Versions and Vergences Flashcards Preview

Motility > Versions and Vergences > Flashcards

Flashcards in Versions and Vergences Deck (29):
1

Infranuclear Controls

CN 3, 5, 6 and their muscles

2

Nuclear Controls

Cranial nuclei

3

Supranuclear Contros

higher order; plans and controls eye movement
cortex, cerebellum, brainstem

4

Versions and Vergences are controlled by....

supranuclear pathway

5

Saccades

FAST conjugate eye movement for refixation/
moves fovea to object of interest
voluntary, some can be reflex

6

Saccade- Version or Vergence?

Version

7

Saccade Latency

time between stimulus and response
120- 200ms

8

Saccades develop by age...

1

9

Pursuits

maintains fovea focus on a slowly moving target
matches eye velocity to target velocity
voluntary

10

Pursuit Latency

shorter than saccades- faster start
125ms

11

Pursuits develop by.....

3-4 months

12

Vestibulo-ocular Reflex
VOR

stabilize retinal image during brief head movements
seen in doll's head maneuver
does not require stimuli

13

VOR is developed by....

Horizontal- at birth
Vertical- later

14

Vestibular damage results in....

horizontal nystagmus

15

Dolls Head Maneuver

eyes move opposite to head turn

16

Caloric Testing

head angled 30 degrees
Cold = opposite
warm = same

17

Optokinetic Reflex

takes over after brief head movement/ VOR
during prolonged head movement

18

Testing Optokinetic Reflex

Rotational Testing
eye moves fast opposite rotation of chair

19

Optokinetic Nystagmus
OKN

slow purusit eye movement followed by fast corrective saccade
head stays still
requires input from visual system

20

OKN develops by.....

3-5 months

21

Pursuits- Version or Vergence?

Version

22

VOR- Version or Vergence?

Version

23

Optokinetic Reflex- Version or Vergence?

Version

24

OKN- Version or Vergence?

Version

25

Fusional Vergence

to correct discrepancies b/t retinal images /
make sure both eyes see the same thing

26

Tonic Vergence

constant inn to EOMs when awake and alert
holds eyes straight since eyes would otherwise diverge

27

Proximal Vergence

induced convergence to view objects at near

28

High AC/A

ET with accommodation
eyes overconverge

29

Low AC/A

XT, harder to converge or cant converge