Testing of Ocular Motility – Evaluation of the
Extraocular Muscles Robert P. Rutstein, ODClaudio Busettini, PhD
Review of the EOMs - Anatomy
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 extorsion of money: taken away)
Actions of EOMs from Primary Position: Horizontal Recti
Actions of EOMs from Primary Position: Vertical Recti
Superior rectus and inferior rectus have adduction as tertiary actions
(View from above of the right eye)
NOSE
not aligned with pivot point
Actions of EOMs from Primary Position: Obliques
Inferior oblique and superior oblique have abduction as tertiary actions
(View from above of the right eye)
NOSE
not aligned with pivot point
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
Field of Action
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 obliqueand of the levator palpabrae superioris (upper eyelid)Visceral motor function:-parasympathetic innervation of the constrictor pupillae (pupillary light reflex)- ciliary muscle (accommodation reflex)
accommodation and pupil responses
excycloduction
incycloduction
upper eyelid control
Innervation: trochlear nerve(cranial nerve IV) ONLY FUNCTION: CONTROL OF
THE SUPERIOR OBLIQUE MUSCLE
Innervation: abducens nerve(cranial nerve VI) ONLY FUNCTION: CONTROL OF
THE LATERAL RECTUS MUSCLE
1. Cover test in different positions of gaze
2. Versions and ductions
Clinical Testing
Cover test
Versions/Ductions
Versions/Ductions
Oculomotor (III) nerve palsy
Trochlear (IV) nerve palsy
Abducens (VI) nerve palsy
2 yo with unusual eye movements
Eye movement recordings: - binocular viewing - monocular viewing - version/vergence - testing different types of eye movements
Deficits affecting both eyes (central issues)
MRI and fMRI
Laboratory Testing
Electro-oculography (EOG) Limbus tracking (LEDs and FTRs) Videoculography Search coil
Types of eye movement recordings
Electrooculography (EOG)
Videooculography
Search coil
Example ofoculomotordata
Example of damage to the trochlear nerve in a monkey
MRIDumars 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 arebarely 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 muscleremains 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.