2. What is Nystagmus?
Involuntary and repetitive oscillatory movement
of one or both eyes
May be physiological or pathological or idiopathic
May be early onset or later onset
Often seriously reduces vision
Gauri S Shrestha, M.optom, FIACLE
3. Depth of Field
Reduced by nystagmus
These patients may be prone to tripping or
clumsiness.
Co-ordination is usually adequate for most tasks,
but nystagmus patients are unlikely to excel at
sports needing good hand to eye co-ordination
Nystagmus is actually a sign not the
diagnosis
Gauri S Shrestha, M.optom, FIACLE
4. Description
Position (Primary or gaze-related)
Frequency (Rapid or slow)
Null zone:
Nystagmus is minimal in this field of gaze (this may be
left or right or on convergence
Direction
May be horizontal, vertical or rotational (Described by
the direction of fast phase)
Waveform (Jerk or pendular)
Amplitude (How far the eye moves)
Gauri S Shrestha, M.optom, FIACLE
5. Representation
Jerky Nystagmus
Rt. Beating
Lt. beating
Pendular
Intense jerk Nystagmus
o No Nystagmus
Gauri S Shrestha, M.optom, FIACLE
7. Null Zone & Neutral Zone
Null Zone
The field of gaze in which nystagmus intensity is
minimal
The eye position in which a reversal of direction of jerk
nystagmus occurs and in which no nystagmus
The null and neutral zones usually overlap; however,
several cases have been recorded where they do not.
Gauri S Shrestha, M.optom, FIACLE
8. Incidence
Nystagmus affects about one in a thousand people.
One survey identified one in every 670 children by
the age of two as having nystagmus.
Gauri S Shrestha, M.optom, FIACLE
9. What Causes Nystagmus?
May be inherited or result from a sensory problem
some cases occur for no known reason
It can also develop in later life, sometimes as a
result of an accident or a range of illnesses,
especially those affecting the motor system.
Gauri S Shrestha, M.optom, FIACLE
10. What Should We Know?
Refractive error Correction
Limitations
Vision often varies during the day
affected by emotional/physical factors such as stress,
tiredness, nervousness or unfamiliar surroundings.
Balance
Poor depth perception, which can make it difficult to go up
and down stairs.
Gauri S Shrestha, M.optom, FIACLE
12. Non-Physiological Nystagmus
Based on Appearance of waveform
1. Jerk Nystagmus
Well-defined slow and
fast phases
2. Pendular Nystagmus
No defined fast phase
(pendulum movement)
Gauri S Shrestha, M.optom, FIACLE
13. Physiological nystagmus...
Optokinetic nystagmus (OKN)
Jerky nystagmus induced by
moving patterned targets across
the visual field.
Slow phase along the direction
of the moving patterns, followed
by a fast phase in opposite
direction.
Also called railroad nystagmus.
Clinical significance in detecting
visual acuity.
Gauri S Shrestha, M.optom, FIACLE
14. Physiological nystagmus
End point nystagmus
Fine jerk nystagmus extreme gaze position
Fixation nystagmus - fine oscilllatory movements
during the maintenance of steady fixation
Caloric nystagmus
Jerk nystagmus caused by altered input from the
vestibular nuclei to the horizontal gaze centers.
Nystagmus induced by caloric test.
Gauri S Shrestha, M.optom, FIACLE
15. Caloric test
If hot water is irrigated into right ear – patient will
develop right jerk nystagmus.
Cold water into right ear – left jerk nystagmus
COWS (cold – opposite, warm – same)
If both ears are stimulated for
Cold water – upbeat jerk nystagmus
Warm water – downbeat jerk nystagmus
Gauri S Shrestha, M.optom, FIACLE
17. Congenital nystagmus
Infrequently observed at birth.
Onset is usually during the first 3-4 months of life
but may emerge as late as the teens.
Prevalence is 1 in 6550. (Hemmes in 1927).
Compensatory head nodding develops at the age
of 20 years.
Gauri S Shrestha, M.optom, FIACLE
18. Congenital Nystagmus
Latent nystagmus
Jerky horizontal nystagmus seen when light stimulus
to one or other eye diminished.
Involuntary rhythmical oscillation of both eyes with
fast phase to the fixing eye
Latent nystagmus applies to patients with binocular
single vision
Gauri S Shrestha, M.optom, FIACLE
20. Manifest congenital nystagmus
Nystagmus evoked when both eyes are open.
Amplitude doesnot change on covering one eye.
Sensory defect nystagmus.
Motor defect nystagmus.
Gauri S Shrestha, M.optom, FIACLE
21. Sensory defect nystagmus
Basic cause is the inadequate image formation on
the fovea
As a result of inadequate anterior visual pathway
disease.
Inadequate image formation interferes with the
oculomotor control of fixation mechanism.
Always bilateral & horizontal.
Often is of pendular type
Assumes jerky character in extreme position of
gaze.
Gauri S Shrestha, M.optom, FIACLE
22. Motor defect nystagmus
Primary defect is in the efferent mechanism.
No ocular abnormalities are present.
Amplitude & frequency may decrease or
nystagmus may disappear completely in one
position of gaze (null point / neutral zone).
Visual acuity may improve at the null point /
neutral zone.
Patient may assume anomalous head posture to
To assume null point.
To improve visual acuity.
Gauri S Shrestha, M.optom, FIACLE
23. Congenital Nystagmus
Pendular Nystagmus
Can be found in patients with known foveal
disorder
Macular Scarring, Macular Hypoplasia, Optic
Nerve Hypoplasia
Congenital idiopathic nystagmus
Bilateral, horizontal and jerky with the fast phase
to the right on right gaze and vice versa.
There is null point between the two positions and
convergence with improved VA
Gauri S Shrestha, M.optom, FIACLE
24. Latent manifest nystagmus
Occurs in children with decreased vision in one eye
where the poorly seeing eye behaves as an
occluded eye.
May be due to blindness in one eye or by deep
suppression due to strabismus.
Gauri S Shrestha, M.optom, FIACLE
25. Nystagmus blockage syndrome
(NBS)
Congenital nystagmus dampens
with convergence or adduction.
Demonstrates an esotropia to
dampen nystagmus.
Features
Infantile esotropia
Pseudoabducens palsy
Manifest nystagmus occurs when
eye moves from adduction to
abduction.
All patients with infantile esotropia
should be screened for nystagmus.
Gauri S Shrestha, M.optom, FIACLE
26. Periodic alternating nystagmus
Unusual form of congenital motor jerk nystagmus
Patient starts with a jerk nystagmus in one direction &
lasts for 60 – 90 sec & then slowly begins to dampen.
A period of no nystagmus lasts for 10-20 seconds and then
the nystagmus begins to jerk in opposite direction (60-90
sec).
Cycle again repeated.
Etiology not known but is associated with oculocutaneous
albinism.
Gauri S Shrestha, M.optom, FIACLE
27. Characteristics of Congenital
Nystagmus
Binocular
Similar amplitude in both eyes
Usually uniplanar (horizontal) in all gazes
Distinctive waveforms
Diminished (damped) by convergence
Increased by fixation attempt
Superimposition of latent component
Intensity increase at lateral gazes – fast phase towards the
direction of gaze
Associated head oscillation
No oscillopsia
Abolished in sleep
Gauri S Shrestha, M.optom, FIACLE
28. Acquired : Spasmus nutans
combination of nystagmus, involuntary head nodding and
abnormal head posture. Intermittent rapid small oscillation
with onset at 3-18 months, resolution at 36 months.
A rare constellation of ocular oscillation
Head nodding &
Torticollis
Begins in infancy (usually between 4 and 18 months of age)
Disappears in childhood (usually before 3 years of age).
Gauri S Shrestha, M.optom, FIACLE
29. Acquired
Acquired pendular nystagmus - result of cerebellar
or brainstem lesions. equal amplitude of
nystagmus in all gazes
Acquired jerk nystagmus - (slow and fast phase),
may be horizontal, vertical or rotary, due to
supranuclear defect
Vestibular nystagmus - horizontal jerky
nystagmus with rotary or vertical element, due to
the destruction of inner ear, vestibular nerves and
vestibular nuclei.
Gauri S Shrestha, M.optom, FIACLE
30. Acquired
Gaze evoked nystagmus -an inability to maintain the eyes
in a lateral or vertical gaze position. The eyes drift back to
the primary position, then make a correction saccade to
look in the position of defective gaze. Cause is
supranuclear defect
Dissociated nystagmus -oscillatory movements of eyes,
dissimilar in direction, amplitude and speed. Cause is
internuclear ophthalmoplegia
Convergence retraction nystagmus -on attempted upgaze,
eyes are converging and retracting with nystagmoid jerk
movements
Gauri S Shrestha, M.optom, FIACLE
31. See-saw nystagmus
Unusual & dramatic type.
Has both vertical & Torsional
components.
Eyes make alternating
movement of elevation &
intorsion followed by
depression & extorsion.
Often associated with lesions
in the rostral midbrain or the
suprasellar area.
Visual field defects are
bitemporal hemianopia.
Neuroradiologic evaluation
mandatory. Gauri S Shrestha, M.optom, FIACLE
32. Downbeat nystagmus: jerky vertical nystagmus
seen with increased amplitude on downgaze. The
eyes drift up and beat down again. Cause is CNS
lesion
Upbeat nystagmus :jerky vertical nystagmus seen
with increased amplitude on upgaze. The eyes
drift down and beat up again. Cause is lesion of
cerebellum or medulla.
Periodic alternating nystagmus :jerk nystagmus
is seen which alters in direction with every few
minutes. Cause may be drugs or multiple sclerosis
Gauri S Shrestha, M.optom, FIACLE
35. Nystagmus Management
Neurological Work-up and appropriate
medical treatment
Refer if necessary
Provide Best Corrected VA
Recommend with contact lenses
Utilize Null Point
Certain eye/head position that minimizes
nystagmus
Vision Therapy
Gauri S Shrestha, M.optom, FIACLE
36. How Can You Utilize Null Point?
Locate with version (ocular motility) testing
Use of Prisms:
Base-Out: if convergence reduces nystagmus
Yoked: in extreme head turn reduces nystagmus
Base toward Null point to reduce head turn
Use Equal power (RE, LE)
EOM Surgery:
Move Null point to primary position
Gauri S Shrestha, M.optom, FIACLE
40. Near Work With Nystagmus
The angle of vision is important.
Null point. Adopt a head posture
Small print.
Visual Aids, Large print materials.
Good Lighting
Be Careful with Light sensitive paients
Reading speed
Reduced due to the extra time needed to scan
Should not be taken as a sign of poor reading.
Gauri S Shrestha, M.optom, FIACLE