Klinische Monatsblätter für Augenheilkunde
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Ocular neuromyotonia is a rare ocular motility disorder characterized by involuntary contractions of one or several ocular motor muscles. In this report a typical case is presented. ⋯ These typical findings permit the diagnosis of ocular neuromyotonia. The characteristic symptoms of ocular neuromyotonia and the typical history of a previous intracranial tumor, treated neurosurgically with adjuvant radiotherapy, lead to the hypothesis that ephaptic transmission in the cranial nerve is the underlying pathophysiological mechanism in the development of ocular neuromyotonia. Hereby, efferent impulses from non-twitch motoneurons could activate neighbouring axons, and spread both peripherally and centrally. Beside other mechanisms discussed, an involvement of proprioceptive elements and their reafference is also a possible cause for the prolonged muscle contraction.