Visual system : Eye movements Flashcards

1
Q

What is Duction?

A

Eye movement in one eye

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2
Q

What is Version?

A

Simultaneous movement of both eyes in the same direction

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3
Q

What is Vergence?

A

Simultaneous movements of both eyes in opposite direction

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4
Q

What is convergence?

A

Simultaneous adduction movement in both eyes when viewing a near object

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5
Q

What is version when it is to the left?

To the right?

A
Left = Levoversion
Right = Dextoversion
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6
Q

What is Saccade?

A

Short fast burst of eye movement: (900/s)

can have multiple types e.g.

  • reflexive saccade to external stimuli
  • Scanning saccade
  • predictive saccade to track objects
  • memory guides saccade
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7
Q

What is smooth pursuit?

A

Sustained slow eye movement

driven by motion of a moving target across the retina (60/s)

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8
Q

What four straight muscles are there?

A

Superior rectus
Inferior rectus
Lateral rectus
Medial rectus

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9
Q

Where to all the eyes muscles except the inferior oblique come in from?

A

Out of a cone from the back of the orbit

  • Inferior oblique comes in nasally
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10
Q

What does the superior rectus do?

A

Moves eye up

attached at 12 oclock

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11
Q

What does the lateral rectus do?

A

Attaches on the temporal side of the eye

Moves the eye toward the outside of the head (towards temple)

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12
Q

What does the medial Rectus do?

A

Attaches to the nasal side of the eye

Moves the eye toward the middle of the head

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13
Q

What does the superior oblique do?

A

Attached high on the temporal side of the eye

Passed under the superior rectus

Moves eye in a diagonal pattern down and out

Travels through the trochlea

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14
Q

What does the inferior oblique do?

A

Attached low on the nasal side of the eye

Passed over the inferior rectus

Moves eye in a diagonal patter = up and out

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15
Q

What muscles does the superior branch of the oculomotor nerve innervate?

A

Superior branch:

  • Superior rectus
  • Levator palpebrae superioris
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16
Q

What muscles does the inferior branch of the oculomotor nerve innervate?

A
  • Inferior rectus
  • medial rectus
  • inferior oblique
  • parasympathetic nerve that constricts pupil
17
Q

What does the trochlear nerve innervate?

A

Superior oblique

18
Q

What does the abducens nerve innervate?

A

Lateral rectus

19
Q

How do we test the lateral rectus?

A

Abducted position

20
Q

How do we test the medial rectus?

A

Adducted position

21
Q

How do we test superior rectus?

A

Elevated and abducted position

22
Q

How do we test for the inferior rectus

A

depressed and abducted position

23
Q

How do we test for inferior oblique?

A

Elevated and adducted position

24
Q

How do we test for the superior oblique?

A

Depressed and adducted position

25
Q

What does third nerve palsy look like?

A

Affected eye is down and out

26
Q

What causes third nerve palsy (describe innervation)

A

(oculomotor not working) Droopy eyelid - loss of elevator palpebrae

Unopposed superior oblique = so look down

Unopposed lateral rectus action = out

27
Q

What does sixth nerve palsy look like? (abducens)

A

Affected eye unable to abduct and deviates inwards.

More apparent when px asked to abduct the affected eye

28
Q

What makes 6th nerve palsy double vision worse?

A

gazing to the side of affected eye

29
Q

What is Nystagmus?

A

Oscillatory eye movement

30
Q

What is Optokinetic nystagmus

A

Smooth pursuit + fast phase reset saccade

31
Q

What is the optokinetic nystagmus reflex?

A

in testing visual acuity in pre-verbal children by observing the presence of nystagmus movement in response to moving grating patterns of various spatial frequencies

  • watch video : the eye ‘flickers’ when watching changing symbols