Week 2.01 Ocular Motility Flashcards
Definitions of incomitant vs comitant
Incomitant:
- varies in size with the direction of
gaze
- varies depending upon which eye fixates
Comitant: remains constant with gaze direction
What’s the difference between congenital and acquired incomitant deviations
Congenital - developmental abnormality e.g. Duane’s retraction syndrome, browns syndrome
Aquired - due to injury or disease, long standing?, recent onset?
What’s the difference between paralysis and palsy
Paralysis is complete loss of muscle action
Palsy/paresis is incomplete loss of muscle action , partial loss
What are the other classifications and what do they mean
Neurogenic - innervation of EOMs
Myogenic - pathology of EOMs
Mechanical - something physically stopping
What are the Extra ocular muscles and what cranial nerves are they innervated by
Lateral rectus
Medial rectus
Superior rectus
Inferior rectus
Inferior oblique
Superior oblique
SO4 LR6 the rest are 3rd cranial nerve
3rd nerve - oculomotor
4th nerve - trochlear nerve
6th - abducens
Define ductions
Monocular eye movements into/from cardinal position (straight ahead)
Define versions
Conjugate binocular eye movements that allow visual axes to move in parallel
Define vergences
Binocular eye movements which allow visual axes to cross. E.g. convergence and divergence
What are Torsions
Rotational movements
What do we do before checking any ocular motility
Observe the eyes in the primary position. Check any manifest deviations. Could do hirshberg test to check corneal reflex are both equal
What is the movement called when both eyes look up and both eyes look down
Supraduction - elevation
Infraduction - depression
What is the eye movements called when both eyes look to the px right. What does each eye do
Dextroversion
RE abducts
LE adduction
What is the movement called when both eyes look to the px left
Laevo-version
RE adducts
LE abducts
What is the movement when both eyes look in
Convergence
RE adducts
LE adducts
What is the main action of the lateral rectus
Abduction
Move the eye temporally
Innervation: abducens 6th nerve
What is the main action of the medial rectus
Main action: adduction
Moves eye nasally
Innervation: 3rd/oculomotor nerve
What is the main and secondary action of superior rectus
Main action: supraduction
Secondary action: incycloduction - turns eye in towards nose, adduction
Innervation: 3rd nerve
What is the main and secondary actions of the inferior rectus
Main action: infraduction
Secondary: excyloduction & adduction
Innervation: 3rd nerve
What is the main and secondary actions of the superior oblique
Main action: infraduction
Secondary: incycloduction & abduction
Innervation: trochlear nerve 4th
What are the main and secondary actions of the inferior oblique
Main action: supraduction
Secondary: excycloduction & abduction
Innervation: 3rd nerve
What is a useful way of remembering secondary actions
RAD SIN
Recti adduct….therefore obliques abduct
Superiors intort….therefore inferiors extort
And remember lateral and medial rectus do not have secondary actions
What muscles does the eyes use when looking to the right and what about left
Right: RLR & LMR
Left: RMR & LLR
What muscles are being used when px looked up and right…how about up and left
Up and right: LIO, RSR
Up and left: RIO,LSR
What muscles are being used when px looks down and right, how about down and left
Down and right: LSO & RIR
Down and left: RSO & LIR
When doing the ocular motility test what does each eye we want to do when we check the diagonal positions
Isolate the main muscle action and minimise the secondary action
So get px to look across first then up
What is the main symptoms that will be noticed my patients during ocular motility test
Diplopia either side by side or one on top of the other
What are yoke muscles
One from each eye that work together and have the same level of innervation
Just think it through using the positions
What are contralateral synergists and ipsilateral antagonists
Contralateral synergists - from each eye doing the same thing
Ipsilateral antagonist - same eye, against each other
How to conduct ocular motility test
Pen torch held about 50mm away from px
Instruct px to follow torch keeping heads still
Move torch below in star pattern
Px instructed to report any discomfort or diplopia
If diplopia present determine whether it is horizontal or vertical and find the area over which it is greatest
Examiner also must careful watch for any muscle restriction
Isolate img to find out which eye sees which image can be done with red or green filters
How can u check which eye sees which spot of light in diplopia img
Use a red filter over one eye and ask px what colour the higher image is if its a vertical diplopia or which one is to the left most if looking left or which is to the right most if looking right
What happens if u see more than one potion for diplopia
Find where diplopia/seperation is greatest
If px sees diplopia on both opposite sides what does that mean
On opp sides usually means bilateral under action
