Wednesday, January 31, 2018
Symmetrical eyes indicates dyslexia - NEUROSCIENCE
Scientists have found that dyslexics have an unusual pattern of cells in their eyes which makes letters appear back to front.
The proposed cause of dyslexia has mainly focused on the brain.
But scientists have discovered that in those with the condition the central area of the retina may have developed in a way that makes letters difficult to read.
In a study, the researchers found dyslexics had light detecting cells – called cones – arranged in a circular way in both of their retinas.
In people with ‘normal’ reading ability, this circular arrangement is only found in the dominant eye. The less dominant eye had an oval arrangement – which leads to a slightly less good image.
During vision, the brain has to ‘knit together’ the two images – each of which goes to a separate side of the brain. For non-dyslexics, the brain grants priority to the dominant eye for the scene – with the other eye playing a less important role.
In the complex task of visually making sense of the world, the brain generates mirror images of what we see, as well as those the right way round.
But in a dyslexic, both eyes were found to have a symmetrical, circular pattern. This means each eye battles for dominance – causing confusion in the brain and leading to some letters such as ‘b’ and ‘d’ becoming confused.
Source: Corina Marinescu