One and a half syndrome
Rare disorder with horizontal gaze palsy in one direction and internuclear ophthalmoplegia.
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The one and a half syndrome is a rare eye movement disorder in which one eye cannot move horizontally at all and the other can only move outward. It results from a single unilateral lesion affecting the paramedian pontine reticular formation and the ipsilateral medial longitudinal fasciculus, or from a lesion of the abducens nucleus with interruption of the medial longitudinal fasciculus. Convergence is spared because the oculomotor nerve and its nucleus are unaffected bilaterally.
More in Disorders of Ocular Muscles, Binocular Movement, Accommodation and Refraction
Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: One and a half syndrome (CC BY-SA 4.0).
- Word definitions: the Codexery glossary, each quoted from its Wikipedia article.
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