Eye coordination, by definition, means that a person’s eyes work together cooperatively to form a single image. This is what people with perfect vision normally experience, so it may help to say that a lack of eye coordination causes problems like double vision or lack of depth perception. This is why eye coordination is the key ability that makes each eye movement precise, well-timed, and well-coordinated.
Poor eye coordination may have different causes. In childhood, vision development may be lopsided because one eye is near-sighted; however, the child adjusts by ignoring the fuzzy image. This can lead to “lazy eye” syndrome, where the eye muscles do not even try to move the weaker eye. Some adults can lose their eye coordination due to diseases or traumatic injuries. In many cases, this is a temporary problem which is resolved when the cause is treated and cured. For example, a person who receives a concussion may have temporary double vision along with other symptoms.
Poor eye coordination may reveal itself in different ways. Children may not realize that they have a problem if it has been present from birth. Signs of impaired vision development in childhood may include problems with catching a ball, rubbing the eyes, quickly tiring while reading, or often squinting one eye shut. The American Optometric Association recommends that children have their eyes tested at 6 months of age and again at 3 years.
Adults may not relate the onset of symptoms such as slight dizziness, headaches, or irritability to vision problems, but it is often a good indicator of distress. Eye fatigue may occur if some of the six major eye muscles weaken, resulting in poor eye alignment, and the extra effort to compensate for a weak muscle causes the feeling of fatigue or strain. Of course, the sudden onset of double vision is another symptom that often triggers serious concern.
Various treatments are available to improve eye coordination. In the simplest cases, merely correcting for near-sightedness or far-sightedness may solve the problem. Exercising the eye muscles is the solution for some, while others may require surgery. Prism lenses in eyeglasses can correct where the image is formed in the eye. In severe cases, it may be necessary to wear a patch or dark lens to keep one eye from interfering with the other.
Some people can control their eye coordination well enough to enjoy stereogram or “magic eye” images. The secret is to cross one’s eyes until two images merge and still keep the image in focus. This requires very conscious control of eye alignment. By contrast, most activities need fast and automatic eye movement to succeed, whether it's catching a ball or reading.