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NYSTAGMUS. Assist.Prof. Dr.Vildan Öztürk Ophthalmology Yeditepe University Hospital. Definition. Nystagmus is a repetetive, involuntary oscillations of the eye. (defoveating-foveating ) Oscillations may be ; -vertical -horizontal -torsional -non-specific - PowerPoint PPT Presentation
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Assist.Prof. Dr.Vildan ÖztürkOphthalmology
Yeditepe University Hospital
NYSTAGMUS
DefinitionNystagmus is a repetetive, involuntary oscillations of the eye. (defoveating-foveating )
Oscillations may be ;-vertical-horizontal-torsional-non-specific
Described in fast component’s direction.
fine - coarsemoderate - high
Classification1-Jerk nystagmus: slow drift followed by a fast
corrective phase.-gaze evoked (ie. vestibuler )-gaze paretic (brainstem)
2-Pendular nystagmus-velocity equal in both directions-horizontal, vertical, oblique, rotatory
3-Mixed nystagmus-pendular in primary position, jerk on lateral gaze
Physiological Nystagmus1- Endpoint nystagmus: fine jerk nystagmus when eyes
are in extreme positions of gaze
Physiological Nystagmus2-Optokinetic nystagmus: jerk nystagmus induced by
repetitive stimuli across the visual field.
• Optokinetic drum, • slow phase is pursuit, fast is saccadic movement.• pursuit by parieto-occipital • saccadic by frontal
• detect malingerers and test children• determines the cause of homonymous hemianopia
Physiological Nystagmus3- Vestibular nystagmus:
Jerk nystagmus caused by altered input from the vestibular nuclei to the horizontal gaze centers.
- pursuit by vestibular nuclei - saccadic by brain stem- caloric stimulation test
(COWS = cold-opposite, warm-same)
Congenital forms of nystagmus
Infantile nystagmusLatent nystagmus
Nystagmus blockage syndrome
Infantile nystagmusInheritance XLR or ADOnset at age of 2-3 months, wide swinging eye
horizontal movementsAt age of 4 months, small pendular movements are
addedAt age 6-12 months, jerk nystagmus and null point
developsCompensatory head nodding developsIt may be dampened by convergence and is not
present during sleep
Infantile nystagmusEtiologyIdiopathicAlbinismAniridiaLeber’s congenital amaurosis
Infantile nystagmusDifferential diagnosisOpsoclonus
repetitive , irregular eye movements by cerebellar or brainstem disease
Spasmus nutans uni/bilateral, small amp. /high freq, head nodding, head turn with nystagmus, onset 3months- 18 months, resolves between 3 years of
age. Glioma of the optic chiasm needs to be ruled out
Latent nystagmus: worsens when one eye is closedNystagmus blockage syndrome:strabismus with eyes and
head in a position to minimize associated nystagmus
Infantile nystagmusWorkup
1- History2- Ocular examination
3- CT and MRI to rule out organic pathology
Congenital forms of nystagmus
Infantile nystagmusLatent nystagmus
Nystagmus blockage syndrome
Latent nystagmusDissappears when both eyes are openHorizontal nystagmus, when the other eye is covered Associated with infantile esotropia and dissociated
vertical deviationFast phase in direction of fixating eyeFor testing visual acuity, fogging rather than occluding
the opposite eye
Congenital forms of nystagmus
Infantile nystagmusLatent nystagmus
Nystagmus blockage syndrome
Nystagmus blockage syndrome
Any nystagmus that;
• decreases when the fixating eye is in adduction • demonstrates an esotropia to dampen the nystagmus.
Congenital forms of nystagmusTreatment 1-Maximize vision by refraction
2-Treat amblyopia 3-If small face turn; prescription of prism in glasses4-If large face turn; muscle surgery
Acquired forms of nystagmus
EtiologyVisual loss( cataract, cone dystrophy)Toxic- metabolic ( alcohol intoxication,
barbiturates, lithium, salicylates, other antikonvulsants and seadtives)
CNS disorders ( thalamic hemorrage, tumor, stroke, trauma, MS)
Nystagmus with localizing neuroanatomic significance
See-saw-pendular oscillation that consists of elevation and intorsion of one eye and depression and extorsion of the fellow eye that alternates every half cycle
-chiasmal and rostral midbrain lesions
Convergence-retraction nystagmus
Contraction of the extraocular muscles, particularly medial recti
Convergence-like movements accompanied by retraction of the globe into the orbit when the patient attemps to look up.
Pineal tumor Dorsal midbrain abnormality (vascular
accidents)
Upbeat nystagmus
Vertical, fast phase beating upwards
Posterior fossa lesions, drugs, Wernicke encephalopathy
Downbeat nystagmusVertical, fast phase beating downwards
Cervicomedullary junction lesions (Arnold-chiari malformation)
DrugsWernicke encephalopathy
Periodic alternating nystagmus
Jerk nystagmus with rythmic changes in amplitude and in direction, usually every 2 minutes
The cycle repeats continuously
Cervicomedullary junction lesions Cerebellar diseaseDemyelinationTraumaDrugs
Rebound nystagmus
Triggered by changing direction of the gazes
The lesion involves the cerebellum
Gaze evoked nystagmus
Appears as the eyes look to the side
Alcohol intoxication, sedatives, cerebellar or brain stem disease
Vestibular nystagmus
Horizontal or horizontal rotatory nystagmusMay be accompanied by vertigo, tinnitus,
deafness
due to dysfunction of vestibular endorgan, eighth cranial nerve
Differential DiagnosisSuperior oblique myokymia; small, unilateral,
vertical and torsional eye movements seen with a slit lamp, benign, resolves spontaneously, Trt. with carbamazepine
Opsoclonus: rapid, chaotic conjugate saccades, drug intoxication, tm or following infarction.
Myoclonus: pendular oscillation associated with contraction of non-ocular muscles (tongue, fascial muscles). Involves olive nucleus in medulla
WorkupHistory: strabismus or amblyopia in childhood,
drug or alcohol use, vertigo, episodes of weakness, numbness or decreased vision in the past?
Family history: albinism, nystagmus, eye disorder?Ocular examinationEye movement recordingVisual field examination (bitemporal hemianopia/
see-saw)Drug /toxin/dietary screen of the urine and serumCT or MRI scanning
TreatmentUnderlying etiology must be treatedPeriodic alternating nystagmus may respond to
baclofen.Severe disabling nystagmus can be treated with
retrobulber injections of botulinum toxin. Correction with prismatic glasses, contact lensesOrthoptic treatmentSurgery