Internuclear ophthalmoplegia
Caused by lesions in the medial longitudinal fasciculus. Results in a disconnection between the abducens nerve nuclei and the contralateral oculomotor nucleus. This leads to a disjointed gaze with impaired adduction and nystagmus in the affected eye (defined as the eye for which the oculomotor nucleus is impaired - contralateral to the affected abducens nerve nucleus). Most commonly caused by multiple sclerosis