Recent literatures related to the evaluations of visual fatigue induced by stereoscopic images (VFSI) are reviewed with the short introduction of cortical mechanisms related to early visual processing, vergence eye movement and lens accommodation. Based on this knowledge, the requirements to prevent visual fatigue and discomfort induced by viewing stereoscopic images were sought. Firstly, the careful alignment in the right/left eye images is required for the stereoscopic vision without discomfort. Secondly, the conflict between the demands for vergence eye movement and lens accommodation in the near response should be avoided, by using modest binocular disparity. Thirdly, the frequency of changes in binocular disparity should be restricted. Finally, the appropriate viewing distance is also recommended to avoid visual fatigue. (c) 2011 Elsevier B.V. All rights reserved.