1. TYPES AND CLINICAL FEATURES
NYSTAGMUS
AETIOPATHOGENESIS
TYPES AND CLINICAL FEATURES
SPEAKER : KUMAR SAURABH

2. HISTORICAL OVERVIEW Nystazho{Greek} Wobbly head movements
of a sleepy or inebriated
individual.

3. DEFINITIONS Nystagmus : Involuntary,biphasic,rhythmic ocular
oscillation which can be either physiological or pathological.
Pursuit : Slow and smooth movements of the eyes to follow a
moving target in the environment.
Saccade : Rapid jerky movement of the eyes to bring back the
image of the target on to the fovea. :

4. CLASSIFICATION AETIOLOGICAL CLASSIFICATION Nystagmus Physiological
End gaze
Optokinetic
Vestibulo-ocular reflex
Pathological
Acquired
Toxic
Neurological
Visual loss
Functional
Congenital
Infantile manifest
Infantile Latent
Infantile Manifest-latent

5. BASED ON MANIFESTATION
Latent
Manifest-latent
BASED ON PATTERN OF MOVEMENT
Jerk
Pendular
BASED ON DIRECTION OF MOVEMENT
Horizontal
Vertical
Rotary

6. SIX LEVELS OF OCULAR MOTOR SYSTEM
PATHOGENESIS OF NYSTAGMUS
SIX LEVELS OF OCULAR MOTOR SYSTEM 1.
UPPER MOTOR NEURON
(Cerebral cortex) 4.
CEREBELLUM 2.
PRE-MOTOR NEURONS
(Brain stem) 3.
LOWER MOTOR NEURON
(Ocular motor neuron,
Neuromascular junction) 5.
VESTIBULAR NUCLEUS 6.
EXTRAOCULAR MUSCLES

7. Lower Motor Neuron (Infranuclear)
Upper Motor Neuron Lesion (Supranuclear)
Nystagmus
Gaze palsy
Involuntary eye movements
Lower Motor Neuron (Infranuclear)
Paralytic strabismus

8. CORTICAL CENTRES FOR MOTOR CONTROL
PURSUIT
SACCADE
Occipital motor area
Middle temporal area (MT)
Middle superior temporal area (MST)
Frontal eye field (FEF)
Supplementary eye field (SEF)
Dorsolateral prefrontal cortex (DLPFC)
Posterior eye field (PEF)

9. BRAINSTEM CENTRES FOR MOTOR CONTROL (Saccade+Pursuit)
HORIZONTAL GAZE CENTRE VERTICAL GAZE CENTRE
ROSTRAL INTERSTITIAL
NUCLEUS OF
MEDIAL LONGITUDINAL
FASCICULUS (riMLF)
PARAMEDIAN PONTINE
RETICULAR FORMATION
(PPRF)

10. CLINICAL FEATURES GENERAL SYMPTOMS : GENERAL SIGNS :
To-and-fro Movement of Eyes.
Reduced Visual Acuity.
Blurred or Unstable Vision.
Oscillopsia : At >8 years of age.
GENERAL SIGNS :
Repetitive movements of eyes.
Binocular or monocular
Direction
Waveform
Effect of gaze
Conjugate or dysconjugate
Any change with change in posture.
Periodicity
Any associated movement.

11. JERK NYSTAGMUS Slow defoveating drift Fast refoveating saccade
Direction – Fast component
Horizontal,vertical or rotatory
Gaze evoked : Vestibular
Gaze paretic : Brain stem damage

12. PENDULAR NYSTAGMUS Sinusoidal,nonsaccadic Slow and equal velocities
Congenital or acquired
Horizontal,vertical,elliptical,torsional
Involvement of pontine tegmentum mainly
Special types :--

13. Horizontal in opposite direction Demyelinating disease
CONVERGENT-DIVERGENT NYSTAGMUS
Dysconjugate
Horizontal in opposite direction
Demyelinating disease
CYCLOVERGENT NYSTAGMUS
Torsional
Upper poles move in opposite direction.

14. PHYSIOLOGICAL NYSTAGMUS
END POINT NYSTAGMUS
Jerk nystagmus
On looking extreme lateral or upwards
Angle of gaze > 45 degrees

15. VESTIBULAR NYSTAGMUS Altered inputs from vestibular nuclei to PPRF
Jerk nystagmus
Altered inputs from vestibular nuclei to PPRF
Demonstrated by Caloric Test
Cold water – Opposite direction
Warm water – Same direction
Cold water in both ears – Upwards
Warm water in both ears -- Downwards

16. 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 the next target
Used for– Detecting malingerers
Testing visual acuity in young
Induced by moving a full visual field stimulus
Slow phase (Pursuit): Eye follows the target
Fast phase (Saccade): Eye fixates on the next target
Used for– Detecting malingerers
Testing visual acuity in young

17. PATHOLOGICAL NYSTAGMUS
UPBEAT NYSTAGMUS
Jerk nystagmus with fast phase upwards.
Defect : Anterior semicircular canal projections.
Lesion:Pontomedullary or pontomesencephalic
junctions.
Amplitude increases on upgaze and supine posture.
Causes : Wernicke’s encephalopathy,
Organophosphates and anticonvulsants,
Lithium,Nicotine,Thallium.

18. DOWNBEAT NYSTAGMUS Jerk nystagmus with fast phase downwards.
Defect : Posterior semicircular canal projections.
Lesion : Commissural fibers between vestibular nuclei.
Flocculus at the craniocervical junction.
Amplitude increases with lateral and downward gaze { Daroff's sign }
May be visible only with change of posture viz. head hanging.
Causes: Chiary malformation Type I,
Foramen magnum tumors,
Alcoholism,
Amiodarone,toluene,anticonvulsants
Magnesium depletion,
Vitamin B12 deficiency.

19. SEESAW NYSTAGMUS (SSN)
Pendular nystagmus.
One eye rises and intorts;other eye falls and extorts.
Lesion : Midbrain-thalamic junction.
Faster and smaller on upgaze;
Slower and larger on down gaze.
Ceases in darkness.
Acquired SSN: Suprasellar tumors,
Leigh’s syndrome,
Jobert’s syndrome
Congenital SSN : Achiasmia.

20. GAZE EVOKED NYSTAGMUS Jerk nystagmus. Absent in primary gaze.
Appears on eccentric gaze.
Fast phase in the direction of gaze.
3-8 beats/second ,coarse.
Defect in neural integrator.
Causes : Old age, Alcohol intoxication,
Cerebellar or brain stem disease,
Barbiturates.

21. GAZE PARETIC NYSTAGMUS
Jerk nystagmus.
Most common nystagmus.
Absent in primary position.
Appears on eccentric gaze.
Fast phase in the direction of gaze.
1-2 beats/second, symmetrical or asymmetrical.
Causes : Brain stem damage at pontine level.

22. PERIODIC ALTERNATING NYSTAGMUS
Horizontal jerk nystagmus.
Present in primary position.
Crescendo-decrescendo fashion.
During transition nystagmus stops or beats vertically.
= 180 seconds or 3 minutes (approximately).
May be congenital or acquired.
Lesion : Damage to the craniocervical junction.

23. REBOUND NYSTAGMUS Horizontal gaze evoked nystagmus.
Nystagmus beats transiently in opposite direction after return to primary position. ( 3 – 25 seconds ).

24. BRUN’S NYSTAGMUS EPISODIC NYSTAGMUS Jerk nystagmus.
Bilateral, asymmetrical.
On the side of lesion :Large amplitude,low frequency oscillations.
On the opposite side :Small amplitude,high frequency oscillations.
Cause : Large cerebello-pontine angle tumor.
EPISODIC NYSTAGMUS
Paroxysmal episodes of ataxia, vertigo and nystagmus.
Lasting up to 24 hours.
Causes :Inborn errors of metabolism
Basilar migraine
Multiple sclerosis

25. ICTAL NYSTAGMUS LID NYSTAGMUS Occurs during refractory seizures.
Mostly horizontal ; may be vertical.
Generally directed opposite to the site of epileptogenic focus.
LID NYSTAGMUS
Rhythmic jerky movements of the upper eye lid.
Conditions when lid nystagmus occurs:
Synchronous with vertical nystagmus
Synchronous with fast phase of gaze evoked nystagmus.
Midbrain tumors.
During voluntary convergence in cerebellar disease

26. CONGENITAL NYSTAGMUS Pendular or jerk type.
Pendular nystagmus often becomes jerk on lateral gaze.
Mostly horizontal,rarely vertical.
Increased amplitude on vertical tracking and distant fixation.
Decreased amplitude on convergence.
Increased amplitude when one eye is covered (Latent superimposition).
May be minimal at a particular point of gaze (Null zone).
Reversal of optokinetic response is characteristic.

27. FEATURES OF CONGENITAL NYSTAGMUS
Present at birth but may be detected later.
Good vision unless there is an afferent defect.
No oscillopsia.
Head titubation may be seen.
Causes :Autosomal recessive or X linked.
Achiasmia,
Achromatopsia,
Albinism,
Aniridia,
Congenital cataract
Retinopathy of prematurity,
Optic nerve hypoplasia.

28. MANIFEST LATENT NYSTAGMUS
MANIFEST NYSTAGMUS
Nystagmus present with binocular vision.
LATENT NYSTAGMUS
No nystagmus with binocular vision.
Nystagmus with monocular fixation with other eye covered.
Slow phase is directed towards covered eye.
Amplitude increases with abduction of fixating eye.
MANIFEST LATENT NYSTAGMUS
Nystagmus present with binocular vision.
Amplitude increases when one eye is covered.

29. SPASMUS NUTANS
Transient pendular nystagmus.
High frequency, low amplitude.
Horizontal, vertical or torsional.
Dysconjugate and asymmetrical.
May be monocular.
Spasmus Nutans Triad : Nystagmus, Torticollis, Titubation.
Onset : 6 – 12 months
Duration : Up to 2 years; maximum 5 years of age.
Causes : Glioma of anterior visual pathway
Empty sella syndrome
Porencephalic cyst.

30. NYSTAGMOID MOVEMENTS OCULAR FLUTTER
Horizontal and conjugate movements.
Intermittent bursts of back-to-back saccades.
Triggered by change of posture.
Aggravated by attempt at fixation.
Defect : Loss of pause cell inhibition of burst neurons at PPRF.

31. OPSOCLONUS Multivector saccadic eye movements.
Spontaneous, chaotic but conjugate movements.
Aggravated by attempt at fixation.
May be associated with myoclonic jerks of limbs
and cerebellar ataxia.
{ Dancing feet-dancing eye syndrome }
Cause :Viral encephalitis,
Multiple carboxylase deficiency,
Hyperosmolar coma,
Multiple sclerosis,
Neuroblastoma.

32. CONVERGENT RETRACTION NYSTAGMUS
Dysmetric horizontal eye movement upon attempted upward saccade.
Rapid convergence with retraction of both globes.
Followed by slow divergent movement.
Cause : Co-contraction of extraocular muscles.
Seen in : Dorsal midbrain ( Perinaud’s ) syndrome.

33. OCULAR BOBBING Rapid downward movement of both eyes.
Followed by slow drift back to primary position.
Seen in : Comatose patients.

34. OCULAR MYOCLONUS Vertical pendular oscillations. Frequency : 160 Hz.
Associated with similar oscillations of soft palate.
{ Oculopalatal syndrome }
Cause : Infarction at the pons.

35. VOLUNTARY NYSTAGMUS Ocular flutter under voluntary control.
Usually horizontal.
May be vertical, torsional or cycloid.
Patient converges to initiate the ‘nystagmus’.
Can be sustained up to 30 seconds.
Familial inheritance.

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