One common form of strabismus, or misaligned eyes, is called exotropia. Exotropia, or “walleye,” occurs when the eyes turn outward. This occurs most often when a child is focusing on distant objects.

The main sign of exotropia is an eye that is not straight. The exotropia may occur only from time to time, especially when the child is daydreaming, tired, or sick. Parents often notice that the child squints one eye in bright sunlight.

Amblyopia, or “lazy eye,” may develop with exotropia, although it is less common than with esotropia (“crossed” eyes), as the deviation is usually intermittent. Children learn to suppress the double vision associated with exotropia so effectively that the deviating eye gradually loses vision. It may be necessary to patch the good eye and have the child wear eyeglasses before treating the exotropia. Prisms and eye exercises may also help control the outward turning in some children.

Exotropia is often treated by surgically adjusting the tension on the eye muscles under general anesthesia. The goal of surgery is to get the eyes close enough to perfectly straight so that it is hard to see any residual deviation. Surgery is usually quite successful, since most children with the condition have binocular vision.

(c) 2007 The American Academy of Ophthalmology