Electro-retinal interface with single-cell resolution for restoration of sight
Abstract
Retinal injury or degeneration may lead to blindness due to loss of photoreceptors. However, a significant number of the inner retinal neurons survive to a large extent, providing an opportunity for restoration of vision by electrical stimulation of these remaining cells. We developed photovoltaic arrays as a substitute for the lost photoreceptors, which directly convert light into pulsed electric current in each pixel, stimulating the nearby second-order retinal neurons. Clinical trials in patients blinded by atrophic Age-related Macular Degeneration confirmed the safety, stability of such implants and spatial resolution closely matching the 100microm pixel size. However, the current geometry of the flat pixels does not allow significant decrease of the pixel size due to rapid increase of the stimulation threshold with smaller electrodes. We will develop a solution to this challenge, which should enable decreasing the pixel size down to single-cell dimensions of about 10microm and thereby enable highly functional restoration of sight. For this purpose, we will use microwells on top of the photodiode pixels having active electrode at the bottom. In this design, electric potential is confined within the microwells, and the tight seal between the cell membrane and the insulating walls of the microwells provides high access resistance. For this reason, stimulation thresholds are expected to be more than order of magnitude lower than with open electrodes. Moreover, insulating walls of the microwells will ensure electrical separation of the neighboring pixels and hence a high contrast of the stimulation patterns. We already demonstrated feasibility of such approach with passive implants, and now they will be developed to the full extent for eventual transition into clinical testing. In addition to high spatial resolution, single-cell selectivity on retinal stimulation may open the door to restoration of color vision.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 06, 2025
- Source ID
- FA95502410138
Entities
People
- Daniel Palanker
Organizations
- Air Force Office of Scientific Research
- Stanford University
- United States Air Force