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

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

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

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

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

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)

Congenital forms of nystagmus Infantile nystagmus Latent nystagmus  Nystagmus blockage syndrome

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

Infantile nystagmus Etiology Idiopathic Albinism Aniridia Leber’s congenital amaurosis

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: worsens when one eye is closed Nystagmus blockage syndrome: strabismus with eyes and head in a position to minimize associated nystagmus

Infantile nystagmus Workup 1- History 2- Ocular examination 3- CT and MRI to rule out organic pathology

Congenital forms of nystagmus Infantile nystagmus Latent nystagmus  Nystagmus blockage syndrome

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

Congenital forms of nystagmus Infantile nystagmus Latent 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 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

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)

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 nystagmus Vertical, fast phase beating downwards Cervicomedullary junction lesions (Arnold-chiari malformation) Drugs Wernicke 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 disease Demyelination Trauma Drugs

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 nystagmus May be accompanied by vertigo, tinnitus, deafness due to dysfunction of vestibular endorgan, eighth cranial nerve

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

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

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