Strabismus is a disorder in which both eyes do not line up in the same direction. Therefore, they do not look at the same object at the same time. The condition is more commonly known as “crossed eyes.” Many things and/or events can cause a strabismus. They include genetics, inappropriate development of the “fusion center” of the brain, problems with the controlled center of the brain, injuries to muscles or nerves or other problems involving the muscles or nerves. Surprisingly, most cases of strabismus are not a result of a muscle problem, but are due to the control system — the brain. Treatment should be directed at the source of the problem.
Six different muscles surround each eye and work “as a team.” This allows both eyes to focus on the same object.
In someone with strabismus, these muscles do not work together. As a result, one eye looks at one object, while the other eye turns in a different direction to focus on another object.
When this occurs, two different images are sent to the brain — one from each eye. This confuses the brain. In children, the brain may learn to ignore (suppress) the image from the weaker eye.
If the strabismus is not treated, the eye that the brain ignores will never see well. This loss of vision is called amblyopia. Another name for amblyopia is “lazy eye.” Sometimes lazy eye is present first, and it causes strabismus.
In most children with strabismus, the cause is unknown. In more than half of these cases, the problem is present at or shortly after birth. This is called congenital strabismus.
A family history of strabismus is a risk factor. Farsightedness may be a contributing factor, often in children. Any other disease that causes vision loss may also cause strabismus.