Subjective responses to display bezel characteristics

High quality flat panel computer displays (FPDs) with high resolution screens are now commonplace, and black, grey, white, beige and silver surrounds (‘bezels’), matt or glossy, are in widespread use. It has been suggested that bezels with high reflectance, or with a high gloss, could cause eyestrain, and we have investigated this issue. Twenty office workers (unaware of the study purpose) used six different FPDs, for a week each, at their own desk. These displays were identical apart from the bezel colour (black, white or silver) and shininess (matt or glossy). Participants completed questionnaires about their visual comfort at the end of each week, and were fully debriefed in lunch-time focus groups at the end of the study. For the white and the silver bezels, the glossiness of the bezel was not an issue of concern. The participants were significantly less content with the glossy black surround than with the matt black surround, and in general the glossy black bezel was the least-liked of all those used. With the possible exception of this surround, there was no evidence of significantly increased visual discomfort, indicative of eyestrain, as a result of high or low bezel reflectance, or of high glossiness

Frequency characteristics of visually induced motion sickness

Objective: The aim of this study was to explore the frequency response of visually induced motion sickness (VIMS) for oscillating linear motion in the foreand- aft axis. Background: Simulators, virtual environments, and commercially available video games that create an illusion of self-motion are often reported to induce the symptoms seen in response to true motion. Often this human response can be the limiting factor in the acceptability and usability of such systems. Whereas motion sickness in physically moving environments is known to peak at an oscillation frequency around 0.2 Hz, it has recently been suggested that VIMS peaks at around 0.06 Hz following the proposal that the summed response of the visual and vestibular selfmotion systems is maximized at this frequency. Methods: We exposed 24 participants to random dot optical flow patterns simulating oscillating foreand- aft motion within the frequency range of 0.025 to 1.6 Hz. Before and after each 20-min exposure, VIMS was assessed with the Simulator Sickness Questionnaire. Also, a standard motion sickness scale was used to rate symptoms at 1-min intervals during each trial. Results: VIMS peaked between 0.2 and 0.4 Hz with a reducing effect at lower and higher frequencies. Conclusion: The numerical prediction of the “crossover frequency” hypothesis, and the design guidance curve previously proposed, cannot be accepted when the symptoms are purely visually induced. Application: In conditions in which stationary observers are exposed to optical flow that simulates oscillating fore-and-aft motion, frequencies around 0.2 to 0.4 Hz should be avoided

Behaviour and the safety of older people on stairs

Behaviour and the safety of older people on stair

Visual fatigue caused by viewing stereoscopic motion images: Background, theories, and observations

The background, theories, and observations on visual stress possibly caused by viewing stereoscopic motion images are reviewed. Visual fatigue caused by stereoscopic images is a safety issue. Fatigue is possible caused by the discrepancy between accommodative and convergence stimuli that are included in the image. Studies on accommodation and convergence are surveyed and an explanation regarding the characteristics of these functions is offered. Studies in the literature on changes in oculomotor function after viewing stereoscopic images, including changes in pupillary responses, are discussed. Evaluation of visual fatigue, particularly in relation to different methods of viewing stereoscopic displays is described

Characteristics of habituation to motion in a virtual environment

Immersion in a virtual environment is known to produce symptoms similar to those of motion sickness. With repeated immersions, these symptoms are generally reduced in prevalence and severity. We aimed to quantify this habituation by immersing 70 people on ten occasions each. Ten participants were exposed every day, ten every 2 days, and so on up to every 7 days. The participants played a PC racing game, viewed through a head mounted display, for 20 min. They rated various motion sickness symptoms both before and after exposure, and rated their level of malaise at 1-min intervals during immersion. After completion of the ten trials, all sets of participants reported a marked reduction in the prevalence and severity of the symptoms. The habituation which occurred was of a similar nature in all of the participant groups regardless of exposure interval, indicating that the number of exposures is a more important factor than the time interval between them

The contribution of behaviour to falls among older people in and around the home

The contribution of behaviour to falls among older people in and around the hom

Buyers’ guide: operating theatre lighting

Buyers’ guide: operating theatre lightin