Low vision Flashcards
Advanced education options for OT in low vision
Low Vision Certificate (CLVT
UAB- 5 courses (CLVT-Certified Low Vision Therapist)
Salus University (CLVT-Certified Low Vision Therapist)
- Certificate Program-30 credits
- Masters of Science in Low Vision Rehab-36.5 credits
Visual Impairment and Orientation and Mobility Professionals Scholarship Program
- VA-relocation, guaranteed job, money
AOTA-Specialty Certification in Low Vision (SCLV) (not offered anymore)
- Micro credentials
- Online courses
CATIS- Certified Assistive Technology Instructional Specialist
CVRT-Vision Rehabilitation Therapists
ACVREP-Academy for Certification of Vision Rehabilitation Education Specialists
COMPS-Certified Orientation and Mobility Specialist
What is an optometrist?
Has a doctor of optometry (OD)
Vision tests and complete eye exams
Diagnosis of some eye conditions
Prescription of contacts and glasses (and meds in some states)
Minor surgical procedures (in some states)
What is an ophthalmologist?
Has a medical degree (MD) or doctor of ophthalmology (DO)
Can do everything an optometrist can do
Medical treatment of eye diseases
Surgical treatment of eye diseases
What is an optician?
Specializes in the fabrication and fitting of glasses
What is the function of the eye?
Sight
Equilibrium
Aid to fine motor (major part of visual perceptual skills- eye hand coordination)
Aid to gross motor
Learning tool: developmental level (bystander play)
Socialization
As we age
- Decline in balance, ROM strength, sensation
- Compounded by vision loss
What are the different layers of the eye?
Outer, middle, inner
Describe the outer layer of the eye.
Sclera- whites
Cornea- window
- Bends light
Describe the middle layer of the eye.
Choroid coat: blood
Ciliary body: muscles to change shape of lens
Lens: focuses light on the retina
Iris: colored part
Pupil: opening, dilates of constricts as light passes
Describe the inner layer of the eye.
Retina
- Rods (black and white), cones (color)
Macula: disk on the retina, behind the lens; all parts of the macula are able to interpret information; OT can help teach people how to use other parts of macula
Fovea: depression in macula that is your preferred point of sight and where your brain interprets change
- Sharpest sight
What is the anterior cavity of the eye?
Aqueous humor
Maintains shape
Pressure of the eye
What is the posterior cavity of the eye?
Vitreous humor
Shape of eye
Hyperopia
Far sighted
Presbyopia
Far sighted due to age
Myopia
Near sighted
Light rays focus in front of the retina
Astigmatism
Problem with a curvature of the lens, several problems
Light rays focus on more than one point (unequal refraction of light in different meridians)
What is a hordeolum?
A sty
Inflamed sebaceous gland
Can turn into cellulitis
Optometrist may be able to perform sx to remove
What is a corneal abrasion?
Scratched lens, retina, eyeball
Very painful
What is cataracts?
Opacity or clouding of the lens
Eye injury, genetics, birth defects, sun
How does a CVA or TBI impact vision with glasses?
Wait 3-6 month to get refitted for glasses
What is glaucoma?
Increase in aqueous humor
Takes away peripheral vision
Side effect to many different diseases, over age 45
Higher risk: AA, Irish, Russian, Asian, Hispanics, Scandinavian, diabetics, infants
What is retinal detachment?
Separation of the retina from the choroid layer
Partial or complete
Usually an injury
- Diabetes
- Elderly can be spontaneous (family history)
Cobwebs, floating spots, flashes of light, shading
Painless
Medical emergency
What is macular degeneration?
Progressive disease, cells of macula die
Leading cause vision loss in US
Loss of “fine vision”
Starts with spots
Slowed with laser surgery-progress to vision loss
- shots
Aging process, hypertension, diabetes, genetics, light iris color
Wet MD: eye water
What is a strabismus?
“lazy eye” (ambloypia)
Genetics, brain injury
May or may not have double vision
Can be surgically fixed
What is conjunctivitis?
“Pinkeye”, irritants, colds, allergy
Can be contagious
What is blepharitis?
Ulceration of edges of eye
Usually due to a clogging of sweat or oil glands
Can be treated with topical medications, surgery, or hot compresses
What is low vision?
Progressive diseases that lead to chronic loss of sight and limit daily function.
- Effects many elderly, as this population increases so does this disorder
What are common causes of low vision?
Macular degeneration
Glaucoma
Cataracts
Diabetic retinopathy
What is the VFQ?
Visual Function Questionnaire
It measures the influence of visual disability and symptoms on generic health domains such as emotional well-being and social functioning, in addition to task-oriented domains related to daily visual functioning.
Visual acuity
Visual field
Contrast sensitivity
Shades of gray
Light to dark ratio
Light modulation
Ability to tolerate different degrees of light
Visual perception
Figure ground
Visual closure
What does insurance do about low vision?
Insurance doesn’t cover low vision services as primary diagnosis. Must put acuity level.
If 20/60 or better insurance won’t cover it
How do you test visual acuity at a distance?
Feinbloom Distance Test Chart
How do you test reading acuity?
Minnesota Low Vision Reading test
- Also called the MN reading card
- Black and white
- Pt needs to be in good light and reading at 90º angle
- Looks at how quickly they can read at different levels
How do you test peripheral field?
Manually test -
Periphery testing
Dyna vision
What is the scotoma assessment?
Usually completed by optometrist or ophthalmologist
Amsler Grid or Tangent Screen test
What environmental factors should you assess with low vision?
Current lighting
Usually cause it’s easier
Possible positions for additional lighting
Organization systems
Current low vision devices
Ergonomics of task performance
Emergency response and danger
Inside and away from home
Interventions for low vision
Education
Use of Devices
- Optical
* Typically enlarge, DOES NOT CLARIFY or remove blind spots or distortions
- Non-optical
* Timers
* Voice operated devices
Lighting Strategies
- Bright vs direct
- Portable
- Overhead or directed
- Handle Glare
* Sunglass, visors
Contrast strategies
Modified methods for peripheral field loss.
Teach scanning techniques
Increased lighting
Increased contrast
Functional Mobility
Modified methods for central field loss.
Increased lighting
Eccentric viewing skills
Increased contrast
Magnifiers
Modified methods for decreased acuity (unable to correct)
Increased lighting
Increased contrast
Magnification
Ideas to improve function in low vision clients
Large Print
- 16-18 pt is recommended
Font
- Avoid decorative
- Bold
- Avoid italics and capital letters
Ue Color
- Headings
- Dark Blues and Greens
Contrast
- Light on Dark
Paper Quality
- Avoid glossy finish
Spacing
- 1.5 to double over single spaced
Tracking
- Close letters are more difficult
Margins
- At least 1-1.5 inches is preferred
- Easier to set up with a magnifier
Functional mobility in low vision clients
High Contrast
Guides
- Sighted Guide p. 161
- Animal
- Cane
Coding and low vision
97003: Evaluation
97530: Therapeutic Activities (scanning, Eccentric training)
97532: Development of Cognitive skills (new compensatory skills)
97535: ADLS and Self Care
97537: Community/Work Integration
Before we can address high level perceptual skills, we must consider:
Acuity, visual fields, and oculomotor function
Warren’s hierarchal model of visual processing
Registration of visual input –> pattern recognition –> visual memory –> visual cognition
Retina
light is transmitted here to focus
Cornea
outer covering of the eye
shape is vital for focus
Aqueous humor
Fluid in the eye behind the cornea
Maintains the shape of the eye
Iris
Colored part of the eye
Works with the pupil (hole) to determine how much light comes in
Lens and vitreous humor
Focus for near and far vision
Cones
Color and visual acuity
Rods
Night and peripheral vision
Pupillary cells
Control dilation and contraction
CN II
Optic nerve
Muscles of eye movement
Three layers of the eye
Sclera –> choroid –> retina
Fovea centralis
Point of preferred or clearest vision
What is vision
The process of integrating vision with other sensory input for survival and adaptation
Cataracts
Decreased acuity
Difficulty seeing at night
Foggy appearance
Glaucoma
Increase pressure
Poor night vision
Loss of peripheral vision
Diabetic retinopathy
Loss of color
Loss of contrast
Poor night vision
#1 cause of blindness in the US
Preventable
Age related macular degeneration
Decreased acuity
Loss of central vision
Hyperopia
far sighted, can’t see up close
Presbyopia
loss of lens accommodation (around 40); usually starts as myopia and develops into hyperopia
Myopia
near sighted, can’t see far off
Strabismus
Wandering eye, lazy eye
Phoria
Controlled strabismus
Retinopathy of prematuiry
Occurs with premature babies that were on high levels of oxygen
Nystagmus
Abnormal response and can interfere with reception
Lack of nystagmus is abnormal
Cortical blindness
Blindness that occurs in the brain
Ptosis
Droopy eye
OD
Right eye
OS
Left eye
OU
Both eyes
What is low vision acuity?
Typically think about 20/20 (ft vs letter size)
Most charts go to 20/200
- Low Vision starts at 20/70 – not fixable
- Legally Blind 20/200
- Low vision can run 20/1000
- Special charts are needed
- Best if assessed in low and high contrast acuity
Intervention for vision
Combination of remediation, compensation, and adaptation
Can’t fix blindness
- redirect visual field
- increase speed, width of sweep and organization
Occlusion
Prisms
Eye exercises
- Think eye “ROM”
- Practice in various directions
- Focus
Practice on location and fixation
Scanning
Tracking
Reading speed, endurance
Typical goals for vision impairment
Increase width of head or eye movement toward effected area
Increase the automatic movement to the blind side
Increase speed with location of items
Execution of search patterns
Attention to and detection of items on effected side
Ability to shift and search
Specific intervention for vision
Help a person identify items used every day that need to stand out:
- Bright colors
- Specific spot/contrast colors
- Counting to stairs or rough mark at bottom or top
General Safety
- Increase lighting (illumination) -direct vs diffuse
* Pink, white, and blue lights are kinder to the eye
* Position of light
- Remove rugs or other hazards
Reduce Clutter
- Safety issue
- Makes things easier to find
- Contrast color on counter tops
Educate a person on how to use other senses
Recommend and train in adaptive equipment
- Low or high tech
Enlarge items
- Blowing it up is not always the answer
- Enlarging doesn’t always help for: visual field or oculomotor deficits
Addressing Visual Fields (VFD)-Perimetry
- Common after CVA
- Hemianopsia
Hemianopsia
If on the same side as the dominate hand, they may not be able to track or use adaption of the UE
Miss parts of reading or omitting letters or small words
How to assess visual fields
As simple as the Confrontation Test
As expensive as (SLO) Scanning Laser Ophthalmoscope ($1200.00)
In between:
Goldmann
DynaVision 2000
Visual perception
the total process of receiving and understanding visual stimuli
2 main components of visual perception
Visual reception
- Extracting and organizing information from the environment
- For example, straight vision says: blue shirt, man, brown hair
* Visual reception tells you that he is a man (organizing), he is out of the ordinary
Visual cognition
- The ability to organize, structure and interpret visual stimuli
- The ability to understand what is seen
Mature visual system
A mature visual system is needed for visual perception to work.
You cannot have normal visual perception without vision.
- blind individuals still have perception, but not visual perception
Integrates all components of a mature system
- Ability to respond and adjust to retinal stimuli
- Move head and eyes to collect data
- Interpret visual information
- Respond with appropriate motor response
Components of a mature visual system
Ability to respond and adjust to retinal stimuli (physical, visual reception)
Move head and eyes to collect data (physical, visual reception)
Interpret visual information (cognitive, visual cognition)
Respond with appropriate motor response (cognitive, visual cognition)
Visual reception
“Eyeball”
Memories, knowledge, experience - give meaning to what you saw
Visual cognition
Take what you saw and use it physically, socially, cognitively, emotionally
8 components of visual reception
First 2 are a hierarchy:
1. Fixation: ability to gaze at a fixed object, stare at a spot on the board
- prerequisite for pursuit and saccadic ability
2. Pursuit or tracking: the ability to follow a moving object
- a ball rolling along the floor, a cat walking along the sidewalk
3. Saccadic or scanning: the ability to move from one visual field to another rapidly
- the ability to “scan” the crowd for your date or to “scan” shelf for a book
4. Acuity: 20/20, how well a person can see at 20 feet
5. Accommodation: the ability to focus on an object, to make a blurry far object clear
- from blurry to clear , just a few seconds
6. Binocular vision: the vision of two eyes into one picture
7. Stereopsis: 3D
8. Convergence and divergence: ability to move the eye in and out
Components of visual cognition
Usually well developed by age 9
There are 4 components of visual cognition, with subcomponents
1. Visual Attention
2. Visual Memory
3. Visual discrimination
4. Visual imagery or visualization
Visual attention
Their eyes check out and are fine, we have a problem with visual cognition
Two levels: visual and cognitive
Visual attention
- alertness
- selective attention
- shared attention
- visual vigilance
Can be under or over or unable to sustain
Kids who can’t differentiate between features of different objects and therefore do not know were to focus
- Descriptive games
Visual memory
Recognition
Retrieval
- difficulty or extended time
- can’t remember details
* visual sequential memory - can’t remember things in order, starts simple - ABC - what about brachial plexus??
* visual spatial memory - the location of things in space, where do I sit, starts simple; think about brachial plexus, which nerve is deeper??
Visual discrimination
Ability to recognize, match, and categorize
- typically, we go from top to bottom and left to right, kids with discrimination issues are hit and miss
- trouble with similar letters, words, or numbers, handwriting, word searches
Object or form vision
- form constancy, visual closure, figure ground
- miss important aspects, don’t like things in different situations
Spatial vision
- often called “dyslexic”, reversal of letters and words
- this shows up physically too
* difficulty with R and L, up and down
* clumsy
Hierarchy of visual perceptual skills
oculomotor control, visual fields, visual acuity –> attention, alert, and attending –> scanning –> pattern recognition –> visual memory –> visual perception –> adaptation through vision
Development of visual perceptual skills
Visual - receptive development
In utero
Birth
- Reflexive fixation and tracking
- Nystagmus
8 Weeks - occulomotor control begins
- Tracking develops- complete by age 5yrs
* Cardinal planes of movement
* Head movement indicates a lack or incomplete development
Peak of occulomotor control is 18 yrs
Vision is the primary way an infant collects information
- Long before they can manipulate an object they can perceive it, recognize a pattern, have form constancy, and depth perception.
To start, they learn to identify objects based on general appearance and later learn to see specific details
- 18 month old: dog
- 4 year old: granny’s dog,
- 7 year old: that’s a poodle
Visual cognitive skills are vital for developing print awareness
- knowledge of letters and words and that they have meaning
Developmental ages to remember
Visual Perception develops differently in different children: environment, opportunity, natural ability, and cognition
Typically developed by 9-10 years
- Figure ground-and form constancy: 6-7 yr
- Spatial relationships:10yrs
What can they draw?
- Verticals: 2
- Horizontals: 3-4 (people get arms)
- Laterality: 6-7 yrs
* Understand or recognize reversals- should stop mixing up b and d
* circles, the letter C
- Directionality: 8-9 yrs
How do visual perceptual skills develop?
General to specific
- Dog
- Brown dog
- Big brown dog
- Big brown short haired dog, lab
Whole to part
- Doll
- Doll’s dress
Concrete to abstract
- “There is a crack in everything, that is how the light gets in”
Familiar to novel
Role of vision and visual perceptual skills in motor development
Highly reliant on vision to get body to work in early stages
Kids with out vision must rely on tactile, vestibular, and proprioception, opportunity may be limited
Linked to hand function
- Babies stare at hands and objects
Ambulation and mobility
- Can’t discriminate differences in flooring, may fall
Role of vision and visual perceptual skills in social environment
Emotional attachment with caregiver
Facial expressions
Social cues
Agnosis
the inability to name an object known to the individual through visual means but able to by feel
- Right occipital lobe damage
Color agnosia
inability to remember what color things should be (grass)
Color anomia
inability to name a color
Metamorphopsia
inability to distinguish the size or weight of an object, often distorting the size
Prosopagnosia
inability to ID familiar faces
- lesion to R posterior hemisphere
Evaluation of visual perceptual skills
Reception first:
- Rule out any of those medical issues
- Snelling only catches about 5% of these problems
- Look at control of vision and eyes, color testing, contrast
Vision/Cognition
- Lots of standard tests
- Clinical observations
* Sorting, selecting, retrieving, recognition, planning
Intervention of visual perceptual skills
Developmental (rehabilitative) or Compensatory or BOTH!
- Developmental
* Start at bottom level and grade up
- Compensatory
* Limit amount of material in session
* Keep it simple
* Use movement-track with finger
Determine learning style - often based on perceptual strengths
- Then use it!
Options and treatment for visual perceptual disabilities
Infants
- Facilitate visual perception
* Dim lights to encourage eye opening
* Faces
* Mobiles off to the side
> Textures and patterns- simple first
- Bright colors
Preschool
- Multi sensory approach
* Tactile- feel it, say it, make it, eat it
* Simon says
* Play dough
* Sand and paint drawing
* Guess the letter
* Graphesthesia: can’t distinguish a letter traced in your hand
Elementary School
- Learning style!
- De busy the room
- Stable posture
- Color coded worksheets
- Block outs
* Rule, card or finger
- Landmarks
- General sensory stim, increase or decrease as needed
- Hands to help the eyes
* Size, weight, texture, direction
Elementary/Middle School Continued
- Reduce competing sensor input
* Earphones, study centers or stations
- Where’s Waldo
- Comfort seating
- Repetitions
- Daily lists with check off or stickers
- Chunking- dividing work into small chunks, divide up a worksheet
- Concentration games
- Scanning instruction
- Maintenance rehearsal- repeating information until it is needed- doesn’t seem to make it to long term memory
- Elaborative rehearsal- link to other info, mnemonics, stories, physical
- Physically touch the words or numbers
- Grab bags, fantasy games, open ended sentences
Visual Attention
The selection of the appropriate input
- alertness
- elective attention
- visual vigilance
- divided, or shared attention
Visual Memory
iconic or sensory memory
few seconds
short term
30 secs
in order to complete a task
> color of Christmas ribbon
long term
describe your pet
working memory
includes short term and and long term
short term represents storage, long term represents storage and retrieval with manipulation of the memory
Visual discrimination
recognition
matching
categorizing
~ Object or form perceptions vs spatial perception
form constancy
Build a Bear
visual closure
figure ground
~ Spatial perception
proprioception: position in space
depth perception
topographical orientation
way finding - cognitive map to find your way, what you will find along the way
Visual imagery or visualization
picture the bottle when the timer goes off
next-words while reading (sight words)-what does growl sound like?
foundation for reading comprehension
