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Understanding Nystagmus: Understanding Nystagmus: Diagnosis, Diagnosis,

Related Disorders,Related Disorders,Treatment, andTreatment, and

ResearchResearch

MitraMitra MaybodiMaybodi, MD, MDChildren’s National Medical CenterChildren’s National Medical Center

George Washington University School of George Washington University School of Medicine and Health SciencesMedicine and Health Sciences

Washington, DCWashington, DC

NystagmusNystagmus

“All that wiggles is not nystagmus.”“All that wiggles is not nystagmus.”

DefinitionDefinition: Involuntary oscillation of the : Involuntary oscillation of the eyes, characterized by a slow phase, eyes, characterized by a slow phase, followed by a fast phase.followed by a fast phase.

Physiologic NystagmusPhysiologic Nystagmus

EndEnd--point point (eccentric(eccentric--gaze) gaze) nystagmusnystagmus

Physiologic NystagmusPhysiologic NystagmusVestibular NystagmusVestibular Nystagmus

Physiologic NystagmusPhysiologic Nystagmus

Optokinetic Nystagmus

InfantileInfantile--Onset Onset NystagmusNystagmus

Congenital nystagmusCongenital nystagmus(Infantile nystagmus syndrome*)(Infantile nystagmus syndrome*)Latent / manifest latent nystagmusLatent / manifest latent nystagmus((FusionalFusional maldevelopmentmaldevelopment nystagmus nystagmus syndrome*)syndrome*)SpasmusSpasmus nutansnutans((SpasmusSpasmus nutansnutans syndrome*)syndrome*)OthersOthers: congenital see: congenital see--saw, downbeat, saw, downbeat, upbeat, or familial vertical upbeat, or familial vertical pendularpendular

(*: Proposed by Classification of Eye Movement (*: Proposed by Classification of Eye Movement Abnormalities and Strabismus Working Group, NIH, 2001)Abnormalities and Strabismus Working Group, NIH, 2001)

Acquired NystagmusAcquired Nystagmus

SeeSee--saw nystagmussaw nystagmusPeriodic alternating nystagmusPeriodic alternating nystagmusDownbeat nystagmusDownbeat nystagmusUpbeat nystagmusUpbeat nystagmusGazeGaze--evoked nystagmusevoked nystagmusVestibular (central or peripheral) Vestibular (central or peripheral) nystagmusnystagmusOthers, including acquired Others, including acquired pendularpendular forms forms

VIDEOSVIDEOS

Congenital Nystagmus: Congenital Nystagmus: Related DisordersRelated Disorders

AmblyopiaAmblyopia: poor vision caused by : poor vision caused by abnormal visual development, abnormal visual development, due to abnormal visual due to abnormal visual stimulationstimulationSusceptible ages: birth to 7 or 8 Susceptible ages: birth to 7 or 8 yearsyears

Congenital Nystagmus: Congenital Nystagmus: Related Related Disorders

Strabismus


Albinism


Optic Nerve Hypoplasia


Aniridia

Rods&

Cones

Congenital Nystagmus:

Related Disorders

Retinal Dystrophies

RodCone

Peter’s Anomaly—Congenital Corneal Opacity

Congenital Nystagmus:Related Disorders

Congenital CataractsCongenital Nystagmus:Related Disorders

Latent / Manifest Latent Latent / Manifest Latent Nystagmus: Nystagmus:

Related DisordersRelated Disorders

Any eye condition that affects normal Any eye condition that affects normal development of “fusion,” usually by development of “fusion,” usually by affecting vision in at least one eyeaffecting vision in at least one eyeAmblyopiaAmblyopia: poor vision caused by : poor vision caused by abnormal visual development, due to abnormal visual development, due to abnormal visual stimulationabnormal visual stimulation–– Susceptible ages: birth to 7 or 8 yearsSusceptible ages: birth to 7 or 8 years

Latent / Manifest Latent Latent / Manifest Latent Nystagmus: Nystagmus:

Related Related DisordersStrabismus

Congenital Cataracts

Latent/Manifest Latent Nystagmus:Related Disorders

Déjà vu? Yes, there isconsiderable overlap!

Peter’s Anomaly—Congenital Corneal Opacity

Latent/Manifest Latent Nystagmus:Related Disorders

SpasmusSpasmus NutansNutans: : Related DisordersRelated Disorders

StrabismusStrabismusAmblyopiaAmblyopiaIn In spasmusspasmus nutansnutans--like disease: like disease: brain abnormalitiesbrain abnormalities

DiagnosisDiagnosis

HistoryHistory–– OnsetOnset–– SymptomsSymptoms

LightLight--sensitivitysensitivityDifficulty in darknessDifficulty in darknessOscillopsiaOscillopsia (sensation of the world (sensation of the world shaking or moving)shaking or moving)Dizziness, etc.Dizziness, etc.

Diagnosis (cont.)Diagnosis (cont.)

Eye examEye examEye movement recordingsEye movement recordings–– To verify type of nystagmusTo verify type of nystagmus–– To characterize details, such as To characterize details, such as

convergenceconvergence--damping, null position, damping, null position, etc.etc.

–– To determine best treatment optionsTo determine best treatment options

Eye Movement Recording

Infrared Oculography

Magnetic Search Coil

Congenital Nystagmus:Congenital Nystagmus:WaveformsWaveforms

Latent / Manifest Latent Nystagmus:Waveforms

Spasmus Nutans:Waveform


ElectoretinographyElectoretinography (ERG):(ERG): for diagnosis for diagnosis of retinal dystrophies in particular (cone of retinal dystrophies in particular (cone and/or rod dystrophies)and/or rod dystrophies)


NeuroimagingNeuroimaging: MRI or CT scan: MRI or CT scan——including:including:–– For acquired nystagmusFor acquired nystagmus–– For any nystagmus with other For any nystagmus with other

associated associated neurologicneurologic abnomalitiesabnomalities

Other testsOther tests

Treatment: Treatment: Optical Correction/AidsOptical Correction/Aids

Glasses, including with tints, prismsGlasses, including with tints, prismsContact lensesContact lensesLow vision aidsLow vision aids

File: /ejf/dlr/ejf/recordings/mitra/11_27_02/BR/BR23.d_OShor

Time

Position

Red: without prismsGreen: with prisms

Effect of Prisms on CN

Treatment:Treatment:SomatosensorySomatosensory StimuliStimuli

Contact lenses, soft or rigid gas permeable Contact lenses, soft or rigid gas permeable Neck / face electrical stimulation or Neck / face electrical stimulation or vibration*vibration*Acupuncture*Acupuncture**Problem: practicality*Problem: practicality(*DISCLAIMER: The presenter does not necessarily promote (*DISCLAIMER: The presenter does not necessarily promote these treatments.)these treatments.)

Treatment:Treatment:MedicationsMedications

Congenital periodic alternating Congenital periodic alternating nystagmus: nystagmus: –– BaclofenBaclofen (not as useful as for (not as useful as for acquired acquired

periodic alternating nystagmus)periodic alternating nystagmus)

PendularPendular nystagmus, in multiple nystagmus, in multiple sclerosis:sclerosis:–– GabapentinGabapentin–– MemantineMemantine

Retrobulbar Space

Botox InjectionTreatment:Medications (cont.)

Treatment:Treatment:Medications (cont.)Medications (cont.)

BotoxBotox injection into orbitinjection into orbitDisadvantages: Disadvantages: –– Possible Possible droopy eyeliddroopy eyelid (“(“ptosisptosis”)”)–– Possible Possible double visiondouble vision–– Wears off in about 8 weeks, Wears off in about 8 weeks,

requiring repeated injectionsrequiring repeated injections

Treatment:Treatment:SurgerySurgery

StrabismusStrabismus correctioncorrection


Head postureHead posture correction (e.g. correction (e.g. AndersonAnderson--KestenbaumKestenbaum procedure)procedure)


Improvement of Improvement of visionvision–– Artificial divergence surgeryArtificial divergence surgery–– AndersonAnderson--KestenbaumKestenbaum–– Combined artificial divergence and Combined artificial divergence and

AndersonAnderson--KestenbaumKestenbaum

Eye Muscle SurgerySite of disinsertion

during surgery

Eye Muscle Surgery

Eye Muscle (hooked and sutured)

Suture

Suture

Nose

Forehead

New Research:New Research:Congenital NystagmusCongenital Nystagmus

Underlying causeUnderlying cause——proposed: proposed: –– Lack of normal visual motion during a Lack of normal visual motion during a

critical period of development in critical period of development in infancyinfancy

–– Possible abnormal Possible abnormal proprioceptionproprioception(sensation of position)(sensation of position)


Diagnosis of waveformsDiagnosis of waveforms is possible in is possible in infancy: 6 months of age or lessinfancy: 6 months of age or lessCorrelation with visionCorrelation with vision


OscillopsiaOscillopsia (=sensation / perception of (=sensation / perception of world moving / shaking)world moving / shaking)–– A debilitating problem in very few A debilitating problem in very few

congenital nystagmus patientscongenital nystagmus patients–– Associated with Associated with decompensateddecompensated motor or motor or

sensory status (e.g. strabismus, retinal sensory status (e.g. strabismus, retinal dystrophy)dystrophy)

–– May be helped with treatment for the May be helped with treatment for the underlying causeunderlying cause


Refractive errorsRefractive errors (i.e. astigmatism, far(i.e. astigmatism, far--sightedness, nearsightedness, near--sightedness)sightedness)–– Wider range in CN / albinism Wider range in CN / albinism

patientspatients–– CN / albinism patients with CN / albinism patients with

refractive errors have less tendency refractive errors have less tendency to progress toward “to progress toward “emmetropiaemmetropia” ” (no refractive error)(no refractive error)


TorsionalTorsional componentcomponent of CNof CN–– Does not significantly affect vision in Does not significantly affect vision in

the null positionthe null position–– Generated centrally (in brain), as Generated centrally (in brain), as

opposed to peripherally (in eye opposed to peripherally (in eye muscles)muscles)

New Research:New Research:Congenital Congenital NystagmusNystagmus

Psychophysical testsPsychophysical tests–– Orientation thresholds:Orientation thresholds:

Lines of different orientations and Lines of different orientations and differing lengths presented for differing differing lengths presented for differing periods of timeperiods of timeCN patients require more time to CN patients require more time to recognize the orientationsrecognize the orientationsCN patients have a harder time with CN patients have a harder time with vertical lines than horizontal linesvertical lines than horizontal lines

Control Patient

Plasma Screen

New New Research:Research:Congenital Congenital NystagmusNystagmus

PsychoPsycho--physical physical teststests

••Latency of Latency of optotypeoptotyperecognitionrecognition

“Static Task:”

500 msec

500 msec

2000 msec

Gaze angles:

5-22o in R or L gaze

At or above visual acuity, CN patients required more time to recognize the “E” than controls

500 msec

2000 msec

“Dynamic Task:”

Stimulus velocities:

10-30o/sec to R or L

At or above visual acuity, CN patients required more time to recognize the “E”than controls


NeuroanatomicNeuroanatomic studystudy of the of the muscle/eye junction (“muscle/eye junction (“enthesisenthesis”)”)–– Differences compared to patients without Differences compared to patients without

nystagmusnystagmus

Enthesial Area

CONTROL HUMAN ENTHESIS

Axon

Myelin

2u

2u

500u

Nerve Ending

Capillary

INS IDIOPATHIC 18 Mos M

Unmylinated Nerve Ending

500u

100u

500u

500u Nerve Endings c Dilated RER

Nerve Endings c Dilated RER

Fragmented Neurolemma


NeuroanatomicNeuroanatomic studystudy of the of the muscle/eye junction (“muscle/eye junction (“enthesisenthesis”)”)–– Suggests a possible role for abnormal Suggests a possible role for abnormal

proprioceptionproprioception (sensation of position) as (sensation of position) as cause of diseasecause of disease


Medication Medication effect:effect:–– One adult CN patient improved with diet pill*One adult CN patient improved with diet pill*–– One child with CN improved with ADHD pill*One child with CN improved with ADHD pill*–– Medications improved vision, strabismus, and Medications improved vision, strabismus, and

depth perception, despite depth perception, despite increased increased nystagmusnystagmusintensityintensity

–– Likely reason: Likely reason: more more foveationsfoveations per secondper second

*These drugs may carry serious side effects and*These drugs may carry serious side effects and have NOT have NOT undergone clinical trial for treatment of undergone clinical trial for treatment of nystagmusnystagmus..


Surgical treatmentsSurgical treatments1. 1. Horizontal Horizontal rectusrectus tenotomytenotomy study in study in

humanshumans (NIH study)(NIH study)–– Improved visual acuity in the childrenImproved visual acuity in the children–– Improved vision subjectively in adultsImproved vision subjectively in adults

(To be published soon(To be published soon——stay tuned…)stay tuned…)

New Research:New Research:Congenital Congenital NystagmusNystagmusSurgical treatmentsSurgical treatments

2.2. LASIKLASIK (laser(laser--assisted in situ assisted in situ keratomileusiskeratomileusis, , refractive surgery)refractive surgery)

–– In 47 In 47 y.oy.o. woman with CN. woman with CNModerate amplitude and frequencyModerate amplitude and frequencyConvergenceConvergence--dampingdampingNo eccentricNo eccentric--gaze nullgaze null

–– After 2 treatments with pupilAfter 2 treatments with pupil--tracking laser tracking laser system:system:

20/40 each eye pre20/40 each eye pre--op with glassesop with glasses20/40 each eye post20/40 each eye post--op without glassesop without glasses

Cornea

Anteriorchamber

Pupil

Iris

Cornea


Surgical Treatment:Surgical Treatment:LASIKLASIK

CorneaCornea

New New Research:Research:Congenital Congenital NystagmusNystagmus

Surgical Surgical Treatment:Treatment:LASIKLASIK

Corneal Flap

Laser appliedto the stroma

Corneal Flap


LASIK for CN (INS) patient??? Only if:LASIK for CN (INS) patient??? Only if:–– ConvergenceConvergence--damping damping nystagmusnystagmus–– No eccentric nullNo eccentric null--pointpoint–– Smaller Smaller nystagmusnystagmus frequencies and frequencies and

amplitudesamplitudes–– Experienced surgeonExperienced surgeon–– Advanced pupilAdvanced pupil--tracking laser systemstracking laser systems–– With full knowledge of the patient about With full knowledge of the patient about

problemsproblems with eccentric ablation zones, with eccentric ablation zones, including monocular including monocular diplopiadiplopia, glare, halos, , glare, halos, and other debilitating symptoms and other debilitating symptoms

New Research:New Research:Acquired Acquired NystagmusNystagmus

Localizing defects in the brainLocalizing defects in the brainOptical treatmentOptical treatment: an electro: an electro--optic optic device, for device, for pendularpendular nystagmusnystagmus, e.g. , e.g. in multiple sclerosisin multiple sclerosisMedicationsMedications, e.g. in multiple sclerosis, , e.g. in multiple sclerosis, periodic alternating periodic alternating nystagmusnystagmus

Thank you for your attention

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