10.Basic Strabismus

8/10/2019 10.Basic Strabismus

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Copyright 1982 - 2009 Dr. Erfan & Bagedo Hospital

Basic Strabismus

Rasha Eltanamly

Consultant Ophthalmologist


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Basic strabismus

What is strabismus?

Manifest misalignment of the eyes which canbe unilateral/alternating , constant /

intermittent, comitant or incomitant.


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Basic strabismus

Why is squint a problem?

Amblyopia Cosmetic appearance

Loss of binocularity


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Basic strabismus

Examination of strabismus

Visual acuity assessment Ocular alignment assessment

Ocular motility assessment

Others e.g. stereopsis & binocularity


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Basic strabismus

Visual acuity assessment in children

NormalTest usedAge (yrs)20/30VEP0-2

20/30Preferential look0-2

CSMFixation behavior0-2

20/40-20/20Allen Pictures2-5

20/40-20/20HOTV2-5

20/40-20/20E game2-5

20/30-20/20Snellen5+


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Basic strabismus


Cover test Cover uncover test

Simultaneous prism & cover


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Basic strabismus

Examination of

strabismus

Cover test (phoria)



Basic strabismus

Examination of strabismus Cover uncover test (tropia)

Measures the exact heterotropic deviationThe patient is made to fixate at a target, then one eye iscovered. If the uncovered eye moves to take fixation, thenheterotropia is diagnosed.

-If the eye moves nasally: exotropia-If the eye moves temporally: esotropia-If the eye doesnt deviate, repeat same for the fellow

eye



Basic strabismus


Simultaneous prism & cover Measures actual angle of squint (tropia)

Cover fixating eye, apply prism in front of deviating eye

simultaneously

Repeat increasing prism power, till the eye no longer

shifts



Basic strabismus


Hirschberg test Krimsky test



Basic strabismus


Hirschberg test



Basic strabismus


Krimsky test



Basic strabismus


Ocular motility assessment

Monocular /binocular

6 cardinal positions of gaze



Basic strabismus

Amblyopia

Types Strabismic

Anisometropic

Deprivation

Diagnosis Treatment



Basic strabismus

Amblyopia

Types Diagnosis

Unexplained difference of visual acuity of 2 lines

Drop of VA with crowding

Treatment



Basic strabismus

Amblyopia

Types Diagnosis

Treatment Removal of the cause

Full correction with glasses

Patching the stronger eye



Basic strabismus

Common types of horizontal strabismus

Esotropia (convergant squint)

Exotropia (divergant squint)


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Esotropia

Infantile (congenital) esotropia

Accomodative esotropia Pseudo esotropia


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Esotropia

Pseudo esotropia


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Esotropia


large constant angle (>40PD)

birth-6 months

amblyopia common (50-60%)

assocciated with

IOOA

DVD

latent nystagmus


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Esotropia


Surgery

Bilateral MR recession

6 months - 1 year


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Esotropia

Accomodative esotropia

Acquired 2 4yrs of age (infancy) Moderate to large angle (20-50 PD)

Variable angle, intermittent

Hypermetropia +2.00 - +6.00


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Esotropia


Full hyperopic correction >+2.00 Response :

Full correction for distance & near glasses

Residual angle for near bifocal add

Residual angle for distance & near glasses &surgery


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Esotropia



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Exotropia

Intermittent exotropia

Congenital exotropia Sensory exotropia


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Exotropia

Intermittent exotropia

Most common form of XT Presents after 1 yr of age

Large exophoria manifest XT

High grade stereopsis when fusing

Suppression when tropic


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Exotropia


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Exotropia


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Exotropia


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Exotropia

Non surgical treatment

Occlusion Over minus

Full correction of hyperopia

Orthoptics (convergence insufficiency)

Surgical treatment


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Exotropia

Surgical treatment

Age 4yrs

Indication

XT> 50% of waking hrs

Increasing tropia phase

Poor fusion recovery on cover/ uncover test

Asthenopia OR diplopia

Type of surgery

Bilateral LR--

Unilateral LR -- & MR ++


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Summary

Strabismus is a common pediatric eye

problem which may lead to amblyopia.

Early diagnosis and proper management

preserves vision and binocularity.

The role of the pediatrician is crucial in early

detection of strabismus.


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10.Basic Strabismus

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