Improved Bionic Implants Could Restore Vision To The Blind
By using blind mice as test subjects, scientists have made essential advancements in discovering how visual information is sent to the brain. This discovery could result in creating the “bionic” implant, believed to be able of restoring vision to blind people.
Researchers have created a microchip which can be inserted into the eye. This microchip contains the neural information used to send images from the eye to the visual centers of the brain.
Scientists belive that in the near future they will be able to build visors for the blind, comparable to the ones in Star Trek. This visors will be capable of restoring sight to over 25 million people suffering from degenerative conditions like macular degeneration and retinitis pigmentosa, which affect the light-sensitive cells in the retina
“It’s an exciting time. We can make blind mouse retinas see, and we’re moving as fast as we can to do the same in humans. This is the first prosthetic that has the potential to provide normal or near-normal vision, because it incorporates the code,” Dr Sheila Nirenberg, neuroscientist at Weill Cornell Medical College said.
Present vision improvement devices use light-sensitive electrodes that simulate the eye’s nerve cells, to make up for the loss of the cons and rods of the retina. Nevertheless, on human patients the prototypes are capable of producing only small spots of light or high-contrast edges.
The actual breakthrough was discovering that the light-sensitive cells of the retina use a certain type of code in order to convert light into the electrical impulses, sent to the brain through nerves cells inside the retina.
Dr Nirenberg and her team improved the existing devices by adding a smart “encoder” between the incoming light and the electrode simulators. This encoder can change the nerve stimulation from the retina to the brain in a way similar to the natural visual process of the retina. The “encoder” has a small microchip that changes the incoming images into electrical impulses. It also has a tiny “projector” that coverts the electrical impulses back into a light impulses, used to stimulate light-sensitive proteins, found in the ganglia cells of the retina.
“Not only is it necessary to stimulate large numbers of cells, but they also have to be stimulated with the right code the code the retina normally uses to communicate with the brain. People had been trying to find the code that does this for simple stimuli, but we knew it had to be generalizable, so it would work for anything faces, landscapes anything a person sees.”, Dr Nirenberg said.
The light-sensitive proteins are inserted into the mouse retina by means of gene therapy techniques. These techniques will also be used on human patients if a bionic device will be built.
To prove their theory, Dr Nirenberg and her team built two prosthetic devices, which they attached to mouse retinas. One prosthetic device has the code and one is without. The results combined with experiments on laboratory mice, show that the bionic implant enabled blind mice to see visual details, said Dr Nirenberg.