Pseudo-Duane retraction syndrome after orbital myositis.

Orbital myositis is a rare, commonly idiopathic, inflammatory condition that affects one or more extraocular muscles. We present a case of unilateral orbital myositis affecting the lateral rectus muscle presenting with gaze-evoked amaurosis, pain, and diplopia, with restrictive limitation of adduction. With improvement in adduction after initiating treatment, we noted narrowing of the palpebral fissure on attempted adduction, mimicking Duane retraction syndrome (DRS). Reported cases of "pseudo-DRS" are associated with multiple etiologies and are characterized by retraction on attempted abduction rather than adduction, as occurs in true DRS. In this case, pseudo-DRS occurred in the setting of idiopathic orbital inflammatory syndrome (orbital myositis) with a motility pattern more consistent with true DRS.