Strabismus For Medical Students & GP Samir Jamal MD, FRCSC KAUH

Strabismus Misalignment of one or both eyes so as the eye (eyes) is not looking straight at the object of regard.

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.

Significance in Adults Frequent sign of neurological disease Frequent presentation of systemic disease ( Thyroid disease & Myasthenia) Cosmetology

Types of Eye Movements Horizontal direction Vertical direction Torsional direction All superior muscles are intortors. All inferior muscles are extortors.

Anatomy & Physiology Muscle Nerve Function Testing MR 3 rd Nasal Look to nose LR 6th Temporal Look away SR 3rd Elevate, intorts, adducts Up & Out IR Depress, extrorts, adduct Down & Out

Anatomy & Physiology Muscle Nerve Function Testing Superior Oblique 4th Intorts, depress, abducts Look Down & In Inferior Oblique 3rd Extrorts, elevates, abducts Look Up & In

Types of Strabismus Esodeviation  eye turned in Exodeviation  eye turned out Hyperdeviation  eye turned up Hpodeviation  eye turned down

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

Non-Accommodative Esotropia

Alternating Esotropia

Exotropia

Alternating Esotropia

Causes of Strabismus Congenital: imbalance between innervations and contraction Refractive errors Loss of vision Paralysis or Neuromuscular Restrictive: thyroid eye disease Tumors

Strabismus secondary to loss of vision from Cataract in Lt. eye

Presenting symptoms of Strabismus Deviation of the eye (cosmesis) Double vision Torticollis (abnormal head posture) Unexplained visual loss in a normal looking eye (Microtropia)

Abnormal Head Posture

Role of GP Confirm Diagnosis Decide on urgency Teach patients Referral to Ophthalmologist

Management of Strabismus History: 4 most important questions: Age of onset Constant or intermittent Unilateral or alternating Diplopia or torticollis

Management of Strabismus Examination: Three objectives: Confirm the diagnosis Diagnose type of strabismus Differentiate paralysis from no paralysis

Examination of Strab Patient To achieve the first and second objectives we do: Simple observation for the nasal white of the eye Corneal light reflex Cover test

Examination of Strab Patient To achieve the 3 rd objective we look for: Presence of torticollis 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.

Examination Test the extraocular movements in all directions of gaze. Paralysis / restriction  Limitation No Paralysis  No limitation

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.

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

Non-Accommodative Squint Non-Accommodative Esotropia Before and After Surgery

Partially Accommodative Squint

Common Forms of Exotropia Congenital exotropia Surgery Sensory deprivation exotropia Third nerve paralysis

Common Causes of Hypertropia or Hypotropia Fourth nerve palsy Third nerve palsy Thyroid disease Myasthenia gravis Orbital floor fracture