Pure Isolated Internuclear Ophthalmoplegia as Presentation of Midbrain Ischemic Stroke: A Case Report.

Internuclear ophthalmoplegia (INO) is a condition characterized by impaired ocular movement, leading to an inability to perform coordinated lateral gaze, resulting in ophthalmoplegia. This impairment results from damage to the medial longitudinal fasciculus (MLF), which can occur because of various types of lesions localized in the pons or midbrain. In this case, we report on a 67-year-old man with multiple comorbidities who arrived at the emergency department with complaints of sudden dizziness and an unsteady gait. During the examination, he exhibited left INO, which was characterized by limited left eye adduction and multidirectional nystagmus of the right eye when performing right lateral gaze.