3. DEFINITION
Disorder of ocular motor instability resulting in
spontaneous, involuntary, rhythmic oscillations
of the eyes
Congenital vs. acquired
“jerk” nystagmus vs. pendular
“true” nystagmus vs. nystagmoid movements
4. Conjugate vs. disconjugate vs. dissociated
Trajectory may be horizontal, vertical, torsional,
or mixed
Description of amplitude, frequency, velocity,
and intensity
may vary with changes in gaze position
May be influenced by the integrity of the
afferent visual system
May exhibit a “null” point
5. 3 main mechanism of maintaining steady
gaze:
1) fixation: a) prevent retinal image drift
b) suppress unwanted saccades
2) VOR
3) eccentric gaze holding
8. Not always a sign of disease…
Physiological:
Usually conjugate
Preserves clear vision during self-rotation
unsustained end-point nystagmus
Vestibular nystagmus (brief sustained rot.)
OKN (visually driven….uses pursuit mech.)
9. CHILDHOOD NYSTAGMUS
Congenital nystagmus:
usually recognized in first few months of life – life long
May have good vision or poor vision
Most often occurs in isolation (motor), but may be associated
with albinism, LCA, achromatopsia, or optic atrophy
Uniplanar, horizontal trajectory irrespective of gaze position
No oscillopsia
Reversal of OKN direction
Exponential increase in slow phase velocity
Conjugate
Null point (may have resultant head turn)
Amplified by attempted fixation (distant)
Dampened by convergence and darkness
Absent in sleep
Association with esotropia
10. Latent nystagmus:
Usually appears within first few months of life
Horizontal jerk nystagmus appearing only
under monocular viewing conditions
Fast phase beats away from occluded eye
Strong association with esotropia
Usually poor stereopsis
May explain subnormal visual acuity tested
monocularly
Manifest latent nystagmus:
Present even when both eyes are open
Loss of peripheral fusion
11. Monocular nystagmus of childhood:
Usually monocular, vertical, low amplitude oscillation
Eye with nystagmus may have afferent visual dysfunction
Requires neuroimaging (chiasmal glioma)
Spasmus Nutans:
Asymmetric or monocular low-amplitude oscillations
May be horizontal, vertical or torsional
Head nodding
Torticollis or abnormal head posture
Begins in infancy, usually resolved by age 3 to 5
Requires neuroimaging
13. PERIPHERAL VS. CENTRAL
VESTIBULAR NYSTAGMUS
PERIPHERAL
Severe vertigo
Days to weeks duration
Hearing loss, tinnitus
associated
Usually horizontal with
torsion
Very rarely purely vertical or
torsional
Dampened with visual
fixation
Commonly peripheral
vestibular organ dysfunction:
labyrynthitis, meniere’s
CENTRAL
• None or mild vertigo
• Often chronic
• May be purely vertical or
torsional
• visual fixation usually has no
effect
• Etiologies commonly
vascular, demyelination,
pharmacologic, toxic
• Downbeat, upbeat, torsional
14. Gaze evoked nystagmus:
One of the most common forms of central
nystagmus
Inability to maintain eccentric gaze
“leaky integrator” -- miscalibration between pulse
and step inputs
Symmetric
cerebellar flocculus implicated
Age, anti-convulsant therapy, alcoholic
degeneration, stroke, demyelination
Baclofen effective
15. Downbeat nystagmus:
Defect in vertical gaze holding
Asymmetric inputs from vertical semi-circular
canals produce upward slow drift of eyes
Defect in fastigial nuclei calibration
Secondary downward corrective fast phase
Obeys Alexander’s law
Localizes to cervico-medullary junction
Arnold-Chiari malformation
Treatment with baclofen, clonazepam, base-out
prisms
16. Upbeat nystagmus:
Present in primary position or upgaze
Classically localizes to a lesion of anterior cerebellar
vermis
More generally implicates posterior fossa disease
Etiologies include stroke, cerebellar degeneration,
demyelination, toxic exposures
Periodic alternating nystagmus:
Horizontal oscillation characterized by a periodic reversal
in the direction of nystagmus due a shift in the null point
Duration of cycles from 30 seconds to 6 minutes
Classically a lesion of the cerebellar nodulus
MS, drugs, ethanol, paraneoplastic syndromes
Baclofen effective
17. •Bruns nystagmus:
• associated with CPA tumors
• high frequency, low amplitude
nystagmus (fast-phase away from lesion)
• low frequency, large amplitude
nystagmus on ipsilateral gaze (fast phase
toward lesion)
• shift from eye movement response to
vestibular imbalance to that of defective
gaze holding
18. See-saw nystagmus:
Disconjugate vertical nystagmus (pendular vs. jerk)
Upward moving eye intorts while downard eye extorts
Localizes to lesions of diencephalon
Visual fields may be useful (disruption of afferents to cerebellum)
Ocular flutter/opsoclonus:
Burst-like, incoordinated saccadic excursions with high frequency,
low amplitude
No intersaccadic latency
Purely horizontal: ocular flutter
Multiplanar: opsoclonus
Reflect pause cell dysfunction (pons)
Must consider paraneoplastic etiology: SCC of lung, ovarian,
breast CA
Neuroblastoma in children
19.
20. Acquired pendular nystagmus:
Can be vertical, horizontal, torsional, or any
combination (usually one predominates)
Usually disconjugate or dissociated
Oscillopsia ++
MS, whipple’s, oculopalatal myoclonus
Combination of afferent dysfunction and
cerebellar calibration
21. Oculopalatal myoclonus:
Vertical pendular eye movements associated with rhythmic
upward movement of palate
Caudal brainstem pathology: red nucleus, inferior olive, and
dentate nuc.
Convergence-retraction nystagmus:
Commonly associated with dorsal midbrain syndrome
May be associated with other Parinaud’s findings
Not a true nystagmus: co-contraction of horizontal recti on
attempted upgaze
Localizes to pretectal area, posterior commissure, INC
Pineal cyst or tumor, demyelination, stroke
22. SUMMARY
Recognize physiologic vs. pathological
Appropriate characterization important
Presence of nystagmus may correlate with significant
afferent visual dysfunction
Recognition of nystagmus may facilitate subsequent
neurological or medical investigations (know where to
look)
Treatment options do exist