Sensation (Vision)

Question 1

What is the relevance of (visual) sensation in function?

Answer 1

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

Question 2

What are the 2 most important somatosensory sensations for function?

Answer 2

Touch & proprioception

We want to know what our hand is touching (awareness)

Question 3

What is ‘Feed-Forward”?

Answer 3

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)

Question 4

How many muscles control eye movement?

Answer 4

6 muscles

Question 5

How does Vision work?

Answer 5

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

Question 6

After Vision Sensory info. is received?

Answer 6

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)

Question 7

Cornea?

Answer 7

Helps concentrate light

Question 8

Pupil?

Answer 8

Constricts & dilates to let light in & out

Question 9

Iris?

Answer 9

Controls the pupil

Controls if the light comes in or not

Question 10

Lens?

Answer 10

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

Question 11

Retina?

Answer 11

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

Question 12

Macula?

Answer 12

Collects info from retina & makes image sharper, clearer, & more focused

Macula Degeneration = Blurred image

Question 13

If a deficit with pupils, what will you expect to see in older population functionally?

Answer 13

Lens problem = Image not as clear (need glasses)

Macula problem = Blurred, dull vision

Muscles around eye pointing different directions = Double Vision

Question 14

Optic Nerve problem?

Answer 14

PNS issue = blackouts

Question 15

Hemianopsia?

Answer 15

Problem with left or right not scanning so can only see one side of field of vision

Question 16

If brain problem (stroke)?

Answer 16

One side of visual field will be affected

they can’t tell where field of vision ends

Question 17

Functional implications of Visual field problems?

Answer 17

• 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

Question 18

‘Confrontation Test’?

Answer 18

Holding 2 fingers up to side with client looking forward

Question 19

Treatment for ‘Hemianopsia’?

Answer 19

Compensatory = Bottom Up!!
(finding cards on table)

Teach to compensate & scan

Question 20

Neglect?

Answer 20

Info. not been acknowledged

Question 21

Visual Acuity?

Answer 21

How clear the image is (clarity)

Goal = to Increase safety in client’s environment

• Increase: print size, background contrast, & illumination
• Decrease: shadows, clutter

Question 22

Diplopia?

Answer 22

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)

Question 23

Cataracts?

Answer 23

Due to aging

= Clouding of eye

Question 24

Glaucoma?

Answer 24

Due to aging

= Decreased peripheral vision

Question 25

Macular Degeneration?

Answer 25

Loss of central vision

Question 26

Presbyopia?

me

Answer 26

Inability to focus on nearby objects

eg.) affects sewing & reading

Question 27

Diabetic Retinopathy?

Answer 27

Diabetes blood supply problem

Retina AND Macula effected

Question 28

Sequencing story?

Answer 28

1 ) Light hits cornea

2) Iris allows light through pupil
3) Lens bends to accommodate light & focus image on retina (inverted)
4) Retina produces a vague image
5) Fovea & Macula sharpen the image
6) Retina changes image to chemical/electrical signal (Complex Cell Structure) & excites optic nerve
7) Nerve transmits signal to Primary Visual Cortex of brain
8) Message is sent to Parietal & Temporal Lobe for “where & what” processing