A Simplified and Practical Approach to Nystagmus

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Dear Colleagues,

Until now, the diagnosis and management of nystagmus has been challenging and somewhat an enigma for most ophthalmologists.

However, the newer diagnostic methods (viz. video nystagmography, high resolution neuro imaging, electro physiological investigations and SD OCT) have improved our understanding about the motor abnormalities in nystagmus and the associated sensory defects. In the recent years the relentless efforts of Louis F. Del ‘Osso, Dr Richard Hertle, Dr Robert Reinecke and Dr Irene Gottlob  have resulted in an acceptable international classification, diagnostic protocols and treatment paradigms for Nystagmus. You will be pleasantly surprised when you will apply these diagnostic and treatment strategies and see the quality of vision of your patients with nystagmus improving.

It may be prudent to avoid the approach of neglect for the patients with nystagmus.

We can cleverly make use of multimodal treatment methods, each resulting in small improvements in the visual function collectively leading to a significant enhancement in the quality of life of the patient. 

This handout is a compilation of a

1)      Few lectures presented in the instruction course on Nystagmus at the Annual Conference of the All Indian Ophthalmological Society, 2014, Agra India

2)      My personal notes (tabular form) on nystagmus.

3)      Relevant medical literature of the Journal articles

 

A soft copy of the handout can also be downloaded from the link www.jyotirmay.com/nystagmus_handout_AIOC_ 2014 or you can send an email to me at drmihirkothari@gmail.com

Efforts are taken to include only “evidence” based literature which will help the clinicians to practice science based management of Nystagmus in hopefully a simplified manner!

Just a word…The handout to you is given in a file that contains a 3D logo of Jyotirmay eye clinic on the front. This logo can be utilised to assess presence or absence of near (global) stereopsis of your patients. It is a lenticular sticker with few objects designed to “pop out” that can be perceived only by the subjects having “TRUE” stereopsis. A study is under way to assess its reliability. Your suggestions and scientific comments will be appreciated.

Yours sincerely,

 

Dr Mihir Kothari

MS, DNB, FPOS, FAICO, Diploma in
Pediatric Ophthalmology and Strabismus (Wilmer Eye Instititue, Johns Hopkins, Baltimore, USA)
Fellowship in Pediatric Neuroophthalmology (Smith Kettelwell Eye Reserach Instt., San Francisco, USA)
Ph: 9324037173  WWW.JYOTIRMAY.COM
Director, Jyotirmay Eye Clinic, Ocular Motility and Binocular Vision Lab and Pediatric Low Vision Center
Jyotirmay Eye Clinic, 205, Ganatra Estate, Khopat, Thane West 40601, Maharashtra, India

IC CODE NO: IC40 TITLE : Practical Approach to the Management of Nystagmus
DATE : 07/02/2014 HALL : C TIME : 08:30 – 09:55

Chief Instructor : Dr.MIHIR TRILOK KOTHARI,
Co-Instructors & Course outline :

Clinical Pathophysiology and Modern Classification of Nystagmus Dr. RAMESH MURTHYdrrameshmurthy@gmail.com 11 mins
Clinical Evaluation of Patient with Nystagmus Dr. RAMESH KEKUNNAYAdrrk123@gmail.com 11 mins
Role of Video Nystagmography, Electrophysiology, OCT & MRI in management of Nystagmus DR. MIHIR KOTHARIdrmihirkothari@gmail.com 11 mins
Non surgical management of nystagmus Dr. SHASHANK RANADEranade.shashank@gmail.com 11 mins
Surgical Management of Nystagmus Dr. PRADEEP SHARMAdrpsharma57@yahoo.com 11 mins
Video Gallery of Common and Less Common Nystagmus Cases Dr. VIMAL FUDNAWALAdoc_vimal@yahoo.co.in 11 mins

 

Panel discussion: 19 mins  Duration : 85 (mins) with 5 mins for change over

 

 

Index:

Section 1

Notes on nystagmus: Dr Mihir Kothari

  • Definition and Current Clinical Classification……………………………………………………………..4-7
  • Pathophysiology of nystagmus………………………………………………………………………………….7-9
  • Relevant “Extra”Examinations in Nystagmus…………………………………………………………..10-11
  • Investigations of Patients with Nystagmus……………………………………………………………….12-17
  • Optical Management………………………………………………………………………………………………….18
  • Pharmacological Management (separate handout)…………………………………………………………19
  • Management of Abnormal Head Postures…………………………………………………………………….20
  • Management of Nystagmus – Dell’Osso algorithm……………………………………………………….21
  • Surgical Management …………………………………………………………………………………………..22-27

Annexures

  • Visual/social function questionnaire for nystagmus

 

Section 2

Instruction course lectures:

  • Clinical Pathophysiology and Modern Classification of Nystagmus – Dr Ramesh Murthy
  • Pharmacological Management (separate handout) – Dr Mihir Kothari and Dr Shashank Ranade


 

Notes on nystagmus.

Classification of Nystagmus

Classification of Eye Movement Abnormalities and Strabismus (CEMAS)

Physiological Nystagmus

1. Vestibular Nystagmus – comes up with head rotation (utilised in Rotation test for vision assessment of young infants). Visual dampening should occur in 5-10 seconds (if it doesnot = visual impairment +). Calorie testings (Hot and cold) are utilised by ENT surgeons as Vestibular function tests.

2. Optokinetic Nystagmus – comes up with fixation on a repetitive moving target. Utilised for assessment of vision in young infants. 3 Smart phone applications have them. The best is Eye Handbook – free Android app and IOS – Apple app

3. Eccentric Gaze Nystagmus

 

Pathologic Nystagmus 1. Infantile Nystagmus Syndrome (INS)
2. Fusion Maldevelopment Nystagmus Syndrome (FMNS) 3. Spasmus Nutans Syndrome (SNS)
4. Vestibular Nystagmus a. Peripheral Vestibular Imbalance
b. Central Vestibular Imbalance c. Central Vestibular Instability
5. Gaze-Holding Deficiency Nystagmus a. Eccentric Gaze Nystagmus
b. Rebound Nystagmus c. Gaze-Instability Nystagmus (“Run-Away”)
6. Vision Loss Nystagmus a. Pre-chiasmal
b. Chiasmal c. Post-chiasmal
7. Other Pendular Nystagmus and Nystagmus Associated with Disease of Central Myelin a. Multiple Sclerosis, Peliazaeus-Merzbacher, Cockayne’s Perioxisomal disorders, Toluene abuse.
b. Pendular Nystagmus Associated with Tremor of the Palate. c. Pendular Vergence Nystagmus Associated with Whipple’s Disease.
8. Ocular Bobbing (Typical and Atypical) 9. Lid Nystagmus

 


 

 

For more details www.nei.nih.gov/news/statements/cemas.pdf

Table Characteristics of Infantile Nystagmus Syndrome – Louis F. Dell’Osso

Clinical observations Ocular motor findings
Binocular with similar amplitude in both eyes Increasing-velocity slow phases (some linear)
Usually horizontal (vertical, diagonal, or elliptical rare and small components missed) Distinctive waveforms with foveation periods and braking saccades
“Pendular” or “jerk” appearance (often misdiagnosed) Many INS waveforms cannot be differentiated, nor can their direction be determined, clinically (misdiagnosed as nystagmus type or jerk direction)
Apparent jerk direction not always correct (often misdiagnosed) “Horizontal” INS actually has a torsional component and subclinical SSN
Asymmetric aperiodic alternation possible (baclofen ineffective) Gaze-modulated, not gaze-evoked, nystagmus
Provoked or increased by “fixation attempt” and stress Normal smooth pursuit, optokinetic, and vestibulo-ocular systems (each causing a shift in the INS “null”)
Abolished in sleep or inattention to visual tasks Reversal of the IN with alternate cover due to INS “null” shift (INS with a latent component misdiagnosed, “FMNS”)
Diminished (damped) by gaze-angle or convergence nulls Two head postures due to the INS “null” shift in INS with a latent component (misdiagnosed as INS with “two nulls”)
Reversal with cover (often misdiagnosed as FMNS) Reversal of the IN during optokinetic stimulation (misinterpreted as “inversion” of the optokinetic refl ex)
Apparent “inversion” of the optokinetic reflex (misinterpreted) Reversal of the IN during smooth pursuit (misinterpreted as “reversal” of smooth pursuit)
Apparent “reversal” of smooth pursuit (misinterpreted) Associated head oscillation not compensatory due to normal vestibuloocular reflex
Associated head oscillation (misinterpreted as compensatory) Head turns or tilts provide waveforms with the best foveation quality
Associated head turn and/or tilt Convergence damping improves foveation over a broader range of gaze angles
No oscillopsia except under rare conditions Tenotomy portion of EOM surgery improves foveation over a broader range of gaze angles
Patients complain of being “slow to see” Target acquisition time much longer than saccadic reaction
time, reducing visual function

 

Pathophysiology of Nystagmus

 

 

 

 

 

 

PATHOPHYSIOLOGY OF Abnormal Headposture – Dr Richard W Hertle

 

Critical Examinations in Nystagmus:

Examination Technique Interpretation Diagnostic utility/relevance
Vision under partial fogging +4D lens in front of the full optical correction Prevents latent nystagmus to become manifest Necessary to assess monocular vision in FMNS / LN
Near vision Vs Distance vision and Convergence dampening Use logMAR for both In 10% patients there is a true convergence dampening that lead to better vision for near These patients are highly benefitted by Base in prisms or MR recesssions
OKN Smart phone app (eye hand book) OKN drum Abnormal vertical OKN (absent in up &/or down gaze)  indicates neurological anomaly The patient will need MRI brain
Abnormal Head Posture(Static / dynamic) Ask the child to read at distance or resolve a target. Use Goniometer (simple protractor with scale) to measure Face turn / head tilt/chin up or down or MIXED Indicates eccentric Null, better vision.Absence of AHP is more likely with SENSORY defect
Cover test Apply a cover in front of one eye and alternate Will reveal any squint of latent nystagmus
Head nodding Ask the patient to read or resolve Associated with Spasmus nutans, INS with or without sensory defects Only in Spasmus nutans, it is compensatory and 180 degrees out of phase with nystagmus that lead to improved vision
Pupil Direct reaction to light, RAPD and near distance dissociation Sluggish reaction / RAPD indicates Anterior visual pathway disease Warrants further investigation – ERG /MRI
Optic disc evaluation Pallor / Hypoplasia Warrants further investigation – ERG /MRI

FMNS= fusion maldevelopment nystagmus syndrome, LN=Latent nystagmus

Recording the Nystagmus

 

  • Ø Side of arrow indicates the direction of fast corrective phase (direction of nystagmus)
  • Ø No of arrows indicate the frequency
  • Ø Length of arrow indicates the amplitude

 

Hertle’s Examination alogorithm for evaluation of abnormal head posture


 

Investigations in Nystagmus

Name of the investigation Indications What can it reveal?
Video Nystagmography / Eye movement Recording Preferably in every patient of nystagmus to objectively assess ——à

Nystagmus with strabismus (to differrentiate INS from FMNS)ü  Type of nystagmus (Classify accurately)

ü  Potential for vision improvement  with treatment (NAFX/ANAF)

ü  Objective documentation of Response to treatment

ü  Null point evaluation

ü  Identifies vertical components in seemingly horizontal nystagmusOCTRetinal dystrophy/mal development

  • Foveal hypoplasia
  • Schisis cavity
  • Accumulation of deposits
  • Retinal/choroidal thinning

ERGSensory Nystagmusv  Achromatopisa

 

v  CSNB

v  LCA

v  Other atypical retinal dystrophiesMRI BrainNeurological disorder (separate table)

  • Space occupying lesions
  • Demyelinations
  • Perinatal damage
  • Cengenital malformations / infections

Red free Fundus photography (Autofluorescence)Macular dystrophyAccumulation of Lipofuscin in various macular dystrophies

 

 

 

Video Nystagmography / Eye movement recording

VNG: Nystagmus eye movements can be recorded at a 500-Hz sampling rate using either an infrared limbus reflection goggle system or a high speed remote video eye tracker

How does it help improve the tratment?

  1. 1.      Correct classification of Nystagmus and hence treatment
Waveform on VNG Description How does it help?
Pendular Nystagmus Vision of the patient is likely to be poor as there are no corrective saccades.

Slow Phase

Jerk with accelerating slow phaseSeen with INS (infantile nystagmus syndrome) with or without sensory defects

 

FAST Phase

Jerk with decelerating slow phaseSeen with FMNS (latent nystagmus). Correct the squint and nystagmus is abolished. Jerk with linear slow phaseAssociated with vestibular or neurological nystagmus.

 

  1. 2.      Assessment of potential visual acuity of a patient with nystagmus using ANAF/NAFX (foveation time calculation)

Automated nystagmus acuity function (ANAF) / expanded nystagmus acuity function (NAFX) –

 

 

  1. Can identify patients who need MRI or ERG.

 

 

 

 

 

 

 

 

 

 

Large vertical component Sensory defect ERG needed

Small/No vertical component INS

Pure vertical Nystagmus needs MRI brain

 

 

 

  1. 4.      Objective evaluation of treatment outcomes

 

Before Azopt Eye Drops              After Azopt Eye Drops

 

 

 

Before Memantine                                    After Memantine

 

 

 

 

Before Surgery                             After Surgery (Augmented KA procedure)

 

  1. 5.      Identification of effect of Bimedial recession on nystagmus in patient with convergence dampening

 


 

 

Investigations in Nystagmus: Neurological / Retinal what is the cause?

 

As many as 90% patients with nystagmus have associated neurological or retinal disease – The anterior visual pathway diseases.

 

When to suspect a “neurological” cause in nystagmus? & Get an MRI brain

 

Symptoms or Signs that warrant investigations Disease Suspected
See Saw nystagmus
Pendular nystagmus with à Optic atrophy, relative afferent pupillary defect and/or visual field loss. Chiasmal Glioma
Pendular nystagmus with à Wasting despitea normal appetite, excessive food intake, diabetesinsipidus, euphoric affect,headache or lethargy Hypothalamic tumors
Spasmus Nutans:“minimal” headnodding, the small-amplitude and the high-frequency of the oscillations, and the asymmetry of thenystagmus is typical for spasmus nutans. A head turn and tilt is common in congenital nystagmus, but it also occurs in about 2/3rd of patients with spasmus nutans.”  Age of onset <4 months or > 2 years, significant vertical component, any systemic/ocular  signs of neurological deficit. Cafe-au-lait spots / stigmatas of Neurofibromatosis Gliomas / subacute necrotizing encephalopathy
Vertical Nystagmus Vertical PendularDown beatUpbeat 1)      Brainstem andcerebellar disease2)      Craniocervicaljunction/cerebellar

disease

  1. Anticonvulsants

4)      Cerebellar/pontomedullary abnormalities

Asymmetric Horizontal Nystagmus Non localising
Abnormal (absent in upgaze and/or downgaze) vertical OKN Non localising

 

 

Hertle’s Criteria for Neurological Work up

 The features that indicate abnormal retina in a “normal appearing fundi” – Warrants an ERG

 

Leber’s congenital amaurosis (LCA) Paradoxical pupil reaction (pupil constrict when room lights are switched off), Oculo digital sign +, Enophthalmos ERG – extinguished (Rule out Mental retardation, SNHL, Cardiomyopathy, Medullary Cystic Renal disease, Cerebellar vermis hypoplasia)
Achromatopsia Pronounced Paradoxical pupil reaction, Light sensitivity, Dyschromatopsia Photopic ERG attenuated. Scotopic ERG normal
Congenital Stationary Nightblindness Paradoxical pupil reaction, Nyctalopia Negative wave ERG (attenuated ‘a’ wave)
JOUBERT SYNDROME Developmentallydelayed infants, Breathing problems, Attenuatedor non-recordable ERG, MRI brain – Cerebellar Vermis Hypoplasia
PEROXISOMAL DISORDERS High, bulging forehead, hepatomegaly, renalcysts, a sensorineural hearing loss, hypotonia,retinal dystrophy.‘ ERG extinguished

 

 

 

 

Nystagmus can be the initial sign of life-threatening neurological or vision threatening retinal diseases / vestibular diseases. Appropriate investigations should be done to rule them out.

 

 

 

Optical Management of Nystagmus

Type of defect Correction measure Remark
Refractive Error Full correction
Convergence dampening Base out prism Typically 7PD base out with -1DS in non presbyopic
Accommodation failure Bifocals Patients with Aniridia, Albinism, Cerebral vision impairment, Foveal hypoplasia etc…may have significant defects in accommodation
Head postures Prisms with apex in the direction of the head (will move the eye to center) Good for small (<20PD) postures. More useful for the vertical torticollis
Nystagmus / Refractive error and Light Sensitivity Contact lenses CL Material does not matter, Correct the refractive error and use Painted Contact Lenses for Aniridia or Albinism
Low Vision Optical and non optical aids
Light sensitivity Photogray / tinted lenses In Specatcles or Contact lenses
Oscillopsia Apex towards head posture (eg apex up for down beat nystagmus) with Image Stabilisation (high – contact lens with high + spectacles)

 

Pharmacological Management of Nystagmus in a separate handout

 


 

 

 

Hertle’s agorithm for management of Abnormal Head posture in patients with Strabismus and Nystagmus

The treatment of nystagmus and outcome evaluation – Louis F Dell’Osso The surgical procedures in nystagmus – my protocol

Abnormality Procedures Principle Benefits of Surgery Indication
Nystagmus ONLY Tenotomy and Reattachment(large 4 muscle recessions are given up) 4 horizontal recti are detached and resutured at the same insertion
  • 25% reduced intensity of nystagmus
  • Broadening of null zone
  • 1-3 lines (logMAR) improvement in vision in 50% patients
  • 40% increase in NAFX in 90% patients
Nystagmus with no null, primary position null or alternating null (periodic or aperiodic).Nystagmus with or without sensory / neurological defects.
Artificial Divergence surgery Bilateral medial rectus recession
  • 70-90% dampening of nystagmus
  • Magnificient improvement in vision
Patients with INS and convergence dampening with near vision > distance visioion
Combined with Abnormal Head Posture Augmented Anderson Procedure 9mm MR recession and 12/13mm LR recession 1)      20 degrees correction of face turn2)      2.5 degree reduction in amplitude of nystagmus3)      1.5Hz reduction in frequency of nystagmus Patients with INS and moderate face turn (<25 degrees)
Augmented Kestenbaum Anderson Procedure Classic 5,6,7,8 figure recess resect augmented  with degree appropriate face turn to move the null to the centre 1)      20-60 degrees correction of face turn2)      25% reduction in amplitude and frequency of nystagmus3)      1-3 lines (LogMAR) improvement in vision Patients with INS with moderate to severe face turn
Oblique Kestenbaum Anderson procedure Inferior advance or recess and superior oblique anterior fibers tenotomy or advancement (Harada Ito)
  1. Correction of head tilt – approximately 5 degrees per mm of surgery
Head tilts
Elevator weakening or depressor weakening IO myectomy with SR recession 5mm for chin down or SO tenectomy with IR recession 4mm for chin up
  1. Correction of the head posture
Chin up or down
Combined squint and nystagmus FMNS with Squint (Diagnosis in VNG/EMR) Correct the squint only
  1. Correction of squint and recovery of fusion and stereopsis
  2. Conversion of Manifest nystagmus to a latent nystagmus
  3. Improvement in vision

 

VNG / EMR needed for any patient with squint and nystagmus to identify this type
INS with Squint Correct the squint and add T and R Benefits of both – squint sx and nystagmys surgery
Combined squint, abnormal head posture and nystagmus FMNS / INS with squint and abnormal head posture Squint surgery on non dominant eye and head posture surgery on dominant eye Benefits of squint surgery, nystagmus surgery and correction of abnormal head postures ++ Use prisms to correct the head posture in front of dominant eye and then correct the squint with prisms in front of non dominant eye and then calculate the amount of surgery

 

T and R = Tenotomy and reattachment of horizontal muscles

Surgical Protocol by Louis F. Dell´Osso

 

Surgical Protocol of Dr Richard Hertle

 

 

OR

 


 

Annexure 1:

NYSTAGMUS FUNCTION QUESTIONNAIRE                                                                                           DATE:

DEAR FRIENDS, THIS QUIESTIONNAIRE IS TO UNDERSTAND THE PROBLEMS SUFFERRED BY OUR PATIENTS WITH NYSTAGMUS. IT WILL HELP US PLAN THE TREATMENT APPROPRIATELY AND KNOW THE RESULTS OF THE GIVEN TREATMENT. PLEASE READ THE QUESTIONNAIRE CAREFULLY, UNDERSTAND THE QUESTIONS WELL AND MAKE A TICK MARK NEXT TO THE MOST APPROPRIATE CHECK BOX. THANKS FOR YOUR TIME AND FAITH.

NAME:                                                                                                        AGE:                                    GENDER

WHAT ARE THE PROBLEMS SUFFERED NIL MILD PROBLEMS MEDIUM PROBLEM SEVERE PROBLEMS BLANK
SHAKY EYES
VISION IS POOR
SQUINT EYES
ABNORMAL HEAD POSTURE
HEAD NODDING

 

ONLY IF VISION RELATED PROBLEMS ARE THERE PLEASE FILL UP THE TABLE GIVEN BELOW.

VISUAL FUNCTION-14 NIL MILD PROBLEM MEDIUM PROBLEM SEVERE PROBLEM
Do you  / your child have any difficulty, even with glasses…..
1 Reading small print—eg, food label, phone book
2 Reading a book or newspaper
3 Reading a large print book or recognising numbers on TV
4 Recognising people when they are close to you
5 Seeing steps, stairs, or curbs
6 Reading traffic signs, street signs, or shop signs
7 Doing fine handwork—eg, sewing, knitting, crafts
8 Filling in forms
9 Playing games—eg, cards, dominoes, board games
10 Taking part in sport
11 Cooking
12 Watching television
13 Driving during the day—omitted from child questionnaire
14 Driving at night—omitted from child questionnaire

TABLE BELOW IS FOR THE CLINIC USE ONLY

RE SPH RE CYL RE AXIS REBCVA LE SPH LE CYL LE AXIS LE BCVA

 

DIAGNOSIS:                                                                 VNG FINDINGS: