Restoration of vision using wireless cortical implants: The Monash Vision Group project

Abstract

Monash Vision Group is developing a bionic vision system based on implanting several small tiles in the V1 region of the visual cortex. This cortical approach could benefit a greater proportion of people with total blindness than other approaches, as it bypasses the eyes and optic nerve. Each tile has 43 active electrodes on its base, and a wirelessly powered electronic system to decode control signals and drive the electrodes with biphasic pulses. The tiles are fed with power and data using a common transmitting coil at the back of the patient's head. Sophisticated image processing, described in a companion paper, ensures that the user experiences maximum benefit from the small number of electrodes. This paper describes key features of this system.

Microstimulation in the primary visual cortex: activity patterns and their relation to visual responses and evoked saccades

“…One of the major goals of microstimulation in V1 is to study the feasibility of cortical visual neuroprosthesis and the development of useful artificial vision at high resolution for blind human patients Lowery et al 2015;). For this goal to be realized, one needs to characterize the neural and behavioral responses evoked by ICMS and compare it with neural responses evoked by visual stimulation.…”

Brain Machine Interfaces for Vision Restoration: The Current State of Cortical Visual Prosthetics

“…Each ceramic tile holds 43 electrodes protruding from its base and contains a receiver coil and an ASIC. A custom-designed BPocket Processor^extracts the useful features from the image captured by the camera and generates a pattern of electrode activation to create the most helpful information for the user depending on the task at hand [71]. They introduced the concept of transformative reality (TR) that instead of being restricted to the direct visual representation of a scene asks the following question: BWhat combination of sensors, processing and rendering gives the most usability?^ [72].…”

Advances in implantable bionic devices for blindness: a review

“…Retinocortical magnification, which results in a significant over‐representation of the foveal visual field on visual cortex, provides for a substantially greater surface area within which to implant stimulating electrodes and thus elicit central phosphenes . On the other hand, much of V1 is relatively inaccessible to the implantation of penetrating electrodes, and current cortical prosthesis development efforts are typically focused on devices that stimulate the occipital pole and its surroundings …”

“…(c) Artist's rendering of the headwear, showing the data and power transmitting/receiving coil overlying the recipient's occiput and the implanted tiles. (a and b) Reproduced from Lowery et al ., with permission (© 2015 IEEE). (c) Supplied courtesy of Monash Art, Design and Architecture and Monash Vision Group.…”