電腦終端機作業(Visual display terminal; VDT)在現今社會極為普遍，然而許多的工作場所照明條件都不甚理想，在不當的照明環境下可能會增加視覺疲勞的程度，導致職業災害或職業病的發生。 本研究以腦波測定所推衍腦波能量指標(EEG power indices)量化心智活動狀態，藉以評估在不同照度環境下，受測者對VDT作業造成視覺疲勞的影響。本研究以42位大學生年齡從18至24歲學生為受試者，實驗分為三個階段，前測五分鐘為第一階段，受測者分別在正常照明(300米燭光)之環境及不當照明環境下經歷三十分鐘的VDT作業，以VDT作業中為第二階段，作業後為第三階段。 研究結果發現：在正常照明環境與不當照明環境下，受測者電腦終端機作業中，不當照明較正常照明環境更容易造成視覺疲勞。而在自覺評估量表在正常照明與不當照明的環境下則無顯著上的差異，顯示生理量測優於自覺評估量表量測。 It is very popular for visual display terminal (VDT) tasks used in modern society. However the illumination conditions seem not good enough in workplace. Under inappropriate illumination conditions might increase the degree of visual fatigue, leading to occupational accidents or occupational diseases. In this study, the electroencephalography (EEG) power indiceswere measuredfor quantitative indicators of inferring mental activity state, in order to evaluate the effect on visual fatigue in VDT tasks under different illumination environment.. 42 college students aged 18-24 participated as volunteer subjects. The experiment was divided into before, during and after VDT tasks. Three stages were used in this study including before tasks as first stage, VDT tasks under normal illumination (300 lux), or no illumination condition as second stage, after VDT tasks as third stage. The study found that: under no illumination condition the visual fatigue level was higher than normal illuminationno illumination conditionlobs For the subjective measurement of visual fatigue, the two conditions had no significant different. It shows that EEG is superior to subjective measurements.