What are some Common obstacles people with disabilities face on the Web?
Blindness makes it impossible to view a standard screen display or printed output. A person who is blind often will use a speech output system to read aloud text that is presented on the screen; this system may be composed of screen reading software and a voice synthesizer. A blind person may or may not be able to use a Braille output system, such refreshable Braille displays that allow line-by-line translation of a screen into a Braille display areas. Scanners with optical character recognition (OCR) that can read printed material and store it electronically where it can be read using speech output or Braille may also be used to read web documents.
People who are blind cannot view the graphical features of your Web site. Many people with visual impairments use voice output programs with nonstandard browsers (such as pwWebSpeak or Lynx) or graphical browsers with the feature that loads images turned off. Include text equivalents or "text alternatives" to make the content in graphical features accessible.
People with visual impairments, including hazy vision, low vision, color blindness, tunnel vision, or near sightedness, have challenges with low or poor color contrasts, small icons and type faces. Large monitors and anti-glare screens, screen enlarger software, color and contrast adjustments, speech output systems and scanners with optical character recognition are adaptive equipment used to navigate the web or reach web output.
Color blindness creates difficulty with poor contrast between the colors used in text and their background, as well as navigation bars and buttons.
People who are deaf or Hard of Hearing may be unable to hear your audible material, including computer prompts. A deaf or hard of hearing computer user may replace the computer prompt or tone with a flash, using options in the operating system. The causes and degrees of hearing loss vary.
Physical impairments impacting mobility may be orthopedic or neuromuscular such as carpal tunnel, various forms of arthritis, cerebral palsy, stroke, muscular dystrophy, arthritis amputation or spinal cord injury. People with physical impairments may have difficulty using a keyboard, or find it difficult or impossible to use a mouse, and will need to rely on the keyboard for Web browsing. Some people will use adaptive technology with their computer to access the Web.
Less severe impairments could make the task of highlighting, manipulating pull-down boxes, or mouse clicks difficult.
Learning disabilities are often considered to be a hidden disability in that it is not obvious in terms of physical appearances. A person with a learning disability may not appear to have a disability, however they may need assistive equipment to support reading, writing and organizational skills. Differences in processing memory, auditory, visual and linguistic or the speed of processing information are symptoms. Enlarged screen display, alternative color contrasts, speech output or reading systems incorporating OCR and speech output are examples of hardware and software used by people with learning disabilities.
Those with learning disabilities may have difficulty with a web site that does not use clear language, has complex vocabulary or sentences. A web page that is not logically structured will present a barrier. Adaptive computer equipment may be used as an alternative way of completing tasks such as reading and comprehension. Therefore, web barriers for deaf and blind populations will also affect populations with learning disabilities. Presenting material in more than one format (print, audio and video) provides alternative ways of learning while assisting those with learning disabilities.
Videos that illustrate how people who are blind or have visual loss access the web are available for online viewing at
http://www.doit.wisc.edu/accessibility/video/ 
.
