Duration of viewing was considered as one of the most important factors of 3D visual
fatigue. However, their relationship was not well studied. We proposed to use brain monitoring
techniques to reveal more details about the variety of brain activity while watching threedimensional
(3D) content. We investigated the spectral patterns in the electroencephalogram related
to the various duration of viewing and showed the power spectral density varied significantly along with
the development of fatigue over occipital lobe, parietal lobe, and right frontal lobe. Moreover, we
first described the trend of brain activity during 3D content viewing and revealed the location of significant
components related to 3D visual fatigue. We believe that absolute power describes more
information and maybe a better indicator of 3D visual fatigue assessment compared with relative
power. We also first revealed the cortex location that is related to 3D visual fatigue. Our findings
may help to define appropriate electroencephalogram features for online 3D visual fatigue detection
while participants viewing 3D content.