Intermittent exotropia is a kind of strabismus between exotropia and constant exotropia. The visual axes are often separated, and when looking at distance, the fused scattering amplitude exceeds the fused collecting amplitude, which produces exotropia; while when looking at near vision, it can maintain the orthotropia, and most of the intermittent exotropia has exotropia before occurring. The onset of intermittent exotropia is mainly due to the imbalance of abduction and pooling functions. When the pooling ability is insufficient and the fusion ability is low, it cannot counteract the excessive abduction ability and makes the eye position tend to be outwardly oblique. Intermittent exotropia often occurs in early childhood, initially only when looking at a distance, but as the disease progresses, the number and duration of intermittent exotropia increases, and eventually exotropia can occur when looking at the near. The apparently oblique phase of intermittent exotropia often occurs with fatigue, illness, drowsiness, or inattention. Intermittent exotropia may be associated with temporary diplopia in visually immature children, which is soon suppressed and has abnormal retinal correspondence. A common symptom is photophobia, which often closes one eye in outdoor daylight for unknown reasons. It is assumed that the patient looks at distant targets outdoors without near object stimulation to bring the two eyes together, and that bright daylight flashes the retina and interferes with fusion. Intermittent exotropia can be combined with A-V syndrome or with other vertical strabismus, such as separated superior strabismus. Even though exotropia is intermittent, it is important to seek early medical attention to treat and prevent the development of strabismus. To prevent permanent exotropia due to monocular suppression, surgical correction should be performed at the right time.