Bionic Vision Australia
http://www.bionicvision.org.au

The main cause of inherited blindness is retinitis pigmentosa, which affects 1.5 million people worldwide and is characterized by the progressive loss of vision. To combat vision loss, Bionic Vision Australia was established as a national consortium of researchers working together to develop a “bionic” eye that can restore sight to people with vision impairment due to retinitis pigmentosa.

Fig. 1 – Surgeon examining the patient, post-op. (Photo credit: David Mirabella)
The project brings together a cross-disciplinary group of world-leading experts in the fields of ophthalmology, biomedical engineering, electrical engineering and materials science, neuroscience, vision science, psychophysics, wireless integrated-circuit design, and surgical, preclinical, and clinical practice.

In August, Bionic Vision Australia researchers successfully performed the first implantation of an early prototype bionic eye into a 54-year-old woman with severe vision loss. The bionic vision system consists of a camera, attached to a pair of glasses, which transmits high-frequency radio signals to a microchip with 24 electrodes implanted in the retina. The electrodes convert these signals into electrical impulses to stimulate cells in the retina that connect to the optic nerve. These impulses are then passed down along the optic nerve to the vision processing centers of the brain, where they are interpreted as an image. An external system is connected to this unit in the laboratory, allowing researchers to stimulate the implant in a controlled manner in order to study the flashes of light seen.

“I didn’t know what to expect, but all of a sudden, I could see a little flash…it was amazing. Every time there was stimulation there was a different shape that appeared in front of my eye,” the implant patient stated.

Feedback from the patient will allow researchers to develop a vision processor so that images can be built using flashes of light. This early prototype does not incorporate an external camera, which is planned for the next stage of development and testing.

Professor Rob Shepherd, Director of the Bionics Institute, led the team in designing, building, and testing the early prototype to ensure its safety and efficacy for human implantation. He said of the patient: “We are working to determine exactly what she sees each time the retina is stimulated using a purpose built laboratory at the Bionics Institute. The team is looking for consistency of shapes, brightness, size, and location of flashes to determine how the brain interprets this information. Having this unique information will allow us to maximize our technology as it evolves through 2013 and 2014.”

Professor Emeritus David Penington AC, Chairman of Bionic Vision Australia, said: “These results have fulfilled our best expectations, giving us confidence that with further development we can achieve useful vision. Much still needs to be done in using the current implant to build images. The next big step will be when we commence implants of the full devices.”

Two prototypes are in development to suit the needs of different patient groups. The first prototype bionic eye, known as the Wide-View device, will use around 100 electrodes to stimulate the nerve cells in the back of the eye. This will allow people with severe vision loss to see the contrast between light and dark shapes and regain mobility and independence.

The second prototype, known as the High-Acuity device, will ultimately use 1,024 electrodes to stimulate the retina. It will provide patients with more detailed central vision, helping them recognize faces and even read large print.

The first set of patient tests in 2014 will use a completely wired device. In the next stage of testing, they plan to use a device with only some wiring, working towards a totally wireless system in the final stage, where both data and power will be transferred wirelessly to the implant.

Bionic Vision Australia is a national consortium of researchers from the Bionics Institute, the Centre for Eye Research Australia, National ICT Australia, the University of Melbourne and the University of New South Wales. The National Vision Research Institute, the University of Western Sydney and the Royal Victorian Eye and Ear Hospital are project partners.

Medical Design Briefs Magazine

This article first appeared in the November, 2012 issue of Medical Design Briefs Magazine.

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