Unobtrusive Refractive Power Monitoring: Using EOG to Detect Blurred Vision.

The rise in population and aging has led to a significant increase in the number of individuals affected by common causes of vision loss. Early diagnosis and treatment are crucial to avoid the consequences of visual impairment. However, in early stages, many visual problems are making it difficult to detect. Visual adaptation can compensate for several visual deficits with adaptive eye movements. These adaptive eye movements may serve as indicators of vision loss. In this work, we investigate the association between eye movement and blurred vision. By using Electrooculography (EOG) to record eye movements, we propose a new tracking model to identify the deterioration of refractive power. We verify the technical feasibility of this method by designing a blurred vision simulation experiment. Six sets of prescription lenses and a pair of flat lenses were used to create different levels of blurring effects. We analyzed binocular movements through EOG signals and performed a seven-class classification using the ResNet18 architecture. The results revealed an average classification accuracy of 94.7% in the subject-dependent model. However, the subject-independent model presented poor performance, with the highest accuracy reaching only 34.5%. Therefore, the potential of an EOG-based visual quality monitoring system is proven. Furthermore, our experimental design provides a novel approach to assessing blurred vision.

Identification of Language-Induced Mental Load from Eye Behaviors in Virtual Reality.

Experiences of virtual reality (VR) can easily break if the method of evaluating subjective user states is intrusive. Behavioral measures are increasingly used to avoid this problem. One such measure is eye tracking, which recently became more standard in VR and is often used for content-dependent analyses. This research is an endeavor to utilize content-independent eye metrics, such as pupil size and blinks, for identifying mental load in VR users. We generated mental load independently from visuals through auditory stimuli. We also defined and measured a new eye metric, focus offset, which seeks to measure the phenomenon of "staring into the distance" without focusing on a specific surface. In the experiment, VR-experienced participants listened to two native and two foreign language stimuli inside a virtual phone booth. The results show that with increasing mental load, relative pupil size on average increased 0.512 SDs (0.118 mm), with 57% reduced variance. To a lesser extent, mental load led to fewer fixations, less voluntary gazing at distracting content, and a larger focus offset as if looking through surfaces (about 0.343 SDs, 5.10 cm). These results are in agreement with previous studies. Overall, we encourage further research on content-independent eye metrics, and we hope that hardware and algorithms will be developed in the future to further increase tracking stability.

Influence of wearing complete dentures on control of head position during walking in edentulous older adults.

BACKGROUND: Coordination between the trunk and head is considered important for walking stability. Recent studies have reported that wearing complete dentures could improve trunk stability during walking; however, its effect on the head has not been clarified. OBJECTIVE: This study aimed to clarify the effect of complete dentures on head stability during walking in edentulous older adults. METHODS: Twenty edentulous older adults (11 men and 9 women; mean age, 78.6 ± 5.8 years) who used complete dentures were included in the study. Acceleration and angle rate sensors were placed on the participants' brow, chin and waist, and they were asked to walk a 20-m passage under two conditions: with and without dentures. The outcomes used to assess head stability were the variance values of acceleration and angle rate, the peak-to-peak values, harmonic ratio, root mean square, integrated values of the difference and dynamic time warping data obtained from the sensors. The variance values of the brow acceleration were compared using a paired t-test, and other outcomes were compared using a Wilcoxon signed-rank test. All significance levels were set at 5%. RESULTS: In acceleration without dentures, the variance values of the chin and the peak-to-peak values of the brow and chin were significantly larger than with dentures. Angle rate without dentures, the variance values and the peak-to-peak values of the brow and chin were also significantly larger than with dentures. CONCLUSION: Wearing complete dentures while walking might improve head stability and contribute to walking stability in edentulous older adults.

Effects of AR-Based Home Appliance Agents on User's Perception and Maintenance Behavior.

Maintenance of home appliances can be tedious. Maintenance work can be physically demanding and it is not always easy to know the cause of a malfunctioning appliance. Many users need to motivate themselves to perform maintenance work and consider it ideal for home appliances to be maintenance-free. On the other hand, pets and other living creatures can be taken care of with joy and without much pain, even if they are difficult to take care of. To alleviate the hassle associated with the maintenance of home appliances, we propose an augmented reality (AR) system to superimpose an agent over the home appliance of concern who changes their behavior according to the internal state of the appliance. Taking a refrigerator as an example, we verify whether such AR agent visualization motivates users to perform maintenance work and reduces the associated discomfort. We designed a cartoon-like agent and implemented a prototype system using a HoloLens 2, which can switch between several animations depending on the internal state of the refrigerator. Using the prototype system, a Wizard of Oz user study comparing three conditions was conducted. We compared the proposed method (Animacy condition), an additional behavior method (Intelligence condition), and a text-based method as a baseline for presenting the refrigerator state. In the Intelligence condition, the agent looked at the participants from time to time as if it was aware of them and exhibited help-seeking behavior only when it was considered that they could take a short break. The results show that both the Animacy and Intelligence conditions induced animacy perception and a sense of intimacy. It was also evident that the agent visualization made the participants feel more pleasant. On the other hand, the sense of discomfort was not reduced by the agent visualization and the Intelligence condition did not improve the perceived intelligence or the sense of coercion further compared to the Animacy condition.

The Effects of Speed-Modulated Visual Stimuli Seen through Smart Glasses on Work Efficiency after Viewing.

It is known that subjective time and work efficiency are affected by visual stimuli. However, existing studies only consider the effects of visual information on the user during viewing and ignore the after effects. Using smart glasses lets users see visual information while moving until just before arriving at the office or school. We hypothesize that the user's effects from the visual information they were looking at just before working or studying affects the subsequent work. Through two user studies, we investigated whether information presented on smart glasses affected subsequent work efficiency. In the first experiment, participants were presented with avatars running at two levels of speed, or no avatars, through simulated smart glasses in a virtual environment. They then solved a dot-clicking task on a desktop monitor. In the second experiment, we investigated whether the same effect could be shown while walking in the real environment, with a running and a fast-walking avatar both at the same speed in order to see the difference in the effects of the different movements. In the first experiment, we confirmed that the speed of later work tended to improve when presenting the running human-shaped avatar. From the results of the second experiment, which was conducted in the real environment, we did not confirm that the subsequent work speed varied depending on the type of avatar being displayed. As a reason for the trend of improvement in the task efficiency in the first experiment, observation of fast human motion may have unconsciously accelerated the observers' body movement speed due to the mirror neuron mechanism. As a reason for why the work speed did not improve in the second experiment, the participants may be affected by other pedestrians and running cars. Additionally, it was difficult to see the images on the smart glasses while walking in the real environment.

Optical see-through augmented reality displays with wide field of view and hard-edge occlusion by using paired conical reflectors.

Optical see-through head-mounted displays are actively developed in recent years. An appropriate method for mutual occlusion is essential to provide a decent user experience in many application scenarios of augmented reality. However, existing mutual occlusion methods fail to work well with a large field of view (FOV). In this Letter, we propose a double-parabolic-mirror structure that renders hard-edge occlusion within a wide FOV. The parabolic mirror increases the numerical aperture of the system significantly, and the usage of paired parabolic mirrors eliminates most optical aberrations. A liquid crystal on silicon device is introduced as the spatial light modulator for imaging a bright see-through view and rendering sharp occlusion patterns. A loop structure is built to eliminate vertical parallax. The system is designed to obtain a maximum monocular FOV of H114∘×V95∘ with hard-edge occlusion, and a FOV of H83.5∘×V53.1∘ is demonstrated with our bench-top prototype.

Head-Mounted Display with Increased Downward Field of View Improves Presence and Sense of Self-Location.

Common existing head-mounted displays (HMDs) for virtual reality (VR) provide users with a high presence and embodiment. However, the field of view (FoV) of a typical HMD for VR is about 90 to 110 [deg] in the diagonal direction and about 70 to 90 [deg] in the vertical direction, which is narrower than that of humans. Specifically, the downward FoV of conventional HMDs is too narrow to present the user avatar's body and feet. To address this problem, we have developed a novel HMD with a pair of additional display units to increase the downward FoV by approximately 60 ( 10+50) [deg]. We comprehensively investigated the effects of the increased downward FoV on the sense of immersion that includes presence, sense of self-location (SoSL), sense of agency (SoA), and sense of body ownership (SoBO) during VR experience and on patterns of head movements and cybersickness as its secondary effects. As a result, it was clarified that the HMD with an increased FoV improved presence and SoSL. Also, it was confirmed that the user could see the object below with a head movement pattern close to the real behavior, and did not suffer from cybersickness. Moreover, the effect of the increased downward FoV on SoBO and SoA was limited since it was easier to perceive the misalignment between the real and virtual bodies.