What is Strabismus?
Strabismus is a visual problem in which the eyes are not aligned properly and point in different directions. One eye may look straight ahead, while the other eye turns inward, outward, upward or downward. The eye turn may be constant, or it may come and go. Which eye is straight (and which is misaligned) may switch or alternate.
Strabismus is a common condition among children. About 4 percent of all children in the United States have strabismus. It can also occur later in life.
Strabismus occurs equally in males and females. It may run in families; however, many people with strabismus have no relatives with the problem.
The exact cause of strabismus is not fully understood. In some cases, strabismus may be due to problems with the muscles controlling eye movement.
Six eye muscles that control eye movement are attached to the outside of each eye. In each eye, one muscle moves in the eye to the right, and one muscle moves the eye to the left. The other four muscles move it up or 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 these muscles.