BaSCO_February_16,_2009

Report
Robert P. Rutstein, OD
Claudio Busettini, PhD
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)
not aligned
with pivot
point
NOSE
Superior rectus and inferior rectus have adduction as tertiary actions
(View from above of the right eye)
NOSE
not aligned
with pivot
point
Inferior oblique and superior oblique have abduction as tertiary actions
(View from above of the right eye)
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
Somatic motor function:
innervation of FOUR of the 6 extra-ocular muscles:
- Medial rectus
- Superior rectus
- Inferior rectus
- Inferior oblique
and of the levator palpabrae superioris (upper eyelid)
Visceral motor function:
-parasympathetic innervation of the constrictor pupillae (pupillary
light reflex)
- ciliary muscle (accommodation reflex)
upper eyelid control
incycloduction
accommodation and
pupil responses
excycloduction
ONLY FUNCTION: CONTROL OF
THE SUPERIOR OBLIQUE MUSCLE
ONLY FUNCTION: CONTROL OF
THE LATERAL RECTUS MUSCLE

1. Cover test in different positions of gaze

2. Versions and ductions

Eye movement recordings:
-
binocular viewing
monocular viewing
version/vergence
testing different types of eye movements

Deficits affecting both eyes (central issues)

MRI and fMRI




Electro-oculography (EOG)
Limbus tracking (LEDs and FTRs)
Videoculography
Search coil
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.

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