The innermost layer of the human visual organ, the retina, contains two types of photoreceptor cells: rods and cones . While the former deal with black and white vision, color perception is the responsibility of the cones. The entire retina is riddled with these biological sensors with the exception of a small region: the entrance zone of the optic nerve . When the image is projected right into that hole, we simply cannot see it. As a general rule, we do not realize it because we usually use both eyes and the light information that one does not capture is supplied by the other. In fact, testing for failure requires covering one eye and exposing another .
The interesting thing is that, recently, scientists from the University of Queensland, in Australia, showed that the size of this area can be reduced with simple training . After training ten people over twenty sessions to try to detect the movement of wavy colored lines around a ring centered over the blind spot of one of their eyes, visual impairment was reduced by as much as 10% . How? According to the researchers, exercise increased the sensitivity of the receptors surrounding the hole. Using the same type of instruction in cases of pathological blindness could be of help to the affected blind.
