Revised Dec 2014 ASMPH Y7

Strabismus & Amblyopia

Alvina Pauline D. Santiago, MD Pediatric Ophthalmology & Strabismus

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Anatomy of Extraocular Muscles

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EOM Mechanisms

!   Actions of muscles !   Ductions & Versions !   Vergence movements: convergence,

divergence ! Hering’s & Sherrington’s laws

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Orbital apex

Medial rectus

www.wikipedia.org

adduction

Lateral rectus

www.wikipedia.org

abduction

Inferior rectus

!  depressor !  adducts !  excyclotorsion

www.wikipedia.org

Superior rectus

!  elevates !  adducts !  incyclotorts

www.wikipedia.org

Superior oblique

!  incyclotorts !  depresses !  abducts

www.wikipedia.org

Inferior oblique

!  excyclotorts !  elevates !  abducts

www.wikipedia.org

08 January 2010 ASMPH Y7

EOM Movements

!  Duction: rotation from one eye !  Versions: movement of both eyes from

primary position (straight) to secondary position

!  Vergence: simultaneous ocular movements !   convergence: nucleus of Perlia (midbrain) !   divergence: midbrain near acoustic nerve nucleus

Ocular Motility

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Laws of Ocular Motility

!   Hering’s law of equal innervation !   explains conjugate eye movements !   Yoke muscles receive equal innervation

!   Sherrington’s law of reciprocal innervation !   concerned with coordination of muscle pairs of one eye !   when agonist contracts, there is inhibition of its direct antagonist

Yoke muscles: Hering’s Law

RLR LMR

RMR LLR

RSR

LIO

RIR LSO

RIO LSR

RSO LIR

Antagonist Muscles: Sherrington’s Law

RLR (-) RMR

RSR

(-) RIR

RIR (-) RSR

RIO

(-) RSO

RMR

(-) RLR

RSO

(-) RIO

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Vision Assessment

Preverbal Age Group

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Visual acuity testing

•  Evaluating fixation and preference •  Using Allen cards or other preverbal test

charts

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Visual milestones

•  Birth Bright lights •  7 days vestibulo-ocular reflex •  3 mos transient FF •  6 mos FF even for distance •  2-3 y 20/30 •  5-7 y 20/20

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Vision Assessment

•  Fixation pattern •  3 mos: transient fix and follow •  6 mos: fix and follow

– “CSM” nomenclature – cover one eye – start distance fixation

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Fixation preference

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Fixation Preference

Son: Left Left Left None

TEXT TEXT TEXT TEXT

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Profound Amblyopia

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Fixation Preference & Visual Acuity

•  Central, steady, maintained CSM 20/20-20/30

•  CS, maintained briefly 20/40-20/60 •  CS, not maintained (NM)20/70-20/80 •  C, NS, NM 20/100-20/200 •  Not C, Eccentric </= 20/300

08 January 2010 ASMPH Y7

Vision Assessment

Non/Pre Verbal

OKN Drum FPL OKN Flag Teller

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Visual Acuity Testing

•  Test Charts –  HOTV / HOTEX –  “E” Game –  Landolt C –  Picture Charts

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Vision Assessment

Picture Charts HOTV SNELLEN

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Strabismus Testing Tests of Ocular Alignment

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Motor Testing

•  Ocular rotations •  Measuring the deviation •  Anomalous head posture

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Ocular Rotations

•  Duction: monocular •  Version: binocular •  Hering’s law •  Sherrington’s law •  Alert to pattern deviations: e.g., A, V •  Grading scheme:

– e.g., inferior oblique & superior oblique

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Ocular Motility Evaluation

RLR

LMR

RMR

LLR

RSR

LIO

RIR

LSO

RIO

LSR

RSO

LIR

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Ocular Rotations: Yoke muscles Cardinal gaze positions

RLR

LMR

RMR

LLR

RSR

LIO

RIR

LSO

RIO

LSR

RSO

LIR

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(L) Inferior oblique dysfunction

+4 +1

-4 -1

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(R) Superior oblique dysfunction

+4 +1

-4 -1

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Ocular misalignment

•  Hirschberg’s light reflex test •  Bruckner’s red orange reflex test •  Alternate prism cover test

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Hirschberg’s Corneal Reflex

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Hirschberg’s Corneal Reflex

Mom: straight Son: RET RET RXT PseudoET

TEXT TEXT TEXT TEXT

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Pseudostrabismus

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Head posture, Anomalous?

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Anomalous head posture

•  Measure in non preferred head posture

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Motor Testing

•  Light reflex tests •  Cover tests •  Other tests

– wear correction – no prisms

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Motor Testing: Light Reflex Tests

•  Bruckner test •  Hirschberg light reflex •  Krimsky/modified Krimsky

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Bruckner Test

® Ametropia ® strabismus

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Hirschberg’s Light Reflex

•  3.5 mm pupil: –  15 degrees at pupil

edge –  30 degrees between

limbus and edge of pupil

–  45 degrees at limbus

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Krimsky vs Modified Krimsky

–  in front of deviating eye (modified Krimsky)

– underestimates true angle

– better at near

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Motor Testing: Cover Tests

•  Primary gaze •  Right and left gaze •  Up and down gaze •  Right and left head tilt

•  Near: primary and down gaze

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Cover Tests

•  Requirements: – appropriate correction – no prisms vs. prisms – accommodative target – distance:

•  6 m: 1/8 D of accommodation •  > 6 m: X(T)

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Techniques in Finding Strabismus •  Bruckner test •  Spielmann

translucent occluder

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(L) Superior oblique palsy

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Direct Ophthalmoscope View: Fundus Torsion

Excyclorotation Incyclorotation

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Paralytic Exotropia:III nerve palsy

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Inferior oblique dysfunction

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Bruckner (Red Orange Reflex)

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Amblyopia

Pediatric Eye Disease Investigator Group (PEDIG)

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Thank You!