A Survey of Visual Display Terminal Work by the Visually Impaired and Development of a New Type of Assistive Device

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The research was composed of a field survey of visual display terminal work by visually Impaired persons and a development of a new type of assistive device for them.The survey by investigating eight low-vision VDT users visiting their workplaces showed that the frequent movement of the gaze position between a closed-circuit television (CCTV) and a personal computer display, plus the associated body movements (of mainly the neck and trunk) to manipulate a text table underneath the CCTV,made the work stressful and resulted in reduced work efficiency.To solve those problems, a novel system for text typing by low-vision persons has been developed and evaluated. The system is characterized by two main features : a visual display unit in shich two screens are displayd (a double windows display performed by 'WINDOWS' operating system) and a power-assisted text table operated by foot switches. In this system, two items are displayd simultaneously on one visual display unit : a field of the text placed on the table and captured by the CCTV,and the screen of a word processing program. The power-assisted text table was made using an X-Y recorder. The text table allows the operator to move it to any of four desired directions (in two dimensions) by using four foot switch buttons. Doubled clicks of one of the switches return the table to the reference point quickly.To evaluate the new system, it was compared with an ordinary two-displays system in the case of two low-vision participants. Their comments were favorable to the new system, especially concerning the decrease in long travel eye movements in shifting the gaze positions and concerning the ease of operating the power-assisted X-Y table. Importantly, the performance of typing tasks using the new system substantially improved.Finally, newly power-assisted X-Y table was developed for practical use.