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...information computer screen accurately using keyboard or mouse. Such technology has the potential to enable people with a broad spectrum of abilities, who may currently be unemployed or underemployed, to fully participate in the workforce.
The World Wide Web has become an indispensable source of information and communication both inside and outside the workplace. For the past few years, work at the IBM Thomas J. Watson Research Center has been directed at creating ways to make the Web more usable for persons with vision and motor limitations. This effort began as a partnership between IBM Corporate Community Relations and organizations serving older adults. Since then, the project has expanded to address the needs of other groups of individuals who have vision and motor limitations that adversely impact their ability to use a computer. Unforeseen when the project began was the software's additional use by low-literacy and limited-English-proficiency students in job-training classes.
This paper begins with background information on the types of problems that may be experienced by Web users, and then describes the Web Adaptation Technology project, the forerunner of the accessibilityWorks project. The Web Adaptation Technology project provided extensions to the Internet Explorer ** browser on the Microsoft Windows ** platform. This paper continues with a presentation of accessibilityWorks, a new open-source development effort initially being tested on the Linux ** platform, which is an outgrowth of that earlier project. The accessibilityWorks project specifically took the findings from the Web Adaptation Technology work and used them in implementing similar capabilities in the Firefox ** and Mozilla ** opensource browsers to provide cross-platform functionality. As will be discussed, accessibilityWorks also provides expanded mouse and keyboard adaptations.
WEB USABILITY
Problems with computer access due to vision and motor limitations can be addressed by various medical, hardware, and software approaches. Large monitors and eyeglasses, for example, can certainly help with visual acuity problems, but these measures may not be sufficient. Consider the case of bifocals worn by many older adults. These glasses can provide some help with acuity difficulties, but wearers of bifocals who spend much time at the computer tend to develop stiff necks from tilting their heads at an awkward angle. This is exacerbated for people with particularly low vision--caused, for example by macular degeneration--because they need to sit very close to computer screens and often develop shoulder and back pain as a result.
Current browsers and desktop environments can adjust some aspects of content presentation to alleviate certain difficulties when reading text. However, although users are often aware that some font enlargement capability is available through the browser, few are aware of browser options for changing colors, font styles, and screen magnification, or for creating style sheets. (1) This lack of awareness is not particularly surprising, given that the options often are configurable only by following a complex series of menu choices and dialog boxes. For example, changing the color of text on a Web page by using Internet Explorer's built-in features requires knowing that Internet Options is the required menu selection from the Tools menu, then further being able to navigate to the Colors dialog box, deselect the Use Windows colors checkbox, set the desired colors, and then return to the Internet Options menu selection to indicate on the Accessibility dialog box that specified Web page colors should be ignored. This is a fairly complex task requiring knowledge of computer software, the ability to see the small boxes to be selected, and the dexterity to click accurately.
Some motor difficulties can be addressed by using the adjustments to mouse and keyboard sensitivity built into current computer operating systems. As with page presentation changes, the use of such adjustments requires that users be aware of the existence of these options, know where they are located in the menu structure, and be able to carry out the steps needed to set the features. Users who have disabilities that impact their hand movement can have great difficulty actually using these tools. (2) Consider the case of key debounce time. Persons with tremors, for example, may depress one key multiple times in rapid succession, causing repeated letters to appear when typing. Microsoft Windows allows users to set a debounce parameter to control the length of the time period in which repeat keys will be filtered out. In order to set this parameter, however, users must not only know that this feature exists and how to find it in the Control Panel options, but must also be able to navigate the steps required for setting the feature, which in turn requires the clicking of tiny graphical user interface (GUI) buttons and checkboxes.
There are special keyboards and mice available to ease difficulties with double-clicking and scrolling, but, in fact, these special devices provide only partial solutions to the problems experienced by older adults. Accurate mouse usage, for example, requires visual acuity; people with poor vision have mouse difficulties whether they possess good motor control or not. (3) Scrolling is another example of a task that is particularly difficult for reasons related to a combination of visual and motor factors. Visually, the small size of the scroll bar, particularly the target box, can be problematic. In terms of motor skills, scrolling requires the complex sequence of moving the mouse to the small target box, holding down the mouse button, and then continuing to hold down the button while moving the mouse in the direction needed for scrolling. Solutions that address difficulties in only one of these aspects of scrolling may not succeed.
Considering all the preceding difficulties, we began our project to address the need to allow individuals to tailor Web interactions to their particular combination of requirements. The goals as the project began focused on meeting changing user needs resulting from failing vision and limited dexterity due to aging. The project did not attempt to address either limited hearing, which was not considered by users to negatively impact their Web experience, (4) or blindness, for which other Web accessibility software exists. (5) As the project evolved, however, it became clear that the needs of the original older-adult user population were not unique. In particular, problems with content size, color, and other display characteristics were typical of many users with vision limitations, regardless of age and the specific medical condition that may have led to the limitation. Similarly, motor disabilities, regardless of origin, created keyboard and mouse problems similar to those experienced by older adults. As a result, at present the IBM Corporate Community Relations project has expanded to include approximately equal numbers of members of organizations serving older adults and organizations serving persons with disabilities. (6)
Web adaptation technology: Internet Explorer browser extensions
The project's software architecture was based on the need for client-side transformations combined with a server-side database for storing user preferences. As detailed elsewhere, (7,8) an original attempt to use a server intermediary for providing the transformations was inadequate with respect to security, copyright compliance, system responsiveness, and transformation accuracy. These shortcomings led to this initial approach being abandoned. A database on the server was still needed, however, for storing user preferences because most people used the software in a shared computing environment. Thus, saving preferences on the local client machines was not a viable option.
The software needed to be used by people for access to the entire Web. Thus, it could not be limited to sites specifically designed or annotated for accessibility. Key to the software design was the fact that many users experience a variety of physical and cognitive limitations that may impact their Web access. These limitations are made more complex by the fact that they can occur in combination and can fluctuate in severity from hour to hour and day to day. (9) Thus, the content transformations needed to work well in combination with each other. Moreover, the sorts of disabilities a...
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