The diagnosis and surgical management of acquired bilateral superior oblique palsy.

Thirty-four patients with surgically treated bilateral superior oblique palsy are presented. The patients are divided into three groups: Symmetrical palsies, Asymmetrical palsies, A group in whom the bilaterality was initially masked. Bilaterality should be suspected in all cases of traumatic IVth nerve paresis, and particularly in cases with a large 'V' pattern, excyclo deviation of more than 10 degrees on down-gaze and when right hypertropia switches to left hypertropia on lateral down-gaze. Bilateral Harada-Ito procedures alone 'cured' 11 of 17 patients (65 per cent) in groups 1 and 2, and is the operation of choice in acute bilateral superior oblique palsy. Cyclo deviation was reduced by a mean of 5.5 degrees in the primary position and by 6-10 degrees in down-gaze. Patients initially managed with other surgery had a more complicated surgical course and required more operations. Seven patients who initially demonstrated only gross fusion recovered good fusion after Harada-Ito surgery.