Intermittent exotropia is a condition in which the visual axes on the right and left eyes are straight but occasionally either eye deviates outward. Intermittent exotropia is the most common type of exodeviation and is usually first observed by the parents in early childhood. In some cases, an exophoria progresses to an intermittent exotropia that eventually becomes constant. Such deviation usually occurs first at distance and later at near fixation. They may be influenced by decreased tonic convergence with increasing age, the development of suppression, loss of accommodative power and increasing divergence of orbit with advancing age. Nevertheless, not all intermittent exotropia are progressive.