Strabismus is a misalignment of the eyes that affects 2-4% of the population; it is often associated with amblyopia. The inward turning gaze commonly referred to as “crossed-eyes” is an example of strabismus. The term strabismus also applies to other types of misalignments, including an upward, downward, or outward turning eye. Depending upon the severity of the strabismus, it may be treated by glasses or surgery or a combination of both.