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Strabismus For Medical Students & GP
Samir Jamal
MD, FRCSC
KAUH
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Strabismus
Misalignment of one or both eyes so as the eye (eyes) is not looking straight at the object of regard.
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Significance In Children
Children need normally aligned eyes to develop vision.
Strabismus in childhood is the second most common presentation of retinoblastoma.
Strabismus is a common presentation for refractive errors.
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Significance in Adults
Frequent sign of neurological diseaseFrequent presentation of systemic
disease ( Thyroid disease & Myasthenia)Cosmetology
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Types of Eye Movements
Horizontal directionVertical directionTorsional direction
All superior muscles are intortors.
All inferior muscles are extortors.
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Anatomy & Physiology
MuscleNerveFunctionTesting
MR3 rdNasalLook to nose
LR6thTemporalLook away
SR3rdElevate, intorts, adducts
Up & Out
IR3 rdDepress, extrorts, adduct
Down & Out
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Anatomy & Physiology
MuscleNerveFunctionTesting
Superior Oblique
4thIntorts, depress, abducts
Look Down & In
Inferior
Oblique
3rdExtrorts, elevates, abducts
Look Up & In
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Types of Strabismus
Esodeviation eye turned in
Exodeviation eye turned out
Hyperdeviation eye turned up
Hpodeviation eye turned down
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Classification of Strabismus
Constant or intermittent Latent or manifest (phoria or tropia) Unilateral or alternating Comitant or incomitant (restrictive or
paralytic) Paralytic or non-paralytic Nuclear or supranuclear
Non-Accommodative Esotropia
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Non-Accommodative Esotropia
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Alternating Esotropia
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Exotropia
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Alternating Esotropia
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Causes of Strabismus
Congenital: imbalance between innervations and contraction
Refractive errorsLoss of visionParalysis or NeuromuscularRestrictive: thyroid eye disease
Tumors
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Strabismus secondary to loss of vision from Cataract in Lt. eye
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Presenting symptoms of Strabismus
Deviation of the eye (cosmesis)Double visionTorticollis (abnormal head posture)Unexplained visual loss in a normal
looking eye (Microtropia)
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Abnormal Head Posture
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Role of GP
1. Confirm Diagnosis
2. Decide on urgency
3. Teach patients
4. Referral to Ophthalmologist
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Management of Strabismus
History:
4 most important questions:
1. Age of onset
2. Constant or intermittent
3. Unilateral or alternating
4. Diplopia or torticollis
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Management of Strabismus
Examination:Three objectives:1. Confirm the diagnosis
2. Diagnose type of strabismus
3. Differentiate paralysis from no paralysis
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Examination of Strab Patient
To achieve the first and second objectives we do:
1. Simple observation for the nasal white of the eye
2. Corneal light reflex
3. Cover test
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Examination of Strab Patient
To achieve the 3 rd objective we look for:
1. Presence of torticollis
2. Answer the following question:
Is the strabismus the same in all directions of gaze or not i.e. comitant or incomitant?
Same = no paralysis. Different = paralysis or restriction.
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Examination
3. Test the extraocular movements in all directions of gaze.
Paralysis / restriction Limitation
No Paralysis No limitation
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Doll's Head Manoeuvre
Used for testing the eye movement when the patient is uncooperative.
The eyes move in opposite direction to the head movement.
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Common Forms of Esotropia
Congenital (No-Accommodative) Surgery.
Accommodative R/ Glasses.P. Accommodative Glasses then
surgery.Sixth Nerve Palsy observation
for 6 M surgery.
Accommodative Esotropia
Before Glasses After Glasses
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Non-Accommodative Squint
Non-Accommodative Esotropia Before and After Surgery
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Partially Accommodative Squint
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Common Forms of Exotropia
Congenital exotropia Surgery
Sensory deprivation exotropia
Third nerve paralysis
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Common Causes of Hypertropia or Hypotropia
1. Fourth nerve palsy
2. Third nerve palsy
3. Thyroid disease
4. Myasthenia gravis
5. Orbital floor fracture