Congenital unilateral adduction deficit with simultaneous abduction. A variant of Duane's retraction syndrome.

Congenital adduction deficit not associated with other signs of oculomotor nerve weakness occurs infrequently. Type 2 Duane's retraction syndrome accounts for some of these cases. The authors identified three children with unilateral adduction deficits and simultaneous abduction of the eyes on attempted lateral gaze into the field of action of the apparently paretic medial rectus muscle. This is the first report of a series of patients with this condition previously termed simultaneous or synergistic divergence. All patients had a large exotropia, and two had a horizontal face turn away from the involved eye. A large (14 mm) lateral rectus muscle recession done on one of these children reduced the face turn but did not eliminate the simultaneous abduction. Clinical, intraoperative, and electromyographic data suggest that this condition is an unusual variant of type 2 Duane's syndrome.