NYSTAGMUS

1. NYSTAGMUS Assist.Prof. Dr.Vildan Öztürk Ophthalmology Yeditepe University Hospital

2. Definition Nystagmus 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 - coarse moderate - high

3. Classification 1-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

7. Physiological Nystagmus 1- Endpoint nystagmus: fine jerk nystagmus when eyes are in extreme positions of gaze

8. Physiological Nystagmus 2-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

10. Physiological Nystagmus 3- 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)

11. Congenital forms of nystagmus • Infantilenystagmus • Latentnystagmus • Nystagmusblockagesyndrome

12. Infantile nystagmus • Inheritance XLR or AD • Onset at age of 2-3 months, wide swinging eye horizontal movements • At age of 4 months, small pendular movements are added • At age 6-12 months, jerk nystagmus and null point develops • Compensatory head nodding develops • It may be dampened by convergence and is not present during sleep

13. Infantile nystagmus Etiology • Idiopathic • Albinism • Aniridia • Leber’s congenital amaurosis

14. Infantile nystagmus • Differential diagnosis • Opsoclonus • 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: worsenswhen one eye is closed • Nystagmus blockage syndrome:strabismus with eyes and head in a position to minimize associated nystagmus

15. Infantile nystagmus • Workup 1- History 2- Ocularexamination 3- CT and MRI to rule out organicpathology

16. Congenital forms of nystagmus • Infantile nystagmus • Latent nystagmus • Nystagmus blockage syndrome

17. Latent nystagmus • Dissappears when both eyes are open • Horizontal nystagmus, when the other eye is covered • Associated with infantile esotropia and dissociated vertical deviation • Fast phase in direction of fixating eye • For testing visual acuity, fogging rather than occluding the opposite eye

18. Congenital forms of nystagmus • Infantile nystagmus • Latent nystagmus • Nystagmus blockage syndrome

19. Nystagmus blockage syndrome Any nystagmus that; • decreases when the fixating eye is in adduction • demonstrates an esotropia to dampen the nystagmus.

20. Congenital forms of nystagmus • Treatment 1-Maximize vision by refraction 2-Treat amblyopia 3-If small face turn; prescription of prism in glasses 4-If large face turn; muscle surgery

21. Acquired forms of nystagmus • Etiology • Visual loss( cataract, cone dystrophy) • Toxic- metabolic ( alcohol intoxication, barbiturates, lithium, salicylates, other antikonvulsants and seadtives) • CNS disorders ( thalamic hemorrage, tumor, stroke, trauma, MS)

22. Nystagmus with localizingneuroanatomicsignificance 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

23. 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)

24. Upbeatnystagmus • Vertical, fastphasebeatingupwards • Posterior fossa lesions, drugs, Wernickeencephalopathy

25. Downbeat nystagmus • Vertical, fast phase beating downwards • Cervicomedullary junction lesions (Arnold-chiari malformation) • Drugs • Wernicke encephalopathy

26. Periodic alternating nystagmus • Jerknystagmuswithrythmicchanges in amplitudeand in direction, usuallyevery 2 minutes • Thecyclerepeatscontinuously • Cervicomedullaryjunctionlesions • Cerebellardisease • Demyelination • Trauma • Drugs

27. Rebound nystagmus • Triggered by changing direction of the gazes • The lesion involves the cerebellum

28. Gaze evoked nystagmus • Appears as the eyes look to the side • Alcohol intoxication, sedatives, cerebellar or brain stem disease

29. Vestibularnystagmus • Horizontal or horizontal rotatory nystagmus • May be accompanied by vertigo, tinnitus, deafness • due to dysfunction of vestibular endorgan, eighth cranial nerve

30. Differential Diagnosis • Superior 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

31. Workup • History: 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 examination • Eye movement recording • Visual field examination (bitemporal hemianopia/ see-saw) • Drug /toxin/dietary screen of the urine and serum • CT or MRI scanning

32. Treatment • Underlying etiology must be treated • Periodic alternating nystagmus may respond to baclofen. • Severe disabling nystagmus can be treated with retrobulber injections of botulinum toxin. • Correction with prismatic glasses, contact lenses • Orthoptic treatment • Surgery