Following a brain injury, people can lose their ability to see the left side of the world, but with a special set of lenses developed by researchers at Dalhousie University, patients can train their brains to see both sides of the world.
Researchers are developing "prism-goggles" to help patients experiencing hemi-spatial neglect as a result of an injury to the right side of the brain, most commonly from stroke.
"They have trouble paying attention to the left side of the world or their body, so they're basically not taking in information from that side of the world," Dr. Gail Eskes, a clinical neuropsychologist and professor at Dalhousie University, told CBC's Information Morning. "It's not that they can't see it and it's not that they can't move in that direction, but somehow they spontaneously seem to forget about it."
Symptoms include bumping into objects or people on the left, or not being able to perceive the left side of a clock.
Shifting the world in the right direction
With glasses that contain prisms made by Halifax company Eyes on Optometry, researchers are helping patients to pay attention to the left sides of their bodies.
The glasses do this by first shifting the wearer's world to the right of where it actually is.
The wearer then goes through exercises, such as throwing bean bags into a bowl or pointing accurately to objects on a screen, using an app researchers have created for that purpose.
"Your normal eye-hand coordination is wrong and you make mistakes that are directed to the right because that's what your visual field looks like right now," said Eskes. "Gradually though, the brain can learn to adapt to this distorted visual field, and it basically makes leftward corrections to do that learning"
As the brain adjusts to the left, the patient can point or throw beanbags accurately, even with the glasses on.
Taking the glasses off
But when they take the glasses off, that leftward correction means that the patient will make mistakes again, throwing the bean bag or pointing too far to the left.
"Now the key thing here is that that leftward bias now is good for people who have [hemi-spatial neglect] because they're already ignoring the left, so now we've basically brought the leftward information into their field of view."
The correction isn't permanent. Eskes said current research suggests that two weeks of training can give users the ability to perceive the world on their left side for up to five weeks
Training in increments
But the best option may be shorter increments of consistent training, and researchers have anticipated that.
"This is why we've developed these goggles and we've developed an app to help you with the training when you've got the goggles on, because then you can just take it home and you can do it on a daily basis."
"It takes 10 minutes to do the training, and then you'll be centred for the day, and then hopefully as time goes on the brain is going to gradually recover and relearn and continue doing what it's supposed to do."