The scientists are one step closer to creating a device which will recover the vision of people who are blind due to the disease which destroyed their retina. Two researchers from the Weill Cornell Medical College discovered the retina’s neural code, the way retina translates images into electrical impulses and sends them to the brain through the optic nerve. This discovery will enable blind people to almost completely regain their vision. Currently existing retinal prosthetics allow blind people to see spots and edges of light to help them move around.
What is retina?
Retina is a photo-sensitive tissue at the back of our eye. Whatever we see passes, like pictures, through the lens of the eye and ends in the retina, which acts just like a film. It is retina’s job to convert images into electrical impulses and send them to the brain through the eye optic nerve. Brain processes these impulses into images we recognize.
Retinas can get damaged by many causes, some genetic and other caused by diseases or lifestyle. Two diseases of our society – high blood pressure and diabetes – are increasing the number of people who became blind because of the damage to the blood vessels that feed retinas. There are 25 million blind people in the world who are blind because of the disease of the retina.
What did the scientists discover?
Because there are 100 times more photoreceptor cells in the eye than ganglion (nerve) cells, retina needs to encode (compress) the images before sending them to the brain through the optic nerve. Without knowing this code, it was not possible creating a retinal prosthetic which would provide more than just basic images.
The discovery of this code was made by Dr. Sheila Nirenberg, a computational neuroscientist at Weill Cornell. Dr. Nirenberg built on the already existing system developed for the retinal prosthetics, which function by implanting electrodes, which stimulate the ganglion cells with electricity. She also built on the discovery of light-sensitive proteins which some scientists introduced into the retina using gene therapy. These proteins increase the number of ganglion cells that are stimulated. With the discovery of the code retina uses to convert images into electrical impulses, scientists will be able to create much more sensitive retinal prosthetics.
While the scientists so far discovered the code for mice and primates, they believe that the science is now in place for the new type of retinal prosthetics for humans, which will allow them to regain normal or near-normal vision. It seems that the famous visor from the Star Trek movies is to become a reality.