Diplopia

Abstract

Binocular diplopia is usually caused by dysfunction of the nervous system. Evaluation of diplopia begins by establishing the dysfunctional eye movement. This is accomplished using a two-step algorithm for horizontal diplopia and a three-step algorithm for vertical diplopia. Horizontal diplopia is most often due to dysfunction of the abducens nerve or medial longitudinal fasciculus. Vertical diplopia is most often due to dysfunction of the oculomotor nerve, trochlear nerve, or brainstem (skew deviation). Myasthenia gravis may produce diplopia in any direction and may fluctuate, even over the course of a single day. Common etiologies for diplopia include ischemia, inflammation, and compression. Important identifiable syndromes include Wernicke encephalopathy, Miller Fisher syndrome, Tolosa–Hunt syndrome, and cavernous sinus thrombosis. Restrictive disease of the extraocular muscles, convergence insufficiency, and spasm of the near reflex are other possible causes of diplopia.