Abduction paralysis with hypotropia: sign of weakness of a contralateral superior oblique.
background The clinical diagnosis of extraocular motor paralysis that is caused by severe cranial trauma can often be complicated. The resulting clinical picture can make the identification of all the components of potentially treatable oculomotor problems difficult. methods We examined five cases of complete abducens nerve paralysis with marked downshoot in attempted abduction seen after severe cranial trauma. results With the patients looking in the field of gaze of the paralysis, a marked infraductive movement of the paralytic eye occurred while the other eye maintained fixation. Other clinical findings confirmed this to be a secondary deviation due to a paresis of the contralateral superior oblique. conclusion Patients with a paralysis of the lateral rectus following a severe cranial trauma who demonstrate a marked downshoot of the involved eye should be suspected of having a paresis of the contralateral superior oblique. This diagnosis has helped us effectively to treat this vertical incomitance by a simple weakening procedure of the contralateral inferior oblique.