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With the development of autonomous vehicle (AV) technology, understanding how pedestrians interact with AVs is of increasing importance. In most field studies on pedestrian crossing behavior when encountering AVs, pedestrians were not permitted to physically cross the street due to safety restrictions. Instead, the physical crossing experience was replaced with indirect methods (e.g., by signalizing with gestures). We hypothesized that this lack of a physical crossing experience could influence the participants’ crossing behavior. To test this hypothesis, we adapted a reference study and constructed a crossing facility using a virtual reality (VR) simulation. In a controlled experiment, the participants encountered iterations of oncoming AVs. For each interaction, they were asked to either cross the street or signify their crossing decisions by taking steps at the edge of the street without crossing.Our study reveals that the lack of a physical crossing can lead to a significantly lower measured critical gap and perceived stress levels, thus indicating the need for detailed analysis when indirect methods are applied for future field studies.Practical Relevance: Due to safety requirements, experiments will continue to measure participants’ crossing behavior without permitting them to physically walk in front of an oncoming vehicle. Our study was the first attempt to reveal how this lack of crossing could potentially affect pedestrians’ behavior, and we obtained empirical evidence in support of our hypothesis, thus providing insights for future studies.

Abuse of alcohol and other drugs is a major risk factor at work. To reduce this risk, workplace drug testing is performed in transportation and other industries. VERIFY, an observational method, is one of the key elements in a procedure adopted by the police of the canton of Zurich, Switzerland, for detecting impaired drivers. The observational method has been successfully applied by adequately trained police officers since 2014. The aim of this study is to examine the interrater reliability of the observational method, the effect of training in use of the method, and the role of having experience in the police force and traffic police force on the outcome when rating a driver’s impairment. For this purpose, driver impairment in staged road traffic controls presented in videos was rated by laypeople (n = 81), and police officers without (n = 146) and with training (n = 172) in the VERIFY procedure. In general, the results recorded for police officers with training revealed a moderate to very good interrater reliability of the observational method. Among the three groups, impaired drivers were best identified by officers with training (ranging between 82.6% and 89.5% correct identification). Trained officers reported a higher impairment severity of the impaired drivers than the other two groups, indicating that training increases sensitivity to signs of impairment. Our findings also suggest that online video technology could be helpful in identifying impaired drivers. Trained police officers could be connected to a road traffic control to make observations via live video. By this method efficiency and reliability in detecting abuse of alcohol and other drugs could be improved. Our findings also apply to workplace drug testing in general.

Abuse of alcohol and other drugs is a major risk factor at work. To reduce this risk, workplace drug testing is performed in transportation and other industries. VERIFY, an observational method, is one of the key elements in a procedure adopted by the police of the canton of Zurich, Switzerland, for detecting impaired drivers. The observational method has been successfully applied by adequately trained police officers since 2014. The aim of this study is to examine the interrater reliability of the observational method, the effect of training in use of the method, and the role of having experience in the police force and traffic police force on the outcome when rating a driver's impairment. For this purpose, driver impairment in staged road traffic controls presented in videos was rated by laypeople (

There is a worldwide interest in implementing collaborative robots (Cobots) to reduce work-related Musculoskeletal Disorders (WMSD) risk. While prior work in this field has recognized the importance of considering Ergonomics & Human Factors (E&HF) in the design phase, most works tend to highlight workstations’ improvements due to Human-Robot Collaboration (HRC). Based on a literature review, the current study summarises studies where E&HF was considered a requirement rather than an output. In this article, the authors are interested in understanding the existing studies focused on Cobots’ implementation with ergonomic requirements, and the methods applied to design safer collaborative workstations. This review was performed in four prominent publications databases: Scopus, Web of Science, Pubmed, and Google Scholar, searching for the keywords ‘Collaborative robots’ or ‘Cobots’ or ‘HRC’ and ‘Ergonomics’ or ‘Human factors’. Based on the inclusion criterion, 20 articles were reviewed, and the main conclusions of each are provided. Additionally, the focus was given to the segmentation between studies considering E&HF during the design phase of HRC systems and studies applying E&HF in real-time on HRC systems. The results demonstrate the novelty of this topic, especially of the real-time applications of ergonomics as a requirement. Globally, the results of the reviewed studies showed the potential of E&HF requirements integrated into HRC systems as a relevant input for reducing WMSD risk., This work has been supported by FCT–Fundação para a Ciência e Tecnologia and MIT Portugal Program under the doctoral Grant SFRH/BD/151365/2021. This work has been also supported by NORTE-06-3559-FSE-000018, integrated in the invitation NORTE-59-2018-41, aiming the Hiring of Highly Qualified Human Resources, co-financed by the Regional Operational Programme of the North 2020, thematic area of Competitiveness and Employment, through the European Social Fund. Additionally, has been also supported by FCT within the Project “I-CATER–Intelligent robotic Coworker Assistant for industrial Tasks with an Ergonomics Rationale”, Ref. PTDC/EEIROB/3488/2021, and within R&D Units Project Scope: UIDB/00319/2020.

In augmented reality (AR), virtual information is optically combined with the physical environment. In the most frequently used combination technique, optical settings in AR depart from the settings in natural viewing. Depending on the combination of viewing distances of the virtual task and its physical background, this deviation may lower visual performance and cause visual disturbance symptoms. The so-called vergence-accommodation conflict (VAC) has been identified as a cause for the visual disturbance symptoms in AR. In this study, for various distance combinations, the performance and symptoms when performing a search task displayed in a see-through head-mounted display (AR HMD, HoloLens 1st generation, Microsoft, USA) was investigated. The search task was displayed at a virtual distance of either 200 cm or 30 cm, and the real background was viewed either at a distance of 200 cm or 30 cm. Three combinations of viewing distances for the background and the virtual task were studied: 200 cm/200 cm, 200 cm/30 cm, and 30 cm/30 cm. Results revealed that both performance and visual disturbance symptoms depend on the combination of the viewing distances of the physical background and the virtual task. When the physical background was viewed at a distance of 200 cm, younger participants showed a significantly better search performance and reported stronger symptoms compared with older participants, no matter whether the virtual task was performed at 30 cm or at 200 cm. However, with the physical background at a distance of 30 cm, the performance of the younger group dropped to the level of the performance of the older group, and younger participants tended to report a stronger increase in visual disturbance symptoms compared with the older participants. From the AR HMD technology used in this study, it can be concluded that a near viewing distance of the virtual task does not cause a negative impact on performance and visual disturbance symptoms, provided any physical background seen through the AR HMD is not at a near viewing distance. The findings indicate that the VAC, which persists in augmented and virtual reality, depends, in addition to the physical component evaluating the optical distance, on a cognitive component evaluating the perceived distance. AR settings should therefore also be evaluated in terms of possible effects on perceived distance.

We present a new reorientation technique, "hyper-reoriented walking," which greatly reduces the amount of physical space required in virtual reality (VR) applications asking participants to walk along a grid-like path (such as the most common layout in department stores). In hyper-reoriented walking, users walk along the gridlines with a virtual speed of twice the speed of real walking and perform turns at cross-points on the grid with half the speed of the rotation speed in the physical space. The impact of the technique on participants' sense of orientation and increase in simulator sickness was investigated experimentally involving 19 participants walking in a labyrinth of infinite size that included straight corridors and 90 degrees T-junctions at the end of the corridors. Walking accuracy was assessed by tracking the position of the head mounted display, and cyber-sickness was recorded with the simulator sickness questionnaire and with open questions. Walking straight forward was found to closely match the ideal path, which is the grid line, but slight errors occasionally occurred when participants turned at the T-junctions. A correction algorithm was therefore necessary to bring users back to the gridline. For VR experiments in a grid-like labyrinth with paths of 5 m in length, the technique reduces required size of the tracked physical walking area to 3 m x 2 m., Virtual Reality, 26 (3), ISSN:1434-9957, ISSN:1359-4338

Hierarchical task analysis (HTA) and cognitive work analysis (CWA) were applied to laparoscopic surgery to identify critical technical, cognitive, and social challenges. Our purpose was to understand the complexity of laparoscopy and use this knowledge to develop a surgical training system. Five laparoscopic procedures were analyzed using the HTA methodology, while generic laparoscopic approaches were analyzed by applying the five phases of the CWA framework. The results from these analyses were applied to a surgical training system. The focus was on the application of partial-task training to areas that could be more technically challenging. Additionally, practical, social, and cognitive training aspects were included into the training system, based on our findings from the analyses. Practical Relevance: The use of digital training systems is becoming increasingly important in complex work systems, especially when it comes to simulations that can have serious consequences in reality. This paper presents the development of a surgical training system.

Vigilance tasks with a high level of attentional demand are becoming more frequent in daily work. High levels of attentional demand are required in critical systems, such as air traffic control, crowd monitoring, visual quality inspection, or sports. In a previous study, we introduced an ecologically valid test for screening visual attention in the general working population. The test requires participants to complete a visual search task at a moderate level of difficulty. In the present work, we increased the test's level of difficulty to enable accurate screening of high levels of attentional skills. To establish reference data, attentional skills were recorded in 60 participants, ranging in age from 19 to 40, performing the test at both, moderate and high levels of difficulty. Increasing the difficulty level of the test resulted in a lower test performance score. Furthermore, an increased level of difficulty reduced the ceiling effects caused by highly-skilled participants. In the present report, we provide normative performance score data and evidence for the reliability of the developed test. Adapting the level of difficulty enables our attention test to effectively screen for attention in occupations requiring moderate or elevated attentional skills. Relevance to industry Demands for visual attention are increasing in a variety of industries. Therefore, screening for attentional performance is becoming more important in accident prevention and quality of work. A previously-reported ecologic test for screening visual attention at a moderate level of attention was adapted to enable screening at an elevated level of attentional demands.

The following report introduces two projects, dealing about ergonomics in ophthalmic microsurgery. The first project is devoted to the development of a method, by means of which the design of microsurgical instrumentation is evaluated quantitatively. Developed method particularly considers conditions of instrument use as found in microsurgical practice. In a first attempt, the method was validated using laypersons. In the second project, various measures are introduced aiming to improve the posture of the surgeon during the microsurgery. One of the measures consists in using a large 3D-monitor to present the microscopic image to the surgeon instead of viewing the image through the oculars of a traditional microscope. The measure therefore enables a more relaxed posture of the surgeon. In addition, a chair was developed, considering to support the surgeon’s posture when operating using the 3D-monitor or the traditional microscope while performing the microsurgery. Practical relevance. The method suggested in the first project closes a gap in product design as it provides developers with a quantitative, objective and ecologic valid methods for evaluating designs of microsurgical instrumentation. The measures presented in the second project will contribute to reduce postural complaints of the surgeon caused by microsurgical interventions.

Fatigue is a high-risk factor for road accidents. It impairs driver’s attention and performance and can thus compromise road safety. Unlike for alcohol, there are no objective measurements to detect fatigue during road a road traffic control, and thus it is difficult for the police to prove that a driver is too tired to drive. However, considering previous studies there are reasons to believe that a formerly developed visual attention test could be a possibility to detect sleepiness to a certain degree. This study investigates the effect of fatigue on the visual attention test. 21 participants drove 30 min on a driving simulator in order to get tired and performed the attention test before and after the drive. During the drive, subjective sleepiness, mental workload, and driving performance were recorded. Participants were divided into two groups with different test sequences to assess the effect of time elapsed between the drive and the second attention test. The results revealed that in young participants, the effect of fatigue induced by a 30-min drive in a driving simulator on visual attention is ambiguous. However, the results indicate that the effect of fatigue might be seen in the last third of the test. This study provides information on the sensitivity of the visual attention test and how the test might be adapted to detect fatigue.

Minimally invasive surgery, specifically endoscopy, is a vital component in modern surgical healthcare. Due to the challenging nature of operating through a restricted endoscopic camera view, novice surgeons must master navigating surgical volumes effectively and efficiently. One of the specific focus areas for these inexperienced surgeons is maintaining the horizon of the camera in the surgical volume. Alongside traditional cadaver training, surgeons use mixed-reality surgical training simulators to improve their surgical skills. In this work, we propose a new method of training novice users in the proper method of maintaining camera horizon alignment in an arthroscopic knee procedure. We ran a study with 21 medical novices on a commercially available surgical simulator. We provided automated verbal cues, digital sine wave audio, or a commercially available visual horizon bar to see if an improvement in performance could be found over the control group that received no additional feedback for the camera horizon. We examined the Overall Workload of the participants, along with the misalignment time of the camera horizon and the procedure time. Results from the study showed that the verbal cues improved procedure time and Overall Workload, and the visual horizon bar improved the horizon misalignment time. Digital sine wave audio was not effective overall.

Using a group of 23 physician trainees, we investigated whether microsurgery training in an augmented reality (AR) training simulator improves motor skills and whether an intelligent tutoring system (ITS) improves training efficiency.Characteristic motor skill steps involved in the peeling of an internal limiting membrane (ILM) were identified and implemented in the AR simulation. For training, implemented steps were either presented in the natural sequence, as in a real ILM surgery, or administered according to the ITS. Participants underwent the training over 5 days for 10 minutes per day. A subgroup of 11 participants performed the 5 microsurgical steps in a natural sequence. The other 12 participants used the ITS method. Motor skill performance was recorded before and after each training session with the AR simulator, and before the first and after the last training session using a method that did not rely on AR.Five steps of the ILM peeling procedure were identified and implemented: insertion of the instrument, flap creation, clockwise peeling, counterclockwise peeling, and retraction of the instrument. Both training methods significantly improved the motor skills of the participants. In both methods, steep learning progress was found within the first three training sessions. In both methods, motor skills continued to improve on days 4 and 5, but at a slower rate. After the 5 training days, performance was significantly improved, but improvement did not depend significantly on the training method. However, within the first 3 days of training, ITS led to steeper training progress than the natural sequence method.It is possible to improve microsurgical motor skills using the implemented AR simulation. Some technical limitations, such as system lag, deserve further improvements. However, the proposed AR solution was highly appreciated by the participants and could help overcome constraints of practice in microsurgical training, such as limited availability of training opportunities or a standardized assessment of motor skill performance.Mit 23 Studierenden der Medizin wurde untersucht, ob mikrochirurgische Manipulationsfertigkeiten mittels eines Augmented-Reality-Simulators (AR: Augmented Reality) trainiert werden können und ob ein Intelligent-Tutoring-System (ITS) die Trainingseffizienz steigern kann.Manuelle Teilschritte des Eingriffs zur Entfernung der Membrana limitans interna, dem sogenannten ILM-Peeling, wurden identifiziert und in eine AR-Simulation implementiert. Beim Training wurden die implementierten Teilschritte entweder in der natürlichen Reihenfolge vorgegeben, wie diese beim ILM-Peeling in der realen Operation durchgeführt werden, oder die Sequenz der Teilschritte wurde durch das ITS vorgegeben. Die Versuchspersonen führten während 5 Tagen 1 × pro Tag ein 10-minütiges Training mit der AR-Simulation durch, wobei eine Untergruppe von 11 Studenten das Training mit der natürlichen Sequenz der Teilschritte und die verbleibenden 12 Personen das Training gemäß ITS durchführten. Die Manipulationsfertigkeiten wurden vor und nach jeder Trainingssession mit der AR-Simulation erfasst. Zudem wurde vor der ersten und nach der letzten Trainingssession der Trainingserfolg mittels einer Methode registriert, die nicht von der AR-Simulation abhängt.Fünf Teilschritte des ILM-Peelings wurden identifiziert und implementiert: Einführung des mikrochirurgischen Instruments in das Auge, Anlegen eines Flaps, Peeling im Uhrzeigersinn, Peeling gegen den Uhrzeigersinn, Rückzug des Instruments. Bei beiden Trainingsmethoden nimmt der Trainingserfolg in den ersten 3 Tagen stark zu, wobei die Trainingskurve beim ITS steiler ansteigt. An den Tagen 4 und 5 nimmt der Trainingserfolg bei beiden Methoden weiter zu, wenn auch nicht mehr so stark. Nach 5 Tagen sind die Fertigkeiten signifikant verbessert, aber es lässt sich kein signifikanter Unterschied zwischen dem Training mit den beiden Methoden feststellen.Mit dem AR-Simulator lassen sich mikromanipulatorische Fertigkeiten erfolgreich trainieren. Technische Verbesserungen, wie die Reduktion der Bildverzögerung in der AR-Brille, sind erforderlich. Dennoch wurde die Simulation von den Versuchsteilnehmern sehr geschätzt und sie mag die in der Praxis oft angetroffenen Beschränkungen der Trainingsmöglichkeiten oder die unbefriedigende Standardisierung der Messung des Trainingserfolgs lindern.

INTRODUCTION Current methods of training microsurgical interventions have various limitations, including limited transferability to the human model, economic demands, and ethical concerns. In this article, we show how surgery simulations can overcome these issues and how, combined with the application of an intelligent tutoring system (ITS), they can be used to train tasks in ophthalmic surgery more efficiently. METHODS We investigated physician trainee efficiency of learning microsurgical skills using our purpose-built microsurgery simulator that tracks a micromanipulator and displays a three-dimensional representation of the interior of a human eye in an augmented reality (AR) headset. The expertise of ophthalmic surgeons helped define five subtasks corresponding to the steps of internal limiting membrane peeling. Using our AR surgery simulation, 50 participants underwent two training sessions, one using the ITS that dynamically adapts the task sequence to the participant's progress and one using a fixed task sequence. RESULTS We found significant improvement in micromanipulation performance in the first training session with both the ITS and classic training. In the second session, however, only the participants training with the ITS had further improvements in performance. CONCLUSIONS Results of this study demonstrate the usability of AR simulation in training micromanipulation skills and support the claim that simulators can be used in ophthalmic surgery training. This study also extends the existing literature by demonstrating an application of ITS for surgical training. The potential of this method is further analyzed in ongoing studies and discussions with experts in ophthalmic surgery.

The comparability or similarity of consumers' behavior in virtual reality (VR) and in real life (RL) is indispensable to successfully take advantage of VR technology in consumer behavior (CB) research. This study investigated the comparability of participants' behavior in a virtual environment and in RL to validate VR for data acquisition in CB research. Participants (N = 98) were randomly assigned to a RL condition or a VR condition in which the settings were chosen to mimic a RL environment as closely as possible. In both conditions, participants ranked 20 types of commercial breakfast cereal by their perceived healthiness from healthy to unhealthy. We observed that the perceived healthiness of the 20 cereals in the VR and RL conditions were highly correlated (r(s) = 0.91, p < .001, N = 20). The information-seeking behavior was not different between the two conditions, t (96) = - 1.11, p = .27. Furthermore, the attributes employed by the participants to evaluate the healthiness of the cereals did not vary between the two conditions. The presence level of the participants in the virtual environment was also examined. The results illustrate that the participants' behavior in the virtual environment and in the real world were comparable, which provides robust evidence for the validity of VR as a beneficial and promising tool for data acquisition in CB research., Swiss National Science Foundation (SNSF), Project “Digital Lives”

Experimental studies are important in the process of gaining a better understanding of people’s food choices. The present study, which tested the validity of a virtual food buffet, delivers a proof of concept. The proposed method uses virtual reality to simulate a buffet with three different foods from which participants could serve a meal. To determine the validity of the new method, a fake food buffet—known to be a valid and reliable method—was used as a comparison. A sample of 34 participants served themselves two meals, one in virtual reality and one from a fake food buffet. The order of the two buffets was randomized. We observed high correlations between the kJs of the foods served in the two conditions (r ≥ 0.75, p

Virtual reality (VR) can be a useful tool for conducting consumer behavior experiments. The aim of this research was to examine whether people standing in front of a supermarket shelf make similar decisions and process similar information as those in front of a shelf in a VR shop. In Study 1, participants were asked to select a cereal from among 33 commercially available types of cereals placed on a shelf. One group performed the task in front of a real shelf, while the other performed it in VR. Eye-tracking data were collected for both groups. No statistically significant differences were observed in the selection of the cereals by the two groups in the two conditions. Eye-tracking data only revealed few differences in the information-seeking behavior. In Study 2, results observed using real products were replicated in VR. Participants were asked to walk through a virtual supermarket and select either a healthy cereal (healthy condition) or a tasty cereal (hedonic condition). Results showed that participants in the healthy condition paid more attention to the nutrition information than those in the hedonic condition. The results of these two experiments suggest that a VR condition wherein participants can walk around and behave as in the real world is a useful tool for conducting experiments related to food decisions., Food Research International, 117, ISSN:0963-9969, ISSN:1873-7145

The efficiency of training visual attention in the central and peripheral visual field was investigated by means of a visual detection task that was performed in a naturalistic visual environment including numerous, time-varying visual distractors. We investigated the minimum number of repetitions of the training required to obtain the top performance and whether intra-day training improved performance as efficiently as inter-day training. Additionally, our research aimed to find out whether exposure to a demanding task such as a microsurgical intervention may cancel out the effects of training. Results showed that performance in visual attention peaked within three (for tasks in the central visual field) to seven (for tasks in the periphery) days subsequent to training. Intra-day training had no significant effect on performance. When attention training was administered after exposure to stress, improvement of attentional performance was more pronounced than when training was completed before the exposure. Our findings support the implementation of training in situ at work for more efficient results. Practitioner Summary: Visual attention is important in an increasing number of workplaces, such as with surveillance, inspection, or driving. This study shows that it is possible to train visual attention efficiently within three to seven days. Because our study was executed in a naturalistic environment, training results are more likely to reflect the effects in the real workplace.

In a self-testing vision screener, examinees use an input device for pointing the orientation of the targets, which are presented inside the vision screener. Examinees operate the input device without visual feedback. In the present study, the suitability of pointing devices was evaluated for conditions such as are present in a self-testing vision screener. The evaluation consisted of an experimental assessment of pointing accuracy and recording subjective ratings while using the various devices. Six commercially available computer input devices – a joystick, a gamepad, a trackball, two track pads and a PC mouse - were evaluated under visual conditions similar to those that would be present when using a self-testing vision screener. Pointing accuracy was found to vary significantly with the type of device (F(3.2, 93.1) = 3.937, p = 0.009) and the effect of the device on pointing accuracy was important (partial η2 = 0.120). The most accurate pointing was achieved when participants used the joystick. Using the joystick, a mean of 96.8% (SD = 4.3%) of pointing trials resulted in the correct orientation. If only diagonal orientations are considered, the correct pointing rate increased to a mean of 99.5% (SD = 1.5%) when using the joystick. In terms of the subjective ranking, the gamepad and the joystick achieved the best and the second best ranks respectively, whereas the trackball was the least preferred device. Based on our findings, we recommend using a joystick as an input device in pointing tasks in order to minimize the effects of suboptimal visual feedback on motor performance. As for the particular case of testing visual acuity, various procedures are suggested. Thus, the effect of suboptimal visual feedback on the outcome of the acuity test is reduced.

We propose a system for a Virtual Reality (VR) driving simulator including an Intelligent Tutoring System (ITS) to train the user's driving skills. The VR driving simulator comprises a detailed model of a city, Artificial Intelligence (AI) traffic, and a physical driving engine, interacting with the driver. In a physical mockup of a car cockpit, the driver operates the vehicle through the virtual environment by controlling a steering wheel, pedals, and a gear lever. Using a Head-Mounted Display (HMD), the driver observes the scene from within the car. The realism of the simulation is enhanced by a 6 Degrees of Freedom (DOF) motion platform, capable of simulating forces experienced when accelerating, braking, or turning the car. Based on a pre-defined list of driving-related activities, the ITS permanently assesses the quality of driving during the simulation and suggests an optimal path through the city to the driver in order to improve the driving skills. A user study revealed that most drivers experience presence in the virtual world and are proficient in operating the car., International SERIES on Information Systems and Management in Creative EMedia (CreMedia), 2017 (2), ISSN:2341-5584, ISSN:2341-5576, ISSN:2341-6165

Background: Clinical assessment of dark adaptation is time consuming and requires a specialised instrumentation such as a nyktometer. It is therefore not surprising that dark adaptation is rarely tested in practice. As for the case of testing fitness of a driver, demands on adaptation in daily driving tasks mostly depart from settings in a nyktometer. In daily driving, adaptation is stressed by high and fast transitions of light levels, and the period of time which is relevant to safe driving starts right after a transition and ends several seconds later. In the nyktometer dark adaptation is tested after completion of the adaptation process. Results of a nyktometer test may therefore deliver little information about adaptation shortly after light transitions. In an attempt to develop a clinical test aiming to fulfill both a short measurement time and offering test conditions comparable to conditions in driving, we conducted a preliminary study in which contrast sensitivity thresholds were recorded for light transitions as found in daily driving tasks and for various times after transition onsets. Contrast sensitivity performance is compared to dark adaptation performance as assessed by a myktometer. Material and Methods: Contrast sensitivity thresholds were recorded in 17 participants by means of a twin projection apparatus. The apparatus enabled the projection of an adapting field and of a Landolt ring both with a variable luminance. Five different stepwise transitions in levels of adapting luminance were tested. All transitions occurred from bright to dark. The Landolt ring was flashed 100 or 500 ms after the transition had occurred. Participants were instructed to report the orientation of the Landolt ring. A Rodenstock Nyktometer, Plate 501, was used to record dark adaptation threshold. Results: Experimental data from the proposed test revealed a noticeably increasing contrast detection threshold measured in dark adaptation in the stronger transition from 14 000 to 8 cd/m2 than in the weaker transition from 2000 to 8 cd/m2. By raising the dark adaption luminance level from 8 to 60 cd/m2 in the stronger transition case, the contrast detection threshold was then improved by a factor of four. Another main finding showed that for the adaptation process from strong glare stimuli to the dark adaptation, a peak deterioration in contrast sensitivity occurred at the light adaptation level of 6000 cd/m2. Comparing the contrast performance assessed by the proposed test with that of the nyktometer test, there was no clear correlation between the two methods. Conclusions: Our suggested method to assess dark adaptation performance proved to be practical in use and, since the patient does not have to spend a long time to attain complete dark adaptation, the method required a short time for measurement. Our negative experience in the use of the myktometer was in agreement with reported experience in the literature.

Large screens have become more popular in recent years. Because of the increasing size of displays, the amount of information presented in the peripheral visual field has gained importance in many tasks on visual display units. Users of displays are often exposed to some change or difference in luminance in or between different areas of a display, which in turn may produce a phenomenon known as discomfort glare. Discomfort glare is likely to affect cognitive performance. The performance in the visual periphery is more susceptible to disturbances as is the case for the performance in the central visual field. This study explored the effects of discomfort glare on detecting and processing peripheral visual information in a complex visual task. The task consisted of comparing the orientation of arrows presented in the central visual field and at 18° in the periphery. The arrows were superimposed on a background video and presented by a projection system in virtual reality. 50% of the presentations were preceded by a mild glare scene with a luminance of 25 cd/m2 flashed prior to the stimulus. Experimental results of 56 participants were analyzed using the theory of signal detection. A significant difference (two-tailed t-test p = 0.01) in detectability of stimuli (d′glare = 1.87; d′no glare = 2.11; Δd′ = 0.24) was obtained when comparing the performance in the two situations of glare. Results show that discomfort glare impairs peripheral visual performance in attending stimuli in a virtual reality environment. We therefore propose to consider discomfort glare as a factor affecting performance in detecting peripheral visual information. Discomfort glare should be included as a quality criterion in rating visual information, as is done in present standards of displays and lighting.

Biomedical Engineering / Biomedizinische Technik, 41 (s1), ISSN:0013-5585, ISSN:1862-278X

Human behavior about sliding their fingers on touch screens needs to be understood for the design of radial menus. For this purpose, data about the angles of finger sliding in performing radial pointing to eight predefined directions were collected. The optimal angle ranges and boundaries for these directions were then determined by the proposed mechanism. Consistent with previous research, results showed that the deviations of slide angles for the four diagonal directions were larger than that for the four orthogonal directions. Therefore, to reduce overall pointing errors, the angle ranges for the diagonal directions should be wider than that for the orthogonal directions. Based on the proposed mechanism, the total probability of pointing errors could be limited to 0.05%, compared to the error of 2.00% if the eight angle ranges were evenly divided by the radii of a regular octagon. Besides the angles, the lengths and starting points of the slides were reported and discussed along with the oblique effect, judder effect, and screen orientation. Possible applications of the proposed mechanism for dynamic and personalized radial menus are addressed. Further research would be worthwhile to examine the effects of screen orientation and the number of predefined directions on pointing performances. Moreover, extending the research to mid-air sliding gestures would be of interest and value in designing three-dimensional radial menus. Relevance to industry The proposed mechanism could effectively enhance the accuracy of the selections through radial menus, and could be applied to the remote controls via smart handheld devices.

Background: Large-scale examinations are costly and time consuming. Costs could be reduced by asking patients to carry out tests by themselves. This study aimed to gain practical experience on how patients handle self-administered acuity tests. Material and Methods: We developed two computerized self-test acuity screening devices consisting out of a commercially available vision screener, an answering box and a PC. The answering box served to record the responses of the participants and to present verbal instructions to the participants. Participants took acuity tests for far (5 m, OS, OD, OU) and an acuity test for near (40 cm, OU) using the self-test screener. For the reason of privacy personal data like age, gender and habitual correction was entered on a separate PC. The devices were installed in two different locations and run without supervision. Results: Personal data records of 2528 participants (4 % women) were collected in both locations. The age in 45 % of the participants ranged between 41 and 50 years. 31 % of the participants declared to wear spectacles and 3 % contact lenses. 66 % of participants declared not to need a correction. A total of 1078 participants completed four acuity tests (OD far, OS far, OU far, OD near) using the self-test screening device. Depending on the acuity test and location, the average duration required to complete one acuity test ranged between 29.7 s to 39.1 s. The total duration for completing the four acuity tests was on average 133 ± 46 s. Conclusions: The duration for completing the acuity tests is considered as being short. Made experience speaks in favor of feasibility of self-tests in acuity screening.

We developed a test for screening visual skills under similar conditions as at workplace. The test was administered to 207 participants, recruited in the working population. Six-digit numbers were super-imposed on a video of a drive and presented for 300 ms in the central visual field and in the periphery. Participants reported whether or not the integer '3' was included in the numbers. Normative data for the test were computed using 150 data sets of participants reporting not to take drugs and with an age ranging between 15 y and 67 y. Participants performed better in the central visual field than in periphery. The test could successfully be completed by participants of all ages without the need of adjustment of settings. Comparison of 46 data sets recorded in participants taking drugs (30 y-68 y) with age matched participants not taking drugs demonstrates an additional potential application of the test. Practitioner Summary: Developed test delivers comparative estimates of visual skills within short time and appears as valuable and cheap complementation to current testing procedures in industrial practice. The test can be used in a preventive and in educative manner to monitor effects of factors like fatigue, sleep deprivation or drug consumption.

Subjective observations made during routine examination of eye movement functions (orthoptic status) reveal that very slow, smooth-pursuit eye movements in cancer patients are irregular. To objectively measure such movements, a video-based system was built to allow analysis of very slow, smooth-pursuit eye movements (1.8 degrees /s). Analysis involves quantification of drift and jerk-like gaze movements that cause deviations in gaze direction from the predicted trajectory. Gaze deviations observed in cancer patients are compared to those for the normal population. Our results show that deviations are more important in cancer patients than in the normal population. The difference is statistically significant (p

In a typical environment for augmented reality, subjects were asked to detect visual information presented at 15–28° in the periphery of the visual field. Information was displayed tachistoscopically for 200, 300 and 600 ms. Popular low cost beamer producing colour breakup was used to present peripheral stimuli. We found that exposure time affects detectability of targets. By extrapolating our results we compute that for a 100% correct detection the stimulus must be displayed for at least 2 s. Age does not affect detectability.

In this study, a fully automatic vision screening system has been established. The present installation enables the testee to accomplish several vision tests in a self-examination environment, without requiring the assistance of a supervisor or examiner. Included vision tests are far- and near- visual acuity, color vision, stereo vision, contrast vision, and visual field test. Specifically designed vision test charts are used in order to provide an easy-to-understand task for the testee to perform. The screening system delivers an ergonomic task design regarding the user interface which includes the input device, software interface, and the test procedure. The whole system is portable and easy for setting up in various test environments. Test results are evaluated in real time by the computerized program and further provide the testee a printout sheet with examination results and necessary recommendations. Such a system is used for large vision screening campaigns in organizations and may be used in smart-home applications for self-health control.

Die derzeit haufig verwendeten neuropsychologischen Tests zur Fahreignungsprufung sind zwar schnell und einfach durchzufuhren, scheinen jedoch zu unspezifisch zu sein. Daher ist eine objektive, effiziente Untersuchungsmethode fur die Durchfuhrung eines solchen Screenings grosser Bevolkerungsanteile wunschenswert.

We assessed discomfort, time and number of saccades for reading a text superimposed to a moving background. When background moved in the main directions of reading (left to right or top to bottom), discomfort was rated significantly lower than when background moved in the opposite directions. Neither time for reading nor number of saccades are affected by background motion. We therefore conclude that increased arousal might be responsible to cope with effects of background motion, resulting in an increased stress and rising discomfort when background moves opposite to main directions of reading. The findings suggest that reading in Augmented Reality for mobile use must be considered as a robust process. However, load may be increased and cause complaints in a prolonged reading task.

Objectives: Hospitals have started to migrate their paper-based records to computerized patient records (CPR). The majority of today's CPR systems are stationary, which means that physicians use a clinical workstation to access CPR information. But health care professionals need to request and enter information at different locations, for example, on their daily ward round. This suggests the use of mobile computers, enabling an ubiquitous access to needed data. Different studies show that health care professionals are reluctant to use poorly designed mobile CPR systems, as the work at the point of care is very time-pressured and hectic. To design a system with high acceptance, it is essential to obtain empirical insight into the work practices and context in which the mobile CPR system will be used. Method: We investigated the physicians' work with the patient record during their daily round. With the help of a compact notation method, the physicians' interaction with the information system was recorded in real time. Fourteen physicians from three different departments (internal medicine, surgery, and geriatrics) of a middle-sized Swiss hospital participated in our study. Results: Physicians have clear access preferences when they interact with the patient record during their daily round. There exists a clear profile of access frequencies and patterns, respectively. As an example, approximately 50% of all patient record accesses concern information about medications, vital signs and lab test results. Discussion / conclusion: A CPR system which is designed to reflect the access frequencies and patterns should improve the efficiency of data entry and retrieval and thus result in a system with high acceptance among physicians in the demanding environment during hospital rounds.

Users of augmented reality (AR) must direct their attention toward real world as well as artificial information. The authors investigated some aspects of interference between the 2 sources of information that affect performance in completing a visual search task. The search task was carried out under 3 different conditions, 2 of them as found in AR in mobile systems. Participants were asked to detect a target that was superimposed on a background. Target and background were presented on a screen subtending a rectangular area of 55� � 43� (horizontal � vertical). The target appeared at 6 different locations on the screen. A video recording of a car drive served as the background. In 1 condition, the recording was replayed continuously. Static images of the record were sampled at 5-sec intervals and replayed as background in another condition. A uniform gray background served as a baseline.

We compared two algorithms, which are used to assess the number of forward saccades in a reading task from records of eye movements. In one algorithm saccades are detected analysing the velocity of eye movements. The third derivate of eye position in time (jerk) is used in the second algorithm for the detection of saccades. Both algorithms were applied on the same set of data, recorded using 24 subjects reading a German text, which was presented on two different displays. Our subjects read the text at a mean reading speed of 258.5 word/min. Both algorithms were found to produce a similar rate of artefacts in the number of detected saccades (2.5%), provided the threshold for detection (velocity or jerk) is set at an appropriate level and the same level of threshold is applied to all data. In both algorithms, the rate of artefacts increases with increasing distance of the threshold from its optimum. Inter-individual variation of the rate of artefacts increases more pronounced in the algorithm based on jerks. Eye blinks were identified as a major source of artefacts. A remedy is proposed, by means of which the rate of artefacts can be reduced.

In an explorative task subjects were asked to track a line presented in combination with other confusing lines on a 3D display. 24 subjects performed the explorative task under three depth cue conditions which were: stereopsis, movement parallax or a combination of stereopsis and movement parallax (stereo and parallax). Task performance was assessed by recording completion time and correctness of answer. The combination of stereopsis and movement parallax gave rise to highest percentage of correct answers (84%), followed by the condition where movement parallax was the only depth cue (80%). Percentage of correct answers in both conditions was found to be significantly higher than it was in the condition with stereopsis (60%). Mean completion time was about the same in the stereo and parallax condition and the stereopsis condition. Compared to the movement parallax condition both means were significantly decreased. Accuracy in completing the task was found to be similar in 3D displays enabling movement parallax and in 3D displays presenting stereoscopic images.

Two experiments were carried out in this study. The first experiment assessed a subject's performance while carrying out a visual search task using a liquid crystal display (LCD) and a cathode ray tube (CRT) with varying refresh rate (48–75 Hz). The subject's task consisted of detecting a target character among distractor characters presented in positive contrast. Search time was similar in all conditions of the experiment. Error frequency was correlated positively with the refresh rate of the CRT. However, this effect failed to be significant (p=0.090). In the condition where LCD was used, error frequency was found to be 22% lower when compared to the condition where the CRT was used with a refresh rate of 75 Hz. A second experiment aimed to assess the role of background luminance in the same task as reported above. The task was carried out on the liquid crystal LCD. The background luminance was varied between 45 and 150 cd/m2 at the LCD and between 45 and 110 cd/m2 at the CRT. Results of this experiment revealed no statistical significant effect of background luminance on visual performance (number of hits, search time). These findings suggest that replacing CRTs with LCDs will improve ergonomics in workplaces using visual displays. Improvements can also be achieved by increasing the refresh rate of the CRT but a very high refresh rate may be required.

We describe a computer-aided self-test vision screener for testing near and far visual acuity. The device generates images separately for each eye on a LCD. Acuity can be measured in the range between 0.1 and 1.6 for any distance between 0.34 m and 6 m. In addition, it also enables testing for colour deficiency, phoria, stereopsis and contrast sensitivity. The device is fully automatic and enables self-testing of the above mentioned functions. Initial practical application in an industrial environment has demonstrated the practicability of the device.

We investigated the perception of brightness for red monochromatic laser light. For this purpose, a modified virtual retinal display (VRD) was constructed. The modification involved projecting the laser beam into the eye. In our VRD, the laser beam pivots in the nodal point of the eye (badal system). The displayed image therefore does not depend on the refractive state of the eye. Brightness perception was assessed by means of psychophysical experiments. The results of these experiments indicate that perception of brightness at 652 nm increases more rapidly with increasing physical stimulus than does the perception of white light (colour temperature 2'935 K). At a wavelength of 652 nm, an optical power of 79 nW is required to produce an image subtending 2 degrees of equal brightness, as is perceived with an image of about 2'900 cd/m2 subtending 2 degrees.

Head-mounted displays (HMDs) are increasingly used in the field and in the laboratory. Prolonged use of HMDs requires their ergonomics to be optimized in order to reduce discomfort. Among factors causing visual load are the physical/optical properties of eyepieces used in HMDs. Many HMD eyepieces are adjusted manually to fit the individual requirements of the user. Proper adjustment of the eyepieces requires some knowledge of visual ergonomics. Additionally, in order to enable comfortable viewing, restrictions on the visual information presented in HMDs, such as the motion of objects in virtual depth, must be considered. Visual performance and therefore visual load depends on the display technology used in HMDs.

In an internal campaign, a large Swiss company carried out an instruction programme with employees concerning ergonomics at a VDU. Before and after this campaign, the existing conditions were recorded regarding ergonomics at the VDU workplace. At the same time, complaints, as well as individual knowledge and interest in ergonomics, were recorded. Based on the information at hand, it can be assumed that the campaign improved the existing conditions of ergonomics, as well as the self-responsibility on the part of those involved. A compilation of the work involved indicates that a training course with the objective of influencing ergonomics at the place of work was cost effective.

Aim : In this study a computer-based approach using random-dot stereograms (RDS) to assess stereopsis is presented for screening applications. Method : The TNO-test is a common method to assess stereopsis using anaglyphic RDS. This technique was transferred to computer-based use. The efficiency of the computer-based approach was analysed by testing 25 subjects for stereopsis using the computer-based approach and the TNO-test. Results : The generation of RDS did not allow an exact separation when using colour filters, regarding the spectral emission of the monitor. An adjustment of the RDS colours to the available colour filters and the spectral emission of the monitor allowed a sufficient separation. The resolution of the monitor required a viewing distance of 2 m. The results from testing the subjects did not produce a significant difference between the methods. Conclusions : A computer-based assessment of stereopsis could use analgyphic methods. The influence of the spectral emission of a monitor with cathode ray tubes and its resolution can be ignored after an optimisation of the colours to generate the RDS and an increased viewing distance for the computer-based use.

Cathode ray tube (CRT) display and liquid crystal display (LCD) were compared for their suitability in visual tasks. For this purpose visual performance was assessed by means of a search task carried out using both displays with different levels of ambient light. In addition, suitability was rated subjectively by users of visual display units (VDUs). Error frequency for search tasks carried out using LCD were significantly smaller when compared to error frequency for tasks at CRT. LCD gave rise to 34% less errors than did CRT. Reaction time in search task was found to be significantly shorter using LCD when tasks were carried out in darkness. Subjective rated suitability of LCD was scored twice as high as suitability of CRT. Results indicate that LCD used in this experiment may give better viewing conditions in comparison to CRT display.