Testing of Ocular Motility – Evaluation of the Extraocular Muscles

1. Testing of Ocular Motility – Evaluation of the Extraocular Muscles Robert P. Rutstein, OD Claudio Busettini, PhD

2. Review of the EOMs - Anatomy

4. Directions of eye movements Adduction: movement towards the nose Abduction: movement away from the nose (think abduction of a person: taken away) Elevation: movement upward Depression: movement downward Intorsion or incycloduction: torsional rotation towards the nose Extorsion or excycloduction : torsional rotation away from nose (think extorsionof money: taken away)

5. Actions of EOMs from Primary Position: Horizontal Recti

6. Actions of EOMs from Primary Position: Vertical Recti

7. not aligned with pivot point NOSE Superior rectus and inferior rectus have adduction as tertiary actions (View from above of the right eye)

8. Actions of EOMs from Primary Position: Obliques

9. NOSE not aligned with pivot point Inferior oblique and superior oblique have abduction as tertiary actions (View from above of the right eye)

11. Actions of EOMs not from Primary Position THE DIRECTION OF ACTION DEPENDS ON WHERE WE ARE WITH RESPECT TO THE MUSCLE PLANE: KEY FACTOR TO CONSIDER WHEN WE TEST OUR PATIENTS LOOKING AWAY FROM PRIMARY POSITION

12. Field of Action

13. Innervation: oculomotor nerve(cranial nerve III) • Somatic motor function: • innervation of FOUR of the 6 extra-ocular muscles: • Medial rectus • Superior rectus • Inferior rectus • Inferior oblique • and of the levatorpalpabraesuperioris (upper eyelid) • Visceral motor function: • parasympatheticinnervation of the constrictor pupillae (pupillary light reflex) • ciliary muscle (accommodation reflex)

14. upper eyelid control incycloduction accommodation and pupil responses excycloduction

15. Innervation: trochlear nerve(cranial nerve IV) ONLY FUNCTION: CONTROL OF THE SUPERIOR OBLIQUE MUSCLE

16. Innervation: abducens nerve(cranial nerve VI) ONLY FUNCTION: CONTROL OF THE LATERAL RECTUS MUSCLE

17. Clinical Testing • 1. Cover test in different positions of gaze • 2. Versions and ductions

18. Cover test

19. Versions/Ductions

20. Versions/Ductions

21. Oculomotor (III) nerve palsy

23. Trochlear (IV) nerve palsy

25. Abducens (VI) nerve palsy

26. 2 yo with unusual eye movements

28. Laboratory Testing • Eye movement recordings: - binocular viewing - monocular viewing - version/vergence - testing different types of eye movements • Deficits affecting both eyes (central issues) • MRI and fMRI

29. Types of eye movement recordings • Electro-oculography (EOG) • Limbus tracking (LEDs and FTRs) • Videoculography • Search coil

30. Electrooculography (EOG)

31. Videooculography

32. Search coil

33. Example ofoculomotordata

34. Example of damage to the trochlear nerve in a monkey

35. MRI Dumars et al. (2008) Magnetic resonance imaging of the endophenotype of a novel familial Möbius-like syndrome Quasi-coronal MRI of posterior right orbit (left column), mid-orbit (middle column), and anterior orbit (right column) for Case1 (top row), Case 2 (middle row), and Case 3 ( bottom row). As seen in the left column, the extraocular muscles are hypoplastic in the posterior orbit and motor nerves are barely detectable. There is relative sparing of the medial rectus (MR) muscles, which appear larger than the inferior (IR), lateral (LR), and SR muscles in the posterior orbit. Note larger rectus muscle cross sections in the mid-orbit (middle column) and anterior orbit (right column), although the levator muscle remains attenuated in the anterior orbit (right column). Note infraplacement of the lateral rectus (LR) relative to the medial rectus (MR) in Cases 1 and 2.