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Neuro (Exam 3) > Eye Movements > Flashcards

Eye Movements Flashcards

1
Q

Saccadic movements

A

Rapid eye movement that brings image of object onto fovea

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2
Q

Smooth pursuit

A

Keeps moving image centered on fovea

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3
Q

Vestibular-ocular movements

A

Holds image steady on fovea during head movements

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4
Q

Vergence

A

Keeps image on fovea when object is moved near

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5
Q

Which eye movements are conjugate movements?

A

Saccades, smooth pursuit, vestibular-ocular movements

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6
Q

Which eye movements are disconjugate movements?

A

Vergence

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7
Q

What controls nystagmus?

A

Cortex

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8
Q

What/where are horizontal saccades?

A
  • Frontal eye fields/superior colliculus

- Paramedian pontine reticular formation (horizontal gaze center)

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9
Q

Horizontal saccades tract

A
  1. R. frontal eye field
  2. PPRF
  3. CN VI
  4. L. lateral rectus m. activated
  5. MLF
  6. CN III
  7. R. medial rectus m. activated
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10
Q

Frontal eye field… voluntary or reflexes?

A

Voluntary

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11
Q

Superior Colliculus… voluntary or reflexes?

A

Reflexes

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12
Q

What is unique to vertical saccades?

A

Rostral interstitial nucleus of MLF (vertical gaze center)

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13
Q

What effect on vision does a red nucleus tumor have?

A

Selective gaze palsy

Pt. cannot look DOWN (CN IV)

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14
Q

What effect on vision does a pineal gland tumor have?

A

Selective palsies of vertical gaze
Pt. cannot look UP (CN III)
* Superior colliculus and posterior commissure affected

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15
Q

What is responsible for voluntary eye movements?

A

Parietal eye fields

Superior colliculus

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16
Q

What is needed for saccadic movements?

A
  1. Burst from excitatory burst neurons to move eyes toward target
  2. Tonic neuronal firing from tonic neurons for final locking on/fixing on target
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17
Q

What happens once target is fixed upon?

A

Pause neurons inhibit the burst neurons - no further movements occur

18
Q

Horizontal burst cells from where?

A

Pontine Paramedian Reticular Formation

19
Q

Horizontal tonic cells?

A

Nucleus prepositus hypoglossi

20
Q

Horizontal pause cells?

A

Omnipause cells of raphe nuclei

21
Q

Vertical burst cells?

A

Rostral interstitial nucleus of MLF

22
Q

Vertical tonic cells?

A

Interstitial nucleus of Cajal

23
Q

Vertical pause cells?

A

Omnipause cells of raphe nucleus

24
Q

How to test for saccadic movements?

A

Have pt. visually jump from one object to another

25
Q

Describe path for frontal gaze center?

A
  • Destructive lesion (eye TOWARD lesioned side)

- Seizure activity (eye AWAY from lesioned side)

26
Q

Smooth pursuit location and tract

A
  1. Parieto-occipital junction (Area 19)
  2. Pontine nuclei
  3. Vestibulocerebellum
  4. Vestibular nuclei
  5. CN VI
  6. MLF
  7. CN III
27
Q

Overall effect of eyes w/ smooth pursuit

A

Right PO jxn stimulated - eyes move Right

28
Q

Optokinetic movement location and tract?

A
  • Utilizes the smooth pursuit pathway (+ nuclei of the accessory optic system)
  • Eyes make quick move in the opposite direction
29
Q

Smooth pursuit testing?

A

Using optokinetic tape, have pt. follow object as you move it through fingers

30
Q

Smooth pursuit path?

A

Lesion of parietal lobe - loss of smooth pursuit mvmts TOWARD lesioned side
- NO optokinetic nystagmus present

31
Q

Effect of vestibular-ocular system on eyes?

A

Head turned right - right labyrinth activated (eye turns left)

32
Q

Testing vestibular-ocular movements?

A
  • Check for doll’s eye maneuver (eyes turn opposite direction of head mvmt)
  • Ice water caloric (COWS… only in conscious pt)
33
Q

Vestibular-ocular movement path?

A
  • In coma pt. w/ brainstem lesion - Doll’s eyes and COWS will be absent
34
Q

Internuclear ophthalmoplegia

A
  • Horizontal eye movements impaired
  • Affected eye has weak ADDuction
  • CL eye has ABduction nystagmus
35
Q

What causes INO?

A

Lesion @ MLF

36
Q

Effect of CN VI lesion?

A
  • IL eye cannot ABduct

- CL eye cannot ADDuct

37
Q

Effect of CN VI nerve palsy?

A
  • IL eye cannot ABduct
38
Q

Components of near reflex?

A
  • Convergence
  • Accommodation
  • Pupillary constriction
39
Q

Describe accommodation

A

Lens thickens so image is focused on fovea

40
Q

Vergence testing?

A

Pt. focuses on near object - near reflex occurs

41
Q

Vergence path?

A
  • D/t Argyll-Robertson pupil (neurosyphilis)

- Absent light reflex, but pupil constricts in near reflex testing

42
Q

Near reflex tract

A
  1. Visual path
  2. Visual association cortex
  3. Sup. colliculus/pretectal plate
  4. CN III
  5. Edinger-Westphal nuc.
    * MLF bypassed

Neuro (Exam 3) (15 decks)

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