What is Strabismus?
Strabismus, commonly known as squint, 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 may turn inward, outward, upward or downward. You may find that the misalignment is a constant feature, or it may come and go. The turned eye may straighten at times and the straight eye may turn.
Strabismus is common among children. About 4% of all children in the United States have strabismus. It can also occur later in life.
In occurs equally in males and females. Strabismus may run in families. However, many people with strabismus have no relatives with the problem.
How do the Eyes Work Together?
With normal vision, both eyes aim at the same spot. The brain then fuses the two pictures into a single three-dimensional image. This three-dimensional image gives us depth perception. When one eye turns, the brain receives two different pictures, which do not exactly overlap. In a young child, the brain learns to ignore the image of the misaligned eye and sees only the image from the straight or better eye. However, the child is likely to lose depth perception.
Adults who develop strabismus often have double vision because the brain is already trained to receive images from both eyes and cannot ignore the image from the turned eye.