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Assistive Technology for Individuals with Sensory Impairments – Vision and Hearing : 

Assistive Technology for Individuals with Sensory Impairments – Vision and Hearing

Vision : 

Vision

Vision Demographics : 

Vision Demographics 15% Americans age 45-64 17% Americans age 65-74 26% Americans age 75+ report some form of vision impairment All but 2% of this group report that they are partially sighted rather than totally blind

Vision Demographics : 

Vision Demographics .6% of persons under 18 years of age are visually impaired (approximately 450,000 children and youth)

Vision Demographics : 

Vision Demographics By Categories Severe vision impairment – 1.8 million Low vision – 3 million Legally blind – 1.3 million Light perception or less – 260,000 Causes of blindness include glaucoma, macular degeneration, cataract, optic nerve atrophy, diabetic retinopathy, retinitis pigmentosa (51%)

Components of the Visual System : 

Components of the Visual System Visual Acuity – Clarity of vision Expressed by notation that describes the size of a visual target and the distance at which the target is identified. 20/20 20/70 20/200 Partially Sighted Legally Blind Light Perception No Light Perception

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Visual Field Areas in which objects are visible to the eye without a shift in gaze Problems that can occur Decreased vision in either central or peripheral field Blind spots Field cuts

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Cataracts Glaucoma

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Macular Degeneration Retinopathy

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Oculomotor Functioning Concerns the functioning of eye muscles that enable eyes to move together smoothly in all directions Conditions include: Strabismus – inability to maintain eyes in a position of binocular fixation due to weak eye muscles causing eyes to cross or diverge Nystagmus – involuntary movement of the eyes causes problems with acuity

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Light and Color Sensitivity Different vision conditions require adjustment of lighting up or down Color perception can be impaired – inability of the eyes to interpret particular wavelength frequencies (most common is confusion of red and green)

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Color Blindness: Simulation Map of Hurricane Isabel (with color)

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Color Blindness: Simulation Map of Hurricane Isabel (simulating red/green colorblindness) Simulated using Vischek (http://www.vischeck.com/vischeck/vischeckURL.php )

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Color Blindness: Simulation Subway map

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Color Blindness May change color settings in browser Approximately 8-10% of the male population and about 0.5% of the female population experiences some form of color deficiency Cell phone, PDA and text browser users may not have color Reds & greens are often indistinguishable Other colors may be indistinguishable

Assistive Technology for Vision Impairments : 

Assistive Technology for Vision Impairments For those who have some vision skills remaining We try to augment the skills rather than rely on another sensory system For those with no residual vision skills We substitute an alternative sensory system

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Color Blindness: Accessible Design Techniques Do not use color alone to convey content Use additional cues or information to convey content The flights listed below in RED have been cancelled. The flights in GREEN are departing on time.Delta 1342United 320American Airlines 787Southwest 2390 The flights listed below that have been cancelled are indicated in RED and by an asterisk. The flights in GREEN are departing on time.Delta 1342*United 320American Airlines 787Southwest 2390*

AT for Vision Augmentation : 

AT for Vision Augmentation Reading Modifications to computers Accessible to those who use enlarged screen output (screen magnification software, built-in magnification of Windows, screen magnifying lenses on monitor, CCTV)

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Magnification Aids Optical aids (magnifiers) Nonoptical aids (large print books, high intensity lamps) Eectronic aids (CCTV)

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Low Vision: Accessible Design Techniques Limit or eliminate text within graphics Have plenty of contrast

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Low Vision: Simulation

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Text presented in graphical form Real Text

AT for Vision Alternative : 

AT for Vision Alternative Reading Modification to Computers Screen reader software Tactile – Braille technology Automatic Reading Devices Scanner and camera “read” the text, optical character recognition translates information into speech or braille

AT for Vision Alternative : 

AT for Vision Alternative Braille is widely used as tactile reading strategy Technology provides us now with refreshable braille displays Recorded audio material Check out National Library Service for the Blind

Hearing : 

Hearing

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Inability to hear sound Varies depending on level of loss Particularly important to consider in the understanding of speech Hearing loss affects 1 out of 11 individuals

AT for Hearing AugmentationAlternatives to Hearing : 

AT for Hearing AugmentationAlternatives to Hearing Listening Devices Amplification devices Telecommunication Devices Amplifiers, TTY Alerting Devices Flash, vibrate, sound

AT for Hearing AugmentationAlternatives to Hearing : 

AT for Hearing AugmentationAlternatives to Hearing Assistive Listening Devices (ADL’s) FM systems Closed-captioned television and movies

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Deaf and Hearing Impaired Audio is unusable Video clips that include audio are unusable Audio clips are unusable

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Deafness: Accessible Design Techniques Provide transcripts for all audio content Provide synchronized captions for all video content (MAGpie – free captioning tool) Many people benefit Students in library w/o headset People with learning disabilities People for whom English is not their primary language People in a noisy environment Everyone (content is presented in >1 medium)