The superior oblique: a challenging extraocular muscle.

Isolated paralysis of one or both superior oblique muscles in a consecutive series of 43 patients was found to occur most often by indirect injury to the skull. The etiology in the group of spontaneous cases was mostly vascular. With rare exceptions the latter recovered spontaneously. Those with traumatic palsy may be due to "contrecoup" trauma at the decussation of the nerves or by decompensation of the cerebral fusional mechanism, with dissociation of the images of the two eyes and subsequent vertical deviation. The traumatic cases never recover spontaneously and recession or myectomy of the ipsilateral inferior oblique with or without recession of the contralateral inferior rectus is recommended but only in cases of more than 8 diopters squint, and in cases which do not adapt themselves by minor head-tilting.