internuclear ophthalmoplegia

internuclear oph·thal·mo·ple·gi·a (INO),

ophthalmoplegia in lesions of the medial longitudinal fasciculus, with failure of adduction in horizontal gaze but with retention of convergence.

in·ter·nu·cle·ar oph·thal·mo·ple·gi·a

(INO) (in'tĕr-nū'klē-ăr of-thal'mō-plē'jē-ă)

Ophthalmoplegia in lesions of the medial longitudinal fasciculus, with failure of adduction in horizontal gaze but with retention of convergence.

internuclear ophthalmoplegia

Abbreviation: INO

Loss of the normal paired movements of the eyes when tracking an object to the left or right. An INO is marked by the failure of one eye, e.g., the left, to cross the midline during an attempt to see an object on the opposite side of the body, e.g., the right.

Etiology

This failure of adduction of the affected eye is caused by a lesion of the medial longitudinal fasciculus of the brain.

Synonym: Roth-Bielschowsky syndrome

See also: ophthalmoplegia