Two Cases of True and Pseudo-internuclear Ophthalmoplegia with Bilateral Exodeviation

ABSTRACT

Internuclear ophthalmoplegia(INO) is characterized by the adduction deficit on lateral gaze associated with dissociated nystagmus of an abducting eye and caused by the lesion in the medial longitudinal fasciculus(MLF). It occurs unilaterally or bilaterally in infarction of brain stem and multiple sclerosis. Ocular myasthenia is a localized form of myasthenia involving extraocular, levator palpebrae perioris, and/or orbicularis oculi muscles. It is frequently confused with a variety of ocular mortility disorders including INO. We experienced 2 patients who had bilateral wall-eyes and diplopia. One was a true bilateral INO due to hypertensive brain stem infarction(Wall-eyed bilateral INO) and the other was a myasthenic bilateral pseudo-INO. Diagnosis was made by Tensilon test, repetitive nerve stimulation test of orbicularis oculi muscles, and serum antibody assay in latter case.