A misalignment of the eyes (pointing in and/or out). This situation may be due to eye muscle problems.
A misalignment of the eyes in which each eye, simultaneously can point in a different direction. Crossed eyes (esotropia) are one type of strabismus; "wall-eyes" (exotropia) are another. The exact cause is unknown, but it appears to be a problem with the eye muscles. Strabismus can affect depth perception.