When he was 2, he had an operation to try to correct a condition called accommodative esotropia, which refers to the crossing of the eyes.

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.

However, the disorder is twice as common among Asian children as esotropia is, which means it may be the most common form of strabismus worldwide.