strabismus
(struh-BIZ-mus)
A condition in which both eyes do not line up with one another in the same direction when looking at an object. For example, one eye may look straight ahead while the other eye turns inward toward the nose. When this occurs, two different images are sent to the brain, one from each eye. In children with strabismus, the brain may learn to ignore the image from one eye. If not treated, this can lead to permanent vision loss in that eye. Strabismus is usually caused by problems with how the muscles involved in eye movement are controlled by the brain. It can occur at any age but is more common in children. There are different forms of strabismus. The most common form is called crossed eyes.