This document summarizes various disorders of spontaneous ocular movements. It describes the different types of eye movements including saccades, smooth pursuit, vestibular-ocular reflex, vergence, and optokinetic reflex. It discusses disorders that can affect eye movements at the supranuclear, internuclear, and infranuclear levels. Specific disorders covered include internuclear ophthalmoplegia, gaze palsies, nystagmus, saccadic intrusions, myasthenia gravis, and third nerve palsy. Causes, clinical features, and localization of various ocular motility disorders are provided.

1. • DISORDERS OF SPONTANEOUS OCULAR MOVEMENTS.
DR.DEVASHISH GUPTA

2. Need for eye movements
• Binocular vision: need to align the eye axis and move the eyes together.
• Development of foveal position (tubular) :need to make rapid eye movements
for multiple fixation.
Saccades, vergences.
• Need for retinal stability during period of fixations : (slow) stabilisation of eye
movements
Smooth pursuit
Vestibulo -ocular reflex.

3. • Extraocular muscles are supplied by 3rd 4th 6th cranial nerves which
have their nuclei in the brainstem.
• Supranuclear
• Internuclear
• Infranuclear.

4. The eyes move in six ways
Fast eye movements :
1. Saccades
2. Nystagmus
Slow eye movements :
1. Smooth pursuit
2. Optokinetic
3. Vestibular
4. vergence

5. Saccades
• Redirect eyes from one target to another.
• Voluntary or reflex(in response to visual, auditory or pain stimulus).
• Always conjugate.
• Ballistic.
• SPEED-slowing of saccades can be seen in AIDS Dementia complex, lipid storage
disorders,PSP
• SMOOTHNESS- Cerebellar diseases.
• Accuracy- Cerebellar diseases.

8. Smooth Pursuit
• slow eye movements that permits the eyes to conjugately follow /track a target
during movements of the target or observer or both
• Have the capacity for compensation unlike saccades.
• Initiated by a slow moving target.
• Visual fixation holds the image of a stationary object on the fovea.

11. Vestibular reflex
• Coordinates eye movements with head movements, holds images steady during
brief head rotations.
• Stimulation of ampulla of horizontal semicircular canal leads to conjugate
movement towards contralateral side.
• Anterior and posterior circular canals – combination of vertical & torsional eye
movements.
• Examination- patient is asked to fix on a target while examiner rotates the head.

12. Optokinetic reflex
• Conjugate nystagmus induced by a succession of moving visual stimuli.
• Stimulus- sustained head rotation.
• Prevents a constant blur from relative motion of the moving visual field.
• Significance:
• The slow phases of the OKN are generated as the patient follows a target.
• The OKN fast phase is a corrective saccade to view the next target.
• The OKN response is involuntary and is difficult to suppress.

15. • An intact OKN response confirms that visual acuity is at least 20/400.
• vision of infants and very young children as well as patients suspected of nonorganic visual
loss.
• Infants – 4 to 6 months of age.
• Testing the OKN is also helpful to elicit subtle adduction weakness in internuclear
ophthalmoplegia.
• Helps in differentiating between parietal and occipital lobe lesions.
• Occipital lobe lesions –OKN is intact.
• Parietal lobe lesions- Blunt OKN.
• OKN abnormalities may be seen in early PSP.

16. SUPRANUCLEAR DISORDERS
• Affects both eyes.
• Don’t produce diplopia.
• Dolls eye phenomenon remain intact.

17. Internuclear ophthalmoplegia
• Lesion of the MLF.
• Failure of the medial rectus to adduct is an isolated abnormality in the affected
eye .
• normality of the lid & pupil distinguish an INO from a 3rd cranial nerve palsy.
• Earliest sign- slowness of adducting saccades compared to the abducting
saccades , demonstrated by Rapid refixations or OKN.
• Bilateral INO – wall-eyed bilateral INO syndrome.( WEBINO).

18. Gaze palsies and gaze deviations
• The frontal eye fields move the eyes into contralateral conjugate horizontal gaze.
• The eyes normally remain straight ahead because of a balance of input from the
FEFs in each hemisphere.
• Seizure activity in one frontal lobe drives the eyes contralaterally.
• Sustained eye deviation can be a manifestation (rarely the only manifestation)
of seizure activity , even of status epilepticus.
• Frontal lobe lesions – gaze palsy.
• PPRF-final common pathway for horizontal gaze and pontine gaze palsies.
• Affects function –voluntary & reflex.

19. • Frontal lobe lesions- gaze away from the side of hemiparesis.
• Pontine stroke – towards the side of hemiparesis.
• Case scenario: A 55 yr old male with headache , acute onset swaying to either
side and inability to look to either side.
• Past h/o htn (poor compliance). Elevated BP on admission.
• Findings- B/L horizontal gaze palsy , preserved vertical eye movements.
• Plantar B/L extensor.
• Reflex horizontal gaze was absent.
• Localization :?????

20. One & a half syndrome
• Most common causes- infarction & demyelination.
• The MLF fibers arising from the CN 6 nucleus decussate just after their origin &
run in close proximity to the PPRF & 6th cranial nerve nucleus on the opposite
side.
• Medial pontine lesion – PPRF on one side & MLF on the contralateral side.
• Example : right pontine lesion
Right gaze palsy with superimposed INO.
The only movement possible is the abduction of the left eye.

21. Vertical gaze abnormalities
• Parinauds syndrome :
• Core feature : impaired upward gaze.
• Convergence-retraction nystagmus.
• It appears readily during forced upward saccades in response to a downward
moving OKN tape.
• Pinealoma.
• “Setting sun sign”

23. • Progressive supranuclear palsy
Degenerative changes in the rostral brainstem & thalamus results in impairment
first of downgaze , then of upgaze & eventually in global paresis.

24. Skew deviation

25. • Skew deviation - acquired vertical misalignment of the eyes resulting from
asymmetric disruption of supranuclear input from the otolithic organs.
• Acute brainstem/cerebellar dysfunction
Patients complain of vertical diplopia.
• What test can help differentiate a 4th nerve palsy from skew deviation?
The upright-supine test helps differentiate a skew deviation from trochlear
nerve palsy:
• a vertical deviation that decreases by ≥50% from the upright to supine position
suggests a skew deviation.
• What is the ocular tilt reaction?
A combination of:
1. Skew
2. Ocular torsion (both eyes are tilted toward the hypotropic eye)
3. Head tilt (toward the hypotropic eye).

27. Nystagmus & other ocular oscillations
• A rhythmic , biphasic , involuntary movement of the eyes.
• Pendular nystagmus : both phases of equal amplitude & velocity.
• Jerk :a fast phase & slow phase.
• Central vs peripheral
• Physiologic vs pathologic.
• Congenital or acquired.

31. Central vestibular nystagmus
Damage to the vestibular nuclei or their connections with the ocular motor nuclei.
Since the vestibular, optokinetic & pursuit systems all converge on a common final
pathway through the vestibular nuclei, they are all impaired.
Cant be suppressed by the fixation maintenance system.
• Downbeat nystagmus
• Upbeat nystagmus
• Convergence retraction
• Periodic alternating

32. Downbeat nystagmus
• fast phases are downwards.
• Arnold chiari malformation
• Basilar invagination
• Foramen magnum tumor
• S.C.A
• MRI – foramen magnum region (sagittal plane ) investigation of choice.
• Rx – treat the underlying cause.
• Clonazepam , 4- aminopyridine & chlorzoxazone.

34. Upbeat nystagmus
• Up-beating nystagmus in primary upgaze.
• The amplitude & intensity of nystagmus increases on upgaze.
• S/O – B/L paramedian lesions of the brainstem usually at the ponto-medullary
junction.
• Rx- baclofen , gabapentin and 4- aminopyridine .
• Periodic alternating nystagmus:
• A horizontal jerk nystagmus in which the fast phase beats in one direction &
• Then stops / damps for a few seconds before changing direction to the
opposite side.
• localization- cerebellar nodulus and uvula.
• Episodic PAN can be a manifestation of a seizure.
• Rx: Baclofen & dextroamphetamine.

36. Gaze evoked nystagmus
• Aka direction changing nystagmus/ gaze paretic nystagmus.
• GEN is an appropriate term : if nystagmus is physiological or pathological.
• Gaze paretic nystagmus implies pathology.
• Most common type of nystagmus ,is usually symmetrical & evoked by eccentric
gaze to either side but absent in primary position.
• In myasthenia , fatigue of gaze maintenance with drifts of the eyes towards
primary position & resetting saccades may mimic the appearance of gaze paretic
nystagmus.

37. Saccadic intrusions
• Brief , unwanted saccadic interruptions of fixation.
1. With intersaccadic interval :
A. Square wave jerks: small –amplitude paired saccades.
• Intersaccadic interval of 150 to 200 ms that briefly interrupt fixation.
• About 2 degrees in amplitude.
• Non dopa responsive variants of parkinsonism.
• Supratentorial origin.
B. Square- wave pulses: aka macro-square wave jerks
• 40 to 80 degrees.
• Latencies of 80ms
• Olivopontocerebellar degeneration & Ms.

39. C. Macrosquare wave oscillations:
Horizontal saccades with intersaccadic intervals > SWJs &
oscillate about the midline of fixation with a crescendo-decrescendo pattern.
Cerebellar disease- caudal fastigial nucleus.

40. Without intersaccadic interval
• Ocular flutter: by definition, occurs only in the horizontal plane.
• Opsolconus : horizontal, vertical & torsional categories.
• Both are precipitated by gaze shifts, rarely they are triggered by a change in
posture.
• Causes:
• HIV-Brainstem encephalitis or Lymphoma.
• Celiac disease
• Encephalitis (viral or pyogenic).
• Thalamic glioma , thalamic hemorrhage.
• Wernickes encephalopathy.
• Transient phenomenon in neonates.

42. Infranuclear disorders of ocular motility
• Orbital disease
• Muscle disease
• Neuromuscular transmission disorders
• Individual nerve palsies

43. Orbital disease
• Masses within the orbit may mechanically inhibit movement of the globe .
• EOMs – trapped in case of blow out fracture.
• Ex. Inferior rectus- limitation of upward gaze & vertical diplopia.
• Mechanically limited eye excursions exist for passive as well as active
movements.

44. Muscle disease
• Two categories: myopathies & restrictive orbitopathies.
• Thyroid eye disease – most common restrictive orbitopathy.
• Inferior rectus most commonly involved .
• Ocular myopathies : weakness of EOMs , with ptosis & weakness of eye closure
Because of myopathic weakness of facial muscles.

45. Neuromuscular transmission disorders
• Ocular involvement – 50 to 70% of patients & it eventually develops in 90%.
• Presents with ptosis or diplopia or both.
• Slowing of saccadic movement on rapid refixation – earliest sign of ocular MG.
• Can present as ophthalmoparesis without ptosis.
• Can cause weakness of any isolated muscle & should be considered in the
differential diagnosis
when ophthalmoparesis doesn’t fit any particular pattern.

46. Oculomotor nerve palsy
• Ischemic lesions usually spare pupillary function.
• Uncal herniation & posterior communicating artery aneurysm cause 3rd CN palsy
with pupil involved.
• Aberrant regeneration of 3rd CN:
• Fibers that originally innervate the medial rectus may reinnervate the LPS.
• Misdirection syndrome – 3months after the inciting event.
• Doesn’t occur after ischemic or idiopathic 3rd CN palsy.
• Attempted upgaze causes adduction & retraction because of misdirection of
Superior rectus fibers to the medial & inferior rectus with co-contraction.
The lid retracts on adduction – synkinesis between medial rectus & the levator
muscles.

47. • Central subcaudal nucleus- B/L Ptosis.
• Conversely ,patients with midbrain disease may have a lid-sparing 3rd CN palsy
if the central caudal nucleus is not involved.
• Most pressing diagnostic consideration in an isolated 3rd CN palsy- PCOM
aneurysm / Basilar artery aneurysm.
• Microvascular ischemic 3rd CN palsy- begin to resolve about 2 months .
• Superior division of 3rd nerve- ptosis & impaired upgaze.
• Inferior division- medial & inferior rectus weakness & pupillary dysfunction .

48. References
• Dejongs the neurologic examination.
• Bradley & Daroffs Neurology In Clinical Practice.
• Brazis Localization in Clinical Neurology.