William R. Freeman
A1 Yu-Hwa Lo
A1 Nicholas W. Oesch
YR 2021
UL http://www.eneuro.org/content/8/6/ENEURO.0506-20.2021.abstract
AB Vision loss from diseases of the outer retina, such as age-related macular degeneration, is among the leading causes of irreversible blindness in the world today. The goal of retinal prosthetics is to replace the photo-sensing function of photoreceptors lost in these diseases with optoelectronic hardware to electrically stimulate patterns of retinal activity corresponding to vision. To enable high-resolution retinal prosthetics, the scale of stimulating electrodes must be significantly decreased from current designs; however, this reduces the amount of stimulating current that can be delivered. The efficacy of subretinal stimulation at electrode sizes suitable for high visual acuity retinal prosthesis are not well understood, particularly within the safe charge injection limits of electrode materials. Here, we measure retinal ganglion cell (RGC) responses in a mouse model of blindness to evaluate the stimulation efficacy of 10, 20, and 30 μm diameter iridium oxide electrodes within the electrode charge injection limits, focusing on measures of charge threshold and dynamic range. Stimulation thresholds were lower for smaller electrodes, but larger electrodes could elicit a greater dynamic range of spikes and recruited more ganglion cells within charge injection limits. These findings suggest a practical lower limit for planar electrode size and indicate strategies for maximizing stimulation thresholds and dynamic range.