Visual systems and TBI

Question 1

sight

Answer 1

recognition and location of objects

Question 2

perception

Answer 2

meaningfulness of what is sighted

Question 3

lens

Answer 3

inverts and reverses incoming visual information

Question 4

fovea

Answer 4

central fixation point

Question 5

photoreceptors

Answer 5

cones and rods

Question 6

cones

Answer 6

acuity, centrally located around fovea

Question 7

rods

Answer 7

night vision

Question 8

blind spot

Answer 8

over the optic disc, where neurons leave the eye

Question 9

visual pathways

Answer 9

optic nerve> optic chiasm (partial crossing of fibers-nasal)> lateral geniculate of the thalamus, midbrain colliculus (pupil reflex)> primary visual cortex

Question 10

does the middle eyes cross

Answer 10

yes

Question 11

do the middle eyes cross

Answer 11

yes

Question 12

do the outer eyes cross

Answer 12

no

Question 13

functional categories of eye movement

Answer 13

integration of information from multiple sources, goals of eye movement, gaze stabilization, direction of gaze

Question 14

goals of eye movement

Answer 14

keep eye stable during head movement, directing gaze at visual targets

Question 15

direction of gaze

Answer 15

saccades-slow movent side to side
smooth pursuit of conjunction-movt side to side but smooth
vergences: near and far

Question 16

gaze stabilization

Answer 16

vestibular-ocular, optokinetic

Question 17

vestibular ocular reflex

Answer 17

action of vestibular information on eyes; with head turns, vestibular system becomes active, information is processed, movement of ocular muscles os stimulates to counter rotation; vertical or horizontal, important for suppress reflex

Question 18

optokinetic reflex

Answer 18

stabilizes moving images on the retina, static head position

Question 19

vestibular ocular motor screening (VOMS)

Answer 19

5 assessments
1. smooth pursuits
2. horizontal and vertical saccades
3. convergence
4. horizontal and vertical vestibular occular relfex (VOR)
5. visual motion sensitivity

Question 20

smooth pursuit

Answer 20

1. position object 3’ from subject
2. Smooth move the object from the midline to 1.5’ to right and 1.5’ to left
3. subject is to follow with eyes without moving head
4. sped: should be 2 sec to left and right
   (2 reps- 1st R>C>L>C)
   repeated vertically

Question 21

saccades

Answer 21

1. hold 2 objects 3’ from patient, place 1.5’ to right and to left
2. look from object to object as fast as possible
   (do not move head)
   -10 reps (1 rep= R>L>R)
   repeat vertically 1.5’ above and below midline

Question 22

convergence

Answer 22

hold the object at arm’s length (14pt font at one end)
have the client bring to face slowly, stop when double vision happens, measure from nose (normally 5cm)
-3 tests

Question 23

VOMS-accommodation

Answer 23

1eye at time
hold object with text at arms length bring to them with one eye covered, stop when it gets blurry, record (15cm or less is normal) -not if corrected vision
-repeat x3

Question 24

VOR

Answer 24

hold object 3’ from face, have client focus on object and rotate head 180 beats/min (fast as possible)
(10 reps- 1=back and forth to starting)
wait 10s, symptoms then vertically 1 rep

Question 25

Visual motion sensitivity

Answer 25

subject stands arms out thumbs up, examiner behind, rotate trunk, arm, head 80 to right and left, maintain gaze on thumb. 5 reps

Question 26

VOMS results

Answer 26

> 5cm NPC=concussion
anything >2 =concusion