Transcript TOTA Low Vision Foundations - Texas Occupational Therapy

Occupational
Therapy Role
in Low Vision
By Serena Speaker OTR SCLV
November 8, 2013
TOTA Mountain Central Conference
Objectives
1. Participant will understand basic
anatomy of the visual system and
primary low vision conditions affecting older adults.
2. Participant will be able to describe how low vision
conditions influence occupational performance.
3. Participant will be able to compare and contrast the
role of the occupational therapist specialist and
generalist in low vision rehab.
4. Participant will demonstrate techniques to improve
ADLS function with low tech devices.
What is low vision?
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Definition of low Vision -a visual impairment
severe enough to interfere with occupational
performance but allowing some usable vision
Legal Blindness (used to qualify persons for
benefits and services) Best corrected visual
acuity of 20/200 or less in better eye (BE) or
visual field of 20 degrees or less in the better
eye
Source: Warren, Mary, MS, OTR/L, FAOTA (2008) Low Vision: Occupational Therapy Evaluation and Intervention with Older Adults,
Revised Editin. Bethesda, M. AOTA Press.
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Low vision is primarily an acquired
condition that is an issue of aging
2/3 are over age 65
30% over age 75
Most are caused by 3 age related conditionsMacular Degeneration, Glaucoma, Diabetic
retinopathy
These account for 90% of low vision referrals
Visual Perceptual Hierarchy
Seven levels of visual processing
Permission From Mary Warren PhD, FAOTA, OTD
Foundation Level
1. visual acuity
2. visual field
3. oculomotor
control
Second Level
Attention
1. Alert
2. Attending
Third Level
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Scanning-ability to look side to side
Level Four-Pattern Recognition
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CNS must have high quality, accurate visual
input to complete object recognition.
1.Visual acuity ensures the clarity of visual input
2.Visual field integrity ensures the presence of
vision-that all of the visual input from the
environment is represented
3.Oculomotor control ensure that visual information
is acquired rapidly and accurately when the body is
in motion or at rest for perceptual stability
Level Five
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Visual memory-the ability to recall or match
the visual object to one’s memory. When an
R is an R and is the first letter in Run. Or a
picture or viewing a water glass means that
there is a memory that means this glass of
water will be able to quench my thirst.
Level Six
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Visuocognition- the ability to use the visual
memory and then relate to past experiences
on a cognitive level. The ability to recognize a
bank check register and then be able to
record the check, determine the balance in
the check book and then reconcile the
balance with the bank statement. Visual tasks
that require cognitive input on a high level of
processing from the initial visual input.
Level Seven
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Adaptation through Vision
1. Solve Problems
2. Formulate plans
3. Make decisions
Source: Warren, Mary, MS, OTR/L, SCLV.FAOTA and Elizabeth Barstow, MS, OTR/L, SCLV (2011). Occupational
Therapy Intervention for Adults with Low Vision, Bethesda, Md, AOTA Press.
Low vision is issue of aging
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Older adults associate low vision with normal
aging process
2/3 have at least one other chronic medical
condition (LV with diabetes=6X greater
likelihood of problems shopping and
socializing, LV with CVD=7X)
Woman’s Issue-more likely to live alone, 75%
of men with low vision are married and have
in-home support compared to 30% for
women
 ICD-9 CMS Definitions of Low Vision and
Blindness table.
 Individuals will not meet CMS medical
necessity requirements unless Visual Acuity
is worse than 20/60 in the better seeing eye
or visual field less than 20 degrees.
 OTs provide services under Part A-acute
care, Part B or Home Health umbrella.
 Additional credentialing is encouraged: SCLV
by AOTA and or CLVT by ACVREP.
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Occupational Therapy Practice Framework
(AOTA) published 2002,
revised in revised in 2008
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Ecology of Human Performance Model
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published 1994 by Dunn, Brown & McGuigan
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describes the domain and processes that define occupational
therapy practice and outlines the OT evaluation and intervention
process. Investigates relationship between the person, context,
tasks, performance, therapeutic intervention.
Occupational Areas
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Activities of Daily Activities
Instrumental Activities of Daily Living
Rest and sleep
Education
Leisure
Play
Social Participation
Work
Daily Occupations Affected by Reduced
Visual Acuity and Contrast Sensitivity
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Self Care
applying make-up
applying toothpaste
completing nail-care
selecting clothing
mending clothing
managing medications
eating neatly
seasoning foods
spreading toppings
Meal Preparation
setting appliance dials
measuring ingredients
determining when food is done
cutting, chopping, slicing
reading recipes, instructions
identifying foods
pouring liquids
operating microwave
cleaning cookware
Instrumental Activities of Daily Living
Shopping
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Accessing transportation
Locating correct aisle/item
Reading prices
Making change
Making grocery list
Money management
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Reading bills/financial statements
Completing check, money order
Debit transaction
Maintaining financial ledger
Addressing/mailing bills
Computer bill payment
Identifying money
Leisure
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Sewing, quilting, needlework
Bingo
Card games
Woodworking
Fishing
Automotive repair
Reading Activities
Informational Reading
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Newspaper
Newspaper ads
Stock quotations
TV guide
Recipes
Food labels
Medication labels
Menus
Telephone directory
Address Book
Incoming mail
Bank receipts/statements
Checkbook ledger
Watch or clock face
Street signs
Aisle marker/store signage
Pleasure Reading
Magazines
E-mails
Books
E-books
Daily devotionals
Cards and letters
Home and Community Activities
Home Maintenance
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Cleaning
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Setting dials on washer/dryer
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Yard maintenance
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Car maintenance
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Minor household repairs
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Ironing
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Thermostat adjustment
Community Activities
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Accessing transportation
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Recognizing acquaintances
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Maintaining orientation in unfamiliar places
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Locating public restrooms
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Eating out in restaurants
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Negotiating curbs, steps, etc
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Avoiding collisions
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Two step process to develop an intervention
plan
 occupational profile
 occupational analysis
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OT evaluates FUNCTIONAL vision
 How it hinders and facilitates occupational
performance to define rehab potential
Results of A Good Evaluation
1. Identify limitations in occupational
performance
2. Identify factors that contribute to the
limitation in occupational performance
3. Determine if intervention is necessary
4. Identify most appropriate intervention to
achieve optimal outcome
Anterior Visual
System
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Cornea
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Iris
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Lens
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Choroid (blood supply)
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Ciliary Body: 2 structures
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Ciliary muscles shape lens, controlled by CN III
Ciliary process - secretes aqueous in anterior chamber
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Anterior Visual System
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Anterior Chamber:
space that is filled
with clear watery
fluid between
the back surface of
cornea and front surface of the vitreous
Aqueous: produced by ciliary body in posterior chamber
and circulates through anterior chamber
 continuously produced and drained away while
maintaining the shape and pressure within the eye
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Overall function of brain is to filter, organize and integrate
sensory information to make an adaptive response to the
environment.
CNS is devoted to taking in sensory input, analyzing it and
responding to it.
Vision is primary sensory system to acquire information about
environment.
 80-90% of learning occurs through visual channel
 1/3 to 1/2 of brain devoted to visual processing
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Most far reaching sensory system
 alerts us to danger or pleasure
 enables us to be anticipatory,
plan for situations
Supplies speed in informational
processing
 tells us exactly what is going on
 instantly identify objects with vision
 Can use other senses but not as quickly
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Example: World Trade Towers
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Size up situations
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Make decisions
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want to see the problem so we can solve it
with visual memory of a previous event
previous problem can help solve a new one
Interpret social interactions
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where to sit in a room
what to select from salad bar
Solve problems
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first impressions are important
avoid certain people
facial expressions
Elicit and guide movement
Maintain postural control
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warn of upcoming obstacles to navigate around objects
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Because of the importance of
vision to the brain, a person with vision-no
matter how limited-will ALWAYS attempt to
use vision to adapt and complete activities
Biggest challenge is that low vision is a
hidden disability and its symptoms are often
attributed to other causes
 we identify low vision if the person has a
white cane or dog guide
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Reduced visual acuity to 20/30-20/40
Dynamic acuity decreases
 affects gaze stability
 more visual blur
Loss of accommodation
 AKA; Presbyopia; lens thickens and
loses flexibility
 bifocals
Floaters: strands of protein that float in vitreous
 generally benign unless accompanied by bright flashes of light
or significant increase in number
Dry eyes
 lacrimal glands decrease secretion
 medication exacerbates condition, treat with artificial tears
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Increased need for light
 pupil diameter decreases, lens thickens and
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Glare susceptibility
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lens and cornea become less smooth
protein strands cause light to scatter
increased discomfort
Reduced dark/light adaptation
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yellows
80 yo needs up to10X more light than 23 yo
more difficult to go from bright to dark than dark to bright since takes
longer to reform and store visual pigments
Reduced Contrast Sensitivity
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caused by changes in color, density, size of pupil
75 yo needs 2X as much contrast as younger person
90yo needs 6X
Macular degeneration
Diabetic retinopathy
Glaucoma
Macular Degeneration
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Other names for this condition: Senile
macular degeneration, Atrophic macular
degeneration (AMD), Age related macular
degeneration (ARMD)
Two forms-chronic and advanced (dry/wet)
Caucasians more susceptible
NEVER results in blindness-disease of
central vision-cone retinal cells
60 to 90% of referrals to low vision clinic
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Two types
1. Chronic: dry or
atrophic type
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Progressive: wet
or hemorrhagic type
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90%
10%
Attacks cone cells
Both types cause
 macular scotomas (blind spots)
 photophobia (light sensitivity)
 fluctuating vision
 slow dark/light adaption
Vision with Macular Degeneration
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Normal vs Macular Degeneration view
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Injected into vitreous cavity
Lucentus (40X cost of Avastin) approved in 2006-4 wks
 Avastin-used off label- every 4 weeks
 Macugen-approved in Germany 2006- every 6 weeks
 Eylea-FDA approved November 2011
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Eliminate existing abnormal blood vessels and turn
off signal for additional vessels to develop
 Works for several weeks to months: repeated
injections if necessary
 Lost vision may be recovered if administered at first
sign of new blood vessel formation
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Avastin and Lucentis are equivalent in
treating Wet AMD
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Avastin most frequently used drug for wet AMD
Two year clinical trial with results published 04-13-12 by National
Eye Institute-NIH
Long term results with either drug resulted in robust and lasting
improvement in vision
As needed dosing vs monthly treatment only yielded ½ line better
acuity in 2 year trial
As needed dosing required 10 fewer eye injections with similar
results, many pts may choose this option
Lasting improvements in vision with there two drugs is
extraordinary
At two years, 2/3 of pts had driving vision (20/40 or better) while
only 15% of pts retained similar visual acuity with previous tx
Source; www.nei.nih.gov/news/pressreleases/043012.asp
 Pathology
gradual destruction of cone cells
 Drusen develops on surface of retina where
atrophy is occurring
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 Gradual
progression
 Often unilateral for many years
 No conclusive medical treatment-eye
vitamins may help
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Side effect of Diabetesmost dangerous as can take
vision rapidly, higher prevalence
in African American,
Native American, Hispanics, Pacific Islanders
Accounts for 9% of low vision referrals
Diabetes has multiple effects in eye-effects entire retina and
can cause any level of vision loss including blindness
Only common eye disease causing varying patterns of vision
loss because it affects blood vessels that support entire retina
50% increased risk for cataracts for people over 50, with
increased complications from cataract surgery
2X incidence of chronic open-angle glaucoma than person
without DR
Disease of optic nerve
although it starts in
the Anterior Chamber
of the eye
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Can result in blindness-most feared
Required good control with drops and frequent eye
exams
Higher incidence in African Americans-significant visual
loss
13% of low vision referrals
Glaucoma continued
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Group of eye diseases
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pressure inside eye is
too high
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traumatic
angle closure
low-tension
or open-angle glaucoma (most common)
all cause damage to optic nerve
50% of people with condition do not know they have
glaucoma
Glaucoma
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Aqueous production
should equal outflow
to maintain pressure
within eye between
9-21 mm HG
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Build up of pressure in anterior chamber
only outlet is optic disc
pressure decreases blood flow to nerve
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Cloudiness or
opacification of lens
Occurs with advancing age
Dulls color
Blurs visual detail throughout
visual field
Affects distance vision before near but eventually dulls
both
Cataract surgery is most common surgery in US with
natural lens removed and a synthetic intraocular lens
implanted through 3 mm incision.
Other vision deficits;
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Parkinson’s Disease-difficulty with
upward gaze and convergence-necessary for
reading.
Hemi Field defect with normal acuity-result of CVA,
TBI, brain tumor: hemianopsia, quandrantanopsia
with reading difficulty, neglect, short term memory
issues with loss of letter and word recognition.
Alzheimers disease-defects in color, depth and
movement perception.
Refractive errors-myopia (near sighted), hyperopia
(far sighted), astigmatism (cornea problems).
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Usually completed by low vision ophthalmologist or
optometrist
Completed not to determine what is gone but what vision
remains
 Functional Vision
Always assess acuity, contrast sensitivity, visual field
Informal assessment-questioning
 dark light sensitivity, glare
 light sensitivity (photophobia),
 phantom vision
 color vision
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Ability to see small
details at specific distance
Two types
 Distance/Intermediate
 Reading
In USA use Snellen equivalent fracture
 20/20 is normal
 what a normal person can see at 20 feet
 Actually it is the ratio of the test distance at which the
smallest optotype subtends 5 minutes of visual arc (or
angle) or minimum angle of resolution-MAR for short
Factors to be considered when Assessing
Visual Acuity
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Lighting
Contrast
Specific chart used
Numbers of targets at each acuity level
Spacing of targets
Difficulty of the targets being identified (ie, letters, numbers,
pictures, etc)
Single letter verses reading acuity
Type of letters (ie, block, serif, etc)
Ease with which the targets are identified
Expressive as well as receptive language skills
Cognitive functioning
Eccentric viewing (body position, eye/head posture)
Source: Scheiman, Mitchell, OD, FAAO (2002). Understanding and Managing Vision Deficits-A guide for Occupational Therapists.
Thorofare, NJ. Slack
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Measurement in the normal to near normal
acuity range-stops at 20/200 (big E)
No measurement for vision worse than
20/200 or anything between 20/100 & 20/200
Subjective measurement below 20/200: count
fingers x number of feet (CF at X feet), hand
movement (HM or HMO), Light perception
only (LPO), no light perception (NLP)
Intermediate Acuity
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Discrete assessment in low vision range
 intermediate distance of 1 meter
 can measure to 20/1200
 best chart uses logarithmic progress
ETDRS chart (lomag Chart) is Gold standard
 same # of optotypes per line
 spacing between letters and rows are proportional to size
of letter
 1 log unit between each level
 enables letter by letter measure
 Test procedure: dominate eye, non-dominate, together
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Ability to read text
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Variety of test cards
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tests near acuity to 20/400
requires accommodation
Warren reading chart
MN read acuity chart
Lighthouse Children
Test procedure: reading glasses on; use both eyes; distance
of 16 inches/40 cm; center at clients midline; start at top and
read down as possible; record acuity at last line of text
accurately read
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Determine level of visual impairment for billing services-OT
paid on level of acuity
Snellen of metric acuity can be used to determine minimum
magnification to read 1M size print-requires 20/50 to read
newspaper
 reduce until denominator is 1
 EX: 20/200=1/10
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magnifier needed at least 10X
Strength of Magnifier
 Size M units read divided by size of goal M unit
 EX: read 50M and want to read 1M Newspaper need 50X
magnifier
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AKA-low contrast acuity
Not Specific for certain disorders
Ability to see item as it degrades in contrast from its
background
most environmental features are low contrast
decreases with any deterioration of macular function
faces very difficult
person will have difficulty detecting low contrast
feature such as water on floor
Why two patients function differently with
same Snellen Acuity.
“This difference can usually be predicted with
contrast sensitivity testing. In general, a poor
contrast indicates that the clinician should
give more attention to glare control, contrast
of viewing materials and illumination. These
factors are often more important than
magnification.”
Source: Freeman, Paul B. OD, FAAO and Jose, Randall T. OD, FAAO. (1991) The Art and Practice of
Low Vision . Newton, MA. Butterworth-Heinemann-division of Reed Publishing (USA).
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Several test formats
Pelli-Robson
gold standard-measures from 100% to 1% which measures
threshold contrast. But threshold contrast is not a prevailing
condition for ADLs.
Lea Number Low Contrast Chart
measure 5 levels: 25% to 1.5%
clients begin to have problems at 25% level-see index
Lea test instruction for Lea chart-reading glasses, both eyes, center
chart at 40cm at midline, explain that test uses numbers, identify first
# each line, continue until unable to read entire line, go back to
previous level and read all #s
Colenbrander Mixed Contrast
Reading Card
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High contrast (HC) and 10% low contrast (LC) (What is the smallest
letter size that can be read at intermediate contrast-assures the high
contrast and low contrast are presented at the same distance with
the same illumination)
More realistic for ADL performance are stimulus of intermediate, low
contrast than high contrast stimulus of an optotype against an empty
background( ie Pelli-Robson, Mars)
Must be careful about low contrast situations (night driving, stepping
off curbs) to avoid serious accidents. Awareness of contrast
problems can lead to many simple ADL adaptations.
A HC-LC difference of 1-2 lines is within normal limits, 3-5 lines
moderate decrease,6-8 lines marked decrease, regardless of visual
acuity will indicate problems.
This can provide a strong demonstration for the patient. The effect of
increased illumination is also easily demonstrated.
Source: Envision 2012, Mixed contrast Measurement, August Colenbrander, MD.
Additional tests
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Visual field;
central and peripherial
Additional Tests continued
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Scotomas-blind spots
in central and
para-central visual fields
Color vision
Dark/light adaptation
Glare sensitivity
Phantom vision-Charles Bonnet Syndrome
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Acuity-intermediate with EDRST chart,
Warren number test
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Acuity-reading or near
Warren reading card,
MNread card
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Contrast Sensitivity Function-LeaNumber
Low Contrast Chart, Colenbrander chart
LAB-Intermediate Acuity
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Test each eye with use of patch or occulder and
then both eyes-compare the results. Are they the
same or different? Why?
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ETDRS Chart
Warren Number Chart
Try the test with simulators and see if your
result are different.
Lab: Near/Reading Acuity
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Warren near test
Tumbling “C” (What type of client would this
test be appropriate for?)
May wear glasses and use both eyes. Client
may move closer than 16” or 40 cm but
must notate on results.
Lab: Contrast Sensitivity
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Lea Number
Do not touch numbers on chart-use cloth or yellow tip
pointer to not damage the test. Read initial number of
each line until unable and then return to prior level and
read all of numbers. Try again with different types of
visual simulators.
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Colenbrander
Read chart with dark and light print forming sentences.
Where does your client have issues? Are there more
than 2 lines of difference between reading the dark and
light (10%) parts of each sentence? Try with different
simulators-any problems?
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Basic approach-Enable person to effectively use
remaining vision to complete needed ADLS and
IADLs
Accomplished by modifying the task and
environment to increase visibility
Assessment combines self-report with observation
of selected task; person will often over or under
estimates skills, reluctant to admit limitation with
task performance
Self-Report Assessment of Functional Visual
Performance Profile-SRVFVP (available on line)
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Average older adult spends 80% of day at home
Home lighting does not meet recommended levels
(Glaucoma and visual functions study: only 2 of 117
participants met recommended lighting levels!!!)
Improved lighting increased Visual Acuity by 2-3 lines in
63% of study participants
Person with macular disease performs better with
additional light because it allows use of relative
scotomas.
Desired qualities-even illumination, maximum lumens,
minimum glare, flexible placement for optimum
positioning
Source: Envision 2012, The Home Environmental Lighting Assessment, Monica S. Perimutter,
OTD, OTR/L, SCLV
The Lighter Side of Low Vision
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Terms for Basic Lighting
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Illumination
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Lumen
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The distribution of light on a horizontal surface. Illumination
is measured in footcandles (ftcd, fc, fcd) English system or
lux in the metric SI system.
The measurement of light emitted by a lamp.
Illuminance
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Is a useful measure of a light source
Usually diminishes with distance and angle
Independent of surface properties (color, finish, texture)
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Footcandle
A measurement of the intensity of illumination: a
footcandle is the illumination produced by one
lumen distributed over a 1-square-foot area.
Color Temperature
The color of the light source. Color temperature is
measured in Kelvin (K) temperature.
Color rendition
How colors appear when illuminated by a light
source. The Color Rendition Index (CRI) is a 1-100
scale that measures a light source’s ability to render
colors the way sunlight does.
Glare
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The excessive brightness from a direct light source that makes it
difficult to see what one wishes to see. A bright object in front of a
dark background usually will cause glare. Glare can be difficult to
control when providing light for people with low vision.
Contrast
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Contrast is the difference in brightness between the background
and text. 100% contrast is pure black on pure white. Many eye
charts have > 80% contrast. Reading materials such as
newspapers or paperback books have low contrast.
*Contrast is property of the page: lighting or filters do not
change it. It is a property of the reflectivity of the page and
ink. Lighting can change perceived contrast, but not actual
contrast.
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Conversions for Light Measures
*1 Lux =1Lumen /sq meter=0.0929 foot
candle (ftcd, fcd)
*1 foot candle = 1 Lumen = 10.752 Lux
Factors affecting lighting recommendation
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Lighting needs are different for everyone due
to :
Age
Medical conditions
Eye conditions
What task is being performed
What the environment is like (current
lighting available)
Age and Lighting
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Less light reaches the retina in an aging eye
than it does in a younger eye.
Pupil size reduces with age so less light
enters the eye.
The lens, which is normally clear in a young
person or pre-presbyope, yellows and
thickens with age, also impeding the
transmission of light.
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*Ages 61-79: Ambient (general) illumination should
be about three to four times higher than is typical for
a pre-presbyope.
*30 foot candles are recommended for general room
lighting.
*Studies have shown that a 65 year old may need
up to 15 times as much light to read as a 10 year
old.
*A visually impaired person may need three times as
much light to read as someone the same age who is
not visually impaired.
Source: http://www.ligthhouse.org/eye-health/the-basic-of-the-eye-aging/lighing:
http://www.ecmag.com/section/lighting/lighting-through-agers\:
http://www.americanlightingassoc.com/about-ALA/Press-Release/featured-article---Aging-Eyes/aspx
Common Environmental Illuminance
values
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Outdoor
Starlight
.0001 lux
Full moon
.27-1 lux
Very dark overcast day
100 lux
Overcast day
1,000 lux
Full daylight (not direct sun)
10,000-100,000 lux
Indoor
General residential lighting
50-100 lux
Residential dining room
100-200 lux
Residential reading
200-500 lux
Classroom or brightly lit exam room
500-1,000 lux
***A brightly lit room is 10-100x dimmer than daylight.
Lighting Guidelines for Specific Tasks
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Examples of tasks that will be most impacted
by illumination.
General lighting: 53.76 lux
Kitchen (counter): 322.56 lux
Reading (casual): 322.56 lux
These are recommended level for patients
with normal vision.
See Appendix 1
Indoor Lighting
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Ambient lighting-general lighting in a room
Overhead lighting should be available in every room if possible
Overhead light fixtures should be deliberately positioned where a
task is performed
Dimmer switches can help to adjust to different lighting levels
and time of day
Over head track lighting allows for even illumination in a room
Vertical blinds on windows allows natural sunlight in a room
Recessed lighting can be used over specific work areas such as
the sink or counter
Painting walls a lighter shade will allow maximum efficiency of
illumination
Task Lighting-specific lighting to a
task or area
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Task lighting is positioned closer to one’s
material to increase light intensity without
having to increase the bulb’s wattage.
Task lighting maybe more crucial if renting vs
owning home.
Adjustable floor, table, or wall mounted lamps
should be used close to where you are
performing various tasks-gooseneck or
swing-arm floor or desk lamps allow the
closest, most efficient task lighting.
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If reading-task lighting comes from behind or the
side of the better seeing eye (if applicable).
Have the light close to and facing your materials.
Sit with your back facing the window so sunlight will
be on the task you are performing.
Have light slightly below eye level to prevent glare.
If writing –have your light coming from the front and
on the side opposite your writing hand.
Outdoor Lighting
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Walkways should be lit with path lights of overhead flood
lights
Awnings or open garage entrances allow for adjustment
of lighting levels from outdoor/indoor for increased safety
Porches/balconies should have light fixtures positioned
so light shines in center of the proper area
Clean bulbs and globes/fixtures regularity for increased
lighting and reduction of glare
Landscape lighting can help with safety
Reflective tape can be use to mark steps or solid surface
changes
Standards to measure lighting
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A light meter measures illuminance (the
amount of light hitting the detector) in lux or
foot candles.
A light meter is recommended when
performing ambient or task lighting
assessments/providing recommendations
Light meters are commercially available and
range in cost form $16 to $300
Lighting with Color Temperature
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Color temperature is a measure of how
“warm” or “cool” the light is
Lighting with lower color temperature are
described as “warm” while higher color
temperatures are described as “cool”
(description is the color not the temperature)
***(Review of wavelength spectrum and
visible light spectrum with color violet at
wavelength 400-420nm up to color Red at
wavelength 620-780nm).
How the Human Retina responds to
color
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Three types of cones:
One type of cone is primarily sensitive to
short wavelengths (blue) another to medium
wavelengths (green) and one to long
wavelengths (yellow)
The yellow cone is usually referred to as the
red cone.
Types of lighting
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Fluorescent and compact fluorescent
Incandescent
Halogen
Full Spectrum
LED
Specialty bulbs
Natural sunlight
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Fluorescent-long tubes, common in public
areas, produce glare and flicker
Compact fluorescent (CFL) now used in
homes for energy efficiency
Incandescent-yellow light most common in
homes-standard light bulb
Warm light/Soft white-full spectrum and
halogen are available as an incandescent
bulb
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Halogen-bright, white light, expensive
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Full spectrum-full range of colors like
sunlight, can be glaring, no UV filters,
available from local stores and specialty lamp
stores that can produce stronger illumination
LED (light emitting diodes)
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white light in various shades
mostly found in portable lighting devices
becoming more readily available in bulbs and fixtures
high efficiency
low voltage (2-3.5 volts)
low cost which allow use of many LEDs in a reasonable-priced
light
provides bright monochromatic source that could benefit those
with color vision defects
longer life than other light sources
Rated life for different light sources
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Incandescent
Halogen
Compact fluorescent
LED
750-1,000 hours
3,000-6,000 hours
6,000-15,000 hours
50,000-100,000 hours
12W LED, 17W CFL, 50W Halogen, 75W
incandescent are equivalent
LEDs use ¼ the power of halogen and 1/6 power of
incandescent
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Lux for typical sources at 50 cmapproximately 18 inches
Incandescent, 75 W = 1662 lux
Compact fluorescent, 15 W = 1019
Halogen, 50 W = 1528
LED, 12 W =1528
Source: Wikipedia
New labeling changes for Bulbs
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The new label will include the brightness
(lumens-ie 380 lumens) of the bulb and the
cost of operation (watt-ie 4 watts) instead of
wattage (amount of energy), the color
temperature (2700K=warm, 6500K=cold) (ie
2700K=warm), size of the base (must match
the fixture ie-A19).
LED Bulbs: The future of Lighting for
the Low Vision Patient?
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An instant start
No ballast hum
Directional light sources
Do not contain mercury
Do not get hot
Replace less frequently
**Phillips L prize, Definity A19 and Sylvania
12, watt found to be best LED light bulbs
Source: http://led-light-bulbs-review.toptenreviews.com
Use of LED lighting as a diagnostic tool
to assess low vision
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“Luminance in Acuity and Reading Performance of Low Vision
Patients” D. Fletcher, R. Schuchard, L.Renninger, Source
Envision 2012 and ARVO 2013
Results:
140 patients with MD saw an average of 2 blocks
increase on MNReasd using white LED light for high
illumination (2070 Lux)
1 in 6 patients had ring scotoma; there was an average
of 4 blocks of increase
“All patients and particularly those with ring scotomas
should have trials with very bright illumination in their
rehabilitation program.”
Home Safety and Lighting
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Visually impaired individual are generally not
aware of the importance of lighting in the
home (Harper, Doorduyn, Reeves, & Slater
1999: Schuchard, Naseer, and de Csatro,
1999).
Low Vision Lighting Assessment
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Can consist of both ambient and task lighting
Primarily task lighting assessments are the focus for
the low vision patient for near vision tasks-reading
writing, meal prep, clothing identification
Education plays a key role
Demo of lighting and participation with low vision
patient is essential for success
Use both objective measures (light meter) and
subjective responses to base determination of
lighting recommendations
Objective Measurements
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Measurement of objective low vision areas assists
the low vision patient in acceptance of the lighting
recommendations. The following are common
improvements demonstrated after lighting
assessment (besides light levels and glare);
MN Read (reading rate)
Accuracy (number of errors)
Acuity (measurement of size print able to read)
Eye comfort (minimizing glare)
Reading duration (eye fatigue)
Home Lighting Assessment
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HELA-Home Environment Lighting
Assessment developed by Monica S.
Permutter, OTD, OTR/L, SCLV (very
comprehensive)
Other lighting assessment available: HOPE,
Housing Enables, and CHIEF
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Increase visibility of the
task and environment
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Enhance visual components of tasks
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Augment performance with other
sensory system input-tactile, olfactory,
auditory
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Ensure lighting is optimal for task performance
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Use contrast to increase visibility of key objects
and landmarks
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Minimize background pattern
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Maximize and enlarge
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Organize
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Use layered lighting=work
spaces, laundry, crafts,
kitchen, shop
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Ambient=general room light
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Task=brighter illumination
for specific activity
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Always behind person to read, eliminate
shadows on surface, as close to task as
person can tolerate, facing hand when
writing to eliminate shadow
Two ways to increase
task illumination
1. move light closer
to surface
2. get a stronger light
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Flashlight/fixture near bed-touch lamp
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Nightlight/path light with rope light
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Additional switches
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Motion or sound activated light
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Head lamp to mount on head
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Under counter lights, tap on light for closets
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Light colored plate on dark placemat
Milk in dark cup/coffee in white cup
Telephone stick on numbers-usually can see white on black
best, computer keyboard-add stick on letters or purchase new
keyboard with different contrast
Two sided cutting board-white for carrots, black for potatoes
Measuring cups-dark/light to measure contrast ingredients
Use contrast to increase environment-tack mat at bottom of
stairs-most falls occur on last step, contrast tape on light
switch
Thresholds that are raised-add contrast electrical tape-yellow,
red, black
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Use solid color on background and support
surfaces
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Eliminate clutter
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When unable to eliminate pattern, increase
contrast of key features-place eating utensils
on solid napkin, place red tape around sharp
knife handles
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Use hands free magnification:
magnifying mirrors,
chest magnifier,
Big eye magnifier
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Enlarge-large print address book, spice organizer with large
letters
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Enhance visual components/augment with other sensory
input-liquid leveler with auditory output, use various material
to mark features of object to increase visibility-contrast touch
dots on microwave
Labs
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Macular Degeneration
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Write Grocery list
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Standard pen and paper-10 items
Use PBS (Print-Bold-Space) on dark lines paper
Read both with vision simulators
Have classmate read your standard list with simulatoryour classmate will go to the store for you-what do you
think you will get!!
Move to goose neck lamp and try again-any difference
Lab
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Diabetic Retinopathy
View newspaper and grocery ads
View with simulators-what is the difference?
Try reading with task lighting
Lab
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Glaucoma
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Look up number in phone book
Dial on your cell phone
Any errors??
Improve lighting-any easier?
Lab-Lighting
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Lighting
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Read with any vision simulator
standard print, then 20 point print without extra
light and then with increased LED, Halogen and
incandescent goose neck lighting? Which is
easier? What can you tell your client?
Try the Vision Edge clip on light (White and Green
LED lights) and try reading in darker area of the
room. What is this like?
Lab-Contrast
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With any vision simulator pour water into clear glass.
Any errors? Pour dark ingredient into light cup and
light ingredient into dark cup. Use liquid leveler to pour
with vision totally occluded.
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Trial of different colored plates on different colors of
placemats with vision simulators. Which colors are
easier? How can you mark utensils for easier
recognition by low vision client?
Lab
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With any simulator
Try to identify classmate without hearing
their voice.
 Walk into hallway and attempt to identify
signage-bathroom, vending machines,
stairs, numbers to rooms.
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Acuity-near & intermediate
Contrast Sensitivity
Environmental Adaptations
ADLs and IADLs adaptations
Low Tech equipment recommendations
Refer to appropriate specialist-LV OT
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Educate patient for vision diagnosis
Identify scotomas and locate PRL
Train with eccentric viewing techniques-near
and intermediate
Select with approval of Optometrist or
Ophthalmologist best diopter of magnifierhand held, stand, or electronic
High Tech options for LV client
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Train with use of magnifier-requires skill to be
successful for spot reading or continuous text
Environmental changes to include lighting,
increase contrast for safety, tactile guides
Bioptic, telescopic training
Sighted Guide techniques-indoor
CVA-hemianopsia for visual field loss or
visual neglect

Low Vision Occupational Therapy
Evaluation and Intervention with Older Adults,
Revised Edition (Self-Paced Clinical Course)
edited by Mary Warren, PhD, OTR/L, SCLV FAOTA
Order # 3025, AOTA Members: $370, Nonmembers $470, 20 CEUs
Low vision In Older Adults: Foundations for Rehabilitation, 2nd Edition,
by Roy Gordon Cole, OD, FAAO, Yu-Pen Hsu, EdD, OT, SCLV, and Gordon Rovins, MS, CEAC
(On-line Course) Order #OL37, AOTA members $265, Nonmembers $345.
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Graduate Certificate in Low Vision Rehabilitation,
University of Alabama at Birmingham,
Mary Warren PhD, OTR/L, SCLV, FAOTA
Associate Professor, Occupational Therapy: [email protected]
(5 semester course on line)
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Lighthouse International-accessibility;
www.lighthouse.org/accessibility
Mdsupport-resource link;
http://mdsupport.org/resources.html
American Foundation for the Blind-senior site;
http://www.afb.org/seniorsitehome.asp
Foundation Fighting Blindness
www.blindness.org
Glaucoma Foundation
www.glaucoma-foundation.org/info
Macular Degeneration International
www.maculardegeneration.org
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www.shoplowvision.com
www.LSSproducts.com
www.maxiaids.com
www.lvs.com
www.goldviolin.com
www.precision-vision.com
www.mattinglylowvision.com
www.lowvisionetc.com
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American Printing House for the Blind
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Ann Morris Enterprises, Inc.
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http://www.dazor.com/
Independent Living Aids, Inc.
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http://www.carolynscatagog.com
Dazor Lighting Specialists
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www.annmorries.com
Carolyn’s Low Vision Products
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www.aph.org/index.html
www.independentliving.com
NoIR Medical Technologies
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www.Noir-medical.com
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Low Vision CEU programs available upon
request.
Please contact me for proposal for your
company or group.
Questions or comments
[email protected]