Abstract
The purpose of this study is to identify the erect of the change in illuminance and color temperatures of task
lighting on the subject's fatigue, visibility, and work efficiency. Nineteen middle-aged and elderly men and
women participated as subjects. They were exposed to 3 different conditions (Condition A; illuminance and
color temperatures were constant, Condition B; Only color temperatures were changed, Condition C;
illuminance and color temperatures were changed). The subjects under the age of 60 were included in Group M
(11 subjects with average age of 53.3) and the subjects aged 60 and over were included in Group E (8 subjects
with average age of 67.5). During the experiment, subjects performed PC tasks, and their physiological and
psychological responses, degree of fatigue, and degree of visibility before and after the task were measured in
the morning, noon, and evening.
The results of flicker tests showed that the increment of the degree of fatigue from the morning to the evening
under the condition C was greater than that under the fixed condition. Also, there was an increase in eye fatigue
and brightness sensation as well as a significant decline in visibility over time. In Group E, sensitivity towards
brightness was observed regardless of the conditions and time. In the evening, the condition B caused greater
fatigue in the focus adjustment function than the fixed conditions. There was a significant decline in visibility
from morning to evening.
