Sightless, but Not Walking Blindly?

After two strokes, he was completely blind, dependent on his cane and his wife's arm to safely walk down the street. But researchers had a hunch: They suspected that, unconsciously, the man might be sensing the world around him through his eyes better than anyone realized.

So the neuroscientists devised a simple experiment: They asked the man to walk down a long hallway unaided by his cane or anyone else -- without telling him they had turned the corridor into a makeshift maze by randomly placing boxes, chairs and other objects in his path.

To their astonishment, the man deftly maneuvered past every obstacle. Then he turned around and did it again, prompting the stunned researchers to burst into applause.

"We were so excited," said Beatrice de Gelder, a cognitive neuroscientist at Tilburg University in the Netherlands and Harvard Medical School who reported the experiment recently in the journal Current Biology. "It was really quite amazing to see."

The first-of-its-kind case is providing doctors with new insights into how vision works, suggesting that even when the brain's primary vision centers have been destroyed, signals entering the eyes are still registering. Although no one thinks the findings could help make the blind see, they do indicate some blind people may have hidden capabilities.

"It's sort of a crowning piece for a fairly long set of increasingly convincing reports that there is a form of vision which is not dependent ... upon the primary areas responsible for processing inputs from the eyes," said Richard Held, a Massachusetts Institute of Technology neuroscientist. "This is the most convincing evidence for that."

On a practical level, the findings hint that such people could learn how to harness these unrecognized abilities to gain more independence.