Vision Flashcards
(84 cards)
1
Q
What are the roles of the visual system?
A
Interaction with environment
Anticipatory function - Warning about potential dangers
Social interactions - Non-verbal communication
Motor movement - Eye-hand coordination, postural control
2
Q
What are zonules?
A
Ligaments connecting the lens to ciliary body.
3
Q
What are the functions of the iris?
A
Eye color
Pupil size
4
Q
What are the ciliary body?
A
Ring-shaped structure with lens muscles
5
Q
What is the cornea?
A
The entry point of light into the eye
6
Q
What is the sclera?
A
Eye white
Provides muscular attachments
7
Q
What is the choroid?
A
Vascular membrane that provides collateral blood flow.
8
Q
What is the macula?
A
The pigmented area with cones for high acuity.
9
Q
How do the numbers of rods and cones compare?
A
There are way more rods (120 milion) than cones (5 million).
10
Q
How do the rods and cones respond to light?
A
Rods are very sensitive to light. Cones need enough light to perceive colour.
11
Q
How do the distributions of rods and cones compare?
A
Rods are distributed equally over the retina, while cones are concentrated in macula
12
Q
How many cranial nerves are involved for the movement of eyes?
A
4
13
Q
Which cranial nerve innervates the eyelid?
A
CN III
14
Q
What are the most common problems with the eye?
A
Acuity (near/far) Cataracts Macular degeneration Glaucoma Diabetic retinopathy
15
Q
What is myopia?
A
Near-sightedness due to eye length being too long.
16
Q
What is hyperopia?
A
Far-sightedness due to eye length being too short.
17
Q
How do acuity issues present?
A
Blurred, fuzzy vision with decreased ability to focus.
Adjusting distance between self and objects.
Uses peripheral vision.
Needs more light.
Cautious when ambulating.
18
Q
Which test is often used for acuity?
A
Snellen letter chart
19
Q
What are the procedures for Snellen letter chart?
A
Test eyes separately and together from 6 feet away. 20/20 considered norm.
20
Q
What are the treatments for acuity issues?
A
Glasses
Surgery
Laser treatment
21
Q
What is presbyopia?
A
Problems with near vision due to degenerative lens thickening starting at over 40 years
22
Q
Why do women need reading glasses before men?
A
Men tend to have longer arms, so they can hold things far for longer until they absolutely need glasses.
23
Q
What are cataracts?
A
Degenerative clouding of the lens which limits light from entering through the lens. The leading cause of visual impairment.
24
Q
What are the symptoms of cataracts?
A
Sensitivity to light Difficulty seeing detail Poor central vision, compensation with peripheral vision (seeing with head turned) Difficulty seeing colours Limited night vision
25
What are the treatment options for cataracts?
Using higher contrast
| Surgery to remove lens and insert artificial lens
26
What is the success rate of cataract surgeries?
95%
27
What are the risk factors for cataracts?
```
Age
Family history
Diabetes mellitus
Smoking
Alcohol
Sun exposure
Medications
Injury
```
28
What is macular degeneration?
Damage to blood vessels resulting in progressive degeneration of the macula, affecting central vision in one or both eyes.
29
True or False: Macular degeneration is age-related.
True. It is the leading cause of vision loss in in elderly.
30
What is the cure for macular degeneration?
There is no cure, only treatments to slow the process.
31
What is glaucoma?
Damage to the optic nerve, often by build up of fluid causing pressure in the eye.
32
What is the main symptom of glaucoma?
Loss of peripheral vision, i.e. tunnel vision
| Less dynamic vision → Avoidance of dynamic environments
33
Glaucoma is often [detected/undetected] and [can/cannot] cause complete blindness.
Undetected
| Can cause complete blindness
34
What are the risk factors for glaucoma?
```
Family history
Age
Myopia
Diabetes
Blood pressure
```
35
What are the treatments for glaucoma?
Delay of progression by medication
| Laser
36
What is diabetic retinopathy?
Damaged blood vessels due to high blood sugar levels causing micro hemorrahges and scar tissue
37
What are the symptoms of diabetic retinopathy?
```
Initially asymptomatic
Decreased contrast sensitivity
Decreased colour discrimination
Decreased night vision
Floaters
```
38
How many sections are in the visual field?
4 quadrants
39
How are the quadrants represented in the primary visual cortex?
Vertically and horizontally mirrored
40
What is hemianopsia?
Blindness in one half of the visual field
41
People with hemianopsia are usually [aware/unaware] that they have vision impairments.
Aware
42
What are the symptoms of hemianopsia?
```
Increased head movements (compensation)
Almost collides/comes close to objects
Looks at the floor or at one side
Ambulates close to the wall or follows other
Uncertain in dynamic environments
Feels off balance
Loses place when reading
```
43
What are the treatment goals for hemianopsia?
Creating awareness and implementing compensatory strategies
44
How is hemianopsia assessed?
Without glasses and with one eye occluded, patient focuses at an object 1 m away. Light is brought into visual field at 20" from the patient's head, and the patient indicates when they see the light.
45
What is the range of the visual field vertically (up and down)?
Up: 60°
Down: 75°
46
What is the range of the visual field horizontally (temporal and nasal)?
Temporal: 100°
Nasal: 60°
47
What is the difference between hemianopsia and hemi neglect?
Hemianopsia is an optic tract impairment resulting in a visual field cut, whereas neglect is a perceptual impairment (within the brain) resulting in inattention.
48
What are the 2 visual perception pathways, and which lobes are responsible for each pathway?
1. The "where" pathway - Parietal lobe
| 2. The "what" pathway - Temporal lobe
49
What deficits do parietal lesions lead to?
Deficits in spatial orientation and attention
50
What deficits do temporal lobe lesions lead to?
Object recognition
51
Impairments with visual perception is more associated with [dominant/non-dominant] hemispheric injuries.
Non-dominant.
52
What percentage of stroke patients are impacted with visual perception impairments?
30-50%
53
What is neglect?
Failure to report, respond, or orient to novel or meaningful stimuli presented to the opposite side of the lesion.
54
What deficit is neglect related to?
Attentional deficits
55
Which lesion is more common in neglect?
Right side of the brain → Left hemi neglect
56
What types of stimuli are not attended to in neglect?
Spatial or extra-personal
Body or person
Motor - Underuse
Extinction - Cannot detect contralateral stimuli when given bilateral stimulation
57
What might be the diagnosis when a client presents who is hesitant to pass midline, shows decreased grooming on a side, skips letters/words when reading, and misses objects on the same side?
Neglect
58
What are the assessment options for neglect?
```
Catherine Bergego scale
Bahavioural inattention test
Line bisection test
Cancellation sheets
Observation in ADLs
```
59
What is separation as in a cognitive phenomenon?
A frontal lobe impairment where the individuals has difficulty stopping an activity and does it multiple times, continues doing it, etc.
60
Stroke patients with perceptual deficits tend to have [less/more] functional impairments than stroke patients without perceptual deficits.
More
61
Clients with neglect tend to have [shorter/longer] recovery times and [fewer/greater] change of institutionalization.
Longer recovery times
| Greater change of institutionalization
62
Neglect is a [negative/positive] predictor of rehabilitation outcome.
Negative
63
What are the treatment strategies for neglect?
```
Awareness/attention training
Scanning training
Limb activation
Mental imagery
Prism glasses
Environmental education
```
64
What are two therapeutical approaches to neglect?
Remedial - Focus on the affected side and provide correction and feedback.
Compensatory - Focus on the non-affected side and provide assist.
65
What are the presentations of neglect and visual field deficit co-existing?
```
Veers to one side
Bumps into objects
Difficulty orienting in environment
Lack attention to body
Misreading clock
Poor carryover for compensatory techniques
```
66
What is agnosia?
Inability to recognize information from a sensory system.
67
What are the types of agnosia?
Visual
Tactile
Auditory
Proprioceptive
68
What are some treatment strategies for agnosia?
Use common, familiar objects.
Use other sensory systems.
Try to make patient aware.
69
What part of vision are the brainstem, cerebellum, and cranial nerves involved in?
Muscle innervation - Occulomotor movements, pupil reaction, focus, smoothness of movements
70
What are ways to test brainstem, cerebellum, or cranial nerve involvement in visual impairments?
Pupillary response - Size, reaction to light, accommodation
Convergence
Acuity
Light sensitivity
71
When assessing the pupillary response, what should be considered?
PEARL = Pupils equal and reactive to light
Size & shape - Round and < 9mm
Fast, smooth change
72
If pupil accommodation does not happen well, what is a possible complication?
Diplopia
73
What are two phenomena that should be observed when assessing accommodation?
Pupil constriction and convergence
74
How are occulomotor movements assessed?
Follow light with eyes only. Watch for smooth movements, full range of motion, and symmetrical movements.
75
What are treatment options for diplopia due to occulomotor movements?
Prism glasses
Taping
Eye patch on non-dominant eye
76
What are the presentation of contrast impairments?
Difficulty seeing water in glass
Moves objects close to see
Difficulty approaching curbs, stairs, or other transitions
Decreased function in dim light
Difficulty distinguishing between colours
77
Who are ophthalmologists vs. optometrists?
Ophthalmologists: Physicians with specialization in vision
Optometrist: Healthcare professional in vision
78
What are the treatment goals for individuals wtih vision impairments?
Focus on safe interaction with environment - Environment Ax and adaptive devices.
Restoring/maintaining independence.
Training using other senses.
Education.
79
What are the components of OT assessment of vision?
```
Acuity (Snellen chart)
Contrast
Visual attention
Visual field
AROM
Neglect
```
80
What are environmental considerations to make for vision impairments?
```
Light
Contrast - Solids
Colour - Brighter
Patterns - Limit
Print size - Larger
Work distance
```
81
What are considerations for light for vision impairments?
```
Avoid glare/fluorescence.
Avoid shadow.
Use high wattage or try different lights.
Increase contrast.
Organize environment.
```
82
What are some assistive technology and devices for vision impairments?
```
Talking phone or watch
Large print
Guide dogs
Spoken books
Cane
Glasses
Braille
```
83
What are the vision guidelines for class 5 driver's license?
When tested with both eyes open and with appropriate corrections:
Visual acuity = 20/50
Visual field = 120 degree in horizontal from the meridian, 15 degrees in peripherals above and below fixation.
84
For what conditions is driving suspended?
Hemianopsia
Diplopia (not corrected)
Telescopic lenses
Others that may cause unsafe driving
