When you hear the term bionic eye, you might think of the 70s TV show “The Six Million Dollar Man” or the movie “Terminator.” Modern science has not yet developed a way to improve on the human eye, but researchers at Bionic Vision Australia (BVA) say they are getting close to their first human trials of a prototype bionic eye that will “provide life-changing vision for recipients." The bionic eye is for patients who have lost vision due to macular degeneration or retinitis pigmentosa.
How the Eye Works
In the human eye, light enters through the lens and lands on the retina, which is the inner lining of the back of the eyeball. The retina is full of light receptors called rods and cones that work together to process images with or without color and in various light situations. The visual image is converted by the rods and cones into electrical energy that is sent through the optic nerve to the brain, where it is perceived as sight.
In patients with macular degeneration or retinitis pigmentosa, the retina is damaged and the eye gradually loses the ability to convert light to electrical energy. A critical factor in these diseases is that the optic nerve is intact and functional. The loss of vision takes place in the eyeball itself. That’s where the bionic eye comes in.
How the Bionic Eye Works
Researchers at the University of New South Wales and the University of Melbourne in Australia are developing a device that can replace the function of the retina in the eye. The bionic eye starts with a miniature camera mounted on a pair of classes to capture visual input. This signal is sent to a processor that fits in a shirt pocket. The processor converts the input into an electric signal that is transmitted to a tiny chip implanted inside the back of the eye up against the retina. The signal from the chip is picked up by the optic nerve and carried to the brain as a visual image.
At the present time, the signal is very low-res and blocky, due in part to the physical limitations of the chip. Think about how newspapers are printed. Each letter is made up of a bunch of tiny dots. The more dots used, the more solid the type looks. The bionic eye’s 100 electrode resolution is similar to 100 dots in print. By comparison, the human eye uses many thousands of dots for each piece of visual information. The current design of the Australian bionic eye uses 100 electrodes to send 100 tiny bits of visual information to the brain. This prototype, which should be ready for the first human trials in 2011, will provide patients with the ability to contrast light and dark and to distinguish large objects so they can avoid walking into them.
The Future of Bionic Vision
The current version of the Australian bionic eye is already a big step up from the first US-based system called the Argus II. That bionic eye had only 16 electrodes. Researchers in Australian are already working on the next version of their eye, which will use 1000 electrodes. They say this second prototype will give patients close to 20/80 vision which will be good enough to recognize faces and read large print. They expect it to be ready for trials with the second generation beginning in 2013.
Sources:
Bionic Vision Australia
Gizmag
Cnet News