Ocular Motility Testing Flashcards

1
Q

What is the “center of rotation of the eyeball?

A

The motion of the globe around a pivot point.

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2
Q

How is each eye suspended in the orbit?

A

By the EOMs and a complicated system of connective tissue and orbital fat.

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3
Q

How many EOMs are in each eye?

A

6.

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4
Q

How many cranial nerves are involved in the motor control of the EOMs?

A

3.

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5
Q

How many oblique muscles are found in each eye? What are they called?

A
  1. One Superior oblique and the other inferior oblique.
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6
Q

How many recti are found in each each? What are they called?

A
  1. Medial, lateral, superior, and inferior rectus.
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7
Q

The medial rectus is controlled by which cranial nerve?

A

Inferior division of Oculomotor Nerve (III).

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8
Q

The lateral rectus is controlled by which cranial nerve?

A

Abducens Nerve (VI).

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9
Q

The superior rectus is controlled by which cranial nerve?

A

Superior division of Oculomotor Nerve (III).

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10
Q

The inferior rectus is controlled by which cranial nerve?

A

Inferior division of Oculomoter Nerve (III).

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11
Q

The superior oblique is controlled by which cranial nerve?

A

Trochlear Nerve (IV)

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12
Q

The inferior oblique is controlled by which cranial nerve?

A

Inferior division of Oculomoter Nerve (III).

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13
Q

The levator palpebrae superioris is controlled by which cranial nerve?

A

Superior division of Oculomotor Nerve (III).

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14
Q

The line connecting center of the eye and point of fixation is called what?

A

Line of sight.

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15
Q

What term is used sometimes as a synonym for the straight ahead position?

A

Primary position.

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16
Q

What term is used to identify a position of view in which one of the EOMs has it’s main action?

A

Secondary or “Cardinal” position.

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17
Q

What are two examples of versions?

A

Saccades and pursuits.

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18
Q

What are two examples of vergence movements?

A

Convergence and divergence.

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19
Q

There are 3 types of eye movements. What are they called?

A

Versions, vergence movements, and duction.

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20
Q

True or False: Versions involve the rotation of the two eyes such that their line of sight move in opposite directions.

A

False. Same directions.

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21
Q

True of False: Vergence involve the rotation of the two eyes such that their line of sight move in opposite directions.

A

True.

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22
Q

Binocular movements in which the two eyes move synchronously and symmetrically in the same direction is called what?

A

Versions.

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23
Q

What are saccadic eye movements?

A

Movements that place the object of interest on the fovea rapidly.

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24
Q

Moving the eyes from one object to another. Voluntarily or as a reflex triggered by the appearance by an object in the peripheral field. Voluntary shift in fixation from one point to another. What is being described?

A

Saccadic eye movement in versions.

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25
Q

Where does the control of saccades occur in the brain?

A

Frontal lobe.

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26
Q

What is an example of saccadic eye movements?

A

Reading.

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27
Q

What is the function of pursuit eye movements?

A

To maintain fixation on an object of interest.

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28
Q

Stimulus is triggered by the movement of the object near the fovea. Speed slow and smooth. What is being described?

A

Pursuit eye movements in versions.

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29
Q

Where does the control of pursuits occur in the brain?

A

Occipital lobe.

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30
Q

Medial rectus contracts in both eyes, pulling the eyes to the nose. What is being described?

A

Convergent vergence.

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31
Q

(During eye converged) Medial rectus relaxes and/or later rectus contracts, pulling the eyes out and away from the nose. What is being described?

A

Divergent vergence.

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32
Q

Rotation of one eye under monocular conditions is called?

A

Duction.

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33
Q

What are two examples of duction?

A

ABduction and ADduction.

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34
Q

Movement of the eye away from the nose is called what?

A

ABduction.

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35
Q

Movement of the eye toward the nose is called what?

A

ADduction.

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36
Q

True or False: Medial (nasal) rotation of an eye is ABduction.

A

False. ADduction.

37
Q

True or False: Lateral (temporal) rotation of an eye is ABduction.

A

True.

38
Q

Movement of an eye upward is called what?

A

Supraduction.

39
Q

Movement of an eye downward is called what?

A

Infraduction.

40
Q

Movement of an eye to the left is called what?

A

Levoduction.

41
Q

Movement of an eye to the right is called with?

A

Dextroduction.

42
Q

Medial and lateral rectus lie in what plane and move the eyes in what direction?

A

Horizontal; left and right.

43
Q

True or False: Medial rectus moves eye nasally (aDduction) while later rectus moves eye temporally (aBduction).

A

True.

44
Q

Superior and inferior rectus lie in what plane and move the eyes in what direction?

A

Vertical; up and down.

45
Q

True or False: Superior rectus depresses the eye whole inferior oblique elevates the eye.

A

False. Superior rectus elevates the eye while inferior rectus depresses the eye.

46
Q

Except for medial and lateral rectus, every other muscles have how many actions?

A
  1. Primary, secondary, and tertiary.
47
Q

What does the superior and inferior oblique muscles do?

A

Superior oblique is responsible for intorsion while inferior oblique is responsible for extorsion.

48
Q

Muscles of the two eyes which simultaneously contract to turn the eyes equally in the same direction is known as what?

A

Yoked muscles or yoked pairs.

49
Q

True or False: Right medial rectus and the left lateral rectus are yoked muscles because they contract simultaneously to move the gaze to the left.

A

True.

50
Q

Name two basic laws of eye movements.

A

Sherrington’s Law of Reciprocal Innervation and Hering’s Law of Equal Innervation.

51
Q

True or False: Hering’s Law states that the contraction of each ocular muscle is accompanied by a simultaneous and proportional relaxation of its antagonist.

A

False. Sherrington’s Law.

52
Q

Are the right medial rectus and right lateral rectus in the same eye antagonists or agonists? Which law is being described?

A

Antagonists. Sherrington’s Law.

53
Q

True or False:The amount of contraction innervation given to the right medial rectus must equal the amount of relaxation innervation given to the right lateral rectus.

A

True. Contraction=relaxation.

54
Q

What does Hering’s Law state?

A

Innervation to the muscle of one eye is equal to that in that other eye, resulting in movement of the two eyes that is equal and symmetrical.

55
Q

Does Hering’s Law describe duction, vergence, or versions?

A

Versions. Rotations of the two eyes moving in the same direction.

56
Q

Which two muscles in the eye are equally innervated when looking to the right?

A

Right lateral rectus and left medial rectus.

57
Q

True or False: Hering’s Law states that the innervation to the yoke muscle in the non-fixating eye must equal the innervation to the corresponding agonist muscle in the fixating eye.

A

True.

58
Q

What happens when an eye has a paretic muscle?

A

Patient sees double. When attempting to fixate in the field of action of the paretic muscle, the other eye’s yoke muscle will overshoot due to the extra effort (innervation) being expended.

59
Q

What two techniques are used to screen for EOM dysfunction?

A

H pattern and O pattern.

60
Q

Should patient wear glasses during a H pattern test?

A

No.

61
Q

The primary gaze position is the straight ahead position. What is the secondary gaze position during an H pattern test?

A

The 6 cardinal positions.

62
Q

True or False: normal versional movements are “yoked” or binocular, with one muscle in each eye being primarily responsible for eye movement to that position.

A

True.

63
Q

Which pattern is used to detect poor or absent innervation, or restriction of one or more EOMs?

A

H Pattern.

64
Q

What are some possible targets for H pattern testing?

A

Toucan on the PD ruler. Penlight with finger on top of the bright light to avoid shining light into patients eye. Anything that captures attention without so much detail.

65
Q

How far is the target presented from the patient during the H pattern test?

A

40 cm or 16 in.

66
Q

When do you know the patient has muscle restrictions?

A

If the patient sees two or has any eye pain.

67
Q

What if the child reports pain during the H pattern?

A

There may be inflammation of the orbital contents or pain can be a symptom of retrobulbar optic neuritis.

68
Q

What if the child reports diplopia during the H pattern?

A

Eyes are not working together (strabismus/tropia/muscle restriction).

69
Q

What do you record if the H pattern testing is normal?

A

Full.

70
Q

What do you record if the H pattern testing is restricted?

A

Restricted.

71
Q

True or False: O pattern is used to identify problems with smooth pursuits.

A

True.

72
Q

What are some possible targets for O pattern testing?

A

Touxan on the PD ruler, “look at the birds eye”. Anything that captures attention with detail for fixation.

73
Q

True or False: During the O pattern test, patient should not wear their glasses.

A

False. They should wear their glasses. H pattern should not be done with glasses on.

74
Q

How far should you present the target to the patient during a O pattern test?

A

40 cm or 16 in.

75
Q

True or False: O pattern is completed by moving a fixated object right, up, down, left, up, down.

A

False. Complete the test in a circular rotation that is about 24 inches in diameter.

76
Q

True or False: During a O pattern test, you should only move the fixated object in a circle once and only in the clockwise direction.

A

False. 2-3 rotations. Both clockwise and counter clockwise.

77
Q

If the O pattern testing is normal, what should be recorded?

A

O: smooth.
Fixation: good.

78
Q

If the O pattern testing is not normal, what should be recorded?

A

O: Jerky.
Fixation: poor.

79
Q

Repetitive, usually rapid, involuntary movement or rotation of the eye is called what?

A

Nystagmus.

80
Q

True or False: Normal individual do not experience nystagmus.

A

False. It is very common for people who have normal vision to experience nystagmus.

81
Q

True or False: Nystagmus is congenital or hereditary.

A

True.

82
Q

Nystagmus is described by what three factors?

A
  1. Direction (horizontal, vertical, torsional, non-specific).
  2. Amplitude (fine or course).
  3. Frequency (how often it occurs: high, moderate, low)
83
Q

What type of nystagmus is known as an involuntary to and fro jerky eye movements on far lateral gaze? Is this considered normal or abnormal? This type of nystagmus occurs at what degree?

A

End-position nystagmus. Normal. May occur when exceeded >50 degrees laterally or >30 degrees vertically.

84
Q

True or False: Latent nystagmus occurs when either eye is covered but otherwise nystagmus absent when not covered.

A

True.

85
Q

When is optokinestic nystagmus induced?

A

By the attempt of fixating an object rapidly in the transverse visual field.
Ex: Train.

86
Q

The detection of End-Position Nystagmus is one of many parts of sobriety testing conducted on suspected impaired drivers by police?

A

3.

87
Q

What modified procedure is used by police in which only the extreme lateral positions along the 180 degree are tested?

A

“Horizontal gaze nystagmus test”

88
Q

True or False: During a field sobriety test, if end-point nystagmus is seen within the central 30 degrees, the patient has had excessive ethanol consumption, over the legal limit.

A

True.