Clinical observations in 101 consecutive patients with Duane's retraction syndrome

We retrospectively studied 101 consecutive patients with Duane's retraction syndrome. Eighty-five percent were unilaterally affected and 15% were bilaterally affected. More patients had straight eyes in primary position than esotropia or exotropia. On lateral version reflex testing the amount of underaction of the lateral and medial rectus muscles could be determined, and could be used to predict whether the patients' eyes were esotropic, exotropic, or straight in primary position. Almost all the patients showed an esotropia when looking to one side and either an exotropia or no deviation to the other side. The degree of the exotropia and the esotropia on opposite sides determined whether a head turn would be present and in what direction. On adduction, the palpebral fissure in the affected eye narrowed in one half the patients because of motion of both upper and lower eyelids, and in 40% because of motion of only one eyelid. When the lower eyelid elevated, it usually assumed a straight horizontal contour with peaking of the punctum lacrimalis (appearing as a small pyramid). The statistical predominance of females and left eyes was more significant among patients whose eyes were straight in primary position. All patients tested demonstrated stereopsis. Most of the amblyopic patients had anisometropia.