vision

Question 1

types of eye movement

Answer 1

voluntary, involuntary

Question 2

why is eye movement necessary

Answer 2

for acquiring and tracking visual stimuli

Question 3

what does contraction of muscles cause

Answer 3

muscle to pull (in agonist-antagonist pairs)

Question 4

define duction

Answer 4

eye movement in one eye

Question 5

define version

Answer 5

simultaneous movement of both eyes in same direction

Question 6

define vergence

Answer 6

simultaneous movement of both eyes in opposite direction

Question 7

define convergence

Answer 7

simultaneous adduction (inward) movement in both eyes when viewing an object

Question 8

2 speeds of eye movement

Answer 8

saccade (short fast burst), smooth pursuit (slow sustained movement)

Question 9

4 types of saccade movement

Answer 9

reflexive saccade to external stimuli, scanning saccade, predictive saccade to track object, memory-guided saccade

Question 10

what drives slow movement

Answer 10

motion of moving target across retina

Question 11

what do extraocular muscles attach

Answer 11

eyeball to orbit

Question 12

2 types of movement

Answer 12

straight, rotatory

Question 13

four straight extraocular muscles

Answer 13

superior rectus, inferior rectus, lateral rectus, medial rectus

Question 14

where does superior rectus attach to eye, and what is its associated movement

Answer 14

12 o’clock, moves eye up

Question 15

where does inferior rectus attach to eye, and what is its associated movement

Answer 15

6 o’clock, moves eye down

Question 16

where does lateral (external) rectus attach to eye, and what is its associated movement

Answer 16

3/9 o’clock, attached to temporal side of eye, moves eye towards outside of head (temple)

Question 17

where does medial (internal) rectus attach to eye, and what is its associated movement

Answer 17

3/9 o’clock, attached to nasal side of eye, moves eye towards middle of head (nose)

Question 18

what are the 2 oblique eye muscles

Answer 18

superior and inferior

Question 19

where does superior oblique attach to eye, what does it pass under and through, and what is its associated movement

Answer 19

attached high on temporal side, passes under superior rectus, travels through trochlea, moves eye diagonally down and in

Question 20

where does inferior oblique attach to eye, what does it pass over, and what is its associated movement

Answer 20

attached low on nasal side of eye, passes over inferior rectus, moves eye diagonally up and out

Question 21

3 nerves innervating extraocular muscles

Answer 21

oculomotor (III), trochlear (IV), abducens (VI)

Question 22

what 2 things are innervated by the superior branch of the oculomotor nerve

Answer 22

superior rectus (elevates eye), lid levator (raises eyelid)

Question 23

what 4 things are innervated by the inferior branch of the oculomotor nerve

Answer 23

inferior rectus (depresses eye), medial rectus (adducts eye), inferior oblique (elevates eye), pupil (PSNS so constricts)

Question 24

what muscle is innervated by trochlear nerve

Answer 24

superior oblique (depresses eye)

Question 25

what muscle is innervated by abducens nerve

Answer 25

lateral rectus (abducts eye)

Question 26

diagram of cranial nerve innervation, extraocular muscle and associated movement

Answer 26

slide 17

Question 27

how is eye movement tested

Answer 27

require patient to move eyes in circle or specific direction depending on muscle investigated (maximise its actions whilst minimising actions of other muscles)

Question 28

elevation of eye: one vs both

Answer 28

supraduction is one eye, supraversion is both

Question 29

depression of eye: one vs both

Answer 29

infraduction is one, infraversion is both

Question 30

right (dextroversion) of eye

Answer 30

right abduction and left adduction

Question 31

left (levoversion) of eye

Answer 31

right adduction and left abduction

Question 32

what is torsion

Answer 32

rotation of eye around its anterior-posterior axis

Question 33

effect of third (oculomotor) nerve palsy

Answer 33

affected eye down and out, droopy eyelid, unopposed superior obique innervated by trochlear nerve (down), unopposed lateral rectus action innervated by abducens nerve (out)

Question 34

effect of sixth (abducens) nerve palsy

Answer 34

affected eye unable to abduct and deviates inwards; double vision worsen on gazing to side of affected eye

Question 35

what is nystagmus

Answer 35

involuntary (oscillatory) eye movement in infancy

Question 36

what is the optokinetic nystagmus reflex used for in infants

Answer 36

tests visual acuity by observing presence of nystagmus movement in response to moving grating patterns of various spatial frequencies; if present, subject has sufficient visual acuity but still being developed