strabismus: is it ‘strabismic’ ? …. neurological? or both? lionel kowal director, ocular...

STRABISMUS: IS IT ‘STRABISMIC’ ?

…. NEUROLOGICAL?OR BOTH?

STRABISMUS: IS IT ‘STRABISMIC’ ?

…. NEUROLOGICAL?OR BOTH?

LIONEL KOWALDIRECTOR, OCULAR MOTILITY CLINIC, RVEEH

SENIOR CLINICAL FELLOW, DEPT OPHTHALMOLOGY, UNIVERSITY OF MELBOURNE

FIRST VICE PRESIDENT, INTERNATIONAL STRABISMOLOGICAL ASSOCIATION, 2002-2010

LIONEL KOWALDIRECTOR, OCULAR MOTILITY CLINIC, RVEEH

SENIOR CLINICAL FELLOW, DEPT OPHTHALMOLOGY, UNIVERSITY OF MELBOURNE

FIRST VICE PRESIDENT, INTERNATIONAL STRABISMOLOGICAL ASSOCIATION, 2002-2010

OVERVIEW….OVERVIEW….

OF THE CAUSES, ASSOCIATIONS AND TYPES OF STRABISMUS

IDENTIFYING SOME COMMON / UNDER- RECOGNISED ASSOCIATIONS

OF THE CAUSES, ASSOCIATIONS AND TYPES OF STRABISMUS

IDENTIFYING SOME COMMON / UNDER- RECOGNISED ASSOCIATIONS

STRABISMUSSTRABISMUS

Any ocular misalignment

INCLUDES:Abnormalities of development of acuity Abnormalities of development of binocularity The variants of congenital nystagmus

Any ocular misalignment

INCLUDES:Abnormalities of development of acuity Abnormalities of development of binocularity The variants of congenital nystagmus

CHILDHOOD STRABISMUSCHILDHOOD STRABISMUS

1. Derive largely from refractive disorders

2. Pure neurological3. Derive largely from abnormal early visual devpt

4. Special types

1. Derive largely from refractive disorders

2. Pure neurological3. Derive largely from abnormal early visual devpt

4. Special types

STRABISMUS: END RESULT OF A COMPLEX JIGSAW

PUZZLE

STRABISMUS: END RESULT OF A COMPLEX JIGSAW

PUZZLE

Abnormalities in one / more of…Sensory developmentRefractionOrbital anatomyEOM anatomy / physiologyCortical / supranuclearAccommodation / convergenceeither cause or are caused by strabismus

Abnormalities in one / more of…Sensory developmentRefractionOrbital anatomyEOM anatomy / physiologyCortical / supranuclearAccommodation / convergenceeither cause or are caused by strabismus

COMPLEX JIGSAW PUZZLEAbnormal Sensory

development

COMPLEX JIGSAW PUZZLEAbnormal Sensory

development

AmblyopiaSuppressionAbnormal retinal correspondence

AmblyopiaSuppressionAbnormal retinal correspondence

COMPLEX JIGSAW PUZZLEAbnormal Refraction

COMPLEX JIGSAW PUZZLEAbnormal Refraction

Hyperopia or ‘plus’ error *Causes esotropia

Any asymmetric refractive errorCauses amblyopia, esotropia if +

*so-called ‘long sighted’ - NOT the mirror image of short sighted. The patient can see clearly by generating focusing effort = accommodation

Hyperopia or ‘plus’ error *Causes esotropia

Any asymmetric refractive errorCauses amblyopia, esotropia if +

*so-called ‘long sighted’ - NOT the mirror image of short sighted. The patient can see clearly by generating focusing effort = accommodation

COMPLEX JIGSAW PUZZLEAbnormal orbital

anatomy1

COMPLEX JIGSAW PUZZLEAbnormal orbital

anatomy1Orbital pulley heterotopyChanges muscle actionsGlobe size distorting muscle cone

Causes pseudo- 6thShallow / deep orbit Shallow: more prone to exotropia

Orbital pulley heterotopyChanges muscle actionsGlobe size distorting muscle cone

Causes pseudo- 6thShallow / deep orbit Shallow: more prone to exotropia

COMPLEX JIGSAW PUZZLEAbnormal orbital anatomy

2

COMPLEX JIGSAW PUZZLEAbnormal orbital anatomy

2

Intorted / extorted orbitMore prone to alphabet patterns

PlagiocephalyMore prone to oblique dysfunction

Intorted / extorted orbitMore prone to alphabet patterns

PlagiocephalyMore prone to oblique dysfunction

COMPLEX JIGSAW PUZZLEAbnormal EOM

anatomy / physiology

COMPLEX JIGSAW PUZZLEAbnormal EOM

anatomy / physiologyOblique muscle dysfunctionAbnormal elevation / depression in AB- or AD- duction

Globe torsion

Abnormal innervation [Duane's, CFEOM]

Strange incomitant strabismus

Oblique muscle dysfunctionAbnormal elevation / depression in AB- or AD- duction

Globe torsion

Abnormal innervation [Duane's, CFEOM]

Strange incomitant strabismus

COMPLEX JIGSAW PUZZLEAbnormal cortical /

supranuclear substrate 1

COMPLEX JIGSAW PUZZLEAbnormal cortical /

supranuclear substrate 1

motor fusion oculomotor ‘shock absorber’ / ‘glue’ that tries to keep eyes straight

sensory fusionstereopsis Abnormal binocular columns

motor fusion oculomotor ‘shock absorber’ / ‘glue’ that tries to keep eyes straight

sensory fusionstereopsis Abnormal binocular columns

COMPLEX JIGSAW PUZZLEAbnormal cortical /

supranuclear substrate 2

COMPLEX JIGSAW PUZZLEAbnormal cortical /

supranuclear substrate 2

Abnormal interneuronsLatent Manifest Latent Nystagmus = LMLN = Fixation Maldevelopment N

Just about any cause / association of devptl delay

ChiariPVL

Abnormal interneuronsLatent Manifest Latent Nystagmus = LMLN = Fixation Maldevelopment N

Just about any cause / association of devptl delay

ChiariPVL

COMPLEX JIGSAW PUZZLEAbnormal Accom - Conv

relationship

COMPLEX JIGSAW PUZZLEAbnormal Accom - Conv

relationship

Accom too much convergence

Conv too much accommodation

*too little is rarely a problem

Accom too much convergence

Conv too much accommodation

*too little is rarely a problem

TYPES OF STRABISMUSTYPES OF STRABISMUS

1. Derives from refractive disorders

2. Pure neurological3. Derives from abn early visual devpt

4. Special types

1. Derives from refractive disorders

2. Pure neurological3. Derives from abn early visual devpt

4. Special types

NORMAL ACCOMMODATIONNORMAL ACCOMMODATION

Accommodation and convergence = Focus and Aim = Focus and Aim are very tightly linked

ACCOMMODATIVE / ‘OPTOMETRIC’ ESOTROPIA

ACCOMMODATIVE / ‘OPTOMETRIC’ ESOTROPIA

+4 : Abn degree of accommodation required to see clearly

Abn amount of accomm convergence is generated

competes against motor fusion [oculomotor shock absorber]

+4 : Abn degree of accommodation required to see clearly

Abn amount of accomm convergence is generated

competes against motor fusion [oculomotor shock absorber]

WHAT DOES +4 MEAN?WHAT DOES +4 MEAN?

For distance, generates same accommodation that ‘perfect’ person generates when looking 1/4 m away.

For distance fixation, eyes will tend to aim @ a point 25cm away

When looking @ an object 25cm away, eyes will aim @ a point 12 cm away

For distance, generates same accommodation that ‘perfect’ person generates when looking 1/4 m away.

For distance fixation, eyes will tend to aim @ a point 25cm away

When looking @ an object 25cm away, eyes will aim @ a point 12 cm away

ACCOMMODATIVE / ‘OPTOMETRIC’ ESOTROPIA

ACCOMMODATIVE / ‘OPTOMETRIC’ ESOTROPIA

Exactly the same can happen with low + and abnormal accomm - convergence relationship*

Many of these bifocals*many synonyms - convergence Xs, high AC/A ratio

Exactly the same can happen with low + and abnormal accomm - convergence relationship*

Many of these bifocals*many synonyms - convergence Xs, high AC/A ratio

Developing an esotropia…

Developing an esotropia…Prolonged accommodation tendency to

inappropriate convergence and increased tone in medial recti

Increased tone will eventually exceed motor fusional reserve and esotropia!

Initially reversible with glassesEventually the medial rectus shortens so much that only botox or surgery will work

Glasses still required to prevent recurrence [and, when older, for clear vision]

Prolonged accommodation tendency to inappropriate convergence and increased tone in medial recti

Increased tone will eventually exceed motor fusional reserve and esotropia!

Initially reversible with glassesEventually the medial rectus shortens so much that only botox or surgery will work

Glasses still required to prevent recurrence [and, when older, for clear vision]

Accommodative esotropia

Accommodative esotropia

Usually 2-5 yrs oldUsually high + [thick magnifying lenses]

Sometimes low / normal + with abnormal relation b/w accomm and convergence

Background of normal visual devpt in first 6mo of life

Usually 2-5 yrs oldUsually high + [thick magnifying lenses]

Sometimes low / normal + with abnormal relation b/w accomm and convergence

Background of normal visual devpt in first 6mo of life

Developing an esotropia…

Developing an esotropia…

Happens more readily * if motor fusion is impaired:

chromosomal defect / devptl delay

AmblyopiaOrbital anomalyLMLN

* younger, lower +

Happens more readily * if motor fusion is impaired:

chromosomal defect / devptl delay

AmblyopiaOrbital anomalyLMLN

* younger, lower +

‘Breakdown of pre- existing phoria…’‘Breakdown of pre- existing phoria…’

Only acceptable as a presumptive label if:

Wears thick magnifying lenses± amblyopiaAccomm disturbed e.g. Ditropan

Only acceptable as a presumptive label if:

Wears thick magnifying lenses± amblyopiaAccomm disturbed e.g. Ditropan

TYPES OF STRABISMUSTYPES OF STRABISMUS

1. Derives from refractive disorders

2. Pure neurological

3. Derives from abn early visual devpt

4. Special types

1. Derives from refractive disorders

2. Pure neurological

3. Derives from abn early visual devpt

4. Special types

‘Pure’ neurological strabismus‘Pure’ neurological strabismus

True cong sup obl palsy

6th

CFEOM [hypoplasia sup div 3rd; KIF mutation]

..have 2ary effects that are dependent on age of onset and associated factors such as refraction

True cong sup obl palsy

6th

CFEOM [hypoplasia sup div 3rd; KIF mutation]

..have 2ary effects that are dependent on age of onset and associated factors such as refraction

R SOP

HEAD TILT TO LEFT

R IO OA

R SO UA

TIGHT RSR RIR ‘UA’

True sup obl palsyTrue sup obl palsy

LSO OK RSO ?absent

REAL CONG R SOP & CONG ET FIXING WITH PARETIC R EYE

R SO atrophicR SO atrophic

Fake SOPConditions that simulate

SOPFalse +ve diagnostic rate ?50%

Fake SOPConditions that simulate

SOPFalse +ve diagnostic rate ?50%

Abnormal cyclovertical anatomyCraniofacial anomalies Posteroplaced trochlea [Bagolini]Fink : 20% of SO and IO have > 30 degrees asymmetry in course

Demer: orbital pulley displacements

Abnormal physiologyBrodsky’s wild pitch

Abnormal cyclovertical anatomyCraniofacial anomalies Posteroplaced trochlea [Bagolini]Fink : 20% of SO and IO have > 30 degrees asymmetry in course

Demer: orbital pulley displacements

Abnormal physiologyBrodsky’s wild pitch

TYPES OF STRABISMUSTYPES OF STRABISMUS

1. Derives from refractive disorders

2. Pure neurological

3. Derives from abnormal early visual development

4. Special types

1. Derives from refractive disorders

2. Pure neurological

3. Derives from abnormal early visual development

4. Special types

1. Abnormal symmetric acuity devpt ‘Congenital

Nystagmus’ * = CN

1. Abnormal symmetric acuity devpt ‘Congenital

Nystagmus’ * = CN

Bilateral bad refractive errorAlbinism : optic n dysplasia, foveal hypoplasia

Bil optic n hypoplasiaBil cataractsCN degrades vision further

* aka Idiopathic Infantile N, Cong motor N, Cong Sensory N,…

Bilateral bad refractive errorAlbinism : optic n dysplasia, foveal hypoplasia

Bil optic n hypoplasiaBil cataractsCN degrades vision further

* aka Idiopathic Infantile N, Cong motor N, Cong Sensory N,…

‘Congenital Nystagmus’ = CN

‘Congenital Nystagmus’ = CN

Pendular / jerkGreater on lateral gazeUNIQUE : CONVERGENCE NULLFace turnsPathognomonic waveform

Pendular / jerkGreater on lateral gazeUNIQUE : CONVERGENCE NULLFace turnsPathognomonic waveform

CN: face turn null & convergence null

CN: face turn null & convergence null

Null zone on R gazedrives face turn / tilt to L

N to L when L of nullN to R when R of null

Convergence null : unique to CN

Convergence null : unique to CN

QuickTime™ and aYUV420 codec decompressor

are needed to see this picture.

Abnormal binocularity devpt Latent Manifest Latent N *

Abnormal binocularity devpt Latent Manifest Latent N *

Caused by…Any strabismusAsymmetric refractionMonocular vision reducing pathology - cataract, optic n hypo,….

* aka Fixation Maldevelopment N

Caused by…Any strabismusAsymmetric refractionMonocular vision reducing pathology - cataract, optic n hypo,….

* aka Fixation Maldevelopment N

Abnormal binocularity devpt Latent Manifest Latent N Abnormal binocularity devpt Latent Manifest Latent N

JerkGreater on ABductionUNIQUE : Fast phase to fixing eye

Face turns : RF R face turn, LF L face turn

Head tilts : RF R tilt, LF L tilt

JerkGreater on ABductionUNIQUE : Fast phase to fixing eye

Face turns : RF R face turn, LF L face turn

Head tilts : RF R tilt, LF L tilt

LMLN LMLN

VIDEO OF POST OP LMLN; NOW ‘PURE’ LN

VIDEO OF POST OP LMLN; NOW ‘PURE’ LN

Esophoria after Exotropia surgeryN to fixing eye

LMLN : N fixing eye

LMLN : N fixing eye

QuickTime™ and aYUV420 codec decompressor

are needed to see this picture.

Fast phase to fixing eye

LMLNLMLN

COMMONLY CONGENITAL ESOTROPIA but can cause / be associated with other strabismus

Also CAUSES DISSOCIATED H & V DEVIATIONS

COMMONLY CONGENITAL ESOTROPIA but can cause / be associated with other strabismus

Also CAUSES DISSOCIATED H & V DEVIATIONS

CONGENITAL ESOTROPIACONGENITAL ESOTROPIA

ASSOCIATIONS OF LMLN & Congenital ET

ASSOCIATIONS OF LMLN & Congenital ET

Down’s 30%Severe neonatal course IVH /HC

near 100%PVL

Down’s 30%Severe neonatal course IVH /HC

near 100%PVL

VERTICALS IN CONG STRAB : DVD

Dissociated Vertical Deviation

VERTICALS IN CONG STRAB : DVD

Dissociated Vertical Deviation

Common pattern:Right fixation: LL fixation: R

Contralateral DVD is the end result of ‘braking’ the torsional component of LMLN in the fixing eye to try and improve acuity

Common pattern:Right fixation: LL fixation: R

Contralateral DVD is the end result of ‘braking’ the torsional component of LMLN in the fixing eye to try and improve acuity

VERTICALS IN CET : DVD

VERTICALS IN CET : DVD

RE fixing LE

CONGENITAL STRABISMUSCONGENITAL STRABISMUS

Head turns / face tilts are common

Caused by attempts to minimise blur effect of the LMLN

Head turns / face tilts are common

Caused by attempts to minimise blur effect of the LMLN

Alternating Face TurnAlternating Face Turn

L Fixation : L Face TurnR Fixation : R Face Turn

Ciancia’s syndrome: preference for fixation in adduction because recruiting medial rectus ‘brakes’ horizontal component of LMLN improved vision

L Fixation : L Face TurnR Fixation : R Face Turn

Ciancia’s syndrome: preference for fixation in adduction because recruiting medial rectus ‘brakes’ horizontal component of LMLN improved vision

Special case:Head tilt to fixing eye

Special case:Head tilt to fixing eye

LF drives HT to LRF : no HT

Caused by Torsional LMLN

LF drives HT to LRF : no HT

Caused by Torsional LMLN

LF drives HT to LTorsional LMLNLF drives HT to LTorsional LMLN

LMLN is the cong nystag seen with disorders of binocular development

[?always] Seen in cong ET= Fixation Maldevelopment N. Usually has H component, sometimes T as well

Fine torsional N on slit lamp

N degrades vision - vision improves when N blocked

LMLN is the cong nystag seen with disorders of binocular development

[?always] Seen in cong ET= Fixation Maldevelopment N. Usually has H component, sometimes T as well

Fine torsional N on slit lamp

N degrades vision - vision improves when N blocked

Special case:Alternating Head TiltSpecial case:Alternating Head Tilt

LF drives L tiltRF drives R tilt

= Ciancia’s syndrome

LF drives L tiltRF drives R tilt

= Ciancia’s syndrome

Recap…Abnormal binocularity devpt Latent Manifest Latent

N

Recap…Abnormal binocularity devpt Latent Manifest Latent

N

Features of this type of strab recognised by the accompaniments.

LMLN, + one/ more of…Head tilt / face turn to fixing eye

DVDsLarge angle esotropia

Features of this type of strab recognised by the accompaniments.

LMLN, + one/ more of…Head tilt / face turn to fixing eye

DVDsLarge angle esotropia

‘Ophthalmic’ PVL‘Ophthalmic’ PVL

Optic n hypoplasia uni-/bi-Cognitive visual problems -

normal acuityReduced acuityLMLNCN

Optic n hypoplasia uni-/bi-Cognitive visual problems -

normal acuityReduced acuityLMLNCN

THINGS THAT LOOK LIKE ‘STRABISMIC’ STRABISMUSTHINGS THAT LOOK LIKE

‘STRABISMIC’ STRABISMUS

CHIARI – later onset

‘deterioration of old latent strabismus ‘ – there always has to be a credible background / predisposition. And a reason for breakdown

CHIARI – later onset

‘deterioration of old latent strabismus ‘ – there always has to be a credible background / predisposition. And a reason for breakdown

THINGS THAT LOOK LIKE ‘STRABISMIC’ STRABISMUSTHINGS THAT LOOK LIKE

‘STRABISMIC’ STRABISMUS

Autoimmune neuropathies

Myesthenia

Autoimmune neuropathies

Myesthenia

Strabismus syndromesStrabismus syndromes

Duane’s

Brown’s

Duane’s

Brown’s

Brown’sBrown’sTight superior oblique tendon

Restricted elevation in aDuction

Duane’sRetraction on

adduction

Duane’sRetraction on

adductionRetraction R on L gazeRestricted aDduction RRestricted aBduction L

Co-firing Lateral rectus on aDuction

Duane’sDuane’s

Retraction L on R gazeRestricted aDduction L

Co-firing lateral rectus on aDuction

THANK YOUTHANK YOU