- 期刊
VDT作業對視覺績效及視覺疲勞之效應
Effects of VDT Work on Visual Performance and Visual Fatigue
摘要
本研究係採三因子完全隨機化集區設計來探討解析度、前景背景顔色以及字體大小對於VDT作業使用者視覺疲勞和視覺績效之效應：解析度分爲640×480、800×600以及1024×768等三個水準，前景背景顏色分爲藍底白字、黑底白字以及白底黑字等三個水準，字體大小分爲9點、12點以及14點等三個水準，視覺疲勞的衡量效標爲閃光融合閾值(CFF)和近點調節值(NPA)的變化以及主觀視覺疲勞評量(SVS)，視覺績效的衡量效標爲搜尋時間(ST)的變化。共有12位受試者參與實驗（其中6位爲男性，6位爲女性），受試者的實驗作業是在VDT前閱讀30分鐘的無意義文字串（30字×11行）。實驗前和實驗後分別測試受試者的眼睛融合閾值、近點調節值和搜尋時間。受試者的實驗作業爲閱讀VDT畫面上每篇30字×11行的無意義文章30分鐘。並搜尋其中的三個特定文字，所搜尋的第1,3特定文字的文字間距固定，第2特定文字間距不定，第1和第3個字之間的搜尋時間即爲視覺績效，最後則要求受試者填寫主觀視覺疲勞評量表。研究結果顯示：(1)解析度對於視覺搜尋(ST)、閃光融合閾值(CFF)、近點調節值(NPA)的變化和主觀視覺疲勞評量(SVS)有顯著的效應，且解析度愈高視覺疲勞程度愈高和視覺績效愈差，640×480的解析度產生最佳的視覺績效和視覺疲勞變化。(2)字體大小對於視覺搜尋(ST)、近點調節值(NPA)的變化和主觀視覺疲勞評量(SVS)有顯著的效應，但對閃光融合×閾值(CFF)的變化則無，14點的字體比12點和9點的字體爲佳。(3)前景背景顏色對於主觀視覺疲勞評量(SVS)有顯著效應，但對於視覺搜尋(ST)、閃光融合閾值(CFF)和近點調節值(NPA)的變化則無顯著的效應，並且解析度與字體大小有交互作用。整體而言，解析度爲640×480，字體大小14點，前景背景顏色爲白底黑字爲最佳的組合，其視覺績效的衰退最小，且最不易產生視覺疲勞。
並列摘要
This study investigated the effects of screen resolution, color combination, and character size on visual performance and visual fatigue during visual display terminal (VDT) work. Twelve college students (6 males and 6 females) were recruited as participants to perform 27 different experiment tasks. Three screen resolutions (640×480, 800×600, and 1024×768), three different color combinations(white-on-blue, white-on-black, and black-on-white), and three different character sizes (9, 12, and 14 points) were evaluated. Visual performance was measured by the change of searching time (ST) of three targets (character), and visual fatigue was measured by the change of critical fusion frequency (CFF), the change of near point accommodation (NPA) and subjective visual strain (SVS). Analyses of variance were conducted on the mean criteria measurements. The results showed that (1) Screen resolution significantly affected the changes of ST, CFF, NPA, and SVS, with 640×480 resolution resulting in the smallest change of visual performance and visual fatigue; (2) Screen character size had significant effects on the changes of ST, NPA, and SVS, and had no significant effect on CDFF, the 14 points was better than the 12 and 9 points; (3) Screen color combination significantly affected subjective visual strain (SVS), however, had no significant effect on the change of other criteria (ST, CFF, and NPA), black-on-white was superior to all other color combinations. In general, the screen resolution of 640×480, character size of 14 points, and color combination of black-on-white was the best combination, and may improve the performance and health of VL)T worker.