The widespread use of the term accessibility dates back only to the early 1990s, coincident with the Americans with Disabilities Act and the growth of the disability rights movement. However, as a research topic, accessibility has been a focus of study at the Arlene R. Gordon Research Institute virtually since its founding. Indeed, much of our work on reading, legibility, color, wayfinding, and even driving, can be viewed as accessibility research, since all of these studies seek to enhance access to things that have been designed primarily with the able-sighted person in mind.

In recent years, the importance of the World Wide Web in human communication has grown vastly in areas as diverse as staying in touch with friends and relatives, commerce, information and entertainment. Because it has become so pervasive in everyday life, Web accessibility to those with disabilities, and to older people who so often are visually impaired, the importance of this issue is now widely acknowledged.

How does one make web sites more accessible to visually impaired persons? Most solutions, which are intended to enhance accessibility for users with hearing and motor as well as visual impairments, encourage good practices that make things more usable for people who may be accessing the site using assistive technology such as a screen reader, which speaks the screen text to the user. For example, they recommend that text alternatives (such as "alt" and "longdesc" html tags) be provided for images, image maps and descriptions for video, so that important information is not lost to blind persons who may be accessing the site. They also recommend logical and consistent presentation structure, and the use of style sheets (which facilitate global changes in presentation style), and alternative provisions for users who may have only simple browser capabilities (e.g., with java, scripts, or frames lacking or disabled). Finally, they make recommendations about typography, color and contrast that are intended to help people with low vision (see (see Arditi, 1999/2002a; Arditi, 1999/2002b). Many of these practices have the beneficial side effect of making things more usable for people who have no vision (or other) disability, as well.

Making a site accessible to a blind person who will be accessing the site without vision, is generally a matter of designing it so that the user can access all the important information efficiently using his or her own assistive technology (usually a screen reader). This is not always easy, but at least all blind users access the site using similar technology: some kind of speech synthesis, converting text to speech.

Accessibility for low vision users, on the other hand, can be quite different. Low vision encompasses an enormous range of visual capabilities, sometimes requiring little or no screen magnification, and sometimes magnification of 20 or 30 times or more, in which only a few letters of text may fill the entire screen. Some low vision users can get away with simple enhancements such as enlarging fonts and/or changing color schemes, accessibility features that are available through the most popular browsers (including Internet Explorer, Netscape, and Opera). But users who require high levels of magnification face special problems: For example, moving a mouse or other scrolling device to navigate a line of text while reading is difficult, and even more difficult is using it to find the beginning of the next line. Also, when the page is highly enlarged, it is extremely difficult to integrate successive views of the page into a "big picture" that can be used for searching, skimming, and other kinds of nonsequential reading. Screen magnification software helps but does not solve these difficulties. Low vision users may benefit from a wide range of page style changes in color, typography, animation rate, background images, and more. Accessible Web designs for low vision, then, must take into account a wide range of access methods, and provide many more features, corresponding to the wide range of visual capabilities of the low vision population. Paradoxically, then, providing access to blind users, who do not see at all, may be easier than doing so for those who see but with low vision.

The Institute's research program in web accessibility focuses on this more challenging low vision aspect of Web accessibility, and seeks to develop improved methods of presenting global (e.g., page layout) and local (e.g., text) information in a manner that allows for easier page navigation and accomplishment of nonsequential reading tasks so important in hypertext processing, like searching for information or skimming a document. A prototype web browser for low vision has been constructed for experimental purposes (Arditi, 2003), and currently we are seeking funds for further development.

Recently, efforts to develop the web browser technology and to develop more general methods for studying web accessibility have focused on the open source Mozilla browser suite, and in particular in the XML based eXtensible User interface Language (XUL) and related technologies. The hope is that in the coming years, Dr. Arditi and Associate Vision Scientist Jianwe Lu can make available a web browser for low vision at no cost, and as open source software, both to increase accessibility for low vision and as a tool for open and collaborative studies of web accessibility.

Further Reading

Arditi, A. (1999/2002a). Effective color contrast: Designing for people with partial sight and congenital color deficiencies. New York: Lighthouse International.

Arditi, A. (1999/2002b). Making text legible: designing for people with partial sight. New York, Arlene R. Gordon Research Institute, Lighthouse International.

Arditi, A. (2000). Print and web design for the visually impaired. Visual Arts Trends, 3S, 2.4-2.5

Arditi, A. (2002a). Web accessibility and low vision. Aging & Vision, 14(2).

Arditi, A. (2002b). Addressing the screen navigation problem in computer displays for low vision. Supplement to Optometry and Vision Science, 79 (12S), 279.

Arditi, A. (2003). Low vision web browsing and allocation of screen space resources. Investigative Ophthalmology and Visual Science, 44, E-Abstract 2767.

Arditi, A. (2003, December). Balancing the load among guidelines, user software and web design. Paper presented at the annual meeting of the American Academy of Optometry, Dallas, TX.

Arditi, A., Hanson, V., Fairweather, P., Brown, F., Crayne, S. Daggett, G., Detweiler, S., Richards, J., Schwerdtfeger, R., Tibbitts, B., & Trewin, S. (2001). A gateway to enhance visual access to the World Wide Web. Supplement to Optometry and Vision Science, 78 (12S), 134.



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