Blind man demonstrates 'blindsight' phenomenon by navigating obstacle course

A man who completely lost his sight after brain damage has astonished scientists by negotiating an obstacle course without his cane, in a powerful demonstration of an eerie phenomenon known as “blindsight”.

The man, known only as TN, was blinded by strokes on both sides of his brain which left him unable to see and devoid of any activity in the brain regions that control vision. He uses a stick to detect obstacles, and has to be guided around buildings. However, TN was known to exhibit blindsight, a strange ability some blind people have to detect things that they cannot see.

He reacts to the facial expressions of other people, for example, and scans of his brain have confirmed that it registers facial emotions such as joy, anger and fear.

He has now shown evidence of an even more remarkable skill – the ability to navigate without being able to see.