Eye Teaming, Focusing & Tracking
Visual Skills Beyond 20/20
Eye Teaming (Binocularity)
Eye teaming, or binocular vision, is a visual efficiency skill that allows both eyes to work together in a precise and coordinated way. Good eye teaming allows sustained, single, and comfortable vision, and is the basis for depth perception. We are continuously attempting to aim both eyes at objects during all visual activities. Each eye sends a separate, slightly different image to our brain’s visual cortex, where the images are combined (or fused) into a single image. If we can do this easily, we will have a stable, 3D view of the world. If we cannot do this easily, objects can appear double or move, creating a confusing uncomfortable view of the world. Eye teaming problems typically cause double vision, headaches, blurred vision and eyestrain, especially during reading and close work.
Focusing (Accommodation)
Most people are not aware that we have to refocus our eyes when we look from one place to another. This is because the focusing system usually operates so well that objects always appear in focus. However, in reality, a focusing adjustment is made every time we look from one place to another. This adjustment is made with the help of a muscle called the ciliary muscle, or focusing muscle, which is located inside the eye.
For example, when a child looks from the board to their desk, they must contract or tighten this ciliary muscle. This causes the lens inside the eye to change shape and allows the child to see the print clearly. When the child looks back up from their desk to the board, they must now relax the focusing muscle to once again achieve clear distance vision.
A focusing problem occurs when an individual is unable to quickly and accurately relax or contract the focusing muscle, or if this muscle contraction cannot be maintained for adequate periods of time such as during reading or desk work.
Tracking (Saccades & Pursuits)
In order to use our vision efficiently, the eyes must move accurately, smoothly, and quickly from place to place. Eye movements allow accurate scanning of the visual environment for information. For example, every time a child looks from the board to their desk, the eyes must accurately jump from one target to another. The same is true for reading as the eyes jump from one word to another while scanning a line of print. Tracking is also important for following moving objects in sports, and for directing our eyes to move our hands towards a target. Eye-hand coordination in any activity starts with accurate eye movements.
Tracking skills are considered the fine motor aspect of vision. When a person has a tracking problem, eye movements are slow, inaccurate, or require head or finger movement to help the eyes track. This can interfere with reading fluency and comprehension, copying, handwriting, and sports performance.
