Adding Low Vision Services to the Generalist OT Program

Evaluations-Regina Budet OTR

Lighting-Tamara Traber OTR

Contrast Sensitivity-Serena Speaker OTR SCLV

AssessmentsRegina Budet, OTR

Northwest Hills Eye Care, Austin, Texas

Regina@nwhillseyecare.com

What is the generalist’s role in assessing vision?

• Often the first ones to interact with visually impaired before they get low vision services (IF they get services)

• Important to recognize signs and behavioral symptoms of VI to make appropriate referrals

• Most age-related low vision can be prevented or progression slowed with prompt treatment

• Other professionals aren’t aware of Low Vision

• Increased dependence for ADLs

• Advocate!

First some quick definitions…

• What is low vision?• Low vision is when -even with regular glasses, contact lenses,

medicine or surgery- people find everyday tasks difficult to do (NEI, 2013)

• What is the difference between an ophthalmologist and an optometrist?

• Ophthalmologist- will look at the health of the eye, medical doctor who may perform surgical interventions

• Optometrist- performs most eye exams, prescribes glasses, most of the low vision physicians fall in this category

Other low vision professionals (that you may not always collaborate with)

• Social Work

• Psychology/Neuropsychology

• Orientation and Mobility

• Diabetic Educators

• Low Vision Teachers and Rehab Specialists

• Vocational Rehab (counselors)

Recognize how vision may affect performance in other assessments

• Central vision loss

• Peripheral vision loss• Field loss/field cut

• Keep in mind that the CONTEXT of the activity will also affect performance

Central Vision loss

• Cone cells= color and details

• Increased difficulty with object identification, fine details, faces

• Tends to be associated with acuity

• “20/20 vision”, “legally blind”

Self Care affected by VA and CSF Self care

• Mending clothing

• Medications

• Locating food on plate

Shopping

• Reading signs and prices

• Navigation

• Labels

• Scanning shelves

Reading-inform

• Mail

• Menus

• Signs

• Telling time

Reading-leisure

• Books

• Magazines

• newspapers

Money Management

• Reading statements

• Maintaining ledger, writing checks

Meal preparation

• Finding items in pantry or fridge

• Cutting, chopping, slicing

• Following recipes

Home Management

• Phone

• Yard work

• Cleaning thoroughly

Community Participation

• Curbs, steps, escalators/elevators

• Navigating unfamiliar places

• Avoiding collisions

Leisure

• Games

• Sports

• Movies and tv

• craftsModified from

BiVABA manual

Peripheral field loss

• Rods= low light detection and movement

• Provides information about environment (just as important as central vision)

• Safety

• Limitations with mobility

Self Care affected by VFDSelf care

• Makeup

• Medications

• Locating food on plate

Shopping

• Reading signs and prices

• Navigation

• Labels

• Scanning shelves

Reading-inform

• Mail

• Menus

• Signs

• Telling time

Reading-leisure

• Books

• Magazines

• newspapers

Money Management

• Reading statements

• Maintaining ledger, writing checks

Meal preparation

• Finding items in pantry or fridge

• Cutting, chopping, slicing

• Following recipes

Home Management

• Phone

• Yard work

• Cleaning thoroughly

Community Participation

• Curbs, steps, escalators/elevators

• Navigating unfamiliar places

• Avoiding collisions

Leisure

• Games

• Sports

• Movies and tv

• crafts

Modified from

BiVABA manual

Consider…

• What behaviors might you notice in an evaluation• Squinting when looking at text

• Inconsistent distance for holding text when reading

• Limited tolerance for reading

• Increased time to read a short passage, requires a lot of energy, avoidance, misreading words or skipping words

• Looking at text at an angle (don’t discourage, they are trying to use strategies)

• May try…• Print modifications (larger print, sans serif fonts)

• Improved contrast (and lighting!)

• Increase spacing of text• **strategies are not universal

Other non-visual assessments to consider• Psychosocial

• Depression scales• Geriatric Depression Scale (GDS)• Patient Health Care Questionnaire-9 (PHQ-9)

• Leisure inventory• COPM

• Cognitive• Many are visually dependent or require memory

• Non visual: Short Blessed Test, MoCA-blind

• Look at functional tasks• EFPT • A-One and AMPS ($$), Weekly Calendar Planning Activity (WCPA), Multiple Errands

Test (MET), other informal assessments

Health Literacy

• Increased risk of co-morbidities and need to manage conditions

• Health literacy assessments• https://www.ahrq.gov/professional

s/quality-patient-safety/quality-resources/tools/literacy/index.html

• Health literacy tool shed http://healthliteracy.bu.edu/

• How to incorporate into patient encounters:

• Ask about current strategies, don’t assume

• Ask about ability to use vision for patient education

• Keep language simple and straightforward

• Don’t rush

• Assist with transportation as needed

• Improve visibility of print materials• “less is more”

OTs and Functional Vision

• OT Assessments specific to functional vision loss• Revised Self-Report Assessment of Functional Visual Performance (R-

SRAFVP)• https://www.uab.edu/shp/ot/low-vision-rehabilitation/free-resources

• Smith’s Low Vision Independence Measure (LVIM)

• Questionnaires• VA Low Vision Visual Functioning Questionnaire

• Lighthouse International Functional Vision Screening Questionnaire

• Lighting• HELA

• LUX IQ

• Also may need to consider….• Ergonomics (computer, device

use)

• Environmental (home safety eval, fall safety checklist)

Lux IQ

Vision assessments

• Acuity

• Color

• Contrast

• Visual Field

• Attention/scanning

Acuity

• Test in a well lit room with minimal distractions

• Test each eye individually, and together

• Test from designated distance• Each test has a set distance

• Reading charts typically tested with both eyes

• Test with glasses if available

• Low vision charts are more specific with measuring acuity beyond “legal blindness”

Acuity Test Charts

• High Contrast Acuity Charts• Symbols, letters, numbers, crowding and spacing variation

• Feinbloom chart• Can be held at varied distances

• Reading Charts• Contrast, reverse-contrast, vary in reading level (Lighthouse card is

most basic) and language

• Contextual: MnRead, Lighthouse, Warren text card

• Non-Contextual: Pepper VSRT, SK Read

If central vision is affected…

• Blind spots in vision are called scotomas

• Patients may not be fully aware of presence• Blurry

• Distorted

• Objects/words may appear or disappear in view, may see word better when looking ahead/before word

• Tests:• Clock Test

• Face test• Identify blurry area when looking at center of target

Color Testing

• Gold standard: Ishihara color plates, Farnsworth D-15 and D-100 tests

• Can be tested informally• Paint chips

• May be helpful when determining labeling strategies

Contrast

• Gold standard: Pelli-Robson

• LEA cards• Numbers, letters, or symbols on flip chart

• Normal contrast: 25 symbols at 40 cm, 20-25 symbols at 1 m, 15 symbols at 3 m

• Colenbrander Contrast Card• Includes computer distance

• Letters, continuous text

• Hamilton Veale

Visual Field

• Gold standard: microperimetry, Humphrey Visual Field Analyzer

• Test each eye individually, both

• Central VF vs Peripheral• Normal ranges: Approximately 180* horizontally, 125* vertically

• May be limited by acuity and contrast to locate targets

• Confrontation testing: • *free*

• About 50% accurate

• Better with high contrast targets

Visual Attention and Scanning

• Can start small and increase scanning area

• May need to start with simple pen-paper tasks in quiet room with minimal distractions to facilitate attention to task

• Pen and paper:• BiVABA subtests

• Timed• Demonstrate search strategy

• Bells test• Line bisection

• Scan course• Scavenger hunt

Summary

• Use clinical judgement to adapt assessment as needed• Refer to appropriate team members as needed

• Not all strategies will work the same for each person• Important to develop client-specific intervention that will meet the needs

of that person

References

• Warren, M. (2013). Promoting health literacy in older adults. Topics in Geriatric Rehabilitation, 29 (2), 107-115. doi: 10.1097/TGR.0b013e31827e4840

• Warren, M., & Barstow, E. A. (Eds.). (2011). Occupational Therapy Interventions for Adults with Low Vision. Bethesda, MD: AOTA Press

• Warren, M. (2006). The BiVABA: Brain Injury Visual Assessment Battery for Adults (4th ed). Visabilities Rehab Services Inc: Hoover, AL.

Right Light?Tamara Traber, OTR, CLVT

Dan Arnold Center for Vision Rehabilitation

tamaratraber@cizikeye.org

Light is made up of electromagnetic particles that travel

in waves. Our retinas are capable of responding to only

a small part of the entire electromagnetic spectrum.

What is Light?

Correlated Color Temperature (CCT) is a measurement of the actual color appearance of light. It is expressed in Kelvins (K). Low CCT numbers define “warm” lighting like yellow and red hues of candlelight at 1500K. High CCT numbers define “cool” light, like blue (5000K to 7000K).

Footcandle (fc) and LUX (lx) are units of illuminance, measuring light on the surface.

50 fc is generally considered sufficient for many tasks. ↑ fc may be needed to do fine work such as threading a needle.

Lumen (lm) is a measurement at the light source (the lamp), and not necessarily at the surface being lit.

Watt is a unit of power equal to work done, at the rate of one joule Wattage is actually a measurement of energy, not of light.

Definitions

You should know :

Cool white, Full spectrum, and Daylight bulbs are all high in blue and Ultraviolet emissions.

They provide increased glare (miserable conditions) when used by most people with low vision.

Visible Light Comes in Three Colors.

Every peak of a light wave demands one

unit of work by each photoreceptor.

Two trillion blue light waves can

fit into the same moment as one

red light wave.

But why?

The visible light spectrum ranges from about 400 nm (shortest) to about 700 nm

(longest). The “visible light spectrum” is that small part of the electromagnetic wave

spectrum that we see as colors.

From highest nanometers (700) to the lowest (400), the colors of visible light in order are:

Red

Orange

Yellow

Green

Blue

Indigo

Violet

2800° Kelvin is in the pink range.

3000° Kelvin is the yellow range.

3500° Kelvin is in the green range.

4100° Kelvin + is in the blue to ultraviolet range.

The Kelvin Scale converts color into numeric values. The higher the Kelvin number, the more blue the light is.

As we get older, we generally need more light to read and to do

near tasks.

In addition, the Need for Illumination is much greater for a person

with a Vision Impairment.

They will likely need 3-4 times as much light as a person their age,

who does not have a vision impairment

Light is needed to trigger the cone cells on the retina, in order to read, to see details, and to tasks

AMD

Stargardt’s

Bests Disease

Retinopathy of Prematurity

Histoplasmosis

Toxoplasmosis

Optic Atrophy

Retinitis Pigmentosa

Glaucoma

Cataracts

The Need for Illumination for Persons with Low Vision is highest in persons with

It is partially dependent on:

Contrast of the item vs. its background

Size of the target being viewed

Age of the person doing the task

Whether the person has a Visual Impairment and

needs additional light

Orientation (south vs. north facing room)

Weather (cloudy vs. sunny day)

Time of day (position of the sun in the sky)

Season (position of the sun)

How much light is needed?

*Reading items written in a #2 pencil vs. those written with a

pen vs. those written with a felt pen.

*Reading items on a blackboard vs. those on a whiteboard.

*Seeing a ball in the gym vs. threading a needle in a room.

Different tasks and targets also require varying levels of illumination

Desired Lighting Qualities

• Even illumination

oNo surface shadow

• Maximum lumens (light output)

• Minimum glare

• Flexible placement

oTo get optimum positioning

Lighting can be measured on a surface in Footcandle or Lux with a LIGHT METER

S Perlmutter, Monica & Bhorade, Anjali & Gordon, Mae & Hollingsworth, Holly & Engsberg, Jack & Baum, Carolyn. (2013). Home Lighting Assessment for Clients With Low Vision.

The American journal of occupational therapy : official publication of the American Occupational Therapy Association. 67. 674-82. 10.5014/ajot.2013.006692.

Bathroom 10 fc

Cafeteria or snack bar 10 fc

Kitchen 50 fc

Classroom 30 fc

Library or study area 30 fc

Computer room 50 fc

Clerical or secretarial areas 30-50 fc

Shops or special labs 50-100 fc

Adopted from Federal Energy Administration Guidelines

https://www.nrel.gov/docs/fy11osti/50125.pdf

Sample lighting standards for different rooms or areas:

Visual tasks with:

High contrast & large size 30 fc

High contrast & small size 50 fc

Low contrast & small size 100 fc

Extremely low contrast & small size 300-1000 fc

These standards just given are for people with “normal” vision. Please remember that a

person with a vision loss may need about 3 times as much light for near tasks as a person

with normal vision.

Based on Standards by the Illuminating and Engineering Society of North America (IESNA)

https://www.ies.org/product/lighting-and-the-visual-environment-for-seniors-and-the-low-vision-population/

Lighting is dependent on the contrast & size of the target

Footcandles (fc) = Total Lumens (lm) ÷ Area in Square Feet

1 Lux (lx) = 1 Footcandle (fc) x 10.76

Lux = Total Lumens ÷ Area in Square Meters

Important Conversions

Therefore, it is important to talk about something called the “Inverse Square

Law” of lighting.

That means that as a light source gets closer, the amount of light delivered is

squared.

Thus, if a lamp used to be 2 feet away And we move it closer so that now it is 1

foot away:

It is not twice as bright, as we may suppose

Instead, it is 4 times as bright, since we square the amount of light delivered

An important principle is not just the amount of light, but the position of the light!

By using a gooseneck or swing arm

Desk lamp, Floor lamp, or Clip-on lamp

Improved Illumination is factor of the Position of the light, using the

Inverse Square Law.

Glare should be avoided by carefully watching the positioning of lighting coming

into the eye, and of items being viewed in relationship to light sources

Perhaps the Best Way to Make Use of the “Inverse Square Law” of Lighting Is to bring a lamp closer

Task illumination can be increased two ways:

• 1. Move the light closer to the surface

2 feet 1 foot

Task illumination can be increased two ways:

• 2. Get a brighter light

2 feet

75 watt

(1180 lumens)

2 feet

100 watt

(1710 lumens)

Address both room and task lighting

• Room lighting

• Overhead light fixtures, floor and table lamps, windows

• Task lighting

• Reading lamps, flashlights etc.

Ambient or Room Lighting

• Since older adults have more sensitivity to glare and slower

responses times to changes in lighting levels, it is important to

provide even, consistent lighting in rooms and corridors.

• Place lights close to the ceiling and ensure LEDs or bulbs are

concealed from direct view.

• Lighting connected to motion sensors are a great addition, especially

at night to illuminate paths to the bathroom.

Task Lighting

• Task lighting should supplement ambient lighting by providing more direct light to activities such as reading, cooking, eating, or sewing.

• Consider swing-arm LED lights placed next to bed, tables, or reading chairs.

• Install LED light strips under cabinets and over countertops.

• Use a Gooseneck table or desk lamp for writing checks, reading mail and other table top tasks.

What bulbs do I buy?

Look at the label.

Sunlight

Fluorescent

Halogen

LED

There are many types of Light

Provide very bright illumination—perhaps the brightest have a

“white” light appearance. They also have a low Kelvin rating—

generally about 3700K to 3900K. Therefore, they do not emit any

ultraviolet or blue light.

They are very hot to work under and dangerous to touch! Because

it is so hot, it can be a safety hazard if not properly used

Halogen Lamps

Provides even lighting with few shadows.

They have a slightly higher Kelvin rating—generally about, 2000K to

4900K except for some models, they generally do not emit ultraviolet

light, and do not emit blue light

May create glare for some

Fluorescent Lamps

May have a lower Kelvin rating of 2,700K to 4,500K— “warm”

white, OR a high Kelvin rating of 5,000K to 6,500K— “cool” white

or “daylight” white

A “warm” LED lamp will not emit any UV or blue light

A “cool” LED lamp may emit both UV and blue light

Are extremely energy efficient.

Can even be battery operated, which makes them very portable.

LED Lamps

Are a type of fluorescent lamp & Generally have Kelvin rating of

5,000K or higher.

Mimic natural sunlight.

Are excellent for color matching, quilting, painting, art work, and

hobbies.

Often have blue light and may have ultraviolet light (UV-A and UV-B).

Therefore, may not be the best for persons with low vision, if they are

concerned about blue light and UV, or if they need enhanced contrast.

Full Spectrum Lamps

“Blue blocker” sunglasses should be worn:

*If you have blue or light colored eyes and fair skin

*If you have other risk factors

*If you spend lots of time in bright sunlight or on water, sand, or snow, which reflects

sunlight

(A sun visor or hat may also be helpful)

The color that blocks blue is yellow, so blue blockers must contain a yellow tint, like:

Amber

Orange

Amber/orange

Yellow

Plum

Blue light are short wave lengths on the nanometer scale of visible light that range from about 400 nm to 470 nm.

• Place the light directly where you need it. Swivel lamps are preferable, as they

can be raised or lowered in order to direct the light.

• Aim the light directly on the task at hand.

• Install dimmer switches for controlling the amount of light in the room.

• Install under-cabinet lighting for tasks in the kitchen or work areas.

• Install extra lighting in places where it may be difficult to move around, such as

hallways and stairs.

• Install light switches in accessible locations.

• Install switch plates that are lighted or contrast with wall color.

• Install preset light timers in difficult areas.

• Watch television in a lighted room. It is easier on the eyes. Be sure, however, that

the light isn’t placed where it will cause glare or reflection off of the screen.

This can be easily checked with the television screen dark.

Here are some additional suggestions for improving lighting in the home and workplace:

*Correlated color temperature (CCT) range of 3000K-4,800K (“warm-to-neutral white”)

for eye safety and best contrast

*Color rendering index (CRI) of at least 80 for good color perception.

*Brightness range of 1000-2000 LUX at 12 inches (30 cm)

*Dimmable to alleviate eye strain

*Easily adjustable fixture to prevent glare

*Easy location and operation of fixture controls

*Coverage diameter of at least 12 inches (30 cm) at a distance of 12 inches (30 cm)

*Cost comparable to similar products

*Sturdy construction for safety and durability

*Transparent and educational advertising

Things to Consider

http://lowvision.preventblindness.org/daily-living-2/lighting-for-low-vision/

"Why test contrast sensitivity? Isn't visual acuity enough?"

Serena Speaker OTR SCLVSerena Speaker OTR PC;

St Joseph Health System, Bryan, Texas;

AMA Home Health, Brenham;

Texas Home Health, Brenham, Texas

Visual Acuity

Visual acuity (VA) has long been the guiding test for many of the decisions that are made for the low vision client.

Testing both near acuity and intermediate acuity gives us information to guide our treatment.

A more comprehensive measure of visual function is contrast sensitivity, which describes visual sensitivity at different contrasts that can significantly affect overall quality of life (4).

• Research is indicating that contrast sensitivity function (CSF) can be just as important or even more important than VA for reading, environmental mobility and other visually guided tasks.

• Contrast sensitivity is one's ability to detect objects in contrast with their background and is an important visual function in enabling persons to detect general forms and contours especially in low lighting. Many of our daily activities require the detection of low contrast features such as dusk or dawn driving or in the rain, filling the bath tub or facial recognition (8)

• Most patients are usually aware of VA deficits since it interferes with important ADLs, such as reading but they are not aware of low contrast problems that influence night driving, stepping off curbs, face recognition along with other low contrast situations.

• Many practitioners only measure high contrast acuity which overlooks the low contrast ADLs that can lead to serious accidents (2).

• Even if the clinician does not have the opportunity to perform a home evaluation to improve contrast issues, a contrast sensitivity test will open the door for patient and family education on improving contrast for improved ADL function and environmental safety.

What is Contrast?

• Contrast can be defined as a measure of how different a luminance level at some point in space or time is, compared to some luminance reference or in layman terms-a measure of the amount of lightness or darkness an object has in comparison to its background (6).

• Or the threshold between what is visible and invisible (5).

CFS Charts

• There is a variety of CSF charts available including letter/number charts, grating tests, computer based charts, and mixed contrast charts.

• There are pros and cons to many.

• Some of the widely used being the Pelli-Robson, Mars, LEA and computer charts including the Test Chart 2000 and Vistech Contrast Chart, Colenbrander Mixed Contrast Reading Chart.

Colenbrander Mixed Contrast Reading Card

• Meant as a screening test for CS with lines that are printed alternately in high and low (10%) contrast with letter sizes from 10M to 0.6M.

• This reading card is important when considering retinal conditions since reading involves a larger retinal area than does letter recognition.

• Two to three line difference in normal. The difference between the number of lines read with high contrast and with low contrast provides a measure of CS that is independent of age and visual acuity (4).

• This test was produced to make contrast testing less time consuming and to detect para-foveal losses which may precede foveal visual acuity loss (10).

iPad Rapid and Reliable Assessment of CFS

• This is on an iPad by Dorr, et al., 2013 project concluded that CSF assessment on a mobile device is indistinguishable from that obtained with specialized laboratory equipment due to the different luminance conditions available on the tablet.

• The tablet-based test also reliably identified changes in contrast sensitivity due to different luminance conditions (4).

• This type of technology will allow more individualized, low cost and better health care in the clinic and home settings.

• CS presents in a variety of LV diagnosis. CS loss does not specify a particular diagnosis, as many diseases generate similar effects on CS function but it is valuable in identifying ocular disease and guiding treatment (6).

Four different factors significantly affect reading rate:

• 1. acuity reserve (print size relative to acuity threshold)

• 2. contrast reserve (print contrast relative to contrast reserve)

• 3. field of view (number of letters visible)

• 4. central scotoma size in cases of maculopathy

• Approximately one-quarter of our population has difficulty in reading newsprint.

• Presenting text in a high-contrast format, such as black laser print on a white page, would increase the number of people able to access such information.

• Additionally, making test available in a format that can be presented on an LED computer monitor would increase access to written documents (1).

Contrast Polarity

• This effect is probably due to abnormal light scatter in eyes with cloudy media.

• Photometric measurements indicate that in a page of black print on a white page, more than 80% of the page is high-reflectance white and a source of light scatter. Less than 20% of the page's surface is covered with black ink.

• In the opposite contrast polarity, these proportions are switched.

• This asymmetry may explain why people with cloudy media read white-on-black text faster (7).

•Contrast applications in the home will improve ADL and IADL function.

Interventions in the Home

• touch dots

• high contrast for table wear,

• tape applied to steps,

• tape applied to pull cords,

• decrease pattern in the environment

• improved lighting

• These will create a safer environment while increasing the clients ability to perform visually guided tasks.

•The more impaired the client's contrast sensitivity function or the lower the contrast in the environment, the greater the need for enhanced lighting (10).

•We are all in agreement that our increasing population of low vision clients will come with other co-morbidities that will require our co-management with other health care providers.

Contrast Sensitivity Charts

Goodlite.com LEA number flip chart $102

Precision-Vision.com Mixed Contrast charts

#4061 10M to 0.6M, $74.75

#4071 4M to 0.32M, $57.50

Mars chart, $395

#2704 Number flip chart, $97.75

Maxiaides.com Boldwriter Pen by Reizen, $1.29, package of 12 $13.80 (Amazon)

Bump dots, single sheet $1.79, package 640 $12.95 (Amazon)

Lab

• Examine evaluation types

• Trial of lights-LED, Halogen, gooseneck, portable type, etc

• Trial of Vision Simulators to view charts, newpaper, newspaper ads, regular print magazine, large print Readers Digest, look at faces

• View reading material under variety of lighting

• Examine contrast with table settings

• As Dr. August Colenbrander stated:

" If you cannot cure the CAUSES, then take care of the CONSEQUENCES."

May each of us apply this concept to our clients.

Questions or commentssspeaker53@gmail.com

References

• 1. Crossland, M.D. and G.S. Rubin, Text accessibility by people with reduced contrast sensitivity. Optom Vis Sci, 2012. 89(9): p. 1276-81.

• 2. Colenbrander, A., Mixed Contrast Measurement. Research Session R-10 Research on Reading Tests for Vision Rehabilitation, Envision Conference 2012.

• 3. Colenbrander, A., Fletcher, D., The MIXED CONTRAST Reading care, a new Screening Test for Contrast Sensitivity. Based on poster presentation at the International Low Vision Conference "Vision 2005", London, April 2005.

• 4. Dorr, M., Lesmes, L, Lu, Z, Bex, P., Rapid and Reliable Assessment of the Contrast Sensitivity Function on an iPAD. Association for research in Vision and ophthalmology, 2013, 7266-7273.

• 5. Pelli, D.G. and P. Bex, Measuring contrast sensitivity. Vision Res, 2013. 90: p. 10-4.

• 6. Richman, J., G.L. Spaeth, and B. Wirostko, Contrast sensitivity basics and a critique of currently available tests. J Cataract Refract Surg, 2013. 39(7): p. 1100-6.

• 7. Rubin, G.S. and G.E. Legge, Psychophysics of reading. VI--The role of contrast in low vision. Vision Res, 1989. 29(1): p. 79-91.

• 8. Warren, M, Barstow, B, Occupational Therapy Intervention for Adults with Low Vision. AOTA. 2011.

• 9. Watson, G.R. (2001) Low Vision in the Geriatric Population Rehabilitation and Management. Journal of the American Geriatric Society, 49 (3): p. 317-330.

• 10. Wolffsohn, J., Eperjesi, F., Napper, G., Evaluation of Melbourne Edge Test contrast sensitivity measures in the visually impaired. Ophthalmic and Physiological Optics,2005. 25 (4): p. 371-374.

• 11. Wood, J.M., Lacherez, P., Black, A.A., Cole, M.H., Boon, M.Y., Kerr. G.K. (2011) Risk of Falls, Injurious Falls, and Other Injuries Resulting from Visual Impairment among Older Adults with

Age-Related Macular Degeneration. Investigative Ophthalmology & Visual Science; 52: 5088-5092.