The effect of lutein supplementation on visual fatigue: A psychophysiological analysis

We used psychophysiological technology to examine the effect of an oral supplement, a combination of lutein, zeaxanthin and blackcurrant extract (LUT), on visual fatigue, within the context of a randomized, double-blind, placebo-controlled cross-over trial. The LUT supplement and placebo samples were randomly assigned to thirteen participants, who took the samples for two LUT (and vice versa) for another 2 week. Each participant completed visual proof reading tasks for 2 h during each of four testing sessions. Saccade tests were administered before and after the proof reading task, during which the participants moved their eyes back and forth between two targets positioned in the center of two checkerboards. We recorded EEG, EOG, heart rate, and facial muscle potential/performance during the saccade tests. Blood pressure was measured and subjective fatigue and stress scores were collected before and after the proof reading task. We averaged EEG starting at saccade offset in order to analyze eye fixation related potentials (EFRP). Our results suggested that the proof reading task induced visual fatigue. An analysis of EFRP and other psychophysiological data revealed significant differences between the LUT and placebo conditions. These results suggest that supplementation with LUT could help to reduce symptoms of visual fatigue.     

Evaluating camouflage design using eye movement data

This study investigates the characteristics of eye movements during a camouflaged target search task. Camouflaged targets were randomly presented on two natural landscapes. The performance of each camouflage design was assessed by target detection hit rate, detection time, number of fixations on display, first saccade amplitude to target, number of fixations on target, fixation duration on target, and subjective ratings of search task difficulty. The results showed that the camouflage patterns could significantly affect the eye-movement behavior, especially first saccade amplitude and fixation duration, and the findings could be used to increase the sensitivity of the camouflage assessment. We hypothesized that the assessment could be made with regard to the differences in detectability and discriminability of the camouflage patterns. These could explain less efficient search behavior in eye movements. Overall, data obtained from eye movements can be used to significantly enhance the interpretation of the effects of different camouflage design.     

Eye movement behaviour viewing colour-coded and monochrome avionic displays

Abstract

This paper reports on two experiments in which subjects' eye movement behaviour was monitored while they searched for target information in colour coded and monochrome horizontal situation indicator (HSI) displays. The first experiment required subjects to locate and report alphanumeric information associated with the active waypoint on the displayed flightpath. Initial fixations in the display were more accurately directed to the target information when it was redundantly colour coded compared with when it was coded by shape and relative positional codes. Fewer fixations and a shorter time were required to locate the colour coded target and verbally report the relevant information. The time advantage of colour coded displays compared with monochrome displays was greatest for visually cluttered displays. In the second study there was no advantage of a coloured display when the task was to count all the displayed waypoint symbols on the flight path. The lack of any benefit for colour coding was a result of waypoint symbols having strong positional predictability due to their relationship to the displayed flightpath in both the colour and monochrome displays. The implication from these results is that colour coded information confers an advantage over a spatial code for targets at unknown spatial location but less benefit when target location can be predicted by other visual cues.     

Work domain analysis for enhancing collaborations: a study of the management of microsystems design

Collaboration is an important process that enables organisations to achieve goals or solve problems and, in design processes, is an important factor for accomplishing interdisciplinary and multidisciplinary tasks. An understanding of the functional configuration of organisations could therefore offer a useful insight into collaborations of designers. This study makes use of work domain analysis (WDA) to analyse the management of design by organisations within the microsystems technology (MST) domain. The WDA considers the functional configuration of MST companies in terms of management constraints and boundaries. This study also makes use of the WDA to suggest ways of establishing collaborative design and enhancing collaboration between organisations. Practitioner Summary: The results of this methodical analysis offer useful insights for managing design functions. This study also presents recommendations for enhancing collaboration in organisations. The ability to manage and collaborate in design functions is valuable for improving the productivity, cost-effectiveness and time-to-market systems.     

Physiological effects of intermittently illuminated textual displays

Optical equipment was developed to simulate visual display terminals (VDTs) with reversed presentation (bright background and dark characters). The decay time and mean luminance were kept constant, while the oscillating frequency varied. During one experiment subjects had to read text aloud for 60min. Before and after the reading, near point distance, critical flicker fusion frequency (CFF), visual acuity, stereo depth perception, lateral heterophoria and contrast sensitivity were measured. The 30 subjects had then to report their subjective reactions on a questionnaire. The following frequencies were used: 0, 30, 60, 90, 180 Hz. In addition subjects read a normally printed text with a luminance of 75 or 150 cd/m². The main finding was that of a strong decrease of the CFF after exposure to 30 and 60 Hz. It is suggested that for reversed presentation the refresh rate should be higher than 90 Hz.     

Can eye-tracking data be measured to assess product design?: Visual attention mechanism should be considered

Eye tracking probes user's perception of real-time reaction to products, while conventional methods (i.e. interviews, focus group, questionnaires and so on) have generally failed because they depend on users' willingness and competency to describe how they feel when they are exposed to a product. Two tasks were designed to explore the indexes of eye movement that can reflect user experience of product, and analyse the attention captured by product attributes and goal-oriented. In task one, participants just browsed two smart phone pictures and evaluated the whole user experience. Binary choices were used in task two to ask participants to select the smart phone picture with higher user experience and then click the mouse. The results showed that in the browsing task, participants had shorter time to first fixation for the smart phone picture with higher level of user experience than the lower. And pupil dilated significantly when participants browse smart phone picture with lower level of user experience. In goal-oriented task, participants' attentions were dominated by visual perception of task driven, mainly reflected on longer fixation time and larger pupil diameter when looking at the smart phone with higher level of user experience. These results support the notion that we cannot assess product design just by several eye-movement indexes without considering the effects of visual attention mechanism.Relevance to industryThe appearance of product plays an important role to attract user's attention and stimulate their intention to experience. And vision is the main channel for users to obtain product information. Hence a thorough research on the inherent mechanism of vision perception can provide technical support for product designers, which in turn can attract more consumers to experience the product, even buy it. Moreover, the seller can find out the real buyers and predict their desired products by tracking user's eyes.     

Which is more prominent for fighter pilots under different flight task difficulties: Visual alert or verbal alert?

To explore the behavioural and cognition patterns of fighter pilots under visual and verbal alert conditions, 20 right-handed subjects participated in the experiment after 200 h of flight task training, and ERP technology was used to conduct EEG experiments under four conditions: high time pressure visual alert, low time pressure visual alert, fast speech speed verbal alert, and slow speech speed verbal alert. The results indicated the following: 1) the highest accuracy rate and shortest reaction time could be achieved under the slow speech speed verbal alert condition, indicating that the slow speech speed alert performance was optimal. 2) Subjects in the verbal alert trial showed a “right hemisphere advantage”, and the brain function area was located in the right temporal lobes. The speech speed correlated negatively with the latency and amplitude of P80.3) Subjects in the visual alert trial showed a “left hemisphere advantage”, and the brain activity was located in the left parietal lobes. 4) The latency of P80 evoked by verbal alert was earlier than that of N140 evoked by visual alert, indicating that a verbal alert causes an earlier attention effect in pilots. Based on the eye movement experiment, the performance of visual and verbal dual-channel alert was significantly higher than that of visual alert.     

EOG-based eye movements codification for human computer interaction

This paper describes a new eye-control method for eye-based computer interaction using EOG. This work aims to resolve some of the problems encountered in current systems when used for long periods of time and users become tired. For this purpose, a new electrooculographic eye model based on wavelet transform and neural networks is proposed. The results obtained demonstrate the system’s reliability in detecting eye movements and show an error of less than 2° during long periods of use. The system proposed may be used to control any graphical interface using eye movements detected by electrooculography.     

Structured and Blank Backgrounds in a Pursuit Tracking Task

An account is presented of an experiment in which subjects moved a sighting device so as to keep a graticule on a moving target. Both realistic and blank backgrounds for the target were used; and subject performances in the two conditions were compared.

It was found that the blank and structured backgrounds were subjectively apprehended by subjects as providing entirely different types of control problem. Performance was inferior with a blank background; and it is suggested that training simulators for this type of control should always feature as realistic a background as possible.     

Objective evaluation of eye strain using measurements of accommodative oscillation

Accommodative oscillations occurring during eye strain induced by two different types of experimental visual search task—visual display terminal (VDT) work and conventional hard-copy (paper) work— were objectively measured using infrared optometry. The low-frequency component (0 to 1-5 Hz) of the accommodative oscillation was found to be significantly increased after the VDT work, but not after the paper work. At other frequencies there were no significant differences between the two work types and no significant effect of the task itself. In a questionnaire survey the subjects using the VDT complained more than the subjects given paper work of ocular symptoms such as eye strain and blurred vision. These results suggest that measurement of changes in accommodative oscillation, particularly the low-frequency component (0 to 15 Hz), may provide an objective parameter of eye strain.     

Does fatigue exist in a quantitative measurement of eye movements?

Abstract

The measurement system for quantitative analysis of eye movements and distribution of eye fixation points was developed through the study. Experiments on physiological fatigue characteristics of eye movements were studied using the system. The subjects involved in the study were six young males. No significant change was quantitatively found in saccadic eye movements during and/or after five hours of rapid eye tracking tasks. The saccadic velocity of two subjects were found in binocular decreased temporarily. The maximum velocity of eye movements obtained in the present experiment was ascertained in order to produce a scale for various visual work as an ergonomic index.     

ENERGY EXPENDITURE OF SOLDIERS PERFORMING COMBAT TYPE ACTIVITIES

The energy cost of ft number of tactical tasks was measured for soldiers during tactically controlled rather than experimentally controlled tasks. The upper range of energy expenditure rates was 400 to 4:10 kcal per hour during these tactical manoeuvres; incipient physical or heat exhaustion was associated with the few much higher values. The realism of the tactical situation, and an estimate of the contribution made by the heat load and wearing of the gas mask to the energy costs measured is presented. The hypothesis is presented that the upper range of energy expenditure rates for prolonged periods is independent of terrain when men are allowed to work at their own pace, but depends on the total weight carried. The relationship between ventilation volume and energy expenditure in this study is compared with data presented by Liddell and supports the argument that calculation of energy expenditure can be reliably made using a single formula to convert ventilation volume par se, particularly within the practical accuracy of field measurements     

An investigation of train driver visual strategies

Train driving is primarily a visual task; train drivers are required to monitor the dynamic scene visually both outside and inside the train cab. Poor performance on this visual task may lead to errors, such as signals passed at danger. It is therefore important to understand the visual strategies that train drivers employ when monitoring and searching the visual scene for key items, such as signals. Prior to this investigation, a pilot study had already been carried out using an eye tracking technique to investigate train drivers’ visual behaviour and to collect data on driver monitoring of the visual environment, Groeger et al. (2003) Pilot study of train drivers’ eye movements, University of Surrey. However, a larger set of data was needed in order to understand more fully train driver visual behaviour and strategies. In light of this need, the Transport Research Laboratory produced a methodology for the assessment of UK train driver visual strategies, on behalf of the Rail Safety and Standards Board and applied this methodology to conduct a large-scale trial. The study collected a wealth of data on train drivers’ visual behaviour with the aim of providing a greater understanding of the strategies adopted. The corneal dark-eye tracking system chosen for these trials tracks human visual search and scanning patterns, and was fitted to 86 drivers whilst driving in-service trains. Data collected include the duration and frequency of glances made towards different elements of the visual scene. In addition, the train drivers were interviewed after driving the routes, to try and understand the thought processes behind the behaviour observed. Statistical analysis of over 600 signal approaches was conducted. This analysis revealed that signal aspect, preceding signal aspect, signal type and signal complexity are important factors, which affect the visual behaviour of train drivers. Train driver interview data revealed that driver expectation also plays a significant role in train driving. The findings of this study have implications for the rail industry in terms of infrastructure design, design of the driving task and driver training. However, train driving is extremely complex and the data from this study only begin to describe and explain train driver visual strategies in the specific context of signal approaches. This study has provided a wealth of data and further analysis of it is needed to investigate the role of other factors and the complex relationships between factors during signal approaches and other driving situations systematically. Finally, there are important aspects of visual behaviour that cannot be examined using these data or this method. Investigation of other aspects of visual behaviour, such as peripheral vision, will require other methods such as simulation.     

Optimization of Chinese interface design in motion environments

The Taguchi method has been successfully applied in engineering fields to deal with a single performance quality problem, but it is not often used in interface design and the handling of multiple performance quality problems. This study investigated a multi-response problem in terms of searching time, number of missing characters/buttons (NMCB), and visual fatigue by integrating the Taguchi method and the weighting method to optimize the Chinese interface design parameters such as display type, character size, font type, and text/background color combination in motion environments. The results indicated that subjects’ visual performance was improved when using the optimum interface setting (LCD, 7.5 * 7.5 mm, Kai font and white/blue color combination) rather than the current interface setting.