Effects of Vertical Viewing Angle on Eye Blink Rate during Computer Work

Abstract

The effects of vertical viewing angles and eye blinking rate during computer work were investigated Twenty subjects read from a computer screen set at four levels of viewing angles. Eye blinks during reading tasks were measured by electrooculography. Subjective ratings on visual and musculoskeletal strain were obtained. Test hypotheses were: (a) blink rate does not change with variations of viewing angle, (b) blink rate does not change with time-on-task, and (c) there is no interaction between viewing angle and time-on-task effects. The results indicated that blink rate increases as the viewing angle approaches eye level, and that blink rate increases with time-on-task. No significant interaction was found between viewing angle and time-on-task. Results and subjective ratings support recommendations of VDT viewing angle range near 15° below eye level.