The document discusses exotropia, defined as an eye turning outward, describing types such as intermittent exotropia, which occurs occasionally, and constant exotropia. It covers evaluation and management of exotropia, including correcting refractive errors, orthoptic exercises, patching, prisms, and surgical options like recession of the lateral rectus muscle. The document provides details on differentiating and classifying types of exotropia based on clinical tests like the prism alternate cover test and monocular occlusion testing.

1. Exotropia
Dr. Aseel Al Rashdi

2. Definitions
• Exodeviation = eye turned outward
• Fovea is Temporal to the pupillary axis , LR will be nasal
Exodeviation = Divergence strabismus
Latent ( Phoria ) X Manifist (Tropia)
• Intermittent X(T)
• Constant XT

3. Pseudoexotropia ( Pseudo= false )
An appearance of exo deviation when
in fact the eyes are properly aligned
Why???
 Wide IPD
 positive angle kappa without other
ocular abnormalities
 positive angle kappa together with
other ocular abnormalities such as
temporal dragging of the macula in
ROP.

4. Exophoria X
1. Exodeviations controlled
by fusion under usual
conditions of seeing
2. detected by alternate
cover test
3. Tx usually unnecessary
4. Can progress to exotropia

5. Intermittent Exotropia X(T)
• Intermittent X(T) / Most common exotropia.
• Eliminated by fusional convergence ( Near 38PD , Distance14PD)
• Manifest with inattention , fatigue , end of the day ( loose ability to
convert ) .
• Exposure to bright light cause reflex closure of 1 eye .
• Good binocular vision , no diplopia .
• Amblyopia is rare.
• 80% progress to constant Exotropia in months to years .

6. • Phase 1 : occasional exotropia when binocular vision is lost at
distance , ortho at near .
• Phase 2 : increase exotropia at distance , occasional exophoria at
near.
• Phase 3 : constant exotropia at distance and near .
Exotropia Phases :

7. Intermittent Exotropia classificatios
Basic
exsotropia
True
divergence
excess
Pseudo-
divergence
excess
Convergence
weakness
Deviation same
at distance and
near
Deviation at
near only (CI)
or
near > distance
Divergence
distance > near
-Intially Divergence
distance > near
After 30 45 min monocular
occlusion
Near = Distance
Eg. Distance X(T) 35 PD
Near X(T) 30 PD

8. Patch Test ( monocular occlusion test ) differentiate
btw pseudo and tru divergence excess.
Step 1 ( true or pseud?):
studying tenacious proximal fusion.
Do monocular occlusion for 45 mins.
• If near PD did not change. It is TRUE DXT
• If near PCT (N) gets higher ( diffirence btw N and D > 10
PD) it is pseudo XDT.
Step 2 ( true with high AC/A ratio or true with normal AC/A
ration?):
Bilateral +3.00 lens.
if near PD gets high after +3 then it is true with high AC/A
ratio.
If near PD didn’t change, it is true WITH NORMAL
AC/Aratio.

9. Conclusion
Change in
findings ?
Monoculr
patch test ( 45
mins )
PCT (N) 20 PD
PCT ( D) 35 PD
remeasure
Yes
PCT ( N) 30PD
PCT ( D) 35 PD
PCT (N) becomes higher
Pesudo divergence
excess
No True Divergent execss
PCT ( N) same afer +3
lens
Normal AC/A ration
PCT ( N) higher after +3
lens
High AC/A ratio

10. Convergence weakness
• Convergence insufficiency ( CI) : only exodeviation at near .
• Usually older patients and complain of symptoms like asthenopia and
double vision when trying to read .
• Poor near fusional convergence amplitude .
• Tx :
• orthoptic exercise , pencil push-ups .
• Base-in reading prisms
• Surgical intervetion (MR rescess)
repeated 15 to 20 times during each session and repeated 2
to 3 times per day

11. Management of Intermittent Exotropia
1. Refractive error
• Myopia : correct fully
• Hyperopia : of > +4 D or hyperopic anisomeropia > +1.5 D
2. Add – (2-4) D lens to induce accommodative convergence .( for
some time ).
3. Patching the dominant eye / makes the divergent eye straight .
4. Alternate patching if no visual preference
5. Orthoptic treatment.
6. Prism : Base-in long term

13. Surgical management of Intermittent
Exotropia
1. Performed if intermittent X( T ) progress or progressing to consant
X(T) .
• Weakening of LR ( LR recession )
• Strengthening MR ( MR resection )
2. Botulinum toxin.

14. Constant X(T)
1. Infantile
2. Sensory
3. Consecutive
4. Decompensated intermittent X(T)

15. Infantile
• < 6 months
• Large angle constant deviation (usually > 35PD)
• Possibly associated neurological or craniofacial impairments .
• Tx :
• Amblyopia
• Refractive error
• Surgical correction ( 4m – 1 yr)

16. Sensory
• Caused by any condition that severely reduces VA in 1 eye
• Eg:
• ansometropia
• corneal/lens/retinal /optic N pathology such as :
• Retinoblastoma
• Unilateral cataract

17. Consecutive
• Formerly esotropic patient
• Either spontaneously
• after surgical overcorrection ( beyound 3-4 wks )
• After over refractive correction of esotropia ( ++ lens )
• Treatment:
◦ Correction of refractive error if present
◦ surgery(cosmetic)

18. Others : Secondary / Incomitant
 Neuromuscular (3rd nerve palsy , Mysthenia gravis )
 Restrictive
 Musculofascial innervational anomalies (Duane syndrome type 2 )
Duane syndrome
Oculomotor
nerve palsy

19. Clinical assessment
Brief History
• Presenting ocular ( onset , timing , near or distance , H/O trauma …)
• Presenting medical
• Past ocular
• Past medical
• Birth hx:
• Developmental hx: milestones
• Family hx:
• Treatment hx:

20. Clinical assessment
Examination :
AHP
VA
Light reflex LR ( Hirschberg LR test )
Steroacuity (check binocularity if possible )
EOM
CT
ACT
PCT
Patch test if needed
Cyclorefraction
Send for anterior and posterior segment examination .

21. Hirschberg Light reflex test

23. CT = LE XT
• Primary gaze
• Cover RE
• Uncover RE

24. Document the control of exotropia
• Good control : resumes fusion rapidly after removing the cover
• Fair control : resumes fusion rapidly after blinking or refixating.
• Poor control : exotropia manifest spontaneously and remain for a
while after cover removal .

25. Prism Alternate cover test
Base –In

26. ACT
Exophoria X
No Exotropia

27. EOM

28. Intermittent exotropia may be associated with
V pattern with Inferior oblique over action
A pattern with Superior oblique over action

29. Q& A
• 7 years old , RE deviated outwards intermittently, but most of the day
.
• Refraction : OD +2.5 , OS + 4 .
• Would you correct the refractive error with spectacles ?

30. Thank you ..
• Watch CT and ACT:
https://www.youtube.com/watch?v=PRa7mPx2XVs