Our eyes are designed to work as a team, but each eye functions independently. When we view an object, the brain receives the image from each eye separately. These images are transmitted via the optic nerves. The brain then combines them into a single picture. In an optimally functioning visual system, the eyes aim to the exact same point in space so that the brain can fuse the 2 images and allow clear comfortable vision. If the eyes aren’t aiming together properly, then the images being recorded are slightly different. This causes confusion in the brain and blurred or double vision.
Unfortunately, about ten percent of school-aged children have eye teaming problems – technically, called convergence insufficiency or convergence excess. At the close up distances required for reading, children with eye teaming problems are only able to aim their eyes together correctly for short periods of time. As their ability to accurately aim their eyes breaks down, their eyes end up pointing at slightly different places on the page.
Children with eye teaming difficulties become tired easily, are distractible, lose place with reading, get headaches and eyestrain and often find school “boring” or too difficult. Some children will end up turning off or “suppressing” one eye to achieve more comfortable vision. Although more comfortable, this is not optimum and such children will become tired and have difficulty with concentration robs the child of concentration. Sometimes children’s eyes.
It is important that children are as visually available for learning as possible. A child does not realise that the way he or she sees is not “normal”.
Glasses and vision therapy can successfully treat both convergence excess and convergence insufficiency.