OPHTHALMOLOGY

1. NYSTAGMUS
By
Dr Alshymaa Moustafa
Ophthalmology Specialist

2. Introduction

3. • Nystagmus, oscillations, and saccadic intrusions are a group of involuntary
abnormalities of fixation.
• In nystagmus, there is an abnormal slow movement away from fixation that is
then corrected by a fast movement (jerk nystagmus) or by another slow
movement (pendular nystagmus).
• In oscillations and intrusions, there is an abnormal saccade away from
fixation, followed by a corrective saccade, i.e. both movements are fast.
• The corrective saccade may be immediate (oscillation) or delayed (intrusion).

4. Classification

5. • History: early or late onset; presence of oscillopsia.
• Abnormal movement away from fixation: slow or fast.
• Corrective movement: slow or fast.
• Direction: horizontal, vertical, or rotatory.
• Symmetry: conjugate or disconjugate.
• Effect on direction/ amplitude of: time, direction of gaze, fixation, head position.
• VA.
• Associated involuntary movements: palate, head, and neck.

6. Schematic for documenting nystagmus

7. Physiological Nystagmus
1. End point N.
2. OKN.
3. Vestibular N.
Infantile Nystagmus syndrome (INS)
1. Idiopathic infantile nystagmus (idiopathic congenital nystagmus)( motor , efferent(.
2. Infantile nystagmus associated with ocular or anterior visual pathway disease (sensory afferent deprivation).
3. Fusion maldevelopment nystagmus (latent/ manifest latent nystagmus).
Acquired Nystagmus
Acquired disconjugate Nystagmus
1. Acquired pendular .
2. SO myokymia
3. Internuclear ophthalmoplegia
4. See-saw nystagmus
Acquired conjugate Nystagmus
1. Gaze-evoked .
2. Periodic alternating .
3. Peripheral vestibular .
4. Central vestibular/cerebellar/brainstem.
Nystagmus
Spasmus Nutans
Pharmacological Nystagmus
1. Carbamazepine.
2. Lithium carbonate.
3. Phenytoin.
4. Amiodarone.
5. Morphine.
6. Fomepizole.
7. Ketamine abuse.
8. Nutmeg.

8. Physiological nystagmus

9. End-point nystagmus
is a fine jerk nystagmus of moderate frequency seen in extremes of gaze.
The fast phase is in the direction of gaze.

10. Optokinetic nystagmus (OKN)
is a jerk nystagmus induced by moving repetitive targets (e.g. OKN drum) across the visual field.
• The slow phase is a pursuit movement in which the eyes follow the target. The fast phase
is a saccadic movement in the opposite direction as the eyes fixate on the next target.
• If the OKN tape or drum is moved from right to left, the 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.
• OKN nystagmus is useful for detecting functional (nonphysiological) blindness and for
testing VA in the very young. It can be helpful in the assessment of an isolated homonymous
hemianopia.

11. Physiological nystagmus – end-point

12. Physiological vestibular nystagmus
• is a jerk nystagmus caused by altered input from the vestibular nuclei to the horizontal gaze
centres.
• The slow phase is initiated by the vestibular nuclei and the fast phase by the brainstem
and frontomesencephalic pathway.
• Vestibular nystagmus may be elicited by caloric stimulation as follows:
○ When cold water is poured into the right ear the patient will develop left jerk nystagmus (i.e.
fast phase to the left).
○ When warm water is poured into the right ear the patient will develop right jerk nystagmus
(i.e. fast phase to the right(.

13. • A useful mnemonic is ‘COWS’ (cold-opposite, warm-same) indicating the
direction of the nystagmus.
○ When cold water is poured into both ears simultaneously, a jerk nystagmus
with the fast phase upwards develops.
○ Warm water in both ears elicits nystagmus with the fast phase downwards
(cold ‘slows things down’).

14. Infantile nystagmus
syndrome (INS)

15. • Nystagmus with onset in infancy is not usually associated with oscillopsia;
however, a minority of patients do get oscillopsia, especially when
looking in the direction of greatest nystagmus.

16. Idiopathic infantile nystagmus
(idiopathic congenital nystagmus)
• Conjugate horizontal (usually) jerk nystagmus, worsens with fixation but improves
within ‘null zone’ and on convergence. The null zone is a direction of gaze in which
the nystagmus is damped down. On vertical eye movements the nystagmus remains
horizontal.
• It has a very early onset (usually by 2mo of age) and may initially be pendular.
• It can occasionally be vertical or rotatory.
• There is usually only mild dVA; strabismus is common.
• Up to 40% of INS are inherited (AD, AR, XL).

17. In primary and vertical gaze is pendular , but in horizontal
gaze is gaze evoked to Rt or to Lt.

18. Infantile nystagmus associated with ocular or anterior
visual pathway disease (sensory deprivation)
• Erratic waveform ± roving eye movements; moderate/ severe dVA due to
ocular or anterior visual pathway disease.
• Common ocular diseases associated include: cataract, albinism, CSNB, cone–
rod dystrophy, LCA, optic nerve hypoplasia.

19. Fusion maldevelopment nystagmus
(latent/ manifest latent nystagmus)
• 2° to poor fusion in infancy.
• Conjugate horizontal jerk nystagmus, with fast phase towards fixing eye, worsens
with occlusion of non- fixing eye and with gaze towards fast phase, but improves with
gaze towards slow phase.
• Null point in adduction.
• head turn typically towards the fixating eye.
• It alternates if opposite eye takes up fixation; often associated with infantile
esotropia.

20. Spasmus Nutans

21. • Spasmus nutans is an unusual acquired form of nystagmus that occurs in children typically
within the first 2y of life.
• It is a benign disorder, with ophthalmic and neurological assessment being directed to ruling out
more serious differential diagnoses.
• Clinical features
• Nystagmus (high frequency with small amplitude— shimmering). It may be horizontal, vertical, or
oblique. Unilateral or bilateral.
• head bobbing.
• Torticollis.

22. • Investigations
• MRI to exclude intracranial lesions.
• eDTs if retinal dystrophy is suspected.
• Prognosis
• Good, usually resolves by 3– 4y of life.
• Vision often normal.

23. Nystagmus is uniplanner , pendular,
equal amplitude in all directions.

24. Acquired Nystagmus

25. Acquired Conjugate Nystagmus

26. Gaze-evoked nystagmus
• Conjugate horizontal (usually) jerk nystagmus on eccentric gaze, with fast phase
towards direction of gaze; it occurs at smaller angles than physiological end- point
nystagmus, i.e. <45°.
• Asymmetric gaze- evoked :
usually indicates failure of ipsilateral neural integrator/ cerebellar dysfunction.
• Symmetric gaze- evoked :
may be due to CNS depression (fatigue, alcohol, anticonvulsants, barbiturates)or
structural pathology (e.g. brainstem, cerebellum).

27. Periodic alternating nystagmus
• Conjugate horizontal jerk nystagmus present in 1° position, with waxing– waning
nystagmus lasting for 90s in each direction, with a 10s gap or ‘null’ period.
• Periodic alternating nystagmus is usually due to vestibulocerebellar disease (e.g.
demyelination, Arnold– Chiari malformation).
• An alternating nystagmus without such regular periodicity may also be seen in
severe dVA.
• NB Periodic alternating nystagmus is easily missed if too brief an assessment of
the pattern of nystagmus is made.

28. Peripheral vestibular nystagmus
• Conjugate horizontal jerk nystagmus, improves with fixation and with time
since injury, worsens with gaze towards fast phase (Alexander’s law) or
change in head position.
• Nystagmus with fast phase away from the lesion is associated with
destructive lesions of the vestibular system (e.g. labyrinthitis, vestibular
neuritis), whereas nystagmus to the same side may be seen in irritative lesions
(e.g. Ménière’s disease).
• It may be associated with vertigo, deafness, or tinnitus.

30. Central vestibular/cerebellar/brainstem
nystagmus
• Conjugate jerk (usually) nystagmus that may be horizontal, vertical, or torsional and that does not
improve with fixation.
• Horizontal central vestibular nystagmus
is usually due to lesions of the vestibular nuclei, the cerebellum, or their connections.
• Upbeat nystagmus
in 1° position is usually due to cerebellar or lower brainstem pathology (e.g. demyelination,
infarction, tumour, encephalitis, Wernicke’s syndrome).
• Downbeat nystagmus
in 1° position is usually due to pathology of the craniocervical junction (e.g. Arnold– Chiari
malformation, spinocerebellar degenerations, infarction, tumour, demyelination) or drug- induced.

31. Down beat nystagmus

32. Up beat nystagmus

33. Acquired Disconjugate Nystagmus

34. Acquired pendular nystagmus
• Usually disconjugate with horizontal, vertical, and torsional components.
• It is associated with brainstem and cerebellar disease, including
toluene abuse.
• It may be associated with involuntary repetitive movement of the palate,
pharynx, and face (oculopalatal myoclonus).

35. SO Myokymia
• Unilateral high- frequency, low- amplitude torsional nystagmus.
• This movement is so small that it may only be detectable at the slit- lamp.
• May cause occasional diplopia.
• It is rarely associated with underlying disease, although it has been reported
after SO palsy, and associated with MS and pontine tumours.

37. Internuclear Ophthalmoplegia
• Nystagmus of the abducting (and occasionally adducting) eye.
• The mechanism is uncertain, possibly due to gaze paresis or ataxia.

38. See-saw nystagmus
• Vertical and torsional components, with one eye elevating and intorting while
the other depresses and extorts.
• It is usually a slow pendular waveform, although a jerk see- saw nystagmus
may also be seen.
• In the congenital form, the torsional element is reversed, i.e. the elevating eye
extorts.

39. Treatment

40. • Treatment is difficult and often disappointing.
• Treatment options depend on visual potential, presence of visual symptoms (oscillopsia), and the location
of a null position.
• Drug treatment includes GABA- ergics (e.g. gabapentin), anticholinergics (e.g. hyoscine), and memantine
(antiglutamatergic, antiserotonergic, and anticholinergic).
• Optical devices aim to stabilize (e.g. high plus spectacle lens with high minus CL) or optimize the null
position (e.g. prisms to move the null position towards p 1° position).
• Surgical procedures may generally stabilize (e.g. bilateral weakening procedures— usually only a transient
benefit) or move the null position and reduce the corrective head posture (horizontal, vertical, or torsional
Kestenbaum procedures).
• Retrobulbar botulinum toxin causes general dampening of ipsilateral nystagmus; however, it is associated
with ptosis, diplopia, and vertigo (hence may not be suitable for ambulatory patients).

41. Saccadic oscillations and
intrusions

42. • In oscillations and intrusions, there is an abnormal saccade away from
fixation, followed by a corrective saccade, i.e. both movements are fast.
• The corrective saccade may be immediate (oscillation) or delayed (intrusion).

43. Saccadic oscillations
• Ocular flutter
• Bursts of moderate- amplitude horizontal saccades without intersaccadic interval.
• It is associated with cerebellar and brainstem disease.
• Opsoclonus
• Bursts of large- amplitude multidirectional saccades without intersaccadic interval.
• It is associated with loss of pause cell activity that may be caused by viruses,
myoclonic encephalopathy, paraneoplastic syndromes (neuroblastoma in children,
small cell lung cancer in adults), and demyelination.

44. Saccadic intrusions
• Small, infrequent square- wave jerks may be physiological. however, other
intrusions are usually pathological, most commonly due to cerebellar disease.
• Square- wave jerks and macrosquare- wave jerks
horizontal 1– 5° (square wave) or 10– 40° (macro) excursions from fixation and
back again.
• Macrosaccadic
oscillations Series of hypermetric saccades attempting to narrow in on the target;
‘ocular past-pointing’.

45. Coma- associated eye movements
• Ocular bobbing
• Conjugate fast downward movements, with slow drift upward.
• Ocular bobbing may be caused by large lesions of the pons, metabolic encephalopathies, or hydrocephalus.
• Ocular dipping
• Conjugate slow downward movements, with fast saccade upward.
• This and other variants of ocular bobbing are fairly non- specific.
• Ping-pong gaze
• Conjugate horizontal movements, alternating side every few seconds.
• This is associated with bilateral cerebral hemispheric lesions.

46. Thanks