Abstract

Current practice in computer interface design often takes for granted the user's sightedness. But a blind user employs a combination of other senses in accomplishing everyday tasks, such as having text read aloud or using fingers along a tactile surface to read Braille. As such, designers of assistive technologies must pay careful attention to the alternatives to sight to engage a blind user in completing tasks. It may be difficult for a sighted designer to understand how blind people mentally represent their environment or how they apply alternative options in accomplishing a task. Designers have responded to these challenges by developing alternative modes of interaction, including audible screen readers, external memory aids for exploring haptic graphs, non-speech sounds for navigating hypermedia, two-finger haptic interfaces for touching virtual objects, haptic modeling of virtual objects, and multimodal (auditory, haptic, visual) feedback for simple computer-based tasks. The effectiveness of these alternative modes of interaction is studied primarily through a usability framework, where blind and visually impaired users interact with specific devices in a controlled laboratory environment. These developments in assistive technology make a point to take advantage of the alternative modes of interaction available to blind users