Design and user evaluation of a joystick-operated full-screen magnifier

The paper reports on two development cycles of a joystick-operated full-screen magnifier for visually impaired users. In the first cycle of evaluation, seven visually impaired computer users evaluated the system in comprehension-based sessions using text documents. After considering feedback from these evaluators, a second version of the system was produced and evaluated by a further six visually impaired users. The second evaluation was conducted using information-seeking tasks using Web pages. In both evaluations, the 'thinking aloud protocol' was used. This study makes several contributions to the field. First, it is perhaps the first published study investigating the use of a joystick as an absolute and relative pointing device to control a screen magnifier. Second, the present study revealed that for most of the visually impaired users who participated in the study the joystick had good spatial, cognitive and ergonomic attributes, even for those who had never before used a joystick.