Various researches identified that the main factors causing visual discomfort from watching 3D video are Vergence-Accommodation linkage conflicts, contrast changes, and some other defects in 3D display. In this paper, we propose a new method to lessen the visual discomfort by reducing blue-light components, which are highly sensitive to human eyes in 3D video. In our experiments, 20 people (9 male, 11 female) participated in watching four 15-minute original and blue-light reduced modified 3D videos, respectively. We surveyed perceived symptom questionnaires before and after watching videos, and measured the participant s eye-blink rates, saccadic movements, and near point of convergence (NPC). Our experimental results demonstrated that the eye-blink rate of the participant was lower in watching the blue-light reduced videos, while saccadic movements of the subject was higher in blue-light reduced videos compared to the original videos. Since eye-blink rate is usually increased when subject s eyes are dried, and slower eye movements are occurred due to tiredness, the blue-light reduced video caused smaller visual discomfort than the original video. Based upon NPC and perceived symptom questionnaires, we confirmed that viewers indeed feel more comfortable watching the blue-light reduced video compared to the original video.