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Motility > 9-Ocular Motility > Flashcards

9-Ocular Motility Flashcards

1
Q

Primary position of the eyes

A

Eyes fixate straight ahead and eyes and head are straight

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2
Q

Secondary position

A

Around the X ad Z axes of Fick. Purely vertical or horizontal

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3
Q

Tertiary position

A

Y axis and head tilt positions

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4
Q

How many cardinal positions do we have

A

6

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5
Q

What are cardinal positions

A

Positions where only 1 muscle in each eye is responsible for movement

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6
Q

What is the field of action

A

The gaze where the effect of a muscle is best observed

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7
Q

Any weakness of the SO can be seen as what

A

Depression in adduction

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8
Q

Why I’d the field of action important

A

Is helps you isolate if a deviation seen is weakness of that muscle, a restriction of action from the antagonist, or both

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9
Q

What is agonist antagonist of motility

A

Pair of muscles in the SAME eye that move in opposite direction

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10
Q

What are synergistic muscles

A

Muscles in the SAME eye that move in the SAME direction

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11
Q

What are yoke muscles

A

Pair of muscles, one in each eye, the produce conjugate eye movements (move eye in same direction)

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12
Q

What is the Sherrington law of reciprocal innervation

A

Increased innervation to on e muscle is accompanied by a decrease innervation to its antagonist in the same eye

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13
Q

What is the hering law of equal innervation

A

During conjugate eye movements, equal and simultaneous innervation flow to yoked muscles

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14
Q

Due to Herings law of equal innervation what will you see if there is a palsy in one muscle

A

The yoke muscle in the other eye will over react

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15
Q

What muscles are important for horizontal versions

A

Vertical rectus muscles and oblique muscles

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16
Q

What muscles are important for vertical versions

A

Horizontal rectus muscles

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17
Q

Primary deviation

A

Unaffected eye fixates

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18
Q

Secondary deviation:

A

Restricted eye fixates

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19
Q

Which is bigger a primary or secondary deviation?

A

Secondary, because there is increased innervation to move the affected eye

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20
Q

T/F Increase innervation goes to the non-fixating eye that causes excessive action and a larger deviation

A

True

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21
Q

Ductions

A

Movement of one eye sound the axes of Fick

Monocular

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22
Q

Versions

A

Binocular

Simultaneous and conjugate eye movements or rotation of both eyes

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23
Q

What are conjugate eye movements

A

Both eyes move in the same direction and same amount

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24
Q

Vergences are

A

Disconjugate eye movements where the eyes rotate or move in opposite directions

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25
Q

What are vergences important for

A

Fusion

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26
Q

Convergence

A

Both eyes rotate in

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27
Q

Divergence

A

Both eyes rotate out

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28
Q

Incyclovergence

A

Rotation of the superior portion of the eyes in

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29
Q

Excyclovergence is

A

Rotation of superior portion of both eyes out

30
Q

T/F versions and vergences have similar late cites?

A

True

31
Q

Which is faster acting movements? Versions or vergences?

A

Versions are faster

32
Q

What is the infranuclear control

A

Cranial nerves (3,4,5) and the muscles they innervate

33
Q

What is nuclear control

A

The cranial nuclei

34
Q

What is Supranuclear control

A

Higher order sensory and motor system that plans and controls eye movements
Cerebral cortex, cerebellum, brainstem

35
Q

What control system controls versions and vergences?

A

Supranuclear

36
Q

What eye movements are included in versions?

A 
Saccades
Pursuits
VOR
OKN
OKR
37
Q

What are saccades?

A

Fast conjugate eye movements that work to keep images on the fovea. They require a strong force

38
Q

What is the latency for saccades?

A

120-200 ms

39
Q

When are saccades developed

A

1 year of age

40
Q

Are saccades voluntary?

A

Yes, but they can be reflexive

41
Q

What are pursuits?

A

Following eye movements

42
Q

What is the latency for pursuits

A

125 ms

43
Q

What is the peak velocity for pursuits

A

30-60 degrees per sec

44
Q

What do pursuits match up

A

Eye velocity to target velocity

45
Q

Are pursuits voluntary or involuntary

A

Involuntary

46
Q

When do pursuits develop

A

3-4 months of life

47
Q

What controls pursuits

A

Parietal lobe on same side

48
Q

What are vestibule-ocular reflex (VOR)

A

Movements that stabilize a retinal image during brief head movements

49
Q

What can the VOR be seen in

A

Dolls head maneuver

50
Q

When do VOR develop

A

Horizontal at birth

Vertical is later

51
Q

What is seen on dolls head maneuver (eye movement)

A

Eye moves opposite of head movement

52
Q

What causes horizontal nystagmus

A

Vestibular damage

53
Q

When is dolls head maneuver contraindicated

A

In trauma where spinal/cervical injuries

54
Q

What is the caloric test? How does the eye move with different temperature water

A

Test that uses warm and cold water to set up a temperature gradient in the semicircular canals. Cold water the eye moves to opposite ear. Warm water it moves toward the same ear that water was injected in.

COWS

55
Q

What is OKR responsible for

A

Continuous eye movements. It kicks in after VOR response fades with continuous head movements

56
Q

What is rotational testing? What does it show?

A

Spin patient in a chair for about 20 seconds. Eyes will move in fast phase in opposite direction of rotation

57
Q

What is OKN

A

Slow pursuit eye movement followed by fast corrective saccades. The head is still. It requires inpu from the visual system.
Has a longer latency

58
Q

When is OKN developed

A

3-5 months

59
Q

When is OKN used

A

In malingering, and cooperative patients

60
Q

What does a + OKN tell you

A

That VA is at or better than the size of the stripes on OKN drum

61
Q

What does a - OKN tell you

A

Nothing

62
Q

How is OKN tested

A

With an OKN drum. Horizontal and vertical

63
Q

Slide 33

A

Big chart

64
Q

What do vergences ensure

A

Bifoveal fusion

65
Q

What is fusional vergences

A

It requires the attention and cooperation of the cerebral cortex

66
Q

What is tonic vergence

A

Constant innervaton tone to the EOMs when awake and alert. To keep the eyes straight forward because the eyes are naturally diverging.

67
Q

What is proximal vergences

A

Induced due to awareness of near

68
Q

What are accommodative vergences

A

Consistent increment of accommodative convergence with each dipter of accommodation gives AC/A ratio

69
Q

What does a high AC/A produce

A

ET with accommodation

70
Q

What dies a low AC/A do

A

Makes it harder to converge, less esotropic, more exotropic

Motility (5 decks)

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