Shin'ichi FUKUZUMI* and Toshimasa YAMAZAKI**
*Human Media Research Laboratories, NEC Corporation
** Fundamental Research Laboratories, NEC Corporation
Stress management is the management of office work to reduce workers' stress levels by evaluating their mental and physical stress levels and taking measures against stress ( Phillips 1988). Stress management for VDT work has to be studied as a problem of serious stress.
Primarily, when measuring workers' mental and physical fatigue or stress levels caused by VDT work, changes in physiological functions before and after the work are measured as an index of fatigue or stress ( Yamazaki, et al 1990). However, the changes in these functions differ depending on whether the worker is tired or not, and also differ depending on the condition of the worker ( Fukuzumi, et al 1987). For this reason, in order to evaluate their stress levels, it is necessary to measure not only the changes in their physiological functions and subjective symptoms before and after the work but also the change in them during a few weeks.
In this study, eye accommodation and body sway were chosen as the physiological functions for evaluating stress levels, because eye accommodation is known to fail due to visual work or mental loads ( Ostberg 1980) and body sway is known to change by mental and physical fatigue ( Oman et al. 1989).
During the VDT work for the experiments, the environment was adjusted as follows; illuminance of the screen was 500 Lux, text luminance was 35 cd/m2