In the news this week, scientists claim to have spotted a major physiological difference between the eyes of dyslexic adults and non-dyslexic adults.
Are you left or right eyed?
Most of us have a partiality as to which hand we use to throw a ball or which foot we use to kick a ball. But did you know we also have a preferred – or dominant – eye?
Our eyes work as a team. However, your dominant eye is the one that provides a slightly greater input to your brain. In fact, it is thought that the dominant eye has more neural connections to the brain than the non-dominant eye. If you are right handed, it is likely you are also right-eyed – but not necessarily.
So what has eye dominance got to do with dyslexia?
There has long been this idea that there is a relationship between ocular dominance and reading and spelling ability. Way back in the ‘70’s, testing of ocular dominance formed part of the test for dyslexia. It was thought that dyslexia was associated with the failure of the child to establish ocular dominance – and that a lack of ocular dominance would somehow lead to confusion about precisely where words and letters are positioned on a page.
But this association of reading disability with a lack of ocular dominance has had a chequered history. In fact, the idea seems to have been discredited and fallen off the radar.
Until this week. Now French scientists have come up with the idea that dyslexic people have different eyes to non-dyslexic people. Sounds too simplistic, doesn’t it?
Apparently, it’s all to do with the arrangement of tiny light-receptor cells in the human eye.
Supposedly, in non-dyslexic people, the cells are arranged differently in each eye. This allows signals from one eye to be overridden by the other, creating a dominant eye and a single image in the brain.
However, in people with dyslexia, the cells are arranged in matching patterns in both eyes. This means those with dyslexia do not have a dominant eye. Instead, two slightly different images are delivered to the brain. If that’s the case, it’s no wonder the brain get confused!
In addition, dyslexics have a delay (of about 10 thousandths of a second) between the primary image and the mirror image in the opposing hemispheres of the brain. The new research suggests we may be able to somehow erase the mirror image that may be confusing dyslexic people. Using an LED lamp, of all things!
So is dyslexia all in the eyes?
What do you think? In the future, we will be able to diagnose dyslexia by simply looking into a child’s eyes? More importantly, I wonder if, as the scientists suggest, we will be able to eradicate reading and spelling difficulties with an LED lamp? Now wouldn’t that be something!
As I said earlier, sounds a little too simplistic, doesn’t it?
You can read the original research here http://rspb.royalsocietypublishing.org/content/284/1865/20171380