Strabismus

1. Strabismus MohamadAbdelzaher 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. Rotation of the eye: center of rotation 12-13 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 • Definition “binocular vision” • Types • Aetiology • Clinical picture - compesatedvsdecompensated -- 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. 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 “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. 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: esotropiaexotropia hypertropiahypotropia • Acc to laterality of deviation: unilateral alternating • Clinical picture - ocular deviation - defective vision - diplopia???

49. Concomitant Esotropias

50. IO overaction