This document provides an overview of different types of nystagmus, including: - Physiological nystagmus like optokinetic nystagmus - Pathological nystagmus like infantile nystagmus syndrome - Characteristics used to classify nystagmus like plane, amplitude and frequency - Specific types like jerk nystagmus, pendular nystagmus, and factors that can induce or alleviate nystagmus. Treatment options for some types are also mentioned, such as contact lenses and eye muscle surgery.

1. Dr. Md. As-Aad Habib
MS Phase B
Department of Ophthalmology, DMCH

2. An involuntary oscillation of the eyes that can
be a
 Physiological phenomenon (following the
rotation of an optokinetic drum)
 Pathological phenomenon

3.  Plane: May be –
◦ Horizontal
◦ Vertical
◦ Torsional
 Amplitude: Extent of Excursion –
◦ Fine
◦ Coarse
 Frequency: Describes how rapidly the eyes
oscillate –
◦ High
◦ Moderate
◦ Low

4.  Jerk nystagmus:
 Saccadic
 Slow defoviating ‘drift’ movement
 Fast corrective saccadic movement.
 Direction of jerk nystagmus is reported as the
directioon of it’s fast component.
 Slow phase component indicates the pathology.

6.  Pendular nystagmus:
 Non-saccadic
 Both the foveating and defoveating movements
are slow; the velocity of nystagmus is
equal in both directions.
 No fast phase.

9.  Mixed nystagmus:
 Pendular nystagmus in primary position
 Jerk nystagmus on lateral gaze.

10.  Conjugate nystagmus:
 Symmetric in direction, amplitude and rate.
 Dissociated/ Disconjugate nystagmus:
 Amplitude of oscillation differs in each eye.
 Disjunctive nystagmus:
 Direction of oscillation differs between two eyes.

11.  Pursuit/ Saccade:
 Pursuit eye movements allow the eyes to
closely follow a moving object.
 Pursuit differs from vestibulo-ocular reflex,
which only occurs during movements of
the head and serves to stabilize gaze on
a stationary object.
 Saccades are quick, simultaneous
movements of both eyes in the
same direction.

12.  It states that the amplitude of jerk nystagmus is
largest in the gaze of direction of fast
component.
 1 degree: nystagmus only in the direction of fast
component.
 2 degree: nystagmus in primary gaze position.
 3 degree: nystagmus in addition to above gazes,
also present in the direction of slow component.

14.  May be asymptomatic.
 Oscillopsia - a sensation of environmental
movement. It commonly occurs with acquired
nystagmus. And with jerk nystagmus, the
environment is perceived to move in the
direction of fast phase.

15.  Monocular or binocular
 Conjugate (ie, the eyes behave similarly)
 Horizontal, vertical, torsional, or mixwd in
paatern
 Continuous or induced by a particular eye
position.
 Characterized by slow phases only, fast and
slow phases, or fast phases only
 Reduced at a null point.

16.  Foveal centration of an object of regard is
necessary to obtain the highest level of visual
acuity.
 Three mechanisms are involved in maintaining
foveal centration of an object of interest:
1. Fixation
2. The vestibulo-ocular reflex
3. The neural integrator

17.  Fixation in the primary position involves the
visual system’s ability to detect drift of a
foveating image and signal an appropriate
corrective eye movement to refoveate the
image of regard.
 The vestibular system is complexly and
intimately involved with the oculomotor
system.

18.  A complex system of neural inteconnections
that maintains foveation of an object during
changes of head position.
 The propioceptors of vestibular system are
the semicircular canals of the inner ear.
 The semicircular canals respond to changes
in angular acceleration due to head rotation.

19.  When the eye is turned in an extreme position
in the orbit, the fascia and ligaments that
suspend the eye exert and elastic force to
return toward the primary position.
 To overcome this force, a tonic concentration
of the extraocular muscles is required.

20.  A gaze holding network called the neural
integrator generates the signal.
 The cerebellum, ascending vestibular
pathways and oculomotor nuclei are
important components of the neural
integrator.

21. A simple classification modified from
“Classification of Eye movements
Abnormalities and Strabismus (CEMAS)” –
1. Physiological nystagmus
2. Pathological nystagmus

22.  Physiological nystagmus:
1. Endpoint nystagmus
2. Optokinetic nystagmus
3. Physiological vestibular nystagmus

23.  Pathological nystagmus:
• Early onset (childhood) nystagmus:
Infantile nystagmus syndrome/ Congenital nystagmus
Fusional maldevelopment nystagmus syndrome (Latent
nystagmus)
Spasmus nutans
• Acquired nystagmus:
Nystagmus due to disorders of visual fixation
Nystagmus caused by vestibular imbalance
Nystagmus due to disorders of gaze holding

24.  Jerk nystagmus
 Induced by moving repetitive targets (e.g. OKN
drum) across the visual field.
 Slow phase- pursuit movement- eyes follow the
target.
 Fast phase- saccadic movement- Opposite
direction as the eyes fixate on the next target.

25.  If the OKN tape or drum is moved
from right to left, left parieto-occipito-
temporal region controls the slow
(pursuit) phase to the left and the
left frontal lobe controls the
rapid (saccadic) phase to the right.

26.  Uses-
Detection of functional (non-physiological)
blindness.
Testing VA in the very young.
Aeessment of isolated homonymous hemianopia.

27.  Moderate frequency jerk nystagmus in
extremes of gaze.
 Fast phase- in the direction of gaze.

28.  Jerk nystagmus
 Caused by altered input from the vestibular
nuclei to the horizontal gaze centres.
 Slow phase- Vestibular nuclei
 Fast phase - brainstem and
frontomesencephalic pathway.

29.  Can be elicited by caloric stimulation:
◦ Cold water- nystagmus of opposite side
◦ Warm water- same sided/directional nystagmus
◦ Cold water in both ears simultaneously- nystagmus
with fast phase upwards
◦ Warm water in both ears simultaneously –
nystagmus with fast phase downwards.
◦ Abnormal test result- peripheral vestibular disease.

30.  Often recognized in the first few months
of life but may not become evident
until several years of age.
 Can occur secondary to poor vision
or to a motor deficit with nystagmus
itself causing poor vision.
 Can be associated with systemic conditions.

31.  Almost always horizontal and conjugate, even
in upgaze and downgaze.
 May be continuous or intermittent.
 Can appears as jerk or pendular movements
in different gazes.

32.  There is usually a null point – a position of gaze
in which nystagmus is minimal.
 Patients often adopt a head turn or posture that
places the eyes in the null position in order to
improve vision.
 Usually amplified by visual attention and fixation
 Dampened by convergence & absent during
sleep.

33.  Reverse response to optokinetic stimulus –
slow phase eye movement in the
opposite direction of the rotating
OKN drum.
 Children with INS usually do not have
oscillopsia.

34. Sensory deficit (afferent) nystagmus:
◦ More common form of infantile nystagmus
◦ In general, children with bilateral poor central vision
under 2 years of age develop nystagmus, the severity of
which is associated with the degree of visual loss.
◦ Causes –
 Congenital Cataract
 Macular hypoplasia
 Laber congenital amaurosis
 Optic nerve hypoplasia
 Albinism
 Achromatopsia

35. Congenital motor (efferent) nystagmus:
◦ Family history is common
◦ X-linked (dominant or recessive) inheritance –
common mode.
◦ Presentation is about 2-3 months after birth and
persists throughout life.
◦ VA – better than sensory deficit nystagmus, 6/12-
6/36.
◦ Primary position – low amplitude pendular
nystagmus, side gaze- jerk nystagmus.

37. Treatment:
◦ Correction of any refractive error.
◦ Use of contact lenses – enhance sensory feedback >
reduce abnormal eye movement > damp congenital
nystagmus.
◦ Prism therapy – Use of base out prism > to shift the
null point to primary position > or to induce
convergence which damp congenital nystagmus.

38. ◦ Eye muscle surgery : Anderson-Kestenbaum
procedure > reposition the eyes and move the null
point into the straight ahead position.
(Face turn to the right-eyes shift to a null point in the
left gaze> yolked left lateral rectus and right medial
rectus muscles are weakened/ recessed> left
medial rectus and right lateral rectus muscles are
strengthened/ resected)

39. ◦ Tonotomy- all four horizontal recti muscles are
detached and then reattached at their original site>
reported to improve foveation time and vision > but
it is controversial.
◦ Memantine and gabapentine > may improve visual
acuity and foveation times > not commonly used
due to side effects.

40.  Early onset, conjugate, horizontal, jerk
nystagmus.
 Both eyes open> No nystagmus> Eyes with
FMN are stable during fusion.
 Occlusion of one eye (elimination of fusion)>
horizontal nystagmus becomes apparent>
fast phase towards uncovered fixating eye.

41.  It becomes manifest under monocular
viewing conditions, i.e. in the presence of
decresed visio in one eye as in anisometropic
amblyopia, strabismic amblyopia, etc.
 Associated with infantile esotropia and
dissociated vertical deviation.

42.  While testing visual acuity in such patients,
one eye should be fogged (by adding plus
lenses in front) rather than occluding to
minimize induction of latent nystagmus.

43.  Presentation – 3 months to 18 months
 Unilateral or bilateral
 Small amplitude, high frequency, horizontal
nystagmus (‘Shimmering’ eye movements)
 Associated with head nodding and an abnormal
head posture (torticollis).

44.  Frequently asymmetrical, increased amplitude
in abduction. Vertical and torsional
components may be present.
 Head nodding, torticollis, or both occurs in
approximately 60% of patients and appear to
damp the nystagmus and improve vision.

46.  Cause:
 Idiopathic ( spontaneously resolve by the age of 3
years)
 Glioma of the anterior visual pathway
 Empty sella syndrome
 Porencephalic cyst

47.  Late onset or acquired nystagmus.
 Characterized by oscillopsia.
 Often associated with neurological abnormalities.
 Includes:
 Nystagmus due to disorders of visual function
 Vestibular nystagmus
 Nystagmus due to disorders of gaze holding.

48.  Also called ‘Vision loss nystagmus’
 May occur due to diseases affecting any part of the
visual system from retina to visual cortex or
conditions interrupting visual projection to the pons
and cerebellum as below:
◦ Nystagmus in diseases of the retina
◦ Nystagmus in diseases of the optic nerve
◦ Nystagmus in diseases affecting the optic chiasma
◦ Nystagmus in diseases affecting the post chiasmal visual
system

49.  Peripheral vestibular nystagmus
 Central vestibular nystagmus
 Upbeat nystagmus
 Downbeat nystagmus
 Torisional nystagmus
 Periodic alternating nystagmus
 See-saw nystagmus

50.  Tends to be solely horizontal, vertical or
torsional.
 Typically of fine amplitude.
 Fast phase away from the side of lesion.
 Improves with fixation.
 Worsens with gaze towards the fast phase.
 Causes:
 Labyrinthitis
 Meniere disease
 Middle or inner ear infections.

52.  Downbeat nystagmus
 Upbeat nystagmus
 Torsional nystagmus

53.  Most common form of central vestibular
nystagmus.
 Lesions compromising the vestibulocerebellum
(i.e. the nodulus, uvula, flocculus and
paraflocculus)> diminish the tonic output of
posterior semicircular canals to ocular motor
neurons> defective vertical gaze holding>
charecterized by an upward drift of the eyes ,
which is corrected with a downward saccade.

54.  May be present in primary position but more easily
elicited in downgaze and lateral gaze.
 Causes-
 Lesions at the foramen magnum:
 Arnold-Chiari malformation
 Syringobulbia
 Drugs:
• Lithium
• Phenytoin
 Wernicke encephalopathy
 Demyelination
 Hydrocephalus

55.  Treatment-
• Medicines-
 Clonazepam
 Gabapentin
 Baclofen
 Memantine
 4-aminopyridine
• Base out prism to induce convergence- it can
sometimes improve the oscillopia associated
with downbeat nystagmus.

57.  Vertical nystagmus
 Fast phase- beating upwards in all positions
 Causes-
 Posterior fossa lesions
 Drugs
 Wernicke encephalopathy

59.  Although peripheral vestibular nystagmus
may have a torsional component, purely
torsional nystagmus indicates a central
lesion.
 Causes-
• Medullary lesions:
 Syringobulbia
 Lateral medullary infarction
• May be a part of ocular tilt reaction.

60.  Conjugate horizontal nystagmus that
periodically reverses direction.
 Active phase- the amplitude and frequency of
nystagmus first peogressively increase than
decrease.
 An interlude- lasting 4-20 seconds, eyes are
steady, may show low-intensity, often
pendular movements.

61.  A similar sequence in the opposite direction
occurs thereafter.
 Whole cycle- between 1 to 3 minutes.
 Cause-
 Congenital
 Cerebellar disease
 Ataxia telangiectasia
 Drugs- Phenytoin.

62.  Pendular nystagmus
 One eye elevates and intorts while the other
depresses and extorts.
 Cause-
 Parasellar tumours (often with bitemporal hemianopia)
 Syringobulbia
 Brainstem stroke

63.  Gaze-evoked nystagmus
 Ataxic nystagmus
 Convergence retraction syndrome
 Brun’s nystagmus
 Rebound nystagmus

64.  Develops due to inability to maintain fixation
in eccentric gaze.
 Most commonly caused by dysfunction of
neural integrators.
 Fast phase- always in the direction of gaze.

65.  The amplitude of the nystagmus increases as
the eyes are moved in the direction of fast
phase.
 Cause-
 Toxic effects from drugs and medications (eg- alcohol,
sedatives, anticonvulsants antidepressents)
 Cerebellar disease.

66.  Jerk nystagmus due to the co-contraction of
extraocular muscles, often the medial recti.
 Can be induced by rotating an OKN drum
downards; the upward refixation saccade
brings the two eyes towards each other in a
convergence movement.

67.  Classically associated with retraction of the globe
into the orbit.
 Fast component- towards the medial side
 Cause-
 Pinealoma
 Stroke
 Trauma
 Multiple sclerosis

68.  Horizontal jerk nystagmus that occurs in the
abducting eye of a patient with INO.

69.  In one eye – A coarse cerebellar horizontal
jerk nystagmus. (Towards the side of lesion)
 In other eye – Fine, high frequency vestibular
nystagmus. (Opposite side of lesion)
 Cause- Cerebellopontine angle tumours such
as – acoustic neuroma

70.  In some patients with gaze evoked nystagmus,
prolonged eccentric gaze (>30 seconds) reduces
the amplitude of the nystagmus.
 However, when the patient resumes central gaze
position, a jerk nystagmus develops in the
opposite direction of the initial gaze-evoked
nystagmus.
 A condition referred to as rebound nystagmus.

71.  Resemble nystagmus, but the initial
pathological defoveating movement is a
saccadic intrusion;
 Only fast phase, no slow phase.
 Includes-
• Ocular flutter and opsoclonus
• Ocular bobbing

72.  Consist of saccadic oscillations with no
intersaccadic interval.
 In ocular flutter, oscillations are purely
horizontal and in opsoclonus they are
multiplaner.
 Cause:
 Viral encephalitis
 Myoclonic encephalopathy in infants (dancing eyes and
dancing feet)
 Drug induced, etc.

73.  Rapid downward conjugate eye movements
with a subsequent slow drift up to the
primary position.
 Cause-
 Pontine lesion (usually hemorrhage)
 Cerebellar lesions: compressing the pons
 Metabolic encephalopathy

74.  Rare condition
 Characterized by intermittent episodes of
oscillopsia and diplopia in one eye (usually
right eye).
 Cause not known.
 Condition may follow ocular or head injury
and rarely brainstem tumors.