Intermittent exotropia is one form of strabismus, a disorder in which the two eyes fail to focus on the same image.

In Western countries, the most common form of strabismus is esotropia, where the eyes turn inward; about 1 percent of U.S. children have intermittent exotropia.

For their study, the researchers reviewed the records of 135 children who were diagnosed with intermittent exotropia between 1975 and 1994.