Internuclear ophtalmoplegia

= due to lesions of the medial longitudinal fasciculus (MLF) dorsomedial pons or midbrain

The side of the internuclear ophtalmoplegia is  ipsilateral to the MLF lesion, the same side to have the adduction deficit.

Signs:

– loss of adduction of the ipsilateral eye

– nystagmus present in the contralateral abducting eye

Causes:

– ischaemia in older patients

– demyelinating lesions in younger patients