Rare congenital disorder affecting muscles of the eye. A form of strabismus characterized by abnormal innervation of the sixth (abducens) cranial nerve, which causes poor coordination of eye muscles and loss of conjugate gaze in certain positions. Typically affects one eye, but may affect both. Three variations exist. Type 1 is most common; its defining characteristic is poor abduction, or limited ability to move the eye outward. Type 2 is defined by poor adduction, or limited ability to move the eye inward. Type 3 presents with poor abduction and poor adduction. Other findings include narrow palpebral fissure, esotropia, exotropia, ophthalmoplegia, diplopia, and vision loss. May lead to amblyopia.

Treatment is supportive. The majority of cases do not require surgery.