More specifically, compression of the vertical gaze center at the rostral interstitial nucleus of medial longitudinal fasciculus (riMLF).

It is a group of abnormalities of eye movement and pupil dysfunction and is named for Henri Parinaud[6][7] (1844–1905), considered to be the father of French ophthalmology.

Parinaud's syndrome is a cluster of abnormalities of eye movement and pupil dysfunction, characterized by: It is also commonly associated with bilateral papilledema.

Specifically, compression or ischemic damage of the mesencephalic tectum, including the superior colliculus adjacent oculomotor (origin of cranial nerve III) and Edinger-Westphal nuclei, causing dysfunction to the motor function of the eye.

Classically, it has been associated with three major groups: However, any other compression, ischemia or damage to this region can produce these phenomena: hydrocephalus, midbrain hemorrhage, cerebral arteriovenous malformation, trauma and brainstem toxoplasmosis infection.