Researchers are making leaps and bounds in the development of a high-acuity retinal implant— a bionic eye with up to 1024 stimulating electrodes made of diamond. As part of the Bionic Vision Australia consortium, the team at the Melbourne Materials Institute, at the University of Melbourne, has developed a technique to fabricate a diamond electrode array for the high-acuity bionic eye.
This is the first application of diamond material for stimulation of neural tissue. Professor Steven Prawer, Director of the Melbourne Materials Institute is leading the team of physicists and electrochemists in this development.
“Diamond doesn’t break down over time and can therefore survive in the body for long periods, making it an ideal material for medical implants,” Professor Prawer said.
This diamond material is grown synthetically in the laboratory by combining methane and hydrogen in a large microwave-like reactor.
“We have doped our diamond material with nitrogen, making it highly conductive and a suitable material to stimulate the retina, using a high-density electrode array with potentially thousands of electrodes in the eye,” Professor Prawer said.
Meanwhile, researchers at NICTA’s Victorian Research Laboratory are finalising the design and testing of the second-generation microchip that will drive the diamond electrode array. Professor Stan Skafidas, from the Department of Electrical and Electronic Engineering, leads the electronics design group; he explains: “We have outstanding results from the tests of our first generation microchip. We have tested features of the stimulation circuitry as well as the data and power transfer system.”
With the final version of the microchip in development, researchers will soon commence bonding the microchip to the diamond electrode array and encapsulation box. This will complete the high-acuity implant prototype and prepare it for the next phase of preclinical testing.
The aim of this technology is to restore a sense of vision to people with profound blindness so they can recognise faces and read large print.
The high-acuity bionic eye will consist of a camera, attached to a pair of glasses, which captures images and sends them directly to a retinal implant, containing a microchip. This microchip decodes the information and triggers electrical stimulation of the retina. These signals are then passed along the optic nerve to the brain where they are interpreted as vision.
This technology aims to restore some sense of vision to people experiencing blindness due to degenerative conditions such as retinitis pigmentosa and age-related macular degeneration