Vision

Question 1

Eye movements

Answer 1

Voluntary eye movement

• smooth pursuit eye follow
• Vergence eye movement (convergence and divergence)

Involuntary eye movements
-Optokinetics nystagmus

Question 2

Central visual system

Answer 2

Dorsal (where)= provides vision for action, integrates movement with object and location
-diff ID info in busy environment

Ventral (what)= process details/spatial/patterns, make sense of objects and faces, vision for perception
-poor facial recognition, can’t ID facial expressions

Question 3

Describe Sense

Answer 3

[-] low visual registration= partial or full in one or both eyes

[+] hypersensitivity to stim= hyper vigilant to particular visual stim

Sub: from parent etc
Obs: what child interacts with in environment

Question 4

Describe Engages

Answer 4

[-] avoids/dislikes= experiences motion sickness when looking at screen, discomfort with bright light/glare/flickering eg migraines, seizures, decreased sensory threshold

[+] overseeks= fixates on lights or items that spin/turn eg Autism

Sub: questionnaire
Obs: behaviour of child, perseverate of tasks with pleasing visual stim

Question 5

Describe Nominated

Answer 5

[-] unable to perceive elements

• diff with skills requiring visual perception of location and timing
• misses details
• cn child see moving objects or only when stationary

[+] unable to suppress irrelevant stim

• overstim by visual stim, distracted in normal environment
• can be environment oriented rather than people oriented. Can tend to want to over-organise environment

Question 6

Describe symmetry

Answer 6

[-] Extinction, hemianopia, hemisensory loss= visual field loss on L or R side of vertical midline
[+] localised hypersensitivity= distracted by one particular colour or pattern

Question 7

Describe adjusts

Answer 7

[-] poor/delayed position adjustments, look/is comfortable= child does not keep eyes and head aligned to horizon when asked to move onto hands and knees

[+] Excessive position adjustment= child excessively ‘locks’ position when on unstable

Question 8

Describe tunes

Answer 8

[-] Under responds to stimuli= does not effectively orientate head/eyes to body and gravity when moving, can’t dissociate head movement with other movement

[+] over responds to stimuli= excessive post rotatory nystagmus

Question 9

Describe integrates

Answer 9

[-] under responds= child down’t scan environment, trips and stumbles, bumps into others

[+] over responds= becomes fixated on certain stimulus and will not process outside stimuli

Question 10

Describe overrides

Answer 10

[-] unresolved sensory conflict= they believe they are moving if a train next to them is moving

[+] detects conflict appropriately

Question 11

Describe Normal

Answer 11

[-] unsafe- accidental injury, risky, poor control= not watching and gauging distance top stop safely and runs into wall to stop

[+] too safe- fear, avoidance, low experience= moves slowly, always turning head to watch where going

Question 12

Eye follow

Answer 12

Ability: smoothly and continually follow stimulus in multiple directions after given visual stimulus

Typical:
- 4w: follow horizontal stimulus, in supine
- 6w: follow vertical direction, can be in sitting
- 4mo: can follow slow circle
- 12mo: can follow in all directions including zig zag
- 4y: may have trouble dissociating eye and head movement, Tp to hold chin
- 6y: can maintain head position and just move eyes
Atypical: can’t follow visual fields, rubbing eyes, blinking, reddening

Question 13

Fast eye follow

Answer 13

Ability: keep visual contact with fast moving stimulus with both eyes in multiple directions

Typical: emerges at 12mo, could have slight over/undershoot  3y has better strategy
Atypical: unable to follow stimulus, adverse eye signs, can’t dissociate head and eye by 6y, jerkiness
- Eye follow problems may indicate brainstem dysfunction, poor VOR or cranial nerve dysfunc

Question 14

Fixation and release

Answer 14

Ability: fixate and release gaze from visual stimulus (binocular and monocular) and then fix on something else

Typical: emerges at 4y, fixate for 3s and release  will eventually be able to do this monocular
Atypical: unable to follow stimulus, adverse eye signs, eyes get ‘stuck’ or ‘lost, child needs to move head to release gaze

Question 15

Convergence and divergence

Answer 15

Ability: smoothly follow slow visual stimulus with both eyes equally when moving away from or towards face

Typical: emergence from 12 mo, follow stim 1m-10cm from face  after 12 mo can do this while one eye covered
Atypical: can’t follow stimulus, adverse eye signs, abnormal eye movement, lack of movement, asymmetry (dysfunction of ocular muscles), strabismus convergent (abnormal positions of visual axes)

Question 16

Optokinetic Nystagmus

Answer 16

Ability: induce visual nystagmus symmetrically in both directions when looking at alternating strips moving across visual field
- Reflex visual nystagmus stimulated by visual input of alternative and symmetrical objects eg. Focusing on passing poles on the train

Typical: present at birth and remains throughout life
Atypical: absence of reflex, only elicited in one direction, abnormal eye movement, loss of balance, dizziness, asymmetrical, inconsistent or variable response