Strabismus is a condition in which both eyes do not look at the same place at the same time. It occurs when an eye turns in, out, up, or down and is usually caused by poor control of one or more of the six eye muscles surrounding the eye. It can also be due to a large uncorrected amount of prescription. Maintaining proper eye alignment is important to avoid seeing double, for good depth perception, and to prevent the development of poor vision in the turned eye. If the eye turning becomes constant and is not treated, it can lead to permanent reduction of vision in one eye, a condition commonly known as amblyopia, or lazy eye. Treatment options available for strabismus include eyeglass or contact lens correction, prism lenses, and/or vision therapy.