The purpose of this study was to investigate the effect of stereoscopic display alignment errors on visual fatigue and prefrontal cortical tissue hemodynamic responses. We collected hemodynamic data and perceptual ratings of visual fatigue while participants performed visual display tasks on 8？ft 6？ft NEC LT silver screen with NEC LT 245 DLP projectors. There was statistical significant difference between subjective measures of visual fatigue before air traffic control task (BATC) and after air traffic control task (ATC 3), ( ). Statistical significance was observed between left dorsolateral prefrontal cortex oxygenated hemoglobin (l DLPFC-HbO2), left dorsolateral prefrontal cortex deoxygenated hemoglobin (l DLPFC-Hbb), and right dorsolateral prefrontal cortex deoxygenated hemoglobin (r DLPFC-Hbb) on stereoscopic alignment errors ( ). Thus, cortical tissue oxygenation requirement in the left hemisphere indicates that the effect of visual fatigue is more pronounced in the left dorsolateral prefrontal cortex. 1. Introduction The visual system is a well-developed sensory organ that involves effortless complex interaction between the visual organ and the brain. It involves physiological and a series of hierarchical neural processes from the photoreceptors, retinal ganglion cells, the lateral geniculate nuclei (LGN) of the thalamus, and the visual cortices [1]. The American Optometric Association [2] identified that prolonged use of the visual system can result in inefficient visual processing functions generally called visual fatigue. In line with that, the American Association of Ophthalmologist (AAO) diagnosed visual fatigue as an ophthalmological disease called asthenopia with the medical diagnostic code of ICD-9, 368.13 with the subclassifications shown in Table 1 [3, 4]. The last two digits of the medical code indicate the seriousness of the ophthalmological disease. The larger the last two digits, the more severe the symptoms of the disease. Table 1: Ophthalmological classification of visual fatigue (asthenopia) with their respective symptoms. Visual fatigue commonly arises when people view stereoscopic motion images [5]. In a stereoscopic image, the viewer watches two images corresponding to the right and left eyes with convergence eye movement. Based on individual characteristics and instrumentation issues, conflicts can occur between convergence or divergence eye movements and the accommodation function thus causing visual fatigue [6]. One of the major problems with stereoscopic displays is that a stereoscopic display produces a mismatch between
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