When rendering the visual scene for near-eye head-mounted displays, accurate knowledge of the geometry of the displays, scene objects, and eyes is required for the correct generation of the binocular images. Despite possible design and calibration efforts, these quantities are subject to positional and measurement errors, resulting in some misalignment of the images projected to each eye. Previous research investigated the effects in virtual reality (VR) setups that triggered such symptoms as eye strain and nausea.
View Article and Find Full Text PDFOcular accommodation is the process of adjusting the eye's crystalline lens so as to bring the retinal image into sharp focus. The major stimulus to accommodation is therefore retinal defocus, and in essence, the job of accommodative control is to send a signal to the ciliary muscle which will minimize the magnitude of defocus. In this article, we first provide a tutorial introduction to control theory to aid vision scientists without this background.
View Article and Find Full Text PDFStudies with monochromatic light stimuli have shown that the action spectrum for melatonin suppression exhibits its highest sensitivity at short wavelengths, around 460 to 480 nm. Other studies have demonstrated that filtering out the short wavelengths from white light reduces melatonin suppression. However, this filtering of short wavelengths was generally confounded with reduced light intensity and/or changes in color temperature.
View Article and Find Full Text PDFPeriodic, well timed exposure to light is important for our health and wellbeing. Light, in particular in the blue part of the spectrum, is thought to affect alertness both indirectly, by modifying circadian rhythms, and directly, giving rise to acute effects. We performed a systematic review of empirical studies on direct, acute effects of light on alertness to evaluate the reliability of these effects.
View Article and Find Full Text PDFThe Trail Making Test (TMT) is used in neuropsychological clinical practice to assess aspects of attention and executive function. The test consists of two parts (A and B) and requires drawing a trail between elements. Many patients are assessed with their non-dominant hand because of motor dysfunction that prevents them from using their dominant hand.
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