Types of Disabilities Flashcards
Blindness
Blindness is generally characterized as sightlessness or a loss of vision. While the term “blindness” is often used to define a total loss of vision, it may also refer to partial blindness, where sight may be extremely limited (low vision).
Causes of Blindness
There are several causes of blindness, including (but not limited to):
Diabetes
Macular Degeneration
Glaucoma
Accidents or traumatic injuries to the eye
Stroke
Retinitis Pigmentosa
Legal Definition of Blindness
In the United States, there is a legal definition of blindness that is used solely to determine eligibility and participation in various programs. According to the U.S. definition of blindness, a person who has a visual acuity of 20/200 with corrective lenses or who has a field of vision (what can be seen in front of the person) that is 20 degrees in the eye that has the best vision is considered to be legally blind.
(Blindness) Screen Readers
Screen readers convert the text on the web page into spoken words. Blind people listen to web pages.
(Blindness - ICT)
Cannot see digital or electronic interfaces (computers, automated teller machines (ATMs), mobile devices, airport kiosks, televisions, printers, copiers, phones, GPS devices, etc.)
Challenges/ Solutions
- Screen readers can read interfaces and content out loud to users by converting digital text to synthesized speech, but only if they have been designed to be accessible. Screen readers do not announce text styles such as font, color, size, bold, and italic.
- Self-voicing interfaces and applications can communicate to users without the need for a screen reader, but these are appropriate mostly for broadcasting information, because they usually do not interact with the interface or content as screen readers do.
- Refreshable braille output devices use screen readers to convert digital text to braille. These devices are typically expensive, and only a minority of blind people know how to read braille.
(Blindness - ICT)
Cannot use screen readers on digital content and interfaces not designed with accessibility in mind
Interface designers and content authors can edit the markup to make it compatible with the assistive technologies used by blind people.
(Blindness - Architecture & Built Environment)
Cannot see when walking
Canes help blind people feel their surroundings as they walk.
Service animals (e.g. “Seeing Eye” dogs), trained to assist blind people, help them navigate their surroundings.
GPS-based walking instructions with an audio interface, either automated or via a remote human navigator.
Raised tiles on the ground to indicate the edge of a platform, a pathway along a sidewalk, the beginning of a staircase, etc.
Eliminate low-hanging architectural features that a blind person could bump into
Clear pathways without obstructions in hallways, sidewalks.
(Blindness - Architecture & Built Environment)
Cannot see signs or other text on buildings or other areas in the built environment
Map and geolocation applications on mobile devices can announce the names and descriptions of buildings and other location-related information.
Braille labels and descriptions on entrances, rooms, bathrooms, historical markers, and other points of interest can allow blind people to explore and understand their surroundings, as long as the person knows braille, and as long as the braille labels are easy to find.
Tactile models of the exterior of buildings, or of floorplans of the interior of buildings help blind people form a mental map of their surroundings.
(Blindness - Consumer & Industrial Products)
Cannot see or feel the controls on flat interfaces on consumer devices such as microwaves, ovens, dishwashers, etc.
Alternative interfaces with knobs or other tactile controls
Audio interfaces
Remote control through applications on mobile devices
(Blindness - Consumer & Industrial Products)
Cannot read the text on the containers or packaging for consumer items such as medicine, toothpaste, shampoo, sunscreen, hand cream, personal care products, foods, drinks, candy
Embossed braille (or braille stickers) on packaging and product containers help consumers identify items both in the store and after purchase.
(Blindness - Consumer & Industrial Products)
Cannot read money to determine its value
Applications on mobile devices can photograph the money and read the value to blind people.
Paper bills and coins could be manufactured in different sizes, shapes, or textures to allow blind people to distinguish the value based on touch.
Non-cash systems of payment can allow blind people to make financial transactions via computers, mobile devices, or on-site payment hardware with screen readers or self-voicing output.
(Blindness - Consumer & Industrial Products)
Cannot read books, magazines, posters, postal mail, or other printed materials
Optical character recognition software can convert scanned images of text into digital text readable by screen readers. The accuracy of the conversion depends on the quality of the original document, as well as font choices, line spacing, and the quality of the conversion software itself.
Information can be placed online or in other digital formats to allow blind people to read the materials using their own assistive technologies.
Low Vision
People with low vision can see, but their vision is still quite far from perfect even with powerful corrective lenses. Those who have low vision may be unable to see well enough to drive or read most printed text unless they enlarge it. Low vision isn’t a single condition. It is a broad category encompassing many different conditions, with varying degrees of vision impairment. They can’t see well enough to read small fonts or to clearly discern details without enlarging them. There is quite a bit of diversity in the kinds of low vision that a person can experience
Blur
For people who have low vision, faces and objects appear blurry. It is difficult for them to distinguish specific features. In terms of using websites, foreground elements may be difficult to see from background elements.
Blur with Low Contrast
People who have low vision or blurred vision can also experience seeing things in low contrast, meaning that there aren’t very many bright or dark areas. Everything tends to appear about the same brightness, which makes it hard to distinguish outlines, borders, edges, and details.
Cataracts
There are some people who experience blind spots in their eyes, which can cause them to miss visual information if it’s in one of their blind spots. A person who has cataracts may see innumerable dark gray spots that can cloud his or her vision and make objects on a website extremely difficult to see.
Diabetic Retinopathy
Diabetic Retinopathy is another eye condition that causes people to see floating dark spots.
Glaucoma
Some people can see only a small area, and have no peripheral vision. The edges are heavily darkened or vignetted. It is like looking through a narrow tube.
Hemianopia
Hemianopia, or Hemianopsia, is another eye condition that limits vision to a smaller area. In the case of Hemianopia, vision loss occurs on either the right or left side of both eyes.
Macular Degeneration
Macular degeneration is an eye disease where there is a loss of vision in the center of the eye, the field of vision. While people with macular degeneration have peripheral vision, the deterioration of the macula can cause either blurred vision or a blind spot to occur in the central vision.
Retinal Detachment
For those who experience retinal detachment, vision can be affected in multiple ways. Some may experience flashes of light in their vision field, see what are called “floaters” in their vision, or a dark shadow covering a significant portion of the field of vision.
Screen Magnification
Reading small text is an extremely difficult task for a user with low vision. Users with low vision may need to use screen magnification like ZoomText, which shows a small portion of the screen at a time. When the screen is magnified, it zooms in on a section of the screen and displays it at high resolution.
Specialized screen magnification software like ZoomText has a large number of features to help optimize the visual experience for people who have low vision.
(Low Vision) Screen Readers
Most people think of blind people when they think of screen readers, but people with low vision can benefit from screen readers too. Hearing the words can help make the visual text easier to understand, especially for those with extreme low vision. ZoomText has basic screen readers built into them. Screen readers bundled with screen magnifiers generally aren’t as full-featured as stand-alone screen readers, but they are adequate for most tasks.
Color Customization
For people with low contrast vision, or low color vision, colors may not be easily visible, and may be hard to distinguish from each other. Text that is too close in color or luminance (brightness) to the background can be hard to read. Some people may also experience pain when looking at bright lights or bright areas on paper or computer screens. All-white backgrounds can be particularly difficult. To attempt to remedy the effects of low contrast and bright areas, users may modify the colors either in the operating system or in the web browser.
Colors can be used in web design, but it is crucial to not use color alone to convey important information since users customize colors based on what is best for them. Make sure the important information is represented in the text.
(Low Vision - General)
Small text can be hard to read.
Screen magnifiers can enlarge the items on the screen to make them easier to read.
Utilities to enhance contrast, change colors, or alter other aspects of visual appearance can improve legibility.
Screen readers can supplement screen magnifiers by reading interfaces and content out loud to users through synthesized speech, but only if the digital information has been designed to be accessible.
Self-voicing interfaces (on ATMs, kiosks, transportation systems, etc.) and applications can communicate to users without the need for a screen reader, but these are appropriate mostly for broadcasting information, because they usually do not interact with the interface or content as screen readers do.
Alternative large print versions of small print text can make printed materials easier to read.
Alternative digital versions (web, mobile applications, etc.) of printed materials can give users the ability to read the materials using their own assistive technologies.
(Low Vision - General)
Low contrast text can be hard to read.
Software or hardware options can enhance the contrast of digital text.
Interface designers and content creators can choose color combinations with high enough contrast to easily read
Color Blindness
Color-blindness does not literally mean that a person can’t see any color at all (except in very rare cases). Color-blindness refers to the inability to distinguish between certain kinds of colors, especially colors that are of equal brightness or luminosity, even if the colors themselves appear quite different to people without color-blindness.
Types of Color-Blindness
There are several kinds of color-blindness, and varying degrees within those types, so it is difficult to provide a precise explanation of which color combinations are the worst for people who experience color-blindness. The most prevalent form of color-blindness, though, is red-green color-blindness. Deuteranopia and Protanopia are two common sub-types of red-green color-blindness. Some people may also have what is known as Tritanopia, or blue-yellow color-blindness. Though very rare, there are those who inherit an insensitivity to all colors. People who have Achromatopsia see colors in grayscale.
Red and Black Colorblindness
In addition to red-green and blue-yellow color-blindness, the colors red and black may be difficult to distinguish for some people. The tabs below illustrate how similar the colors may be to those who are colorblind.
Assistive Technologies for People with Color-Blindness
There aren’t many assistive technologies for people with color-blindness. For the most part, it is a condition that people just have to live with. A company called EnChroma claims to have developed glasses that can help compensate for some kinds of color-blindness.
(Color-Blindness - General)
Certain color combinations—red and green in particular—can be difficult to distinguish
Materials can be designed in a way that does not depend on color as a way to convey information.
Deafblindness - Braille Displays
If a person is both deaf and blind, the only option is to use a refreshable braille display in combination with a screen reader. Rather than have the screen reader read out loud in an audio format, people who are both deaf and blind have the screen reader output the text to the braille display, which they can then feel with their hands.
(Deafblindness - ICT)
Digital text cannot be seen
A screen reader can convert text to braille on a refreshable braille device, or “printed” in a braille embosser.
(Deafblindness - ICT)
Audio (including the audio portion of videos) cannot be heard
A text transcript of the audio can be converted to refreshable braille by a screen reader, or “printed” in a braille embosser.
Auditory Disabilities
Auditory disabilities involve hearing impairment, hearing loss, and deafness. People who have hearing impairment or hearing loss have diminished hearing and may have difficulty understanding speech and distinguishing foreground noise from background noise. Depending on the condition, some people may use hearing aids as an assistive technology or may rely on lip reading to communicate with others. For those who have total loss of hearing, augmentative and alternative communication (AAC) such as sign language or communication boards are used to communicate with others.
Central Auditory Processing Disorder (ADP)
Another auditory disability which results in difficulty with processing sounds or speech. A person with this disorder doesn’t have any measurable hearing loss, but instead there are challenges with interpreting, organizing, or analyzing what they hear. ADP may be confused with other disorders, such as ADHD, learning disabilities, or emotional delays. The exact causes of ADP aren’t known, but it may be related to illness such as meningitis or nervous system disorders, premature birth or low weight, head injury, or genetics.
Causes of Auditory Disabilities
There are several causes of hearing loss and deafness. These causes may include genetics, premature birth, infections/illnesses, ear trauma, exposure to loud noises, and aging, to name a few.
Deafness versus Deaf Culture
The terms “deaf” with a lowercase letter “d” and “Deaf” with an uppercase letter “D” have two separate meanings. The lowercase “deaf” term refers to the condition of deafness, the partial or total hearing loss a person experiences from a medical perspective. The uppercase usage of “Deaf” refers to Deaf Culture or Deaf Community. Deaf culture or Deaf Community focuses on the beliefs, cultural norms, values, and experiences shared between a group or groups of people who are deaf. The capitalization of the term “Deaf” is used to reference a member of the Deaf Community.
Deafness is not viewed as a loss by those in the Deaf Community. Those who identify with Deaf Culture view deafness using the social identity or cultural affiliation model of disability.
Web Accessibility for Deafness
The concern with deafness is the accessibility of audio, in either audio-only formats, or audio combined with video, as is often the case. For pre-recorded audio-only files, the best solution is usually a transcript of the audio. The transcript should include all of the narration, dialog, and other important sounds, such as applause, crashes, music, etc.
Video files usually contain audio synchronized with video itself. Time-dependent audio and video require captions. A transcript is not sufficient, because without synchronized captions, viewers can’t know exactly where the transcript lines up with the video.
(Deaf or Hard-of-Hearing - ICT)
The audio portion of videos cannot be heard
Provide synchronized captions with videos
Provide sign language interpretation
(Deaf or Hard-of-Hearing - ICT)
Audio content cannot be heard
Provide a transcript
Provide sign language interpretation
(Deaf or Hard-of-Hearing - General)
Speeches and talks cannot be heard by deaf people in the room
Provide sign language interpretation
Provide live captions on a monitor during the speech
(Deaf or Hard-of-Hearing - Architecture and the Built Environment)
Doorbells, alarms, and other sounds may not be heard
Provide alternative visual alerts, such as lights that flash, pulse, dim, turn on, or turn off.
Mobility Disabilities
Mobility disabilities affect a person’s ability to move independently and purposely. For example, people who have missing limbs, multiple sclerosis, cerebral palsy, stroke, partial or complete paralysis, or arthritis may experience limitations with moving their body or parts of their body. Disabilities in this category can be present from birth, occur due to aging, or be the result of a disease. They can also be temporary, permanent, or periodically recur or relapse. Approximately 3.5% of adults in the US have a mobility disability.
Body size or shape disabilities
Are related to a person’s stature, proportions, or shape. For example, dwarfism, rheumatoid arthritis, acromegaly (increased bone size), and obesity would all fall under this category. A person may experience various related conditions such as muscle weakness and muscle fatigue (extreme exhaustion), hearing loss, vision loss, and diabetes. Statistics show that 1% of the world’s population has rheumatoid arthritis, while 39-40% of adults have obesity.
Flexibility disabilities
There are many different disabilities affecting mobility, flexibility, and motor control, all with different characteristics and somewhat different accessibility needs, but with at least this one principle in common: all web content must be operable no matter what method a person uses to access the computer. Whether by mouse or keyboard or a disability-specific assistive technology, the web content needs to work. The content must be compatible with a wide variety of input devices and methods. For example, a person may be completely missing one or more hands, forcing the person to use other body parts — such as the feet — to access a computer. They may use a foot mouse to operate their machine.
Assistive Technologies Used by People with Motor Disabilities
The assistive technologies used by a person with a motor disability are specific to that person’s needs. Here are some of the assistive technologies available: Vertical Keyboard with Mouth Stick, One-Handed Keyboard, Expanded Keyboard with Raised Sections Between Keys, Speech Recognition
Speech Recognition
Some people can take advantage of speech recognition software that translates the user’s spoken words into language that the computer can understand. Speech recognition can be used to type text, enter data into forms, and navigate web pages using keyboard-style interactions or using a mouse emulation mode.
(Mobility, Flexibility, and Body Structure Disabilities - ICT)
May be unable to use a mouse due to difficulty or inability to use hands
Alternative keyboards, mouth sticks, single switch devices, speech recognition software and eye tracking technologies enable users to use a computer without the need for a mouse
Developers and designers can ensure digital content is accessible using keyboard devices