Control of eye movements: fixation, saccades, pursuit and gaze centres

Regulation
Exam priority: medium

The brain keeps both eyes pointed at the same target: it holds them still, jumps them fast to new targets and lets them follow moving ones.

Updated Nov 13, 2026

Also called: Gaze centres, Medial longitudinal fasciculus (MLF), Internuclear ophthalmoplegia

See it in 3D: Oculomotor nerve (III) · Trochlear nerve (IV) · Abducens nerve (VI) · Pons · Midbrain · Medial rectus · Lateral rectus

Key points

Horizontal gaze: paramedian pontine reticular formation (PPRF) → ipsilateral abducens nucleus → lateral rectus, plus interneurons crossing in the contralateral MLF → oculomotor nucleus → medial rectus.
Vertical gaze is organized in the rostral midbrain (rostral interstitial nucleus of the MLF).
Frontal eye field (area 8) drives voluntary saccades to the opposite side: a destructive lesion makes the eyes look toward the lesion; a seizure focus drives them away.
A pontine (PPRF) lesion makes the eyes look away from the lesion, toward the hemiparetic side.
Internuclear ophthalmoplegia (MLF lesion): the eye on the lesion side fails to adduct on lateral gaze, the other eye shows abducting nystagmus, convergence is spared; bilateral INO in a young adult suggests multiple sclerosis.

What it is

Eye movements keep the image of interest on both foveas. Fixation holds the eyes on a target, saccades jump them to a new one, smooth pursuit tracks a moving target and the vestibulo-ocular reflex cancels head movement. Cortical and collicular commands converge on brainstem gaze centres, which drive the cranial nerve nuclei of both eyes together through the medial longitudinal fasciculus.

How it works, step by step

Fixation: tiny drifts and microsaccades keep the image moving slightly on the cones, so the picture does not fade; corrective flicks re-centre it.
Saccade: burst neurons in the PPRF (horizontal) or riMLF (vertical) fire a high-frequency pulse that overcomes orbital viscosity.
A tonic step from the neural integrator (nucleus prepositus hypoglossi, cerebellum) then holds the eye in its new position.
Both eyes move together because one gaze centre drives the abducens nucleus and, through the MLF, the opposite medial rectus subnucleus.
Pursuit uses motion signals from MT/MST; the cerebellum matches eye speed to target speed.

Typical eye-movement values (healthy adult)

Parameter	Value	Note
Saccade peak velocity	up to ≈ 500–700 °/s	larger saccades are faster
Saccade duration	≈ 20–100 ms
Saccade latency	≈ 200 ms
Smooth pursuit, accurate up to	≈ 30–50 °/s	faster targets need catch-up saccades

Approximate values for a healthy adult at rest; each laboratory sets its own ranges.

Regulation

+Frontal eye fields: Voluntary saccades to the contralateral side; also suppress reflex saccades so a target can be held.
+Superior colliculus: Reflex saccades toward sudden visual, sound or touch stimuli; holds a map that points eyes and head to a location.
+Parieto-occipital cortex (MT/MST) → pontine nuclei → cerebellum: Smooth pursuit of a moving target, ipsilateral in direction.
+Vestibular nuclei (VOR): Move the eyes opposite to head rotation so the image stays still.
−Omnipause neurons (pons): Silence saccade burst neurons during fixation; they pause to let each saccade start.
+Cerebellum (flocculus, vermis): Calibrates saccade size and pursuit gain, and holds gaze steady off centre.

Clinical notes

Nystagmus has a slow drift and a fast corrective phase and is named by the fast phase; gaze-evoked nystagmus suggests cerebellar, brainstem or drug effects.
One-and-a-half syndrome (PPRF or abducens nucleus plus adjacent MLF): no horizontal movement in one eye, only abduction in the other.
Abducens palsy causes horizontal double vision worse on gaze to the affected side; the eye cannot abduct.

Test yourself

Think of the answer, then tap the question to see it.

On right gaze, the left eye does not adduct and the right eye shows nystagmus; convergence is normal. Where is the lesion?

The left medial longitudinal fasciculus (left internuclear ophthalmoplegia); convergence is spared because it does not use the MLF.

A large left frontal stroke causes right hemiparesis. Which way do the eyes deviate?

To the left, toward the lesion: the intact right frontal eye field pushes the eyes to the left, unopposed.

Which brainstem structure generates horizontal saccades?

The paramedian pontine reticular formation (PPRF), which drives the ipsilateral abducens nucleus.

Why does a target moving at 100 °/s need saccades to be followed?

Smooth pursuit matches target speed only up to about 30–50 °/s; above that, the eyes lag and catch-up saccades are added.

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Connections

See it in 3D7

The structures of Durgical's 3D anatomy where it happens.

← All of physiology

Educational physiology content; not a diagnostic or treatment guide and no substitute for a health professional's advice. Values are approximate references. No doses are given.

Sources: Anatomy, Head and Neck, Eye Extraocular Muscles (StatPearls (NCBI Bookshelf), 2024); Neuroanatomy, Cranial Nerve 6 (Abducens) (StatPearls (NCBI Bookshelf), 2024); Multiple Sclerosis (StatPearls (NCBI Bookshelf), 2024); Nystagmus: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2024).

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