Divergence insufficiency: characteristics, diagnosis, and treatment.

Although the entity of divergence insufficiency was described as early as 1886 by Duane, it has received relatively little attention in the literature. Patients presenting with a greater eso deviation at distance than at near, a concomitant deviation, and diplopia pose a challenging and critical diagnostic and therapeutic puzzle for the clinician. Divergence insufficiency, a benign condition, must be differentiated from divergence paralysis and sixth nerve palsy, two conditions that present with somewhat similar findings yet have underlying etiologies of a serious nature. This paper reviews the literature and clarifies the etiology, diagnosis, and treatment of divergence insufficiency and related conditions.