Abstract: This paper is the experimental results of our study on the relation- ship between the luminance contrast of a VDT and visual fatigue. The accommodation and convergence time of the subjects' eyes were used as an evaluation oriterion in our experiment. The screen luminance was 20, 30 and 40 cd/m~2. The range of contrst was from 3 : 1 to 15 : 1. The results were as follows: (1) The visual fatigue was not serious within the range of luminan- ce contrast from 9 : 1 to 11 : 1; The more contrast levels deviated from the range, the more the degree of visual fatigue became greater. (2) The level of screen luminance significantly affects visual fati- gue. When the contrast was under 7:1, the visual fatigue caused by high level lunminace had less than that caused by low level luminance. When the contrast was above 7:1, the visual fatigue caused by high level lun- minace was more serious than that caused by low level luminance.

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