Visual Fatigue and Cathode Ray Tube Display Terminals

Study I investigated the effects of display type, amount of information presented, and display contrast on the visual mechanism during a visual search task. In the first phase, two subjects performed the visual task for four 3-h sessions. In the second phase, subjects were tested for two 6-h sessions. CRT usage for 3 h produced measurable visual fatigue in the eye movement and/or accommodation mechanism, as measured by increased durations to move from a near point and focus on a far point (and vice versa). Such visual fatigue was not present in the hard-copy visual search task. In a second study, subjects performed the visual task for two 4-h sessions. Two h of CRT usage produced measurable fatigue in the eye accommodation mechanism as well as an increased blink rate. Such visual fatigue was also present in the hard-copy task but to a lesser extent. In both studies, I-h breaks produced a marked reduction in visual fatigue indices.