Assistive Technology for Persons with Visual Impairments

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Assistive Technology for Persons with Visual
Impairments
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Learning Objectives

• Recognize advantages and limitations of assistive
  technology devices
• Describe factors influencing successful
  incorporation of technology into daily living
• Identify and describe effective teaching
  strategies
• Describe proper set up of workstations
• Select most appropriate technology for various
  visual conditions

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Visual Limitations
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Visual Limitations

• Reduced reading visual acuity
• Reduced contrast sensitivity function
• Visual field deficits
• Size and location
• Impaired oculomotor control
• Conjugate eye movement for reading saccades
• convergence
• Impaired visual attention

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ADL Limitations Requiring Technology
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ADL Limitations Requiring Technology

• Functional communication
• Reading
• Writing
• Use of telephone
• Time telling
• Math calculation
• Mobility
• Wayfinding
• Limitations in these tow areas cause cascade
  effect on other ADLs

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Common Types of Assistive Technology

• Low tech
• Standard magnifiers
• Magnifying mirrors
• Simple talking devices
• Watches
• Calculators
• Scales
• Health care devices

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Electronic Magnification-CCTVs

• CCTVs Stand Alone Units
• Excellent optics
• Better positioning
• of screen
• Can easily
• complete both
• reading and
• writing

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CCTVs continued

• Units paired with monitors (TVs)

• Flipper port EVS

Mouse Unit EVS Max
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Sacrifice some optical quality depending on TV
screen used but gain greater fiexibility and
color at a better price
Videoeye Swing Arm
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CCTVs Head Worn
Portable and flexible Harder to adapt to more
motion sickness balance challenges Expensive
Max port Head Worn
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CCTVs hand held

• Betacom
• Visable video
• telescope

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Electronic Magnification-Software

• Screen enlargement software programs
• Software is loaded onto computer and
• works with other software programs
• can enlarge all or portion of the screen
• Best known
• Zoomtext (aisquared.com)

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Screen Readers

• Read contents of computer screen
• Auditory
• Tactual
• Can read email and access web
• Can use OCR scanner to load documents into
  computer for reading

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Auditory Screen Readers

• Read the text presented on the screen
• Provide audio feedback of characters pressed and
  words typed
• Allow access to Web, email, and other software
  programs
• Require OCR scanner to input materials
• Types
• Auditory-speech synthesis
• Web Wizard
• Open Book 5.0 (Freedom Scientific)
• JAWs (Job Access with Speech)

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Tactual Screen Readers

• Display screen
• contents in refreshable
• braille
• Hardward attaches
• to computer as a
• peripheral
• Requires software to
• translate screen to
• Braille
• Braille embosser used
• to print a hard copy

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Screen Readers cont.

• Tactual only
• Window Eyes
• Speech only
• Openbook (arkenstone)
• Jaws (job access with speech)
• Both tactual and speech
• Window Eye Professional
• Zoomtext Extra 7.0.6

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Scanning and Reading Devices

• Self contained units
• Those combining
• OCR with computer
• speech synthesizer

Vera Reading System
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Self contained Reading and Scanning Devices
UPC bar code scanner
Money ID
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Keyboard Input Devices

• Braille or letter input that is synthesized to
  speech or braille output later
• Called note takers
• Complete basic word processing
• Have some functions of PDA
• Calendar, clock, calculator
• Dont require a monitor, making them lightweight
  and portable
• Download files into computer

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Keyboard input devices

• Braille n speak
• Type n speak
• Betacom Tactual mouse

Braille Lite
Tactual Mouse
Type n Speak
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Voice Activated

• Note takers
• PDAs
• telephones

Parrot Plus and voice Mate
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Issues Affecting Successof Treatment Intervention
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Matching Person and Technology Model

• Advocates addressing
• Exact characteristics of environment and
  psychosocial settings in which technology will be
  used
• Pertinent features of persons personality and
  temperament
• Salient characteristics of assistive technology

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Acceptance Issues

• Technophile vs. technophobe
• Statistics show that persons over 60 have the
  fewest numbers of high tech products in their
  homes
• High tech devices must be carefully introduced
• Training is essential
• Assume nothing

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Performance Components

• Physical limitations

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Performance Components

• Physical limitations
• Hand function
• Strength
• Dexterity
• Tremor
• Upper arm strength
• Forearm and shoulder support
• Upper trunk, neck mobility
• Placement of device
• Small size of older user
• Seating
• Comfort and endurance

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Performance components

• Sensory limitations
• Auditory
• Hear and discriminate speech
• Tactual
• Sensitivity of finger tips to feel tactual
  prompts
• Cognitive limitations
• Attention
• Retention and carryover of new learning
• Comprehension
• Ability to sequence
• Key ability often limited in older adults

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Performance Components

• Financial resources
• Can be very expensive
• the older adult objection
• Ive lived this long.and I dont have much time
  left
• Rarely a covered item by insurance
• State may have assistive technology act that
  provides some funding
• Veterans may receive assistance through VA
• Never rule out private sources

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Fitting Technology to the Person

• For persons with usable vision, the key issue is
  visibility
• Screen and keyboard
• Features of the device

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Fitting Vision Users

• Keyboards
• Can overlay with enlarged letters
• Modify with tactual prompts
• Add concentrated lighted

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Screen Presentation
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IMAGE SIZE
A
Larger images reduce need for convergence Reading
speed is related to number of
characters displayed on screen
A
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Image size

• Buy the largest monitor you can afford and that
  will fit into the computer work area
• Use zoom function on the computer
• Move closer to the screen
• Purchase screen enlarging software
• Purchase a screen magnifier overlay

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CONTRAST
CAT CAT
CAT
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Contrast

• Experiment with best contrast setting on the
  screen
• Alter the color of letters and background on the
  screen
• Reduce ambient lighting in room

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PATTERN DENSITY
Reduce density by increasing size and
spacing text
High density demands good oculomotor control
Good attentional skills and good acuity and All
of this together makes it very difficult to read
And see the screen and keep track of where You
are on the screen or even tell if youre making A
mistake in typing and mis-spelling every thing.
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Pattern

• Reduce pattern density by
• Enlarging text
• Using sans serif fonts
• Eliminating graphics unless they serve an
  invaluable function

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FIELD OF VIEW
Mary ha
Mary had a little
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Field of View

• The wider the monitor the greater the field of
  view
• Flat screen reduces distortion at edges and
  increases usable field on screen

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Glare, Definition, Clarity

• Flat screens are considered superior in providing
  image quality
• LCD liquid crystal display
• Can reduce glare by reducing ambient light
• Do not let light source shine directly on screen

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Task Considerations

• Carefully consider the demands of the tasks and
  the client desired level of performance
• Person with large volumes of reading to complete
  may be technically capable of using screen
  magnification but is more functional with speech
  synthesis

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Persons without Usable Vision

• Must use speech or tactual interface
• Often use a combination of both
• Tactual interface with keyboard
• Loc dots or velcro
• Braille keyboard
• Text recognition software
• Scanning and reading
• Braille or auditory or both

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Non Vision Users

• Must have good tactual and/or auditory
  capabilities
• Must have good sequencing capability

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Assessment

• Two basic categories
• Personal use
• Vocational

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Personal Use

• Identify the ADLs that require use of technology
• Highly individualized
• Ask person to describe a typical day
• Pay close attention to quantity, quality and type
  of reading material needed to complete daily
  activities
• Example handwritten materials will require use
  of CCTV

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Vocational Assessment

• Required job duties/tasks
• Quantity and quality of reading materials
• Time frame for completion of reading
• Amount of handwritten materials
• Distances from which person is required to read
• Meetings with overheads/power point
• Instruments with calibrations
• Overhead signage
• Quantity and quality of writing required

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Vocational Assessment cont

• Computer set up
• PC with server based network
• Stand alone microprocessor can be adapted
• Mainframe computer with dummy terminal
• Cant use software programs unless a separate
  stand alone microprocessor is attached to work
  station
• Second microprocessor must be able to communicate
  with mainframe
• Shared computer
• Adaptations must be removable or unobtrusive

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EnvironmentVisibility of Work Space
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Lighting

• Two types
• Room
• Task
• Desired qualities
• Sufficient
• Even
• Non-glaring

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Environment Visibility cont..

• Contrast/Pattern
• Structures person interacts with should be easy
  to locate
• Examples?
• Organization
• Increases efficiency
• Reduces stress and work place fatigue

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Treatment Intervention

• Goal is to provide a visible and comfortable
  workspace that promotes efficiency

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Computer Ergonomics

• Keyboard
• Elbows at 90 degrees flexion
• Wrists in neutral position
• Key pad should be visible without hunching or
  leaning
• Monitor
• At or slightly below eye level
• Raise or lower the person
• Raise or lower the monitor

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Computer Ergonomics cont..

• Pointer (mouse)
• As close to keyboard as possible
• 90 degrees elbow flexion
• Less frequently used peripherals
• Should be accessible but not in the way

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Work Station
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Work Station

• Good contrast
• Good lighting
• sufficient
• good quality
• no sources of glare
• Minimal pattern
• minimal clutter
• Organized

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General Training Strategies

• Present only one task at a time
• Many systems multi-task read email, magnify
  screens etc
• Laying out all options at once may confuse and
  overwhelm
• Make sure person masters one activity before
  moving on to another
• Present the task in simple steps
• For older users, dont explain rational for
  function
• Extra information is confusing -will become
  overwhelmed if too much information is provided
  at once

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General Training Strategies

• If person has difficulty sequencing steps
• Chain the steps
• Complete the most complex steps for the client,
  letting the client finish the final step so h/she
  can see the results of successfully completing
  the task
• Provide ample opportunity for supervised practice
  of each step
• Older adults need much more practice than younger
  ones
• Provide step by step written or taped
  instructions
• Record using persons own description of the step