gave me Nystagmus- Neuro-ophthalmology, physiological and pathological nystagmus

1. Nystagmus and
Spontaneous eye
movement disorders
DR. NAMRATA GUPTA

2. Definition
Fixation instabilities that are involuntary and
rhythmic
 Nystagmus- inability to maintain fixation due to
slow drift away from fixation followed by rapid
corrective eye movement
 Saccadic intrusion and saccadic oscillations
result from spontaneous rapid eye movement
without slow phase

3. Background
 Foveal centration of an object of regard is necessary to
obtain the highest level of visual acuity
 Three main control mechanisms maintain steady gaze—
• Fixation
• The vestibulo-ocular reflex
• The neural integrator

4. Fixation
 Involves the visual system's ability to detect drift
of a foveating image
 Signal an appropriate corrective eye movement
to refoveate the image of regard

5. Vestibulo-ocular reflex

6. Neural integrator
 A gaze- holding network : Complex integration
between cortical centers, cerebellum, ascending
vestibular pathways and ocular motor nuclei

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

8. Failure of control system- disruption of steady fixation
A. Nystagmus
B. Saccadic intrusion or saccadic oscillations

9. Nystagmus
 Nystagmus is a repetitive, involuntary to and fro
movement of the eyes (horizontal, vertical or
torsional) with 2 phases:
1. Involuntary defoveating drift of the eye from
the target of interest followed by
2. Corrective refixation saccade back to the
target

10. Terminologies
• Saccade/ Pursuit
• Jerk / Pendular
• Null zone
• Amplitude
• Frequency
• Intensity
• Conjugate / Dissociated

11. Saccade/ Pursuit
 Saccades are sudden, simultaneous movements of
both eyes in the same direction to place the object
of interest on to the fovea
 Pursuit eye movements allow the eyes to closely
follow a moving object located by the saccadic
system
 Pursuit differs from the vestibulo-ocular reflex, which
only occurs during movements of the head and
serves to stabilize gaze on a stationary object

12. Jerk / Pendular
Jerk nystagmus Pendular nystagmus
Alternation of slow defoveating
drift and rapid corrective
saccade in opposite direction
Sinusoidal oscillation with slow
phase in both directions and no
corrective saccade
Direction of jerk nystagmus =
direction of the fast phase
Pendular nystagmus may be
horizontal or vertical
• Right or left beating
nystagmus
• Upbeat or downbeat
nystagmus
Not characterised by
right,left,up,down beating as
there is no fast phase

13. Pendular nystagmus
Jerk nystagmus

14. Amplitude
 Amplitude is the excursion of the nystagmus
 Fine : less than 50
 Medium : 50-150
 Coarse : greater than 150

15. Frequency
 Frequency is the number of to and fro movements
in one second
 Described an cycles/sec or Hertz (Hz)
 Slow : (1-2 Hz)
 Medium : (3-4 Hz)
 Fast: (5 Hz or more)

16. Intensity
 Intensity = amplitude x frequency
 Null zone: position where intensity of nystagmus is
minimized, foveation period long
 Patient assumes a head posture, such that the eyes
are in null zone

17. Conjugate/Dissociated
 Conjugate : Nystagmus which is symmetric in
direction, amplitude and rate between two eyes
 Dissociated: When it differs in any one of the
parameters between two eyes
 Disconjugate: Direction of the oscillations differ
between two eyes

18. Schematic for Nystagmus

19. Nystagmus
waveforms

20. Alexanders law
 It states that the amplitude of jerk nystagmus is
largest in the gaze of direction of fast component
 Grade I : nystagmus only in the direction of the fast
component
 Grade II : nystagmus in primary gaze position
 Grade III : nystagmus evident in all positions of the
eyes

21. Classification
• Optokinetic
• Vestibular
• End-point
Physiological
• Congenital nystagmus
• latent nystagmus
• Spasmus nutans
Early onset
(childhood)
• Gaze-evoked
• Vestibular
• Upbeat/downbeat
• Dissociated nystagmus
• Periodic alternating nystagmus
Pathological

22. Physiological
 End point nystagmus
 Vestibular (caloric or rotational) nystagmus
 Optokinetic nystagmus

23. End point nystagmus
 Jerk nystagmus
 On looking extreme lateral or upwards
 Small amplitude <20 and Angle of gaze > 450 ,
dampens in 6 secs
 Common in older patients
 Pathological if-
 Asymmetric
 Persistent nystagmus
 Other features
physiological

24. Vestibular nystagmus
 Jerk nystagmus due to
altered inputs from
vestibular nuclei to PPRF
physiological

25. Vestibular nystagmus
Types:
 Rotatory vestibular nystagmus- stimulation of
vestibular labyrinth or nerve secondary to rotation
 Caloric vestibular nystagmus:
• Cold water : opposite side
• Warm water : same side
• Cold water in both ears: upwards
• Warm water in both ears : downwards

26. physiological
Optokinetic nystagmus
 Jerk nystagmus
 Induced by moving a full visual field stimulus
 Slow phase (pursuit) : eye follows the target
 Fast phase ( saccade): eye fixates on next target
 Uses: Detecting malingering
Testing visual potential in children

27. Early onset (childhood)
 Congenital nystagmus
 Latent nystagmus
 Spasmus nutans

28. Congenital nystagmus
(Infantile nystagmus syndrome)
 80% of all nystagmus
 Usually not noted at birth , apparent during first few
months of life
 Positive family history may be present

29. Characteristics
Congenital nystagmus
 Horizontal nystagmus ( mixed pendular and jerk)
 Bilateral conjugate movements of the eyes
 With or without normal visual acuity
 Head turn to achieve null point
 Accentuation with distant fixation and decreased
by convergence
 Abolished in sleep
 No oscillopsia
 Strabismus present in 15% patients

30.  Reverse response to OKN stimulus ( fast phase in
direction of moving OKN drum)
 Exponential increase in velocity of slow phase with
distance from fixation
Congenital nystagmus

31. Treatment
 Base out prisms to induce convergence
(dampens the nystagmus and may improve visual
acuity)
 Use of prisms to shift the viewing position to null
position
Congenital nystagmus

32. Surgical
Congenital nystagmus
 Includes moving the extraocular muscles to place
the null zone in primary position(kestenbaum
procedure)
 Recessing all 4 rectus muscles to decrease tension
(large recession procedure)

33. Latent nystagmus
(Fusional maldevelopment nystagmus
syndrome)
 Conjugate jerk nystagmus
 Beginning or accentuation when binocular fusion is
disrupted
 After mono-ocular occlusion- fast phase beats
towards viewing eye; slow phase towards the other
 Congenital esotopia
 May co-exist wit INS
 Manifest latent nystagmus- latent nystagmus present
with both eyes open during physiological suppression

34. Spasmus nutans
Triad of symptoms:
 Pendular Nystagmus
 Head nodding
 Torticollis (head tilt or head turn)

35. Spasmus nutans
 Onset usually in the first year of life (3-15 months)
 Disappears by 3-4 yrs of age
 Intermittent , binocular, small-amplitude, high
frequency, horizontal pendular nystagmus
oscillations
 It can be monocular, asymmetric, and variable in
different positions of gaze
 Usually benign
 Neuroimaging recommended ( gliomas may mimic
spasmus nutans)

36. Infantile monocular pendular
nystagmus
 Monocular vertical or elliptical high frequency
nystagmus
 Heimann-Bielchowsky phenomenon- with long
standing poor vision
 Usually due to visual loss(optic neuropathy,
amblyopia or chiasmal glioma)

37. Acquired nystagmus
Nystagmus associated
with poor vision (sensory)
 Anterior segment:
cataract, aniridia
 Retinal diseases: RB,
ROP, Intrauterine
infections
Nystagmus associated with
neurological diseases (motor)
 End gaze paretic nystagmus
 Vestibular nystagmus
 Downbeat nystagmus
 Upbeat nystagmus
 Periodic alternating
nystagmus
 Dissociated nystagmus

38. Gaze paretic nystagmus
 Most common type
 Jerk nystagmus at 30° of fixation
 Fast phase in direction of eccentric target
 Absent in primary position and is not visually
disabling

39. Gaze paretic nystagmus
 Dysfunction of neural integrator- nucleus prepositus
hypoglossi and medial vestibular nucleus
 Symmetric- mental fatigue: barbiturates,
anticonvulsants, tranquilizers
 Asymmetric- lesions of brain stem, cerebellum and
cerebrum

40. Gaze paretic nystagmus

41. Vestibular nystagmus
Feature Peripheral Central
Disease of vestibular origin
Rotary nystagmus
Disease of the brainstem
Pure horizontal, vertical
Direction • Decreased innervation-slow
component
towards affected ear
• Increased innervation-fast
component toward
affected ear
• Direction of
nystagmus may
change with gaze
• Lesion contralateral to
fast component
Visual fixation Inhibits nystagmus No inhibition
Severity of vertigo Severe Mild
Induced by head
Often Rare
movements
Associated eye
movement deficits
None Pursuit or saccadic
defects
Other findings Hearing loss, tinnitus CNS involvement

42. Upbeat nystagmus
 Type of jerk nystagmus with fast phase upward in
primary position
 Often worsens in upgaze
 Causes: lesions of lower pontine tegmentum,
medulla, cerebellar vermis, midbrain
• Multiple sclerosis, infarction, intra-axial tumor, brainstem
encephalitis, cerebellar degeneration
 Rx: base up prisms in reading glasses can be
used to force the eyes downward

43. Upbeat nystagmus

44. Downbeat nystagmus
 Type of jerk nystagmus with fast phase downward in
primary position
 Often worsens in downgaze(convergence)
 Oscillopsia is usually prominent
 Causes:
 lesions at cerebellum and pons- infarction, cerebellar
degenerations, tumors, multiple sclerosis, congenital
malformations
 Vitamin B12 deficiency, magnesium deficiency, lithium
toxicity, Wernicke’s encephalopathy
 Rx: Base down prisms in reading glasses can be used
to force the eyes upward

45. Downbeat nystagmus

46. Periodic alternating
nystagmus (PAN)
 A repetitive cycling of right beating and left
beating nystagmus in primary gaze
 PAN is a conjugate, horizontal jerk nystagmus with
the fast phase beating in one direction for a period
of 1-2 minutes
 An intervening null phase lasting 10-20 seconds
 Nystagmus begins to beat in the opposite direction
for 1-2 minutes then, the process repeats itself

47. Periodic alternating nystagmus
 Periodic alternating head turn towards fast
component to minimise nystagmus & oscillopsia
 Causes:
 lesions of the cerebellum
 Severe binocular vision loss- vitreous hemorrhage,
cataract, chronic papilloedema

48. Periodic alternating nystagmus

49. Dissociated Nystagmus
Difference between two eyes in amplitude of ocular
oscillations
A. Acqiured pendular nystagmus in adults:
• Lesions of pons, medulla, midbrain, cerebellum
• Oculopalatal myoclonus- associated tremors of soft
palate tongue, facial muscle, pharynx

50. Dissociated Nystagmus
B. Monocular or bilateral vision loss
1. Monocular -
• Children: High frequency pendular nystagmus
• Adults: low frequency, irregular, vertical dift and
jerk nystagmus
• Abolished with recovery of vision
2. Binocular:
• large amplitude oscillations superimposed with
small amplitude ones
• Impaired vestibulo-ocular response
• Head nodding present

51. Dissociated Nystagmus
C. Seesaw nystagmus:
 Disconjugate vertical pendular nystagmus
 Elevation and intorsion of one eye simultaneous
with depression and extorsion of other eye
 Followed by reversal of cycle, so that the eyes
move like a seesaw

52. Seesaw nystagmus
 Causes:
 Parasellar lesions, pituitary tumors
 Less common- head trauma, brain stem infarction
 Produces very disabling oscillopsia that responds
poorly to any Rx

53. Dissociated Nystagmus
D. Inter nuclear
ophthalmoplegia
 Lesion of medial longitudinal
fibers
 Isolated slowing of
adduction of ipsilateral eye
 Abducting nystagmus of
other eye in horizontal gaze
opposite to lesion

54. Convergence-retraction
nystagmus
 Not truly a nystagmus
 b/l adducting saccades causing convergence of
both eyes
 Elicited by having the patient to look up, the eyes
converge & retract
 Co-contraction of all extra-ocular muscle
 Causes: Dorsal midbrain lesions
 Collier’s sign- paresis of upgaze, pupillary light near
dissociation, skew deviation, bilateral eyelid retraction

55. Convergence-retraction nystagmus

56. Nystagmus associated
with strabismus
 Manifest-latent nystagmus
 Manifest nystagmus
 Nystagmus blockage syndrome

57. Manifest nystagmus Manifest-latent nystagmus
Pendular nystagmus Jerk nystagmus
No change on abduction Increased on abduction
No change on covering one
Increase on covering one
eye
eye
Null zone is present Fast phase always towards
fixing eye
Less commonly associated
with infantile esotropia
Always associated with
esotropia
Binocular visual acuity same
as uniocular
Binocular visual acuity better
than uniocular

58. Nystagmus blockage
syndrome
 Inverse relationship with esotropia
 Esotropia is a mechanism of blocking the
nystagmus
 The fixing eye is preferred to be in adduction ,face
turn is in the direction of fixing eye

59. Nystagmoid conditions
• Reflex saccades to objects in visual field is inhibited by
pathways from frontal lobe to basal ganglia and
superior colliculus
• Frontal lobe disease- inappropriate saccades
• Alzhimer’s disease, Huntington disease, progressive
supranuclear palsy, schizophrenia
 Saccadic intrusions:
1. Normal intersaccadic intervals
2. Without normal intersaccadic intervals

60. Saccadic intrusion with normal inter-saccadic
interval
Square wave kerks
Macro- square wave kerks
Macrosaccadic oscillation

61. Saccadic intrusion without normal
inter-saccadic interval
 Ocular flutter- Burst of small amplitude, high
frequency, horizontal movements
 Opsoclonus (saccadomania) – multidirectional
eye movements, high frequency, high amplitude

62. Saccadic intrusion without normal inter-saccadic interval
Ocular flutter/Opsoconus
Etiology –
• Unknown in healthy individuals
• Omnipause neurons of pons
• Neuroblastoma
• Small cell carcinoma of lung
• Cancer of breast and ovaries
• Multiple sclerosis, brainstem encephalitis

63. Ocular bobbing
 Characterized by rapid downward movement of
both eyes
 Followed by slow drift back to midline
 Causes:
• Comatose patients with massive pontine lesion
• Metabolic encephalopathy

64. Superior oblique myokymia
 Defined as high frequency oblique oscillation of one
eye due to intermittent firing of the superior oblique
muscle
 Produces oscillopsia or intermittent vertical diplopia
 Very small amplitude observed in slit lamp

65. Superior oblique myokymia
 Usually benign
 No underlying etiology is found
 Neuroimaging : r/o post fossa tumors
 Refractory cases:
• Carbamazepine
• Surgical weakning of the superior oblique muscle can be
performed

66. Treatment
Nonsurgical : non neurological causes
 Optical devices
• Glasses: High minus lenses stimulate accommodative
convergence and thus dampens nystagmus
• Contact lenses: helpful in high refractive errors by
giving good visual stimulus for fusional control

67. Nonsurgical : non neurological causes
 Prisms :
1. To induce fusional convergence by using 7 PD base
out prism in front of each eye
2. Pre op evaluation in a patient with face turn - prisms
are inserted with the apex in direction of gaze
Useful as a diagnostic trial ,but as a therapeutic
alternative are not helpful

68. Nonsurgical : non neurological causes
Occlusion therapy:
 Trials with conventional occlusion have been found
to be effective
 As amblyopia gets corrected and vision improves,
nystagmus finally decreases

69. Pharmacologic management
 The drugs hypothetically inhibit excitatory
neurotransmitters within CNS
1. Baclofen (GABAB receptor agonist) : congenital
nystagmus, seesaw nystagmus, periodic
alternating nystagmus
2. Carbamazepine: widely used for superior oblique
myokymia

70. Pharmacologic
denervation
 Botulinum toxin A act by blocking the
neuromuscular transmission
• 3 units of toxin is injected in each of the 4 horizontal
rectus muscles
• Single large dose of drug into the retrobulbar
space
• Effect last for only few months

71. Surgical
Based on 2 principles:
 To shift the null position if any to the primary position
 To reduce the amplitude of the nystagmus by
weakening the muscle force of all recti

72. Kestenbaum surgery
 Devised first surgical approach using recession-resection
of all four horizontal recti
 Advocated an equal amount of 5 mm for all recti
 Left face turn (null in dextroversion):
 Right eye: LR recession & MR resection
 Left eye : MR recession & LR resection

73. Anderson surgery
 Advocated only recessions
 Left face turn (null in dextroversion):
 Right eye : LR recession
 Left eye : MR recession

74. Parks surgery
 Recommended lesser amount of recessions and
resections for medial rectus surgery compared to
lateral rectus surgery
 Advocated a 5,6,7,8 plan
 MR recession : 5 mm
 MR resection : 6 mm
 LR recession : 7 mm
 LR resection : 8 mm

75. Summary
 Nystagmus- Slow defoveating drift followed by rapid
corrective saccade eye movement
 Physiological, childhood onset, pathological
 Abnormalities of cortical, subcortical and ocular
motor nuclei with vesibular nuclei and cerebellum
 Inability to maintain fixation, decreased fixation and
oscillopsia
 Saccadic intrusions- not ture nystagmus with lack of
slow component, rapid defoveating drift with fixation
intervals
 Medical, optical, surgical management may be
satisfactory in achieving null point

76. Bibliography
 American Academy of Ophthalmology. Neuro-
Ophthalmology. Section 5. 2013-2014
 Kanski Jack J. Clinical Ophthalmology: A
Systematic Approach. 7th ed. Elsevier;2013: 841-
846.
 Myron Yanoff & Jay Duker. Ophthalmology,3rd
edition,2008: 9:1040-1048.
 Khurana AK. Anatomy and physiology. 2nd ed.
New Delhi; rerinted 2010

77. Thank you