Types of nystagmus: gaze-evoked, downbeat, upbeat, see-saw and pendular
Quick answer
Nystagmus is a rhythmic, involuntary to-and-fro movement of the eyes. In jerk nystagmus a slow drift is followed by a fast corrective flick, and the nystagmus is named by the direction of the fast phase; in pendular nystagmus both phases have the same speed. Downbeat nystagmus usually points to the craniocervical junction or cerebellum, upbeat nystagmus to the brainstem or cerebellum, see-saw nystagmus to the parasellar region, and gaze-evoked nystagmus to cerebellar dysfunction or drugs such as alcohol and anticonvulsants.
Open the simulatorHow to describe nystagmus
- Waveform: jerk (slow phase, then fast phase) or pendular (equal speed both ways).
- Direction: named by the fast phase — horizontal, vertical (upbeat or downbeat), torsional or mixed.
- Amplitude and frequency: fine or coarse, slow or fast.
- Gaze dependence: present in primary position or only in eccentric gaze, and whether it increases when looking toward the fast phase (Alexander's law).
- Conjugacy: the same in both eyes, or different between the eyes (dissociated), as in INO or see-saw nystagmus.
- Modifiers: the effect of fixation, convergence, covering one eye and head position.
Types of nystagmus and what they suggest
| Type | What it looks like | Where to look / common causes |
|---|---|---|
| Gaze-evoked | Jerk nystagmus beating in the direction of gaze, absent in primary position | Alcohol, anticonvulsants and sedatives; cerebellar or brainstem disease. A few beats at extreme gaze can be normal (end-point nystagmus). |
| Downbeat | Fast phase downward; usually increases on looking down and to the side | Craniocervical junction lesions (Chiari malformation), cerebellar degeneration, lithium or anticonvulsant toxicity, Wernicke encephalopathy |
| Upbeat | Fast phase upward in primary position | Lesions of the medulla, midbrain or cerebellar vermis; Wernicke encephalopathy; multiple sclerosis; stroke; tumors |
| See-saw | One eye rises and intorts while the other falls and extorts, then they swap | Parasellar masses such as pituitary tumors or craniopharyngioma, often with a bitemporal hemianopia; midbrain lesions |
| Pendular | Smooth sinusoidal oscillation with equal speed in both directions | Infantile nystagmus; acquired pendular nystagmus in multiple sclerosis and oculopalatal tremor |
| Peripheral vestibular | Horizontal–torsional jerk nystagmus beating away from the affected ear, reduced by fixation | Vestibular neuritis, Ménière disease; positional bursts in benign paroxysmal positional vertigo |
How to examine nystagmus
- Watch the eyes in primary position while the patient looks at a distant target.
- Move the target to each position of gaze and hold for a few seconds, staying within about 30 degrees of center to avoid end-point nystagmus.
- Check convergence, and cover each eye in turn to bring out latent nystagmus.
- Remove fixation — with Frenzel goggles, or by viewing the optic disc with an ophthalmoscope while the other eye is covered — to reveal peripheral vestibular nystagmus. Through the ophthalmoscope, horizontal and vertical directions appear reversed.
- Record direction, amplitude and gaze dependence on a simple nine-position diagram.
When nystagmus needs urgent attention
- New nystagmus with acute vertigo together with headache, unsteadiness, slurred speech, double vision or weakness: consider a posterior circulation stroke.
- Purely vertical or purely torsional nystagmus, or gaze-evoked nystagmus that changes direction with gaze, in a patient with acute vertigo: these are central signs that need urgent assessment.
- See-saw nystagmus with a bitemporal field defect: image the pituitary region.
- New nystagmus in an infant: needs prompt eye and neurological assessment, because it can signal poor vision from eye disease or, rarely, a brain tumor.
Practice it on the virtual patient
- Open gaze-evoked nystagmus and move the target to each side.
- Compare downbeat and upbeat nystagmus in primary position and in downgaze.
- Watch the alternating vertical and torsional movement of see-saw nystagmus.
- Finish with pendular nystagmus and compare its waveform with jerk nystagmus.
Frequently asked questions
How is nystagmus named?
Jerk nystagmus is named by the direction of its fast phase, even though the slow drift is the abnormal movement. In left-beating nystagmus, for example, the eyes drift slowly to the right and flick quickly back to the left.
What is Alexander's law?
Alexander's law says that jerk nystagmus becomes stronger when the patient looks in the direction of the fast phase and weaker when looking the other way. It is typical of peripheral vestibular nystagmus but also occurs in some central nystagmus.
Is end-point nystagmus normal?
Yes. A few small, symmetric beats at extreme horizontal gaze that fade within seconds are normal. Sustained or asymmetric nystagmus, or nystagmus within about 30 degrees of center, is not.
Which type of nystagmus suggests a pituitary tumor?
See-saw nystagmus, especially together with a bitemporal hemianopia, suggests a parasellar mass such as a pituitary tumor or craniopharyngioma.
Related guides
- Internuclear ophthalmoplegia (INO), one-and-a-half syndrome and gaze palsies Localize INO, one-and-a-half syndrome, gaze palsies and Parinaud syndrome from eye movements.
- Ocular motility and the H-test: ductions, versions and the nine positions of gaze Trace the H, know which muscle each gaze position tests and interpret limited movements.
- Visual pathway lesions and the visual field defects they cause Localize a lesion from its field defect, from the optic nerve to the occipital cortex.