Strabismus

Strabismus, condition in which the 2 eyes do not see the identical image simultaneously; usually one eye is directed in a slightly different direction from the other. Most often this condition is the result of an eye muscle weakness (eye movement is controlled by 6 different muscles); it can also come from brain and nerve involvement. Forms of strabismus include heterotropia (squinting); esotropia (cross-eyes), where one or both eyes look inward; exotropia (walleyes), where one eye looks outward; and diplopia (double vision).