In Vivo Photovoltaic Performance of a Silicon Nanowire Photodiode-Based Retinal Prosthesis

Area of Science:

• Biomedical Engineering
• Neuroscience
• Ophthalmology

Background:

• Retinal prostheses aim to restore vision in degenerative diseases.
• Subretinal implants offer a promising approach for vision restoration.

Purpose of the Study:

• To evaluate the efficacy of a novel subretinal prosthesis with 1512 silicon nanowire photodiodes.
• To assess the visual cortex activation via electrical stimulation of the retina using optically driven prostheses.

Main Methods:

• Electrically evoked potential responses (EEPs) were measured in rabbit visual cortex.
• The subretinal nanowire prosthesis was illuminated with pulsed 852-nm infrared (IR) light.
• Responses were compared to visually evoked potential responses (VEPs) using visible and IR light.

Main Results:

• IR light activation of the prosthesis produced significantly higher EEP amplitudes compared to IR light alone or background activity.
• EEP latencies were faster than focal VEP latencies.
• A noninvasive corneal electrode method was demonstrated for monitoring implant function.

Conclusions:

• Subretinal electrical stimulation using nanowire electrodes successfully elicited EEPs in the visual cortex.
• This provides evidence for the viability of subretinal nanowire prostheses for vision restoration.
• The study supports the potential of this technology for patients with retinal degeneration.