The document discusses different types of divergent strabismus (exotropia), including congenital, primary, sensory/secondary, and consecutive exotropia, detailing their characteristics, symptoms, and potential treatments. It emphasizes the importance of early diagnosis and intervention to prevent complications such as amblyopia, and it outlines various patterns of strabismus related to vertical gaze. Treatment options vary based on the type of exotropia and may include amblyopia therapy, surgical procedures, and vision therapy.

1. DIVERGENT STRABISMUS

2. DIVERGENT STRABISMUS/EXOTROPIA
 Exotropia is characterised by outward
deviation of one eye while other eye fixate.
TYPES
 Congenital exotropia /Infantile exotropia
 Primary exotropia
 Sensory/secondary strabismus
 Consecutive exotropia
 XT of divergent excess type.

3. CONGENITAL EXOTROPIA
 It is an extremely rare condition
 Infantile exotroia has been defined as
large(>30 d) constant exotropia that develops
during first 6 to 12 months of life.
 Size of the angle may increase over time.
 Chance for amblyopia is much greater in this
exotropia.

4. SYMPTOMS OF INFANTILE EXOTROPIA
 Cosmetic disfigurement.
SIGNS OF INFANTILE XT
 Large angle constant exo deviation mostly more than 35
PD.
 Poor fusion
 Patient may have co existing craniofacial-ocular or
systemic abnormality
 Eg; Albinism, cerebral palsy,

5. TREATMENT OF INFANTILE XT
 Amblyopia therapy to be treated as early
as possible
 Surgical procedure; recession of
bilateral lateral rectus .

6. PRIMARY EXOTROPIA
 It may be unilateral or alternating and may present as intermittent
or constant XT.
INTERMITTENT XT
 It is the most common type of exodeviation.
 Age of onset is usually early between 2-5 years.
 Deviation become manifest at times and latent at others.
Precipitating factors include bright lights, fatigue, ill health and day
dreaming.
 Sensory testing usually reveals good fusion, stereopsis and no
amblyopia.

7. CONSTANT XT
 If not treated in time the intermittent XT may
decompensate to become constant XT.
TYPES
 Convergence insufficiency type :
○ XT greater for near than distance.
 Divergent excess type:
○ XT greater for distance than near.
 Basic or non-specific type:
○ XT equal for near and distance

8.  It usually starts at the age of 2 yrs &
associated with normal fusion and no
amblyopia.
 Stereopsis is usually absent.

9. SENSORY/ SECONDARY STRABISMUS
 It is a constant unilateral condition that
develops as a result of poor visual function
in one eye.
 Common causes are traumatic cataract,
unilateral aphakia, corneal opacity, optic
atrophy, anisometropic amblyopia, retinal
detachment, organic macular lesions and
any other organic cause of unilateral loss
of vision.

10. CLINICAL FEATURES
 Monocular vision loss
 Cosmetic complaints
SIGNS
 Large angle(30-60PD) unilateral
strabismus.
 VA is decreased in the affected eye
 There may be relevant history of
congenital cataract, ROP, trauma etc.

11. TREATMENT
 Surgery

12. CONSECUTIVE XT
 It refers to occurrence of XT in an eye which was
previously esotropic.
CLINICAL TYPES
 Surgical overcorrection of esotropia.
 Spontaneous consecutive exotropia is change of
esotropia into exotropia without exogenous mechanical
factors or an acquired paralysis of medial rectus muscle.
 Hypermetropia >+4.50D is the srongest risk factor for
the non-surgical development of XT,

13. SYMPTOMS
 Cosmetic problems.
 Diplopia is rare, but it may occurs in the strabismus
deviation changes in adulthood.
SIGNS
 Moderate to large angle usually constant exotropia is
present.
 The deviation may not be concomitant if the patient had
prior surgery.
 There may be H/O infantile esotropia that may have been
treated surgicaly.

14. TREATMENT
 Reduction of the hyperopic correction or
the use pf overcoorecting minus lenses
(it stimulate accommodation).
 Surgery.

15. XT OF DIVERGENT EXCESS TYPE
 It is an intermittent XT whose angle of
deviation at distance is atleast 10-15PD
grater than at near.
SYMPTOMS
 Photophobia
 Cosmetic problems
 Asthenopic symptoms and diplopia are
rare.

16. SIGNS
 A concomitant XT is greater at distance
than at near.
 An XT of V-pattern may be present.
 When eyes are in orthoposition ,
patients generally exhibits normal retinal
correspondence, good steriopsis and
good NPC.
 When the deviation is present either
NRC with suppression or ARC.

17. TREATMENT
 Vision therapy or surgery.

18. A-V PATTERN
 Horizontal deviations (esotropia & exotropia) which may be
comitant in horizontal gazes, may not be comitant in
vertical gazes, on looking up and looking down. They are
said to be ‘vertically incomitant-comitant horizontal
deviations’.
 In simpler terms they are described as A-V pattern.
 Thus an exodeviation, which becomes more divergent in
up gaze and less divergent in down gaze is said to have a
‘V’ pattern.
 An eso deviation with ‘V’ pattern would be more converge
in down gaze and less converge in up gaze.

19.  The reverse is ‘A’ pattern.
 In addition to these four common
patterns, other patterns are also seen
there.

20. 1 A - EXOTROPIA Exo deviation more in down gaze & less in up
gaze
2 A - ESOTROPIA Esodeviation more in up gaze and less in down
gaze
3 V - EXOTROPIA Exodeviation more in up gaze & less in down gaze
4 V – ESOTROPIA Eso deviation more in down gaze & less in up
gaze
5 X - EXOTROPIA No deviation/ only a small one in primary position,
but a significant XT is present in up gaze as well
as in down gaze.
6 Y – EXOTROPIA Exotropia only in up gaze
7 λ – EXOTROPIA Exotropia only in down gaze
8 E -EXOTROPIA
(DIAMOND)
Exodeviation is more in primary position only and
not in the up and down gaze.

21. M

22. ETIOLOGY
1. HORIZONTAL SCHOOL
 It says the role of horizontal recti by
assuming that the lateral recti are more
effective in up gaze and medial recti are
more effective in down gaze.
 So overaction of the lateral recti causes
V- exptropia and underaction of medial
recti causes A- exotropia.

23. PATTERN CAUSE
V- EXOTROPIA OVERACTION OF LR
V- ESOTROPIA OVERACTION OF MR
A- EXOTROPIA UNDERACTION OF MR
A-ESOTROPIA UNDERACTION OF LR

30. V PATTERN EXO TROPIA

32. V PATTERN ESOTROPIA

33. A -PATTERN EXOTROPIA

34. A -PATTERN

35. V PATTERN

36. 2. STRUCTURAL FACTORS
 Variation of skull and orbital bones are
known to have underaction or overaction
of oblique muscle.
 This may be due to variations in the site
of origin or insertion of inferior oblique or
superior oblique.

37. 3. ANOMALIES OF MUSCLE INSERTION
 Anomalies of insertion of vertical and horizontal rectii
or oblique muscle are also known to cause A-V pattern
4. VERTICAL SCHOOL
 It says the role of vertical rectii, in the etiology of A-V
pattern
 The principle behind being the adducting property of
vertical recti.
 Thus weak SR would result in less adducting power in
upgazes causing a V- pattern.

38.  Since the action of vertical recti and
oblique muscles are linked inseperably.
 Thus underaction of SR would have
underacting SO (ipsilateral antagonist of
contralateral synergist).
 It is also called as cycloverical school.

39. OVERACTING MUSCLE & PATTERN
CAUSED
OVERACTING
MUSCLE
UNDERACTING
MUSCLE
PATTERN
CAUSED
IR, IO SR, SO V- PATTERN
SR, SO IR, IO A- PATTERN

41. INVESTIGATION
 Horizontal deviations are measured in
25* upgaze and 35* downgaze in
addition to primary position.
 A 15 PD difference is taken as
significant for V- pattern and 10PD
difference is taken as significant for A-
pattern.

42. Treatment
 Pre Treatment Evaluation
 Detailed History
 Assessment of BCVA
 Cycloplegic Refraction and correction
 Measurement of angle of deviation in all the 9
positions of gaze for near and far, with and
without optical correction
 Uniocular and binocular motility.

43.  If the pattern is significant and syptomatic it
needs to be operated.
 all cases of exodeviations & esodeviations
should be checked for A & V patterns.
 In case of muscles over action , it should be
weakened
 In case of muscles under action , it should
be strengthen.