The Study of Visual Fatigue by Monitor Letter Contrast with an Eye Tracker

Purpose: This study is to investigate correlation between eye fatigue and letter contrast according to letter contrast changes on monitor display. Methods: Reading speed test were carried out for 53 subjects (mean age: $22.68{\pm}1.85$ years) who have over Best-corrected visual acuity (BCVA) 1.0, and 45 subjects, who could read over 123 out of 163 letters among 53 subjects were selected. They were asked to read the letters which were composed of Black (contrast 100%), Dark gray (contrast 80%), Gray (contrast 80%), Light gray (contrast 30%) randomly. The change of their eye fatigue by letter contrast on monitor display was measured by monitoring their eyes with an eye-tracker while they were reading letters. Results: Event Duration (sec) was 33.635 for Black, 32.266 Dark gray, 33.936 for Gray, and 34.848 for Light gray. Average of Fixation Duration (sec) was 0.224 for Black, 0.218 for Dark gray, 0.239 for Gray and 0.243 for Light gray. Average of Pupil diameter (mm) was 41.133 mm for Black, 41.160 mm for Dark gray, 40.880 mm for Gray and 40.459 mm for Light gray. Frequency (blinks/sec) was 0.211 for Black, 0.206 for Dark gray, 0.221 for Gray, and 0.238 for Light gray. Conclusions: Event Duration and average of Fixation Duration were the shortest for Dark gray and the longest for Light gray. In average Pupil diameter was the biggest Dark gray and the smallest for Light gray. Blink Frequency (blinks/sec) was the lowest for Dark gray and the highest for Light gray. Visual fatigue by brightness of letters on monitor display was the least for Dark gray followed by Black, Gray and Light gray.

아이트래커를 이용한 모니터 글자 대비도에 따른 눈의 피로도 연구

목적: 모니터 글자 대비 변화에 따른 눈의 피로도를 측정하여 모니터 글자 대비도와 눈의 피로도의 연관성에 대해 연구하고자 하였다. 방법: 최대교정시력 1.0 이상의 피검자 53명(평균연령 $22.68{\pm}1.85$) 중 읽기속도 검사에 통과한 45명(평균연령 $22.68{\pm}1.85$)을 대상으로 각각 Black(대비 100%), Dark gray(대비 80%), Gray(대비 60%), Light gray(대비 30%) 글자로 이루어진 4가지 시표를 무작위로 읽도록 하였다. 피검자가 시표를 읽는 동안 아이트래커로 피검자의 안구를 추적하여 모니터 글자 대비에 따른 피검자의 눈의 피로도의 변화를 측정하였다. 결과: 피검자들의 평균측정시간은 Black, Dark gray, Gray, Light gray에서 33.635 sec, 32.266 sec, 33.936 sec, 34.848 sec로 측정되었다. 평균안구고정시간은 Black, Dark gray, Gray, Light gray에서 0.224 sec, 0.218 sec, 0.239 sec, 0.243 sec로 측정되었다. 평균동공크기는 Black, Dark gray, Gray, Light gray에서 41.133 mm, 41.160 mm, 40.880 mm, 40.459 mm로 측정되었다. 평균 눈깜박임 빈도수는 Black, Dark gray, Gray, Light gray에서 0.211 blinks/sec, 0.206 blinks/sec, 0.221 blinks/sec, 0.238 blinks/sec로 측정되었다. 결론: 피검자들의 평균측정시간과 평균안구고정시간은 Dark gray가 가장 짧았으며, Light gray에서 가장 길었다. 평균 동공크기는 Dark gray에서 가장 컸으며, Light gray에서 가장 작았다. 평균 눈 깜박임 빈도수는 Dark gray에서 가장 적었으며, Light gray에서 가장 많았다. 모니터 글자 밝기에 따른 눈의 피로도는 Dark gray에서 가장 적었으며 Black, Gray, Light gray 순으로 증가하였다.