Barriers to Information Access and Factors for Improvement

Disabilities Affect Access

• visual impairment:
  • blindness
  • low-vision
  • color blindness
• hearing impairment
  • partial hearing loss
  • total hearing loss
• motor impairment
• cognitive and learning disabilities
  • dyslexia
  • Attention deficit disorder
• temporary and situational disabilities

Visual Impairment: Characteristics

• Unable or difficult to obtain a bird-eye-view of the screen.
• Unable or difficult to understand the layout of items on the screen
• Unable or difficult to note dynamically changing visual content.

Visual Impairment: Barriers to Access

• Images that do not have text-form alternatives
• Complex images (e.g., graphs or charts) that are not adequately described
• Video that does not have sufficient description by either text or audio
• Dynamically changing content
• Content whose semantic is presented only by visual appearance

Visual Impairment: Assistive Technologies

• Use of screen reader
  • Speech output
  • Braille output
• Use of screen magnification software

Hearing Impairment: Characteristics

• Unable or difficult to obtain auditory information.
• Unable or difficult to note existence of auditory content.

Hearing Impairment: Barriers to Access

• Lack of captions or transcripts of audio on the Web
• Lack of content-related images in pages full of text, which can slow comprehension for people whose first language may be a sign language instead of a written/spoken language
• Automatic playback of audio
• Requirements for voice input on Web sites

Hearing Impairment: Assitive Technologies

• Visual bell

Mobility Impairments

• Weakness
• Limitations of muscular control (such as involuntary movements, lack of coordination, or paralysis)
• Limitations of sensation
• Missing limbs
• Pain caused by some motions

Mobility Impairments: Barriers to Access

• Time-limited response options on Web pages
• Web pages that require complex operation of pointing devices
• Browsers that do not support keyboard alternatives for mouse commands

Mobility Impairment: Assistive Technologies

• Switches and software keyboard
• Alternative hardware

Cognitive & Neurological Disabilities: Barriers to access

• Lack of alternative modalities for interaction with Web sites
• Distracting visual or audio elements that cannot easily be turned off
• Use of unnecessarily complex language on Web sites
• Lack of graphics on Web sites
• Lack of clear or consistent organization of Web sites

Three Players Responsible for Web Accessibility

• Content Creators --- Accessibility of the Web content must be improved.
• User-Agent Developer --- User-agents must be designed so that it benefits from accessible content.
• Users --- Users need to learn how to make use of accessible content with well-designed user-agents.

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