nystagmus

1. Nystagmus
la rythmic oscillation of the eyes. It has
many different patterns, and may arise in 3
situations
»Physiologically
»Sensory Deprivation
»Motor Imbalance

2. Classification
lNystagmus can be either:
»Jerk - fast one direction, slow the other
»Pendular - equal velocity in both directions
»Mixed - of above
lAnd can be
lHorizontal/Vertical/Oblique or Rotary
lIn overwhelming majority of cases both eyes move in a co-
ordinated manner

3. Classification
Pendular
jerk

4. Physiological Nystagmus
lnot due to a disease process
lHas no benefit, except as a diagnostic tool
lNot associated with reduced VA
lExamples include
»End point nystagmus
»Postrotational nystagmus
»Induced caloric testing
»Optokinetic nystagmus
»Voluntary nystagmus

5. Sensory deprivation
lDue to a defect in the neural control of fixation
lPoor macular function that cannot be restored and
therefore of little clinical significance
lTypically pendular and horizontal
lReduced by convergence and head posture
lIf a child loses vision before 2 yrs they will
invariably develop nystagmus
lAfter 6 yrs they do not
lIn between ??? Less predictable

6. Motor Imbalance
lCongential
lSpasmus Nutans
lLatent nystagmus
lAtaxic nystagmus
lDownbeat nystagmus
lUpbeat nystagmus
lConvergence retraction nystagmus
lSee-Saw nystagmus
lPeriodic alternating nystagmus

7. CONGENITAL NYSTAGMUS
ldue to a congenital anomaly of the motor
system or to a congenital disorder of vision
lInherited as X-link recessive or autosomal
dominant trait
lmay appear during early childhood but is
rarely present at birth.
lGenerally horizontal jerk type
lAbsent in sleep
lVisual impairment is variable

8. Spasmus Nutans
lNystagmus, involuntary head movements, AHP
lOnset 3-18 months of age
lFine rapid eye movements; jerky, small amplitude, high
frequency
lHorizontal, vertical or rotary, or a combination of these
lConsiderable variation in nystagmus in different positions
of gaze
lInvoluntary head movements comprising nodding or
shaking, or a combination of both; variable.

9. Spasmus Nutans
lHead movements do not appear to compensate for eye
movement as they are of a different frequency
lMost cases resolve spontaneously by age 3 years.
lBenign, but can be associated with CNS disease, therefore
should be investigated.

10. Latent Nystagmus
lHorizontal jerk nystagmus presents when the light
stimulus is reduced to either eye (eg by occluding).
lIn latent, no observable movement is present on
uncovering and full BSV is restored.
lJerk nystagmus with fast phase towards the
uncovered eye
lOften noted in early childhood but can be observed
in adults (especially if they have had strabismus
surgery or in DVD)

11. Ataxic Nystagmus
lOccurs in abducting eye in internuclear ophthalmoplegia

12. Downbeat Nystagmus
lHas a fast downward beat
lPathognomic of a brain lesion at the cervicomedullary
junction at the foramen magnum

13. Upbeat Nystagmus
lCommonly caused by drug intoxication (eg phenytoin -
used a san anticonvulsant)
lMay be associated with a brain lesion at the posterior fossa

14. Convergence Retraction
Nystagmus
lJerk nystagmus
lFast phase generating convergence and retraction of globe
into orbit
lUsually associated with brain lesion in the pretectal area

15. See-Saw nystagmus
lUsually an acquired motility disorder
associated with chiasmal lesions
lwhere one eye elevates and intorts followed
by depression and extorsion of the other eye
lMay be associated with a chiasmal lesion
(bitemporal hemianopia could be present)
lRare

16. Periodic Alternating nystagmus
lVery rare jerk nystagmus
lNystagmus changes amplitude and direction
lAssociated with vascular or demylinating
brainstem disease

17. Fundamental questions when you
see a Px with nystagmus
lWhat type
»May help provisional diagnosis
lHow long has it been present
»Recent = refer
lThe cause
lThe activity of the lesion
»Some may produce deficient inhibitory neural activity
leading to neurologic hypofunction other excessive
excitory neural activity - hyperfunction

18. lAny form of nystagmus which is of recent
onset requires fairly urgent referral for
an ophthalmic opinion and if necessary
further neurological investigation

19. Clinical procedure for
nystagmus cases
lClose questioning as to the onset of the nystagmus, family
history, general health, medication, history of CNS
disorders, associated symptoms (oscillopsia, vertigo,
unsteadiness and loss of vision all imply acquired forms)
lCarefully note the type of nystagmus, distance/near,
latency, AHP etc
lVA recorded uni- and binocularly, with and without AHP,
dist and near and compared
lFull ophthalmoscopic, slit-lamp (transillumination), and
binocular vision assessment