PARALYTIC STRABISMUS
Assist.Prof. Dr.Vildan Öztürk
Ophthalmology
Yeditepe University Hospital
STRABISMUS
Strabismus involves deviation of the
alignment of one eye in relation to the
other.
1. Non-paralytic strabismus
2. Paralytic strabismus
concomitant strabismus;
– due to faulty insertion of the eye muscles,
resulting in the same amount of deviation
regardless of the direction of the gaze
nonconcomitant strabismus;
– in which the amount of deviation of the
squinting eye varies according to the direction
of gaze
Strabismus=Squint, Wandering
eye
Esotropia=Crossed eyes
Exotropia=Walleye
ANATOMY
Anatomic axis
Visual (optical) axis
Kappa angle:
ANATOMY OF EXTRAOCULAR
MUSCLES:
The lateral and medial
walls of the orbit make an
angle of 45 degrees with
each other.
In primary position the
optical axis forms an
angle of 22.5 degrees
with the orbit.
ANATOMY OF EXTRAOCULAR
MUSCLES:
Primary action of the muscle is its major effect when
the eye is in primary position
Subsidiary actions are the additional effects of the
position of the eye
Listing plane is an imaginary frontal equatorial plane
passing through the center of rotation of globe.
-The globe rotates left and right around the vertical Y
axis
-The globe moves up and down around the horizontal X
axis.
-Torsional movements occur around the Z axis which
traverses the globe from front to back.
Z axis
X azis
Y axis
EYE MOVEMENTS
Ductions are monocular eye movements
around the axis of Fick. (X, Y, Z)
Adduction; movement of the eye nasally
Abduction; is temporal movement
Supraduction; elevation
Infraduction; depression of the eye
Incycloduction (intorsion); nasal rotation of the
vertical meridian
Excycloduction (extorsion); temporal rotation
of the vertical meridian.
SIX CARDINAL POSITIONS OF
GAZE
Up / right
Up / left
Right
Left
Down / right
Down / left
HORIZONTAL RECTUS
MUSCLES:
-Medial rectus: it’s action is
adduction
-Lateral rectus: it’s sole action is
abduction.
VERTICAL RECTUS MUSCLES
Superior rectus:
 primary action is elevation
 secondary actions are adduction and intorsion
Inferior rectus:
 primary action is depression
 secondary actions are adduction and
extorsion
OBLIQUE MUSCLES
Superior oblique muscle
– incyclotorsion.
– depression
– abduction
Inferior oblique muscle
– excyclotorsion
– elevation
– abduction
Muscle
Innervation
Primary
action
Secondary
action
Medial rectus
CN III
Adduction
Superior
rectus
CN III
Elevation
Intortion
Adduction
Inferior rectus
CN III
Depression
Extortion
Adduction
Inferior oblique CN III
Extorsion
Elevation
Abduction
Superior
oblique
CN IV
Intorsion
Depression
Abduction
Lateral rectus
CN VI
Abduction
--
--
Tertiary
action
--
--
Tillaux’nun Spirali
LAWS OF OCULAR MOTILITY
Agonist : the primary muscle that moves an eye
in a given direction
Synergist; muscle in the same eye that moves
the eye in the same direction as the agonist
Antagonist; muscle in the same eye that moves
the eye in the opposite direction of the agonist
muscle
Sherrington Law, increased innervation to any
muscle (agonist) is accompanied by a
corresponding decrease in innervation to its
antagonists.
LAWS OF OCULAR MOTILITY
Yoke muscles
– Primary muscles in each eye that accomplish
a given version.
– Each extra ocular muscle has a yoke muscle
in the opposite eye to accomplish versions
into each gaze position.
Herring Law;
– Yoke muscles receive equal and
simultaneous innervation;
– Magnitude is determined by the fixating eye.
BINOCULAR EYE MOVEMENTS
Conjugate (versions) are movements
of both eyes in the same direction
-Dextroversion is movement of both eyes
to the right,
-Levoversion is movement of both eyes
to the left.
-Supraversion; elevation of both eyes,
-Infraversion; depression of both eyes,
BİNOCULAR EYE MOVEMENTS
Disconjugate (vergences) are
movements of the eyes in opposite
directions.
-Convergence is movement of both eyes
nasally
-Divergence is movement of both eyes
temporally.
-Vertical vergence movements also may
occur.
TYPES OF STRABISMUS
Esotropia is inward turning
Exotropia is outward turning
Hypertropia is upward turning
Hypotropia is downward turning of
the eye.
ESOTROPIA
EXOTROPIA
HYPERTROPIA
HYPOTROPIA
HIRSCHBERG TEST
DIPLOPIA
Simultaneous
appreciation of two
images of one object.
It results from a failure
to maintain binocular
vision.
Binocular, monocular,
physiological
MUSCLE INNERVATIONS
medial rectus (MR)—cranial nerve III
lateral rectus (LR)—cranial nerve VI
superior rectus (SR)—cranial nerve III
inferior rectus (IR)—cranial nerve III
superior oblique (SO)—cranial nerve IV
inferior oblique (IO)—cranial nerve III
Extra ocular muscle paralysis resulting
from destructive lesions in one or all of
these cranial nerves results in failure of
one or both eyes to rotate in concert with
the other eye.
(LR6SO4)3
OCULAR MOTOR NERVE PALSIES
1. Third nerve
2. Fourth nerve
3. Sixth nerve
OCULOMOTOR (III.) NERVE
PALSY
• The oculomotor nerve innervates
•
•
•
•
•
superior rectus, inferior rectus, medial rectus,
inferior oblique,
levator palpebrae,
ciliary muscle
iris sphincter.
OCULOMOTOR (III.) NERVE PALSY
Anatomy of third nerve
Oculomotor nucleus
Pituitary gland
Red nucleus
Carotid artery
Cavernous sinus
Pons
III nerve
Post cerebral artery
Clivus
Basilar artery
Nuclear portion
Fascicular portion
– intraparenchymal midbrain portion
– subarachnoid portion
– cavernous sinus portion
– orbital portion
OCULOMOTOR (III.) NERVE PALSY
ANATOMY
The pupillomotor and ciliary muscle
neurons derive from the Edinger-Westphal
subnucleus, which is in the midline in the
most rostral and anterior part of the
oculomotor nerve nucleus.
These autonomic pathways are all
ipsilateral or uncrossed
Applied anatomy of pupillomotor nerve fibres
Blood vessels on pia mater supply surface
of the nerve including pupillary
fibres ( damaged by
compressive lesions )
Vasa nervorum supply part
of nerve but not pupillary
fibres ( damaged by medical
lesions )
Pupillary fibres lie dorsal and
peripheral
OCULOMOTOR (III.) NERVE PALSY
ETIOLOGY
A- Pupil involving
More common: Aneurysm ( particularly a post.
communicating artery aneurysm)
Less common: Ischemic microvascular disease ( DM
or HT), tumour, trauma, congenital
Rare: Uncal herniation, cavernous sinus mass lesion,
pituatery apoplexy, orbital disease, herpes zoster,
leukemia, in children ophthalmoplegic migraine
OCULOMOTOR (III.) NERVE PALSY
ETIOLOGY
B- Pupil–sparing: Ischemic microvascular
disease; rarely cavernous sinus syndrome,
giant cell arteritis (GCA)
C- Relative pupil-sparing: Ischemic microvascular
disease; less likely aneurysm
Etiology
Important causes of isolated third nerve palsy
Idiopathic - about 25%
Vascular disease - hypertension, diabetes
Trauma
Posterior communicating aneurysm
Extradural
haematoma
Midbrain
pushed
across
Edge of
tentorium
Aneurysm
Chiasm
Prolapsing
temporal
lobe
Third
nerve
Posterior
cerebral
artery
OCULOMOTOR (III.) NERVE PALSY
ETİOLOGY
Nuclear and fascicular midbrain portion
– Infarction
– Hemorrhage
– Neoplasm
– Abscess
OCULOMOTOR (III.) NERVE PALSY
ETIOLOGY
– Fascicular midbrain portion infarcts
Benedikt syndrome
– upper mid brain includes
– ipsilateral third cranial nerve palsy
– contralateral flapping hand tremor
– ataxia
Weber syndrome
– slightly more ventral lesion at the level of the third
cranial nerve fascicles in the mid brain
– ipsilateral third cranial nerve palsy
– contralateral hemiplegia or hemiparesis
OCULOMOTOR (III.) NERVE PALSY
ETIOLOGY
Fascicular subarachnoid portion
– Aneurysm
– Infectious meningitis - Bacterial,
fungal/parasitic, viral
– Meningeal infiltrative
– Carcinomatous / lymphomatous / leukemic
infiltration, granulomatous inflammation
(sarcoidosis, lymphomatoid granulomatosis,
Wegener granulomatosis)
OCULOMOTOR (III.) NERVE PALSY
ETIOLOGY
Fascicular cavernous sinus portion
– Tumor - Pituitary adenoma, meningioma,
craniopharyngioma, metastatic carcinoma
– Vascular
– Giant intracavernous aneurysm
– Carotid artery-cavernous sinus fistula
– Carotid dural branch-cavernous sinus fistula
– Cavernous sinus thrombosis
– Ischemia from microvascular disease in vasa
nervosa
– Inflammatory - Tolosa-Hunt syndrome (idiopathic
or granulomatous inflammation)
OCULOMOTOR (III.) NERVE PALSY
ETIOLOGY
Fascicular orbital portion
– Inflammatory, orbital inflammatory
pseudotumor, orbital myositis
– Endocrine (thyroid orbitopathy)
– Tumor (hemangioma, lymphangioma,
meningioma)
OCULOMOTOR (III.) NERVE PALSY
FREQUENCY
%30 of paralytic strabismus
MORTALİTY / MORBİDİTY
subarachnoid hemorrhage from berry
aneurysm of the posterior communicating
artery
meningitis or meningeal infiltrative
disorders, both infectious and neoplastic
OCULOMOTOR (III.) NERVE PALSY
SYMPTOMS
Binocular diplopia
Ptosis
Mydriasis
With or without pain
Signs of right third nerve palsy
• Ptosis, mydriasis and
cycloplegia
• Abduction in primary
• Normal abduction
• Intorsion on attempted
downgaze
position
• Limited adduction
• Limited elevation
• Limited depression
OCULOMOTOR (III.) NERVE PALSY
CRITICAL SIGNS
External ophthalmoplegia ( motility impaired)
1-Complete palsy: Limitation of ocular
movement in all fields of gaze except
temporally
2-Incomplete palsy:partial limitation of ocular
movement
3-Superior division palsy: Ptosis and inability to
look up
4-Inferior division palsy: Inability to look nasally
or inferiorly: pupil is involved
OCULOMOTOR (III.) NERVE PALSY
CRITICAL SIGNS
Internal ophthalmoplegia ( Pupil reaction
impaired)
1-Pupil involving: A fixed, dilated minimally
reactive pupil.
2-Relative pupil sparing: Pupil partially
dilated and sluggishly reactive to pupil
Hess chart of right third nerve palsy
Contraction of right chart and expansion of left
• Right chart - underactions of all muscles except lateral rectus and
superior oblique
• Left chart - overactions of all muscles except medial rectus and inferior
oblique
•
OCULOMOTOR (III.) NERVE PALSY
WORKUP
History
Complete ocular examination, Hess chart
Full neurologic examination
Internal medicine examination
Imaging study
MRI
CT
Cerebral angiography
OCULOMOTOR (III.) NERVE PALSY
WORKUP
Lumbar puncture
Histological findings
CBC
ESR
OCULOMOTOR (III.) NERVE PALSY
TREATMENT
Treat the underlying abnormality
If diplopia, an occlusion patch ( not for
children) or prisms
NSAIDs commonly are used to treat the
pain in ischemic third cranial nerve palsy.
Surgery may be performed after 6 months
Botulinum toxin injections
OCULOMOTOR (III.) NERVE PALSY
FOLLOW UP
Pupil sparing:
Observe daily for 5 to 7 days
Recheck every 4 to 6 weeks
If the function is not regained in 3 months, refer to
the internist+MRI
Pupil involving
If imaging and angiography are negative, follow
as pupil sparing case
OCULOMOTOR (III.) NERVE PALSY
Medical / Legal Pitfalls:
– The most common misadventure is failing to
undertake adequate workup for aneurysm in a
patient with third cranial nerve palsy.
– On the other hand, performing cerebral
angiography on patients with ischemic third
cranial nerve palsy poses distinct risks for
these patients, many of whom have severe
atherosclerosis.
Trochlear (IV.) nerve palsy
In 1935, Bielschowsky correctly noted that
trochlear nerve palsy was the most
common cause of vertical diplopia and
introduced his classic head-tilt test.
With greater clinical interest, the number
of identified fourth nerve palsies has
increased.
Trochlear (IV.) nerve palsy
The fourth cranial nerve innervates
superior oblique muscle
– intorts
– depresses
– abducts the globe.
Can be congenital or acquired, unilateral
or bilateral.
SO-LID
Anatomy of fourth nerve
Internal carotid artery
Postr. communicating
artery
III
VI
Postr.cerebral artery
Supr.cerebellar artery
Basilar artery
IV
•
•
•
Only cranial nerve to emerge dorsally
Crossed cranial nerve
Very long and slender
Trochlear (IV.) nerve palsy
Frequency
% 11 of all paralytic strabismus
Trochlear (IV.) nerve palsy
Pathophysiology
Congenital lesions are frequent. Head
posture is gained.
– secondary to dysgenesis of fourth nerve
nucleus
– abnormalities of peripheral nerve
– abnormal superior oblique muscle or tendon
Trochlear (IV.) nerve palsy
Pathophysiology
Acquired
– The long course of the trochlear nerve makes
it especially susceptible to injury in
association with severe head trauma.
Contrecoup forces can compress the nerve
against the rigid tentorium
– Vascular lesions are common.
Trochlear (IV.) nerve palsy
Etiology:
Idiopathic,
Severe head trauma,
Microvasculopathy secondary to diabetes,
atherosclerosis, or hypertension
There are rare reports of thyroid
ophthalmopathy and myasthenia gravis
presenting as isolated fourth nerve palsy.
Trochlear (IV.) nerve palsy
Etiology
Tumor, aneurysm, multiple sclerosis, or
iatrogenic injury
After cataract surgery. (Patients with underlying,
well-controlled, and asymptomatic fourth nerve
palsy may decompensate gradually as they lose
binocular function resulting from cataract.
Following restoration of good vision, these
patients become aware of diplopia.)
Trochlear (IV.) nerve palsy
SYMPTOMS
Binocular vertical diplopia
Reading diffuculty
Sensation that objects appear tilted
May be asymptomatic
Signs of right fourth nerve palsy
Right hyperdeviation in
primary position when left eye
fixating
• Excyclotorsion
•
•
Right underaction on
depression in adduction
• Vertical diplopia
•
Right overaction on left gaze
Trochlear (IV.) nerve palsy
SIGNS
Head tilt toward to contralateral shoulder to
eliminate diplopia. (Bielschowsky test )
Positive Bielschowsky test in right fourth nerve palsy
Absence of right
Increase in right
hyperdeviation on ipsilateral hyperdeviation on
contralateral head tilt
head tilt
Trochlear (IV.) nerve palsy
THREE-STEP TEST
Each step reduces by half the number of possible
affected muscles until only 1 remains.
First step is to identify the hypertropic eye in primary
gaze.
– This implicates depressors of hypertropic eye or elevators of
hypotropic eye.
Second step is to ascertain if hypertropia is worse on left
gaze or right gaze.
– This will identify 4 muscles that act in that direction of gaze.
Third step is to determine if hypertropia is worse on right
head tilt or left head tilt.
Trochlear (IV.) nerve palsy
WORKUP
History
Old photographs
ESR, fasting blood sugar, blood pressure
MRI, CT
Three step test
Hess chart
Hess chart of right fourth nerve palsy
•
•
•
•
•
No significant difference in chart size
Upward deviation of right fixation spot on inner chart (hypertropia)
Downward deviation of left fixation spot on inner chart
Right chart - underaction of superior oblique and overaction of inferior oblique
Left chart - overaction of inferior rectus and underaction of superior rectus
Trochlear (IV.) nerve palsy
TREATMENT
Treat the underying cause
Occlusion patch or prism in spectacles to relieve
the diplopia
Botulinum toxin also has been studied in
treatment of fourth nerve palsy. It is a
neuromuscular agent that acts presynaptically to
block neurotransmitter release and results in
muscle weakening. It may be used best to
correct residual deviation after strabismus
surgery to delay or avoid further surgery.
If head tilt and severe diplopia for reading insists
after 6 months, surgery may be performed
FOLLOW UP
Congenital IV. Nerve palsy; routine
Acquired IV. Nerve palsy;
Follow of the underlying cause
If work up negative, follow monthly up to 6 month,
then surgery may be needed
ABDUCENS (VI.) NERVE PALSY
Innervates the ipsilateral lateral rectus
which functions to abduct the ipsilateral
eye.
It has the longest subarachnoid course of
all the cranial nerves; therefore, its
syndromes are similar to those of the
fourth nerve because of their long
intracranial courses.
Anatomy of sixth nerve
Basilar artery
Medial
lemniscus
Pituitary gland
Carotid artery
4th ventricle
Cavernous sinus
Petroclinoid
ligament
Vestibular
nucleus
Clivus
VI nerve
Pyramidal tract
ABDUCENS (VI.) NERVE PALSY
ETIOLOGY
Younger patients; postviral syndrome,
trauma, increased intracranial pressure,
pontine glioma, Gradenigo’s syndrome
Adult population; vasculopathic, increased
intracranial pressure, GCA, cavernous
sinus mass
FREQUENCY
The most commonly affected of the ocular
motor nerves; % 45 of paralytic strabismus
Important causes of isolated sixth nerve palsy
Vascular - hypertension, diabetes
Raised intracranial pressure
Acoustic neuroma
Dilated
ventricles
Petrous
tip
Brainstem pushed downwards
ABDUCENS (VI.) NERVE PALSY
Mortality/Morbidity:
A young patient should have aggressive
workup because of the greater likelihood
of a neoplasm causing the palsy.
Patients older than 40 years require a less
aggressive workup because of the greater
likelihood of the etiology being more
benign in nature eg ischemic
mononeuropathy
SYMPTOMS
Patients usually present with horizontal
diplopia( side by side image) and an
esotropia in primary gaze. Esotropia
Head-turn
Recent right sixth nerve palsy
Right esotropia in primary
position due to unopposed
action of right medial rectus
Marked limitation of right
Abduction due to right lateral
rectus weakness
Old right sixth nerve palsy
Straight in primary position due to partial
recovery
Limitation of right abduction and
horizontal diplopia
Normal right adduction
WORKUP
Adults
History
Neurologic and ophthalmologic examination
Blood pressure , fasting blood sugar, ESR
MRI of the brain
Children
History
Neurologic and ophthalmologic examination
Otoscopic examination
MRI
Hess chart of recent right sixth nerve palsy
Contraction of right chart and expansion of left
• Right chart - marked underaction of lateral rectus and mild overaction of
medial rectus
• Left chart - marked overaction of medial rectus
•
TREATMENT
Underlying cause treated
Occlusion patch or prism in spectacles for
adults
Strabismus surgery for stable deviations
that persist more than 6 months
FOLLOW UP
Every 6 weeks until it resolves
MRI repetititon, if resistance 3 to 6 months