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Oc Motility > Week 7 > Flashcards

Week 7 Flashcards

1
Q

What are the 2 stimuli to cause vergence?

A
  1. Disparity

2. Retinal Blur

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2
Q

Fusional vergence reduces retinal disparity to a minimum using what type of feedback system?

A

Negative Visual Feedback

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3
Q

Accommodative vergence has no direct effect on retinal blur stimulus using what type of feedback system?

A

Open-loop

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4
Q

After accommodative vergence, what vergence will correctly align the eyes?

A

Fusional vergence

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5
Q

How many msec for the accommodative vergence signal to blur?

A

200msec

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6
Q

How many msec for a disparity stimulus?

A

180msec

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7
Q

Vergence and accommodation are sped up when it occurs in association with ____?

A

Saccades

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8
Q

What eye movement is apart of a strategy to facilitary disparity-driven vergence?

A

Blinks - slow down convergence, divergence and saccades

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9
Q

What neurons must be inhibited to allow for vergence to occur?

A

Omnipause neurons

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10
Q

If someone cannot converge or diverge, what part of the brainstem are we concerned about?

A

Midbrain

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11
Q

An important component of the neural substrate for rapid vergence-saccade movements is the ____?

A

PPRF

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12
Q

The PPRF house pre-motor burst neurons that are important for ?

A

horizontal saccades (receives signal for vergence)

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13
Q

What is essential for optimal visuo-motor function?

A

Adaptive capability

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14
Q

If a prism is placed in front of an eye, then the phoria is changed by______. How long will this need to be sustained?

A
  • will change by amount of prism (called phoria adaptation)

- must hold vergence for 30 secs

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15
Q

A robust phoria adaptation mechanism might limit the efficacy of prism tx. This is called ?

A

Eating prism - phoria adaptation mechanism overcomes effect of prism

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16
Q

Prism is not a good mechanism for tx of ___ ____?

A

Convergence insufficiency

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17
Q

Prism and Vergence adaptation cause what 2 things?

A
  1. Reduction in FD

2. Change in phoria toward direction of stimulus (if exo, now eso)

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18
Q

In response to binocular disparity, what type of fusional vergence is stimulated?

A

Fast fusional vergence (stressful on vergence system)

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19
Q

To overcome the stress, a ___ fusional vergence is evoked. This is called what?

A

Slow fusional vergence

- called prism adaptation

20
Q

Prism adaptation converts what ?

A

Converts FFV to SFV

21
Q

What is used as a feedback mechanism to change from fast reflex accom. to slow reflex accomm.?

A

Blur

22
Q

What is used as a feedback mechanism to change from FFV to SFV?

A

Fixation disparity

23
Q

CA/C sends info from the vergence system to the ____ system.

A

accommodative

24
Q

AC/A sends info from accommodative system to ____ system?

A

vergence

25
Q

What converts the fast reflex accom. to the slow reflex accom.?

A

Accom. Amplitude

26
Q

Accommodation and vergence change in unision via the cross-link interaction between?

A

CA/C and AC/A

27
Q

BD: High AC/A with?

A

Low accommodative Response

28
Q

BD: Low AC/A with?

A

High accommodative response

29
Q

BD: High CA/C with?

A

Low PA

30
Q

BD: Low CA/C with?

A

High PA

31
Q

What are the 2 ways to manage binocular disorders?

A

Passive and Active

32
Q

What ways can we passively manage BDs?

A

Prisms and Lenses

- to relieve stress of system

33
Q

What ways can we actively manage BDs?

A

Vision therapy

34
Q

What are the 3 neural components needed to cause vergence eye movements?

A
  1. Cerebral Cortex
  2. Brainstem vergence generator
  3. Ocular motor neurons
35
Q

Where is the brainstem vergence generator located?

A

Mesencephalic reticular formation

36
Q

What type of cells are in the brainstem vergence generator? Which cell is found more abundantly?

A

Premotor convergence and divergence cells

- more convergence neurons

37
Q

What 4 cortical areas are in the cerebral cortex?

A
  1. Frontal Cortex
  2. Parietal Cortex
  3. MT
  4. MST
38
Q

What cells are involved in the cerebral cortex vergence decision?

A
  1. Near cells
  2. Far cells
  3. Size coding cells
39
Q

Vergence tonic cells carry what signal?

A

step/position signal

40
Q

Vergence burst cells carry what signal?

A

pulse/velocity signal

41
Q

Vergence burst-tonic cells carry what signal?

A

both step & pulse signals

42
Q

An acute lesion in a human’s cerebellum causes ?

A

convergence weakness

43
Q

Acute ablation in a monkey’s cerebellum causes what?

A

transient paralysis of vergence

44
Q

Jump/Saccadic Vergence refers to ? What test can we use to determine this?

A
  • refers to quick changes and maintenance of vergence angle

- Vergence Facility testing (12BD, 3BI)

45
Q

Smooth/Pursuit Vergence refers to what?

A

slow changes in vergence angle due to smooth tracking of target

46
Q

Anisometropic correction is best using spectacles or CLs?

A

CLs

Oc Motility (10 decks)

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