A man who went blind as a result of brain damage has demonstrated the power of blindsight by making his way around obstacles without assistance.
In a study led by Professor Beatrice de Gelder of the University of Tilburg in the Netherlands, the sightless man, identified as TN, walked around boxes and chairs without using his stick.
He did not bump into any of the obstacles.
TN, who was left blind after suffering strokes, usually uses a stick and needs help to go around buildings.
Prof de Gelder, whose findings were published in Current Biology, said: "It shows us the importance of evolutionary ancient visual paths. They contribute more than we think they do for us to function in the real world."
A theory of blindsight is that these visual paths enable people such as TN to take in information via their eyes, although they are not consciously aware of it.
Other people who have sight problems that are correctable may wear contact lenses to improve their vision.
by Alexa Kaczka