1. Mohamad Abdelzaher MSc
Strabismus
Mohamad Abdelzaher
MSc

2. The reason why so few good books are written is that so few people who can write know anything.
Walter Bagehot

3. Anatomy of EOMs
4 recti
2 obliques

4. Origin

5. Annulus of Zinn

6. Course of EOMs

7. Insertion of recti:
Spiral of Tilluax

8. Insertion of obliques

9. Nerve Supply:
III nerve: all except,
L6 SO4

10. center of rotation 12-13 mm behind cornea
Rotation of the eye:
center of rotation mm behind cornea
Adduction (Z)
Abduction (Z)
Elevation (X)
Depression (X)
Intorsion (Y)
Extorsion (Y)

11. Action of EOMs

12. Orbital vs Visual axes * Action of right SR

13. Action of right SO

15. Regarding the torsion movement:
“There is only on (I) in the sentence”
SO Intorsion
IO Extorsion
SR Intorsion
IR Extorsion

16. Action of EOMs

17. Binocular movement

18. Diagnostic positions of gaze

19. Binocular Vision

21. Pseudo Strabismus Pseudo eso Pseudo exo Pseudo hyper Pseudo hypo
CORNEAL LIGHT REFLEX

22. Epicanthus

23. Ptosis

24. Heterophoria - compesated vs decompensated
Definition “binocular vision”
Types
Aetiology
Clinical picture
- compesated vs decompensated
-- how to dissociate binocular vision:
1) cover test
2) Maddox rod
3) Maddox wing

25. Cover test Cover – Uncover test Orthophoria, normal
No complaints, asymptomatic

26. Cover – Uncover test
Esophoria, abnormal, common
Only seen when eye is covered
Often asymptomatic, no complaints
Note OS does not move.

27. Cover – Uncover test
Exophoria, abnormal, common
Only seen when eye is covered
Note OS does not move
Often asymptomatic, no complaints.

28. Maddox rod

29. Maddox wing

30. 1) correct refractive error
Treatment:
Indications
Lines:
1) correct refractive error
2) orthoptic exercise: pencil-nose exercise
exercising prism
synoptophore
3) Relieving prisms
4) Surgery

31. Exercising prisms
e.g. base-out prism to exercise exophoria

32. synoptophore

33. Paralytic squint Definition “angle of deviation”
Aetiology: LMNL - nuclear
- nerve
- muscle
Congenital
Traumatic
Inflammatory
Vascular
Neoplastic
Metabolic
Toxic

34. Symptoms:
Diplopia
Ocular deviation
Abnormal head posture

35. Signs:
Ocular deviation:
“Hering law” “Angle of deviation”

36. 2) Limitation of movement 3) Binocular diplopia - homonymous
“9 diagnostic positions of gaze”
3) Binocular diplopia - homonymous
- heteronymous

37. 4) Diplopia chart

38. Complications: Direct antagonist ------------- contracture
Indirect synergist  contracture
Contralateral antagonist --- underaction

39. False projection (Hess screen)
OD LR Palsy

40. Clinical features of nerve palsies
6th nerve palsy:
Ocular deviation
Binocular diplopia
Limitation of ocular movement
Abnormal head posture

41. 4th nerve palsy: Ocular deviation Binocular diplopia
Limitation of ocular movement
Abnormal head posture

42. Pupil 3rd nerve palsy: Ocular deviation Binocular diplopia
Limitation of ocular movement
Abnormal head posture
Pupil

43. Treatment: - Treat the cause Temporary treatment: occlusion, prisms
Surgical treatment: weakening > recession
strengthening > resection

44. Questions
1. You have a patient with diplopia. His left eye is turned down and out and his lid is ptotic on that side. What nerve do you suspect and what should you check next?
This sounds like a CN3 palsy, and you should check his pupillary reflex. Pupillary involvement means the lesion is from a compressive source such as an aneurysm.

45. 2. This 32 year old overweight woman complains of several months of headaches, nausea, and now double vision. What cranial nerve lesion do you see in this drawing. What other findings might you expect on fundus exam and what other tests might you get?
This looks like an abducens palsy … actually a bilateral 6th nerve palsy as the patient can’t get either eye to move laterally. While the majority of abducens palsies occur secondary to ischemic events from diabetes, this seems unlikely in a young patient. Her symptoms sound suspicious for pseudotumor (obese, headaches). You should like for papilledema of the optic nerve, get imaging, and possibly send her to neurology for a lumbar puncture with opening pressure.

46. 3. A patient is sent to your neurology clinic with a complaint of double vision. Other than trace cataract changes, the exam seems remarkable normal with good extraocular muscle movement. On covering the left eye with your hand, the doubling remains in the right eye. What do you think is causing this case of diplopia?
The first question you must answer with a case of diplopia is whether it’s monocular or binocular. This patient has a monocular diplopia. After grumbing to yourself about this patient being inappropriately referred to your neurologic clinic, you should look for refractive problems in the tear film, cornea, lens, etc..

47. 12. A young man complains of complete vision loss (no light perception) in one eye, however, he has no pupil defect. Is this possible? How might you check whether this patient is “faking it?”
Assuming the rest of the eye exam is normal (i.e. the eye isn’t filled with blood or other media opacity) this patient should have an afferent pupil defect if he can’t see light. There are many tests to check for malingering: you can try eliciting a reflexive blink by moving your fingers near the eye. One of my favorite techniques is to hold a mirror in front of the eye. A seeing eye will fixate on an object in the mirror. Gentle movement of the mirror will result in a synchronous ocular movement as the eye unconsciously tracks the object in the mirror.

48. Concomitant squint Definition “angle of deviation” Types:
- Acc to direction of deviation: esotropia exotropia
hypertropia hypotropia
Acc to laterality of deviation: unilateral alternating
Clinical picture
- ocular deviation
- defective vision
- diplopia???

49. Concomitant Esotropias
Non Accommodative
Accommodative
Essential: 6 mo, >15ᵒ, ref +2D, DVD,IO overaction Cross fixation
Sensory (Amblyopia)
Convergence excess
Divergence insuffeciency
Basic
Microtropia
Acute
Refractive
(normal AC/A ratio)
- Full
- Partial
Non-refractive
(abnormal AC/A ratio)
Accommodation weakness

50. IO overaction

51. DVD

52. AC/A Ratio

53. Refractive Accommodative Esotropia

54. Refractive Partially Accommodative Esotropia

55. Convergence excess esotropia

56. Concomitant Exotropias
Early onset: at birth, normal refraction, large angle, associated neurological manifestations, surgical ttt
Intermittent: around 2 years, decompesated exophoria
Sensory: older children & adults
Consecutive: following surgical correction of ET

57. Management of strabismus
History: age of onset, duration, glasses
Exam ocular media: cornea, lens, …
Fundus exam & refraction (cycloplegic)
VA: Amblyopia
Motility in 9 directions of gaze

58. Cover test Alternate Cover test Exotropia, intermittent
May be visible with or without alternate cover
May have intermittent diplopia, especially when tired or sick
Mom sees misalignment every now and then.

59. Alternate Cover test
Exotropia, Constant
May be visible with or without alternate cover
May or may not have constant diplopia

60. Measurement of angle of deviation:
Corneal reflex: pupillary magin ᵒ
midway ᵒ
limbus ᵒ
Prism: 1ᵒ = 2 ∆
Synoptophore

61. Alternate Cover test with Prism Exotropia, Constant
Prism cover test 20
Alternate Cover test with Prism
Exotropia, Constant
Use prism to quantitate the deviation.
Change prism power until movement is neutralized.

62. Worth 4 dot test (Binocular vision)

63. Treatment Aims: Lines: Restore binocular vision Improve VA
Restore normal appearance
Lines:
Cycloplegic refraction & error correction
Treat amblyopia: occlusion – penalization
Treat eccentric fixation (Pleoptics)
Orthoptics
Surgery

64. Nystagmus Definition Types Pendular Jerky Vestibular Central Ocular
Physiological
Pathological

65. Clinical Approach to squint

66. History Age of onset: - Documentation - Significance
Direction of deviation: Eso, Exo, Hyper, Hypo
Which eye: Alternate? Always the same eye?
Mode of onset: sudden? Gradual? Ppt factors
Type of deviation: Constant? Intermittent?
Family photos
Essential ET (6mo) – Accommodative ET (3yrs)
Amblyopia
H/O trauma, fever, neurologic disorder
Intermittent  fusion present  good prognosis

67. 6) Prior treatment: Glasses. Occlusion. Prisms. E. D. Surgery
6) Prior treatment: Glasses? Occlusion? Prisms? E.D? Surgery? 7) Medical History: Birth weight, Incubation, Neurological
ROP
Mysthenia

68. Clinical Approach to squint
Family photos
Amblyopia
H/O trauma, fever, neurologic disorder
Intermittent  fusion present  good prognosis
Intermittent exotropia, corneal or conj disease
ROP
Mysthenia

69. Inspection of the patient
Lid fissure:
Ptosis
III nerve palsy - mysthenia

70. Exophthalmos - Enophthalmos
Graves’
blow out fracture

71. Hypertelorism - Epicanthal folds
Pseudo Exotropia
Pseudo Esotropia

72. 2) Head posture
Face turn
Head tilt
Chin up/down
Right VI palsy

73. 3) Fixation preference:
Unilateral
Alternating
Amblyopia

74. Alternate Cover test
Exotropia, Constant

75. 4) Constancy of deviation:
Constant
Variable
- Incomitant
- Uncorrected refractive error
Hering law

76. 5) Nystagmus
Essential ET
Oscillopsia

77. III nerve palsy - mysthenia
Graves’ – blow out fracture
III nerve palsy
Pseudo strabismus
Amblyopia
- Incomitant
- Uncorrected ref error

79. Assessment of vision in non verbal children
Visual Acuity
Assessment of vision in non verbal children
Fixation and following
Preferential looking
Catford drum
VEP

80. Stereopsis
Binocular Vision
Titmus Fly test

81. Ductions & Versions
Duction movement

82. Binocular movement

83. Diagnostic positions of gaze

84. Cover test Cover – Uncover test Orthophoria, normal
No complaints, asymptomatic

85. Cover – Uncover test
Esophoria, abnormal, common
Only seen when eye is covered
Often asymptomatic, no complaints
Note OS does not move.

86. Cover – Uncover test
Exophoria, abnormal, common
Only seen when eye is covered
Note OS does not move
Often asymptomatic, no complaints.

87. Cover test Alternate Cover test Exotropia, intermittent
May be visible with or without alternate cover
May have intermittent diplopia, especially when tired or sick
Mom sees misalignment every now and then.

88. Alternate Cover test
Exotropia, Constant
May be visible with or without alternate cover
May or may not have constant diplopia

89. Alternate Cover test with Prism Exotropia, Constant
Prism cover test 20
Alternate Cover test with Prism
Exotropia, Constant
Use prism to quantitate the deviation.
Change prism power until movement is neutralized.

91. Questions
A mother brings in her 5-month-old boy because his eyes have been tearing for a couple of months. On further questioning, she reports no discharge or redness, but he squints and turns away from bright lights. He has no significant past ocular or medical history. 
 1   What is the differential diagnosis?
  2   What exam findings would you look for?

92. You are asked to see a 3-year-old girl with an eye turn
You are asked to see a 3-year-old girl with an eye turn. Apparently the child's eyes have turned inward since she was a baby, but now the mother notices that the left eye also goes up.  
1   What is the differential diagnosis?
 2   What exam findings would enable you to determine the correct diagnosis?
Additional information: her best-corrected visual acuity is 6/6 OU with +1.00 D OD and +1.50 D OS. The AC/A ratio is normal. The ET is comitant and measures 35 prism diopters at distance and near. She does cross fixate, and there is inferior oblique overaction. There is also no dissociated vertical deviation (DVD) or latent nystagmus present. Worth 4 dot testing demonstrates suppression OS
 3   What type of esotropia does this girl have?

93. Thank you