Strabismus is a visual defect in which the eyes are misaligned and point in different directions. One eye may look straight ahead, while the other eye turns inward, outward, upward or downward. Patients may always notice the misalignment or it may come and go. The turned eye may straighten at times and the straight eye may turn.
Strabismus is a common condition among children. About 4% of all children in the United States have strabismus.
It occurs equally in males and females. Strabismus can run in families. The exact cause of strabismus is not fully understood.
Six eye muscles, controlling eye movement, are attached to the outside of each eye. In each eye, two muscles move the eye right and left. The other four muscles move it up and down and at an angle.
To line up and focus both eyes on a single target, all of the muscles in each eye must be balanced and working together. In order for the eyes to move together, the muscles in both eyes must be coordinated.
The brain controls the eye muscles. Strabismus is especially common among children with disorders that affect the brain, such as: cerebral palsy, Down’s syndrome, and brain tumors. However, most children with strabismus are otherwise healthy.
Although glasses, exercises or prisms may reduce or help control the outward turning eye in some children, surgery is often needed. During surgery, the ophthalmologist makes a small incision in the tissue covering the eye to reach the eye muscle. Certain muscles are repositioned during the surgery, depending on which direction the eye is turning. As with any surgery, eye muscle surgery has certain risks including infection, bleeding, excessive scarring and other rare complication that can lead to vision loss.