This document provides information on the management of intermittent exotropia. It defines intermittent exotropia as an abnormal outward deviation of one eye that is intermittent and has a constant angle of deviation. The causes include loss of concentration and fatigue. Intermittent exotropia is classified into basic type, divergence excess, and convergence insufficiency. Treatment involves glasses, occlusion therapy if needed, orthoptic exercises, and surgery if non-surgical methods fail or the deviation progresses to constant exotropia. The goal of treatment is to prevent amblyopia, which is commonly associated with intermittent exotropia. Regular follow up is important as intermittent exotropia is a progressive condition.

1. MANAGEMENT OF
INTERMITTENT XT
DR MOUSTAFA

3. INTERMITTENT EXOTROPIA
What is intermittent XT ?
It is abnormal relation between visual axis of both eyes which
characterized by:
1) Intermittent manifest outwards deviation of one eye .
2) Intermittent deviation control .
3) Constant angle of deviation .
It is the most common type of Exotropia
female represent 60–70% of patients who have intermittent Exotropia.
Age of onset < 5 years
It is a progressive disease .

4. What are the causes of intermittent XT ?
It is Stimulated by :-
1) loss of concentration / daydreaming .
2) Fatigue ( general / ocular )
3) Stress .
how ??
It has been explained by 2 theories :-
1. ( worth theory ) due to absent of fusion center in the brain . It is also
called (sensory cause) .
1. Chavasse theory ( mechanical cause ) / any lesion occurs during the
period of flux ( 3 months - 6 years ) leading to loss of SBV .

5. What are the clinical presentation of intermittent XT ?
1) Blurred vision .
2) Photophobia ( commonly results in Monocular eye closure )
3) Panoramic vision ( awareness of ++ VF )
4) +/- Transient diplopia .

7. CLASSIFICATION OF INTERMITTENT
EXOTROPIA

10. It can be classified into :-
a) Basic type
b) Divergence excess ( +++) which can be classified into /
1. True .
2. Simulated / pseudo.
c) Convergence insufficiency.

11. a) Basic type
o Exodeviation is equal or within 10 PD at far and at near fixation
b) Divergence excess
o Exodeviation at far is > deviation @ near ( > 10 PD ).
o It can be classified into :-
1. True divergence excess
2. Pseudo / Simulated divergence excess.
How to DD ( ) true & pseudo divergence excess ??
Exclude pseudo = true

12. Pseudo/ Simulated divergence excess
 It can be due to :
1) High AC/A
2) Tenacious proximal convergence . ( resistance to exodeviation)
 How to DD ??
Calculate AC/A . How ??
1) ------------------
2) -------------------
3) -------------------
RESULT :
 if +++ AC / A = pseudo XT.

13. If normal AC/ A = occlude one eye for 1hr. ( Marlow occlusion)
Why ??
To disperse the tonic convergence .
Means ??
To induce near exodeviation .
 Re- measure angle of deviation @ far and near .
 Result :
If deviation at near = deviation at far = pseudo XT.
 NB :
IF difference between deviation @ far and near is < 10 PD =
Diagnostic .

14. CONVERGENCE INSUFICIENCY
( reading Asthenopia )
• Def.
It is inability to maintain proper binocular eye alignment when the object moves
from distance to near.
• Causes
1) Idiopathic
2) Refractive ( uncorrected hyperopia, presbyopia )
3) head trauma
4) Lesion in pretectal area (convergence center)
5) TED
6) Psychological ..

16. Clinical presentation :
• Ch.ch by :
1.Asthenopia
2.Blurred near vision
3.Diplopia
4.False projection / poor stereopsis .
5.Difficult in Reading .
NB :
It is the COMMONEST Cause of Headache In ( Teenage )

17. What is normal near point of convergence ??
It is ( 6 – 10 ) cm
What is normal near point of accommodation ??
It is variable and differs with the age

18. How to treat ( convergence insufficiency ) ??
 If NPA = normal = means it is only convergence insufficiency.
 If NPA = REDUCED = convergence insufficiency + accommodative insufficiency.
From above :
Normal NPA /
1) Orthoptics exercise .
2) Relieving prism
3) Resection of MR BE
IF REDUCED NPA /
1) Orthoptics exercise .
2) Exercise prism ( base in )
3) Resection of BE MR followed by glasses .

19. What are the typical characteristics of intermittent Exotropia as it
worsens? ( how to grade intermittent XT ? )
At distance At near
Phase 1
Exophoria Orthophoria
Phase 2
Intermittent XT Orthophoria
Phase 3
XT Intermittent XT / Exophoria
Phase 4
XT XT

20. How to diagnose ( intermittent XT ) ??
 VA ??
To ----------------------
 Refraction ??
To -----------------------------
 CRT ( corneal reflex test ) & cover uncover test to detect is
there tropia ( manifest squint ) or not ?
 EOM ??
To DD ( ) -------------------------------------------------

21.  Measure the angle of deviation :
 What we mean by ( angle of deviation ) ??
--------------------------------------------------
 How to measure ( angle of deviation ) ?
1. PCT ( prism cover test ) .
2. Krimisky test .
3. Synoptophore
 What is most accurate method ?
--------------------------------
 How to select between PCT & Krimisky ?

30. How to manage ( intermittent XT ) ??
DON’T FORGET RULE OF ( GOOS )
G = GLASSES
O = OCCLUSION ( IF NEEDED )
O = ORTHOPTIC EXERCISE
S = SURGERY

31. Glasses ( spectacles )

32. Is there any special criteria for spectacles in children ?
yes
What are the criteria for spectacles in children ?
1) ---------------------------------
2) ---------------------------------
3) ----------------------------------
4) ----------------------------------
5) -----------------------------------

33.  What are the types of lenses ( depends on power ) can be used
for spectacles in children ?..
1) Monofocal . *
2) Bifocal **
3) Progressive ***
 Can we use trifocal lenses for spectacles in children ? Why ?
-----------------------
----------------------

34. Pt. with bifocal glasses -1.5 DS -0.75 DC 100 AX ADD +2.5 D how to
prescribe trifocal lens ?
- 1.5 DS -0.75 DC 100 AX ADD ( +1.25)( +2.5 )D
What are the types of bifocal lenses?
1. Flat top ( standard )
2. Round top ( ½ moon )
3. Executive
4. Blended ( the line in between is very fainted ) **

37. How High hyperopia can lead to XT ?
It cause blurs retinal images (due to inability to sustain
accommodation ) = BAD FUSION = XT.
How to correct hyperopia ?
1. Partial correction ( usually )
2. If high hyperopia = do full correction why ??
To improve the retinal image = good fusion = correct XT.

38. How to correct myopia ?
1. If simple myopia = Full correction ( usually )
2. If high myopia = over correction ( -2 to -4 D) why ??
To stimulate accommodative convergence to help control
the exodeviation.
What is the main disadvantage of using over correction in
myopia ?
-------------------------------------
don’t forget (-) lens stimulate accommodation …. So ??

39. Occlusion therapy

40. Don’t forget to answer on these questions
1) Which eye I'm going to cover ?
2) What are the types of patches used ?
3) What is the patching protocol ?
4) For how long I have to use the patching ?
5) If no improvement , what is the reasons ??
6) Is there any incidence of recurrence ?

41. Qu. Which eye going to be occluded ?
If centric fixation :
Cover the sound eye .
Why ??
to force the amblyopic one to act .
 if eccentric fixation :
Cover the amblyopic eye
Why ?
Try to force the eye to use the real fovea .

42. Qu. what types of eye patches used ?
It can be classified according to technique to /
1. Full time & part time
2. Full patch & partial
3. Direct & inverse .
 According to the material used /
1) Normal eye patches .
2) CL
3) Stickers over the eye if using glasses .
4) Frosted glasses can be used .
5) Translucent filter over the glasses .

48. Qu. what is patching protocol ?
1st of all , don’t forget the rule of
( one week / year )
Means ??
a) If my patient came at the age of 2 years = need 2 weeks
occlusion therapy .
b) At 3 years = needs 3 weeks of occlusion therapy .

49. Qu. How to select my patching protocol ?
1. According to the age of child :
Full time ( working / activities hrs. with 6 HRS maximum )
E.g.. School time
Disadvantages /
Can cause amblyopia in normal eye if used for a long time .
Part time ( depend on the age of child ) .

50. Age Duration
Birth – 1 month NO PATCH
< 6 months 15 min
6 – 12 30 min
12 – 18 ½ - 2 hrs.
18 – 3 yrs 2 – 4 hrs.
3 – 6 years 6 hrs.
> 6 years 6 hrs.

51. 2. According to severity of amblyopia :
Severity V/A Snellen Hours of patching / day
Mild
> 6 / 12 2hrs.
Moderate
6 / 24 4hrs.
Severe
6 / 36 6hrs.

52. Important notes
We should include at least 1hr. Of near activities of the
child among the occlusion hrs. .
So ,
1) At what time we have to start occlusion therapy ??
2) What is the best time of occlusion therapy ?
3) When can I say to the parents ( sorry it is now too late ) ?

53. For how long I have to use the patching ?
If no improvement after 3 months of treatment we can
consider as
failed .
then
try for active methods of treatment.

54. If no improvement , what are the reasons ??
1. Misdiagnose , untreated causes. ( doctor side )
2. Pt. noncompliance i.e. mother cant follow
instructions ( pt. side )
3. Irreversible amblyopia (nature of disease itself )
i.e. amblyopia become irreversible if child age > 13
years .

55. Can we get a recurrence of amblyopia ??
Yes
How ??
When the occlusion therapy interrupted for any reason

56. Orthoptics exercise

57. • Active Orthoptics treatment .
o Should be done with tt. Of amblyopia .
o It is mainly for near XT ( convergence insufficiency)
Give examples of Orthoptics exercises?
1. Pencil-push up exercise
2. Dot card exercise..

60. • Base in prisms ( relieving prism )
It is a Short term management especially in convergence
insufficiency with normal NPA.
Why ??
to abolish the complain of headache , but tropia will be there.
Pt. with convergence insufficiency with reduced NPA ,
which prism you are going to use ?
Exercising prism ( base out ) .

61. What is relieving prism ?
What is exercising prism ?

63. Surgery

64. Surgical treatment
Indications
1) Progression to constant Exotropia .
2) Manifestation of the deviation more than 50% of the daily time
3) After the age 7 years .
4) After 5 years of strabismus duration .
5) If poor control .
Procedures
o Recession of both LR ** commonly done
o Recession of 1 LR and resection of Ipsilateral MR especially in basic
type
o Unilateral LR recession – small exodeviation

67. Take home message
Amblyopia is commonly associated with intermittent
XT . SO ??
Treatment should be started ASAP.
Intermittent XT is a progressive disease SO ??
regular Follow up is very important ( every 6 months )

68. Thanks for attention