INO (InterNuclear Ophthalmoplegia): Affected eye cannot adduct (IN) and "N"ystagmus in "O"pposite eye (NO) | MLF syndrome is caused by injury or dysfunction in the medial longitudinal fasciculus (MLF), a heavily-myelinated tract that allows conjugate eye movement by connecting the paramedian pontine reticular formation (PPRF)-abducens nucleus complex of the contralateral side to the oculomotor nucleus of the ipsilateral side
Bilateral Internuclear Ophthalmoplegia in Multiple Sclerosis - Getaw Worku Hassen, M.D., Ph.D., and Namita Bhardwaj, M.D. N Engl J Med 2013; 368:e3January 17, 2013. The patient had an adduction deficit in the right eye and nystagmus in the left eye on leftward gaze (Panel A). He also had an adduction deficit in the left eye and nystagmus in the right eye on rightward gaze (Panel B). Upward gaze (Panel C), downward gaze (Panel D), and normal primary position (Panel E) were unremarkable.