Nadia Northway
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Deviation varies with size and or direction of
gaze
In truth nearly all forms of strabismus are
incomitant to a degree but clinically there is
usually more than 5o difference before
incomitancy is noted.
C la ssifica tion
C o n ge n ital
N e u rog e n ic
T h ird n e rve p a lsy
F o u rth n erve p a lsy
S ixth n e rve p la sy
M e cha n ical
B ro w n's S ynd ro m e
D u a ne 's S yn dro m e
Classification
Acquired
Adults and childhood
Neurogenic
Third nerve palsy
Fourth nerve palsy
Sixth nerve plasy
Mechanical
Brown's Syndrome
Duane's Syndrome
Rare
Myogenic
Dysthyroid Eye disease
Myasthenia G ravis
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Vascular affects all nerves equally
Head trauma more commonly affects IVth
nerve but may affect all
Aneurysm most commonly affects IIIrd nerve
Neoplasm
Unknown
Other
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Diabetes
Thyrotoxicosis
Hypertension
Aneurysm
Giant cell arteritis
Multiple Sclerosis
Myasthenia Gravis
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History and symptoms
External Examination
Cover test
Motility
Ophthalmoscopy
Fields
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Diplopia
Abnormal head posture-chin, turn and tilt
Acuity
Associated symptoms
General health
Injury
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Strabismus
Lid position
Injury- chemosis, oedema
Proptosis
Pupils
Asymmetry
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Always turn in direction of action of palsied
muscle e.g. LMR palsy will turn to right
Always move chin in direction of action of
palsied muscle e.g. LSR palsy will elevate chin
Always tilt to lower eye
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Small deviation in primary position may
indicate very recent onset < 36 hours or
mechanical problem
In palsy- will be greater when fixing with the
affected eye and usually larger size of
deviation
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Know muscle actions
Take patients eyes into extremes of gaze
Use objective and subjective assessmentcorneal reflexes and CT. Do not rely on pt
reporting diplopia since suppression or poor
VA may affect results.
Hess chart and diplopia chart.
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RAD SIN- recti adduct and superiors intort
Recti muscles pull the eye in the direction of
their name in the abducted position
Obliques push the eye in the direction
opposite to their name in the adducted
position
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Original palsy
Overaction of the contralateral synergist
Overaction of the ipsilateral antagonist
Inhibitional palsy
This applies to neurogenic palsy and
after all stages of sequelae have occurred
concomitancy is achieved
IO
IO
SR
SR
MR
LR
LR
IR
SO
SO
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Overaction of contralateral synergist only
Left Brown’s syndrome overaction of right
superior rectus is seen
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Look for smallest field to identify affected eye
Look at center circle to determine deviation in
primary position
Look for area with greatest deflection to
identify affected muscles
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Used to differentiate between SR and SO palsy
Muscle sequelae identical
In left SO palsy deviation will increase when
head tilted to left due to unopposed action of
the LIO
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Complete or partial
Rare to find individual muscles affected but
Congenital SR palsy quite common
May also be multiple muscle involvement
including pupil and ciliary body
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Hypotropia of affected eye and may be
slightly exo
Chin elevation
Can be longstanding -usually have enlarged
fusion range and some suppression
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Hypertropia in primary position
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Hypotropia in primary position with possible
slight eso.
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Exo deviation
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Exotropia with hypotropia, ptosis and
possible dilation of pupil and accommodation
palsy
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Esotropia which is greater on distance
fixation
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Hypertropia with slight eso , eye also
extorted, greater at near
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Small devation in primary position but
hypotropia of affected eye on elevation in
adduction
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May be hypotrpia or hypertropia
Infraorbital anaesthesia
Chemosis
Vertical diplopia
Restricted eye movement in upgaze and
downgaze
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Wet phase when muscles swell -myogenic
Dry phase when eye movement restrictions
become mechanical in characteristics
Muscles affected - IR MR SR rarely LR
Proptosis or exophthalmos
Check Fields
Lid retraction and lid lag
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Mechanical
Small deviation in pp
Ductions and
versions equal
Ceasing of
movement abrupt
Pain
Reversal of diplopia
Upshoots and
downshoots
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Neurogenic
Large deviation in pp
Ductions better than
versions
Gradual failure of
movement
No pain
No upshoots and
downshoots
Differentiation of mechanical and
neurogenic palsy
• Mechanical
• Muscle sequelae- only
overaction of contra
syn
• Hess chart -pointed
field which look
squashed
• Neurogenic
• Full muscle sequelae
• Smoother filed on
Hess
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Longstanding
AHP - fixed and pt
usually unaware
No diplopia
Enlarged fusion
ranges
Old photographs
Gradual onset of
symptoms usually
Amblyopia
Suppression
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Newly acquired
Pt aware of AHP and
uncomfortable
Diplopia
Sudden onset
No enlarged fusion
range
Differentiate SR and SO palsy
• SO
• SR
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• Exo deviation more
typical
• AHP- chin elevation
• V exo pattern
• Greater deviation in
distance
• Bielchowsky -ve
• May have history of ptosis
• Diplopia greatest on
elevation
Eso deviation more typical
AHP - chin depression
V eso pattern
Greater vertical deviation
at near
• Bielchowsky +ve
• Diplopia greatest on
depression
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Sudden onset diplopia
Incomitant deviation previously unidentified
Uncomfortable head posture
Patient has localisation disturbance
Patient symptomatic
Other signs and symptoms