By: Qurat-ul-ain Ophthalmic Medical Technologist/ MBA Health & Hospital management

1. EXTRA OCULAR
MOVEMENTS
AND
STRABISMUS
By: Qurat-ul-ain
Ophthalmic Medical
Technologist/ MBA Health &
Hospital management

2. PREAMBLE
• EOM and their innervation
• Actions of EOM
• Duction
• Versions
• Vergences
• Strabismus

3. EXTRAOCULAR MUSCLES
• Muscles of the eyeball are called as Extra-ocular muscles (EOM).
• The eye-ball is chiefly moved by six extrinsic muscles. Distance between the
insertion of muscles and limbus for each EOM varies:
• Superior rectus  7.5 mm
• Lateral rectus  7.0 mm
• Inferior rectus  6.5 mm
• Medial rectus  5.5 mm
• :

4. INNERVATION
• Superior rectus
• Inferior rectus
• Medial rectus
• Inferior oblique
Aforementioned muscles are innervated by the oculomotor nerve (CN3).
• Superior oblique  innervated by trochlear nerve (CN4)
• Lateral rectus  innervated by abducent nerve (CN6)

5. ACTIONS OF EOM:
MUSCLES PRIMARY ACTION SECONDARY ACTIONS
Medial Rectus Adduction -
Lateral Rectus Abduction -
Superior Rectus Elevation Adduction & Intorsion
Inferior Rectus Depression Adduction & Extorsion
Superior Oblique Intorsion Depression & Abduction
Inferior Oblique Extorsion Elevation & Abduction

6. DUCTION:
Agonist Primary action moving the eye in any one direction.
Antagonist Muscles act in opposite to the Agonist muscles.
Synergist Muscles that support the action of agonist muscles.
Sherringtons Law of reciprocal
innervations
When agonist contracts, antagonists relax.
Involves the movement of only eye. Actions includes:
Adduction
Abduction
Supraduction
Infraduction
Incycloduction
Excycloduction

7. VERSIONS:
The four tertiary positions of gaze are:
• Dextroelevation
• Dextrodepression
• Laevo elevation
• Laevo depression
Six cardinal positions of gaze:
• Dextroversion
• Laevoversion
• Dextro elevation
• Laevo elevation
• Dextro depression
• Laevo depression
Binocular movements in the
same direction.
The four secondary positions of
gaze are:
• Dextroversion (right gaze)
• Levoversion (left gaze)
• Supraversion (Up gaze)
• Infraversion (Down gaze)

8. • Yoke muscle:
A muscle of one eye is paired with a muscle of the other eye while moving the eye
into each of the six cardinal position of gaze.
Dextroversion (LR of right eye and MR of left eye)
Dextroelevation (SR of right eye and IO of left eye)
• Herings law of equal innervation:
It says that during any conjugate eye movement equal and simultaneous innervations
follows to the yolk muscle. So, a paresis of one muscle is associated with over action
of its yolk muscle or contra lateral synergist and it results in more secondary angle
deviation in paralytic squint.

9. VERGENCES:
Binocular movements but in the opposite directions (convergence &
divergence). The convergence may be voluntary or reflux. The reflux
convergences are of 4 types:

10. Tonic
Due to inherent
tone of medial
recti muscle.
Proximal
Due to
psychological
awareness of a
near object.
Fusional
Maintained by
binocular
single vision
(BSV), so that
similar images
are projected
onto the
corresponding
rertina.
Accommodati
ve
Each diopter of
accommodation is
accompanied by a
constant increment in
accommodative
convergence, giving the
AC/A ratio. This is the
amount of convergence
in prism diopter per
diopter. The normal value
is 3-5 prism. This means
that 1D of
accommodation is
associated with 3-5 prism
of accommodative
convergence.

11. SUPRA-NUCLEAR EYE MOVEMENT
Saccadic
Rapid- voluntary and
refixating eye
movements
Pursuits
Smooth following
movements to maintain
vision on a slow moving
object.
Vestibulo-ocular
Vestibular nystagmus in
caloric test.

12. STRABISMUS

13. TYPES OF STRABISMUS
a) Pseudo-strabismus
• It’s a clinical impression of ocular
deviation when no squint is present.
• Epicanthal folds
• Abnormal interpupillary distance
• Angle kappa
b) Heterophoria
• May present clinically with associated
visual symptoms when the fusional
amplitudes are insufficient to maintain
alignment, particularly at times of stress
or poor health.

14. c) VERGENCE ABNORMALITIES
Convergence
insufficiency
(CI)
Typically affects individuals
with high near visual
demand.
SIGNS
Remote near point of
convergence (NPC)
independent of any
heterophoria & poor fusional
convergence amplitudes.
Accommodative
Insufficiency (AI):
Occasionally also present.
May be idiopathic or post-
viral. The minimum reading
correction to give clear vision
is prescribed.
Divergence
insufficiency
Divergence paresis or
paralysis is a rare
condition typically
associated with
neurological disease, such
as intra-cranial space-
occupying lesions,
cerebrovascular accidents,
and head trauma. May be
difficult to differentiate
from 6th CN palsy &
primarily a concomitant
esodeviation.
Near reflex
insufficiency
Presents as dual
convergence &
accommodation
insufficiency. Mydriasis
may be seen on
attempted near fixation.
Complete paralysis in
which no convergence
and accommodation can
be initiated due to mid
brain disease or after
head trauma.
Spasm of the
near reflex
It’s a functional condition
affecting patients of all
ages. Diplopia, blurred
vision and head aches are
the presenting symptoms.
Signs:
Esotropia, pseudomyopia,
miosis
Spasm may be triggered
when testing ocular
movements.

15. d) ESOTROPIA
Accommodative Esotropia
• Refractive
Fully accommodative
Partially accommodative
• Non-refractive
With convergence access
With accommodation weakness
Mixed
Non-accommodative
Esotropia
• Early onset (congenital, essential infantile)
• Microtropia
• Basic
• Convergence excess
• Convergence spasm
• Divergence insufficiency
• Divergence paralysis
• Sensory
• Consecutive
• Acute onset
• Cyclic

16. EXOTROPIA
• Constant (early onset)
• Intermittent
• Sensory exotropia
• Consecutive exotropia

17. CONGENITAL CRANIAL
DYS-INNERVATION
DISORDERS
• Duane retraction syndrome
• Mobius syndrome
• Congenital fibrosis of the EOM
• Strabismus fixus
ALPHABET PATTERNS
V- pattern
A- pattern

18. THANK YOU!