Scientists have developed a new way to create “sight” for blind people. The approach bypasses the eyes and delivers a sequence of electrical signals to the brain, creating the perception of a glowing light that traces a shape. The method might one day restore aspects of vision to people with damaged eyes or optic nerves.
The team “drew” letters of the alphabet on blind people’s brains by giving them specific patterns of electrical stimulation. Tiny jolts of electricity to the visual cortex, a span of neural tissue at the back of the brain, can make a person “see” small bursts of light called phosphenes. When electrical stimulation was used to dynamically trace letters directly on patients’ brains, they were able to ‘see’ the intended letter shapes and could correctly identify different letters. They described seeing glowing spots or lines forming the letters. Researchers said their inspiration for this was the idea of tracing a letter in the palm of someone’s hand.
So far, only simple shapes, such as the letters C, W and U, have been tested. But outlines of common objects, such as faces, houses or cars, could be traced using the same idea, they said.