Researchers at Bionic Vision Australia (BVA) have produced a prototype version of a bionic eye implant that could be ready to start restoring rudimentary vision to blind people as soon as 2013. The system consists of a pair of glasses with a camera built in, a processor that fits in your pocket, and an ocular implant that sits against the retina at the back of the eye and electronically stimulates the retinal neurons that send visual information to the brain. The resulting visual picture is blocky and low-res at this point, but the technology is bound to improve, and even in its current form it’s going to be a major life-changer for those with no vision at all. And the future potential – even for sighted people – is fascinating.
Thanks to an Australian government injection of almost $40 million in 2009, Bionic Vision Australia has been able to revise the timeline of its innovative bionic eye program from “around 2020” to as close as three years away. This week, researchers demonstrated a prototype of the device they hope will begin restoring sight to blind people as early as 2013.
How it works
The retina can be very simplistically described as a matrix of nerve cells that fire when they’re struck by certain types and levels of light. Those neurons send an electrical signal back to the brain’s visual cortex, where information about color, light intensity, edges and lots of other interesting stuff is reassembled and the brain can begin processing it to try to work out what’s going on – working out what objects you’re looking at, what’s moving, what’s important.
It’s an incredibly complex and fascinating system, but it all starts with the retina, where light that comes into the eye is converted to nerve impulses. You could view the bionic eye implant as an aftermarket replacement for a retina that’s no longer capable of performing this function.
BVA’s bionic eye works in a similar way to the US-based Argus II system. A small camera is mounted on top of a pair of glasses, and the resulting images are sent to a small processor unit that can be kept in a patient’s pocket. This processor sends a crunched image to a tiny 2x4mm chip that’s implanted directly onto the retina – and the chip directly stimulates the visual neurons, sending a rough visual signal to the brain for processing.
The resolution challenge
The challenge in bionic eye design is not to get a signal through to the brain, but to improve the resolution and detail of that signal. The first version of the Argus system had only 16 electrodes, so it effectively sent a 16-“pixel” image to the brain. The next-gen Argus II carries 60 electrodes.
The prototype unveiled this week by BVA is a little more advanced, but still quite rudimentary in the scheme of things. It offers 100 electrodes – so the eventual picture will still be blocky and difficult for somebody with normal vision to interpret. But researchers say it will be enough to give enough vision to a patient to let them walk around without assistance: “Patients would be able to contrast light from dark and move more independently, with the ability to distinguish large objects and to avoid walking into them. They will be able to see outlines such as buildings, cars and park benches. This prototype should be ready for the first human implant in 2011.”