Sensory Aids for Persons with Visual Impairments

What does 20/20 vision mean?

You can see size 20 font from 20 feet away

Opthamalogist

• looks at eye diseases and does surgeries

Optometrist

• looks at visual acuity, prescribes prescription lens

Visual accommodation

• ciliary muscles change the curvature of the lens

• 20 yr old

  • 10 cm, 50 + 30 CM or more

Visual field

• peripheral vision

• ability to see surroundings when looking straight

  • ex. at the DMV

Blind

• visual system does not provide useful input

Low Vision

• standard size font, contrast, spacing etc. is inadequate

Near sighted

• can see clear near, not far

Far sighted

• can see clear far, not near

Visual Disorders

• age related macular degeneration

  • breakdown of the macula

• glaucoma

  • increase in ocular pressure

• cataracts

  • cloudiness over lens

• diabetic eye disease

  • damage to the optic nerve

Sensory aids - minor or mild

• augment the sensory information

  • augment assists with vision

• glasses/contact lens

• increasing size

• increasing contrast

• positioning in proper place in visual field

Blind canes

• white and have a red tip

Augmenting a visual pathway - severe

• must use alternate sensory pathway

• tactile

  • braille, canes

• auditory

  • speech

• technical and advanced

  • computerized environmental interface

  • camera

  • information processor

  • display

  • screen reader

Video magnifiers

• large amount of magnification

  • 45 to 80x

• images can be manipulated and controlled

  • brightness, contrast

• consist of environmental interface and user display

Topaz

• computer screen and video monitor

• has split screen

Considerations for electronic aids

• size

• size of the monitor limits the amount of magnification, split screen helps with this

Jaws

• commercially available readers

  • reads text or uses refreshable Braille display

• stands for Job Access With Speech

Braille

• traditionally embossed on heavy, bulky, takes up a lot of space

• costly and error cannot be easily fixed

• portable braille note takers and organizers with speech output

• braille label makers and labels

• refreshable braille display

  • dots keep changing

Less than __% with severe visual impairment learn to use braille

10

Portable Braille Devices

• PDA/Note-takers

• some models have a Braille and QWERTY keyboard and may have a synthetic speech built in

• include things that would be found on phone

  • calendar, notes, email, etc.

• may have wifi or bluetooth access

Speech and Screen Readers

• recorded or read material

• often special devices were needed in the past to increase the speed of the playback

• different formats in different areas/countries. Attempts to codify it with digital audio-based information systems consortium

• OCR

Optical character recognition (OCR)

• will recognize word by word and scan it to a word document or JPEG

• drawbacks

  • some of alphabet does not get transcribed correctly

PDF

portable document format

Graphical User Interface (GUI)

• pointer is moved around screen

• menu of icons

• one or more windows provide a menu of choices

GUI features

• clicking and dragging

• designed to save typing, reduce effort and make user more successful and allows for more intuitive use

• allows for consistency

• uses visual emtaphor’s

• not easily displayed in alternate methods - need to be labeled

Problems with GUI

• pointer location

• multiple windows

• spatial organization

• elements such as size, color, and style

• graphical information

Solutions to GUI

• auditory icons

• earcons

• hearcons

Auditory icons

• sound to alert of things happening

• ex. tapping sound when new window opens

Earcons

• auditory labels that do not have a direct relationship in the event

• use rhythm, pitch, timbre, or register

• ex. bell when opening file

• ex. drum when closing file

Hearcons

• nature sounds, musical works, or instruments

• are completed sounds

• ex. melody rather than a single note

Other features for GUI

• invert colors

• enlarge text

• mouse tails/trails

• enlarged mouse

• none of these are meant to replace commercially available options

Considerations for phone for individuals with low vision/blindness

• lighting

• cost

• many have built in features

• smartphones may not be right for everyone

Magnification Aids

• vertical or horizontal

• optical aids

  • enlarge an image presented through a glass lens

• non optical aids

• electronic aids

  • when camera focuses on print material it is projected onto a larger viewing screen

• for conrast

  • hues, lightness, and saturation

Web guidelines for colors

• use colors that differ as little as possible in lightness

• avoid colors from the ends of the spectrum

• avoid white or gray with any color of the same lightness

• avoid colors adjacent to each other on the color spectrum

• avoid pastels

Portable Magnifiers

• some are cell phone or tablet based

• take a picture of the text and then magnify it for display on the built in screen, can zoom in on individual letters

• many have screen readers attached and may be able to be printed out in braille

• KNFB reader

  • take picture of text, speaks it back to you

Computer Magnifying Software

• 2-36x

• give up full access to the screen

Computer output

• braille reader

• screen readers

Orientation and Mobility

• attention using the other senses but may not allow for knowledge of dangerous obstacles

  • bikes, streets, ladders, branches

5 approaches of orientation and mobility

1. guide dogs

2. long cane

3. electronic aids

4. orientation system

5. navigation system

Long canes

• maximize tactile and auditory input from the environment

Long Cane Pros

• allows you to search for obstacles

• better for distant objects

Long Cane cons

• can get stuck

• someone could come after you can the area thinking it is clear

• if cane is electronic, might not work in some weather conditions

• crowds make it harder to use

ETA and OD

• support guide dog use

• presence of more distant objects compared to cane

• can be built into canes

• uses laser/electronic waves and signals the user with auditory or tactile information

• some can be worn on body

Navigation Aids

• adapted compasses

  • on phone

  • tell longitude and latitude

• talking signs

• GPS

  • allows for knowing where you are, landmarks, and intersections

    • uses process of triangulation

3 kinds of GPS

• Stored digital maps

  • current location and points of interest

• Use of data bases only

  • checkpoints along the way for guidance

• User generating their own routes

  • user stores a series of announcements that are used as landmarks

Household items

• tactile levels and tape measures

• board games

• beeper balls

  • in bowling or baseball tells when to let go or swing 

• bar code readers

Bar code readers

• Originally ones like ID Mate that allowed you to record your own short descriptive message

• Scan talker for the PACn Mate

• Voice output is available on some mainstream household appliances

  • Many appliances already have this

  • Timer on oven that will tell you when it is done preheating

• Will read the text associated with the bar code