Low Vision Flashcards
1
Q
Eccentric viewing
A
Technique used by people with central vision loss
2
Q
Visual acuity
A
Ability to see small visual detail ensuring that precise visual input is provided to the CNS
3
Q
Snellen fraction
A
Most common visual acuity measurement
4
Q
Presbyopia
A
Difficulty focusing on near objects and is a common age-related change in adults over 50 as the lens of the eyes becomes less flexible, reducing the ability to read small print
5
Q
Myopia
A
Nearsightedness - not able to see far away objects
6
Q
Hyperopia
A
Farsightedness - not able to see close up objects
7
Q
Legal blindess
A
20/200 visual acuity or less in the better eye after correction
8
Q
Contrast sensitivity
A
Ability to perceive and detect objects in relationship to the background of their environment (distinguish various shades of gray)
9
Q
Impairments in contrast sensitivity is difficulty for…
A
Navigating environments safely
10
Q
Visual field components
A
- Peripheral (ambient visual system)
- Central
11
Q
Peripheral vision
A
Provides background info about position in relation to environment
12
Q
Central vision
A
The central 20 degrees of vision
13
Q
Accommodation
A
Ability to adjust focus of vision at different distances
14
Q
Oculomotor control
A
Ability of eyes to move smoothly and in coordinated manner through full ROM to maintain focus on object by both retinas
15
Q
Oculomotor allows for…
A
Binocular vision - seeing with two eyes and ensuring that only one object is seen together which supports 3D and judging distances/depth
16
Q
Convergence
A
Muscle action of eyes causing adduction which allows for focusing on nearby objects
17
Q
Diplopia
A
Double vision
18
Q
How to eliminate double vision
A
Assume head position that eliminated need to use the paretic eye muscle to create stabilization
19
Q
Exophoria
A
Eyes turns out when not focusing on object
20
Q
Esophoria
A
Eye turns in when not focusing on objects
21
Q
Visual attention
A
Ability to identify specific features of an object and ignore other irrelevant sensory information
22
Q
Hemi-attetnion
A
Occurs when visual search patterns are only on one side of visual array, asymmetric search pattern that neglects one side
23
Q
Pattern recognition
A
Ability to identify configuration/holistic object and its specific features
24
Q
Visuocognition
A
Ability to manipulate and integrate visual info and process with other sensory input
25
Common age-related visual impairments
- Decreased ability to see close objects
- Increased blurriness
- Decreased ability to see at night
- Adapt more slowly to change in light
- Contrast sensitivity decreases
- Decreased ability to view objects in low light
- Decreased color distinguish
- Narrow visual acuity
26
Macular degeneration
Age-related degeneration of macula (center portion of eye) responsible for fine details for near-distance activities that can cause objects to appear distorted in shape
27
Common functional impairment due to macular degeneration
- Difficult reading labels or instructions for IADL tasks
- Difficulty with functional mobility with low-contrast surfaces (steps, curbs)
28
Glaucoma
Loss of peripheral vision due to blocked fluid and increased pressure causing reduced blood flow to optic nerve
29
Common functional impairment due to glaucoma
- Bumping into things during functional mobility
- Getting startled due to objects/people suddenly appearing from peripheral
- Reading and writing due only being able to see small portion of page
30
Diabetic retionopathy
Retina blood vessels swell and leak or abnormal blood vessel growth causing blurred vision, spots/floaters, central vision loss, decreased contrast sensitivity, color discrimination (can be fluctuating)
31
Cataracts
Lens of eye becomes opaque and clouded which reduced light going into retina which results in blurry vision, reduced visual acuity, faded colors, glare, decreased ability to tolerate bright sunlight and poor night vision
32
Homonymous hemianopsia
Half visual field in each eye is lost resulting in difficulties scanning environment during functional mobility and with reading (post TBI)
33
Common impairemtns with poor oculomotor function
Difficulty with eye-hand coordination, writing, reading, walking, driving, leisure activities
34
Visual neglect
Combination of hemi-inattention and left visual deficit resulting in inattention to the left side side (spatial and body)
35
Interventions for low vision
- Provide education on home/work modification to improve performa
-
36
When to refer client to certified orientation and mobility specialists
When the client has difficulty with or myst learn new strategies for crossing streets, planning routes, detecting curbs, walking w/o sidewalk, following public transportation routes or using white cane
37
Melbourne Low-Vision ADL Index
Assesses impact of person's visual impairment on ADL and IADL
38
Assessments for Low vision
Melbourne Low-Vision ADL Index
COPM
Model of human occupation screening tool
39
Model of Human Occupation Screening Tool
Assess impact of volition, habituation, skills and environment on occupational performance during informal observation
40
COPM
Semistructured interview that assesses patients perception of their performa in self-care, productivity and leisure as well as rate the importance of activities and performace on the activities
41
How to assess near visual acuity
Lighthouse near visual acuity test
42
How to assess distance visual acuity
Snellen E chart or tumbling E chart (aphasia or illiterate)
43
How to assess contrast sensitivity
Pelli-Robson Contrast sensitivity chart (fading letters on white backround)
44
How to assess peripheral visual filed
Confrontation testing - have pt. fixate on central target while acknowledging appearance of stimuli in variety of visual fields
45
How to assess central visual field
Amsler grid (boxed grid with dot in center - poor vision if lines are missing / wavy with one eye occluded)
46
How to assess oculomotor function
Brin injury visual assessment battery (variety of subtests that address contrast sensitivity, eye dominance, distance acuity, near acuity, scanning, searching, scanning while completing functional mobility
47
Eccentric viewing steps
1. Increase pt. awareness of blind spot
2. Determine head positioning for optimal viewing by rotating head/trunk to view using area of peripheral vision
3. Learn to track and view through magnification
4. Practice scanning exercises
48
Preferred retinal locus
Using peripheral vision to view object with when pt. presents with central vision loss
49
Relative distance magnification
Moving body closer to object to make it relatively larger
50
Relative size magnification
Size of object increased
51
Sensory subsituations
Using other senses to compensate for visual impairment
52
Tactile markers
Use on most frequently used objects and setting on appliances to help locate position (puff paint, bump dots)
53
Visual acuity broad categories of intervention
1. Eccentric viewing
2. Magnification
3. Lighting
4. Contrast
5. Organization
54
Strategies for addressing visual field loss
1. Rotation of head and trunk to view entire field
2. Organized scanning to identify hazards/locate objects
3. Line guide and bold lines on affected side for reading to ensure viewing of entire page
4. Develop wider visual search pattern during functional mobility
55
Options for diplopia
1. Occlusion with compensatory eye shutting
2. Occlusion with eye patch
3. Prism glasses to re-establish single vision
4. Eye exercises
5. Surgery to change position of eye in socket
- Need to consult ophthalmologist/optometrist before use
56
What should you assess for someone with diplopia
Oculomotor function (speed, control and coordination of the eye)
57
Deficit associated with poor visual acuity
Blurred vision
58
Deficit associated with visual field cut
Difficulty locating objects and frequently bumping into things due to reduced search pattern
59
Near-total visual impairment or near-total low vision level
20/1000
60
Severe visual impairment or severe low vision level and intervention
20/200 (increase illumination and enlarge print)
61
Intervention for visual field deficit
Develop organized visual search pattern
62
Task lighting positioning
Position light opposite writing hand or near the best seeing eye - avoid shinny surfaces, patterns and low contrast to improve visibility
63
Visual foundation skills
Visual acuity
Oculomotor control
Pursuits
Saccades
Visual fields
64
Visual perception skills
Figure ground
Form discrimination
Spatial relations
Visual closure
Form constancy
Visual memory
Object recognition
65
Visual perception
Ability to organize and interpret visual input and give it meaning
66
Perceptual completion
CNS autocorrects for visual field deficit internally to complete visual scene on the basis of visual info expected to be found with patient being unaware of the deficit
67
Presbyopia
Difficulty keeping items focuses as they get close, farsightedness deficit caused by loss of elasticity of lens of eye
68
Saccades
Quick, simultaneous movement of both eyes between two or more phases of fixation in the same direction
69
Pursuits
Smooth slow tracking of one stimuli
70
Perimetry
Visual field test for central and peripheral vision
71
Stereopsis
Depth perception due to binocular vision
72
Cortical visual impairement
Permanent visual impairment in children (1-3) due to brain dysfunction resulting in decreased visual acuity, difficulty recognizing faces and objects, abnormal visual responses and eye movements
73
Retinopathy of prematurity
Abnormal blood vessels grow in the retina in pre mature babies causing strabismus, diplopia, nystagmus
74
Microphthalmia
One or both baby eyes small which can cause vision loss or blindness
75
Anophthalmia
Birth defect where a baby is born without one or both eyes
76
Common postural and motor presentation in children with visual impairment
Hypotonia
Shoulder/pelvis instability
Pronounced head tilt
Hyperextended neck
Wide base of support
Tendency to move in straight planes
High guard posture with walking
77
Physical red flags for visual problems
Eyes shake
Excessively large or small pupil
Eyes do not rest in alignment
Pupils opaque
78
Behavioral red flags for visual problems
Need to move closer for visual attention
Squinting, straining, rubbing eyes
Headache complaints
Avoidance of tasks with short attention span
79
Performance red flags for visual problems
Clumsiness
Difficulty locating items
Difficulty with spatial recognition
Difficulty drawing, writing, copying
80
Social red flags for visual problems
Lack of interest
Anxiety
Decreased self-confidence
81
Categories of object perception
Form constancy
Visual closure
Topographic orientation
82
Warrens model of assessment hierarchal model
1. Primary visual skills
2. Visual attention
3. Scanning
4. Pattern recognition
5. visual memory
6. Visual cognition
83
Visual-receptive dysfunction
Difficulty completing work in timely manner, avoidance of reading/writing, visual fatigue, inattention to visual input
84
Refractive errors
Inability of eye to adjust to different light condition, perform accommodation or other oculomotor functions
85
Presbyopia
Poor accommodation and foucs for near objects
86
Strabismus
One eye turns in, out, up or down due to muscle imbalance
87
Phoria
Tendency for one eye to move in out up or down
