Sensation (Vision) Flashcards
(28 cards)
What is the relevance of (visual) sensation in function?
It presents physically so we need to address the inside to see why its happening
Visual impairments:
- Increased risk of falls
- Difficulty with ADL’s
- Poor rehab outcome
What are the 2 most important somatosensory sensations for function?
Touch & proprioception
We want to know what our hand is touching (awareness)
What is ‘Feed-Forward”?
Informs the motor plan to tell you what’s coming
eg.) escalator
Feed-forward picks a motor plan based on what vision sees (it predicts)
- If vision is occluded it won’t work & you’ll fall (feed-back)
Feed-forward = Intermittent (a prediction) Feed-back = On all time (a reaction to something)
How many muscles control eye movement?
6 muscles
How does Vision work?
1) Sensory receptors receive info.
2) Goes from visual receptors to Thalamus (via optic nerve)
3) Information fans out to Primary Visual Cortex (via optic tract)
Primary visual cortex is in Occipital Lobe
After Vision Sensory info. is received?
It needs to have meaning
Visual Association Cortex processes info. & decides what we are looking at
(If vision is impaired we don’t know what to do)
Object recognition is important
(color, shape, size, where it goes, how its used)
Cornea?
Helps concentrate light
Pupil?
Constricts & dilates to let light in & out
Iris?
Controls the pupil
Controls if the light comes in or not
Lens?
Flexible to focus around the light coming in so can accommodate to different signals from near or afar
(the reason for glasses)
Age 40 = lens less flexible
Age 60 = inflexible
Retina?
Back of eye
Contains rods & cones:
- Cones = daylight gives color
- Rods = detect movement in peripheral fields better at night
Early evening (candle hour) don’t work fully
Macula?
Collects info from retina & makes image sharper, clearer, & more focused
Macula Degeneration = Blurred image
If a deficit with pupils, what will you expect to see in older population functionally?
Lens problem = Image not as clear (need glasses)
Macula problem = Blurred, dull vision
Muscles around eye pointing different directions = Double Vision
Optic Nerve problem?
PNS issue = blackouts
Hemianopsia?
Problem with left or right not scanning so can only see one side of field of vision
If brain problem (stroke)?
One side of visual field will be affected
they can’t tell where field of vision ends
Functional implications of Visual field problems?
- Fall risk
- Problem judging distance
- Ambulation where they put cane etc. impacted
- Functional activities compromised:
(eg. ) dialling a phone, finding a sweater = more challenging)
Having 2 of these can cause depression
‘Confrontation Test’?
Holding 2 fingers up to side with client looking forward
Treatment for ‘Hemianopsia’?
Compensatory = Bottom Up!!
(finding cards on table)
Teach to compensate & scan
Neglect?
Info. not been acknowledged
Visual Acuity?
How clear the image is (clarity)
Goal = to Increase safety in client’s environment
- Increase: print size, background contrast, & illumination
- Decrease: shadows, clutter
Diplopia?
Double vision:
(occular motor dysfunction)
- Reduced depth perception
- Decreased visual attention
- Reduced scanning
TREATMENT:
Partial occlusion of non-dominant eye (transparent)
- We occlude the central or nasal area
Full occlusion (eye patch, long periods only, exhausting to dominant eye)
Cataracts?
Due to aging
= Clouding of eye
Glaucoma?
Due to aging
= Decreased peripheral vision
