Blind woman can see objects – but only when they move – in extremely rare case
The unique phenomenon is called Riddoch syndrome.
A rare case of a blind woman able to see moving objects has been confirmed by scientists in Canada.
Milena Canning has been diagnosed with Riddoch syndrome, where a blind person can consciously see an object when it is moving but not if it is stationary.
To help understand her unique vision, the team from Western University’s Brain and Mind Institute used brain-mapping techniques to examine the real-time structure and workings of her brain.
Ms Canning, 48, from Scotland, lost her sight 18 years ago after a respiratory infection and a series of strokes followed by an eight-week coma.
Months later, she began to occasionally see moving things, like her daughter’s ponytail bobbing as she walked or water swirling down a drain, but was unable to see her daughter’s face or stationary objects, like a tub already full with water.
Ms Canning was then referred to the Canadian institute by an ophthalmologist from Glasgow, where the team found she was missing a piece of tissue at the back of her brain that processes vision.
Neuropsychologist Jody Culham, who led the research team at the Brain and Mind Institute, said: “In Milena’s case, we think the ‘super-highway’ for the visual system reached a dead end.
“But rather than shutting down her whole visual system, she developed some ‘back roads’ that could bypass the superhighway to bring some vision – especially motion – to other parts of the brain.”
The researchers found Ms Canning was able to recognise the motion, direction, size and speed of balls rolling toward her. She was even able to catch some of the balls at the right time and navigate around chairs.
But when it came to the objects themselves, she was unable to consistently identify their colours or detect whether someone’s hand in front of her showed thumb-up or thumb-down.
Ms Canning said: “I can’t see like normal people see or like I used to see. The things I’m seeing are really strange.
“There is something happening and my brain is trying to rewire itself or trying different pathways.”
The scientists say Ms Canning’s brain, in essence, “is taking unexpected, unconventional detours around damaged pathways”.
Ms Culham said: “This work may be the richest characterisation ever conducted of a single patient’s visual system.
“She has shown this very profound recovery of vision, based on her perception of motion.”
The research is published in the journal Neuropsychologia.