藍光對跳視眼動與注意力脫離的影響

Abstract

現代人習慣在 3C 產品(電腦營幕、手機)上閱覽，因此經常暴露在高能 量的藍光環境中。目前有許多號稱護眼的過濾藍光產品隨之而出，然而過濾藍 光是否有利於或有損於閱覽時進行的眼動跳視的處理效率，此議題則未曾被探 討過。過去文獻指出，藍光會影響我們的晝夜節律、警覺性、執行功能、與動 態視力。近期的研究也顯示，和眼動及注意力導向相關的腦區，例如額葉眼動 區，會受到對藍光敏感的自發性感光視網膜神經節細胞的影響。本研究利用和 眼動反應與注意力相關的間隔效應派典來探討藍光是否影響跳視眼動與注意力 脫離。間隔效應是指對於視野周邊呈現之目標物的跳視眼動或手指按鍵反應， 會因為中央凝視點在目標物出現前消失(相對於凝視點持續存在以致於和目標 物的呈現時間重疊)而增快的現象。參與者在連續兩天的實驗中，暴露在藍光 或橘光的背景光源下，並針對視野周邊出現的目標物盡可能快速且正確的反 應。實驗一發現藍光會縮短在重疊情境的跳視潛時。實驗二發現只有當注意力 與眼動共同活動時，我們方能獲得穩定的藍光對於跳視潛時的增快效果。實驗 三發現了藍光會促進視覺醒目刺激的處理。總結而言，本研究顯示當注意力與 眼動系統為一體時，藍光會增快我們的跳視潛時，這樣的結果支持了注意力的 前運動理論。本研究提供了一個藍光有效提升眼動效率的方案，顯示在透過 3C 產品進行閱覽時，藍光的照射有利於跳視眼動。

People nowadays usually read or browse on 3C products (such as computer screen or cell phone) via saccades, hence exposing to high intensity of blue light very often. Recently, several products that claimed to filter blue light spring up, and yet whether filtering blue light is beneficial or detrimental to saccadic efficiency is unknown. It has been shown that exposure to blue light affects our circadian rhythm, alertness, executive functions, and dynamic visual acuity. Recent studies also showed that brain regions related to eye movements and attentional orientation such as frontal eye fields were activated by blue-light-sensitive intrinsically photosensitive retinal ganglion cells (ipRGCs). The current study adopted the gap effect paradigm to investigate whether saccadic eye movement and attentional disengagement would be affected by blue light. The gap effect refers to the phenomenon of facilitated saccadic or manual response to a peripherally presented target by extinguishing the fixation shortly before the target onset (compared to when the fixation remains on the screen and overlaps with the target presentation). Participants were exposed to blue (vs. orange) light in two consecutive days, and they were instructed to respond to peripherally presented targets as quickly and accurately as possible. Experiment 1 showed that blue light facilitated saccade latency in the overlap condition. Results from Experiment 2 indicated that only when attention and eye movements activated simultaneously would we obtain a stable blue-light facilitation effect. Experiment 3 further showed that blue light also facilitated the processing of a salient target. We conclude that when attention and oculomotor system operate together, blue light facilitates saccade latency, supporting the premotor theory of attention. Our findings provide evidence and suggest a way for facilitating the efficiency of saccade. When reading or browsing on 3C products, the exposure of blue light is beneficial to saccadic eye movement.