Why Technology Might Not Help Restore Sight To All Blind People

In some cases, sight can be partially restored to people who have been blind for a long time. However, the brain rewires the senses to compensate for blindness, meaning that most long-term blind people may never fully regain their sight. In the blind, the visual cortex can route sound for echolocation and touch for reading Braille. But the blind can still mentally picture objects like tables, except for color.