Your doctor can check for strabismus by looking at where light reflects off the pupils (the white dot in the above pictures). The light normally reflects in the center of each pupil. When the eye is turned, the light reflects off of one side or off the bottom or top.

Three of the most common types of strabismus are esotropia, exotropia, and hypertropia. In esotropia, one or both eyes turn inward. In exotropia, one or both eyes turn outward. And in hypertropia, one eye points more upward than the other.