Mobile Eye Research Articles

Eye Tracking in Dogs: Achievements and Challenges.

In this article, we review eye-tracking studies with dogs (Canis familiaris) with a threefold goal; we highlight the achievements in the field of canine perception and cognition using eye tracking, then discuss the challenges that arise in the application of a technology that has been developed in human psychophysics, and finally propose new avenues in dog eye-tracking research. For the first goal, we present studies that investigated dogs' perception of humans, mainly faces, but also hands, gaze, emotions, communicative signals, goal-directed movements, and social interactions, as well as the perception of animations representing possible and impossible physical processes and animacy cues. We then discuss the present challenges of eye tracking with dogs, like doubtful picture-object equivalence, extensive training, small sample sizes, difficult calibration, and artificial stimuli and settings. We suggest possible improvements and solutions for these problems in order to achieve better stimulus and data quality. Finally, we propose the use of dynamic stimuli, pupillometry, arrival time analyses, mobile eye tracking, and combinations with behavioral and neuroimaging methods to further advance canine research and open up new scientific fields in this highly dynamic branch of comparative cognition.

Moderate Severity SARS-CoV-2 (COVID-19) Affects Ocular Vergence Indices: Eye Tracking-Based Study.

Since the start of the SARS-CoV-2 (COVID-19) pandemic, it has become clear that the brain is one of the main targets for acute and chronic damage. Although neurodegenerative changes have yet to be investigated, there is already a large body of data on damage to its fiber tracts. A mobile eye tracker is possibly one of the best tools to study such damage in a COVID hospital setting. At the same time, the available data indicate that eye tracking parameters, even in healthy volunteers, demonstrate a distinct gender-specific difference.The aim of the work is to evaluate functional and structural impairments of the fiber tracts and to find possible gender-specific dynamics of eye tracking indicators in the acute period of COVID-19 pneumonia (Delta variant) of moderate severity. A single-center non-randomized retrospective study included 84 patients in the acute period of moderate severity SARS-CoV-2 (COVID-19) pneumonia (Delta variant) (Group 1). The mean time from admission was 1.4±1.2days. M:41, F:43. According to thoracic CT, the lung involvement ranged from CT 1 to CT 2. SpO2 ranged from 95% to 99%. The mean age was 35.5±14.8years (from 18 to 60). The control group (Group 2) included 158 healthy volunteers without pathology of the vision organs and central nervous system.The eye vergence index (VRx) was determined using eye tracking as a motion correlation coefficient between the angular velocities of the left and right eyeballs and was a measure of the conjugation of horizontal and vertical eye movements.The mobile complex Eye Tracker Low-Speed 20 (BVG LLC, the Netherlands) was used. Eye tracking parameters were assessed by vertical and horizontal eye vergence (VVRx and HVRx).Statistical analysis was done using the methods of parametric and non-parametric statistics. Moderate COVID-19 pneumonia resulted in a significant decrease in both VVRx and HVRx compared to controls (0.763±0.127 and 0.856±0.043; p<0.000001; 0.729±0.018 and 0.776±0.023 p<0.000001, respectively). VVRx values were significantly higher in men (0.775±0.046 and 0.747±0.091, p=0.019, respectively), while ХVRx values were significantly higher in women (0.665±0.018 and 0.728±0.024, p<0.0000001, respectively). SARS-CoV-2 (COVID-19) of moderate severity is accompanied by a significant deterioration in eye tracking performance proving functional and structural impairments (p<0.05). VVRx was significantly higher in men, and HVRx was substantially greater in women reflecting gender-specific differences.

Using Natural Head Movements to Continually Calibrate EOG Signals.

Electrooculography (EOG) is the measurement of eye movements using surface electrodes adhered around the eye. EOG systems can be designed to have an unobtrusive form-factor that is ideal for eye tracking in free-living over long durations, but the relationship between voltage and gaze direction requires frequent re-calibration as the skin-electrode impedance and retinal adaptation vary over time. Here we propose a method for automatically calibrating the EOG-gaze relationship by fusing EOG signals with gyroscopic measurements of head movement whenever the vestibulo-ocular reflex (VOR) is active. The fusion is executed as recursive inference on a hidden Markov model that accounts for all rotational degrees-of-freedom and uncertainties simultaneously. This enables continual calibration using natural eye and head movements while minimizing the impact of sensor noise. No external devices like monitors or cameras are needed. On average, our method's gaze estimates deviate by 3.54° from those of an industry-standard desktop video-based eye tracker. Such discrepancy is on par with the latest mobile video eye trackers. Future work is focused on automatically detecting moments of VOR in free-living.

Methodological limits on sampling visual experience with mobile eye tracking

Methodological limits on sampling visual experience with mobile eye tracking

Cognitive load, working memory capacity and driving performance: A preliminary fNIRS and eye tracking study

A common cause of road traffic incidents is driver distraction, which can occur when the driver’s attention is engaged in a concurrent secondary task. However, the relationship between cognitive demands, individual differences in working memory capacity and driving performance has received little research attention. Using a fixed-base driving simulator, the aim of this study was to use a combination of self-report, functional near infrared spectroscopy (fNIRS) and mobile eye tracking data to investigate the impact of cognitive load on drivers’ gaze behaviour and driving performance, as well as explore the relationship between working memory capacity and driving performance under increased cognitive load. Twenty-one participants with a range of driving experiences (e.g., 0–14 h per week) completed a simulated driving task in a simple environment (i.e., country highway) under single-task (driving only) and dual-task (driving + modified 2-back task) conditions. Cognitive load was assessed via fNIRS data that manifested as changes in regional oxygen saturation (rSO2) in prefrontal cortex as well as self-report data of perceived mental effort. Participants’ working memory capacity was assessed using the Operation Span Task. Findings showed that prefrontal rSO2 and perceived mental effort was significantly greater under dual-task conditions compared to the single-task condition. In the dual-task condition, participants’ gaze dwelled for longer on the road and they made fewer fixations, of longer durations. Participants were able to maintain driving performance in this condition, although this was at the expense of secondary task performance. Interestingly, driving infractions under dual-task conditions were negatively correlated with participants’ working memory capacity. The findings suggest that engaging with distracting secondary tasks while driving may increase drivers’ cognitive load and change their gaze behaviour. Driving performance can seemingly be maintained under such conditions, but this may be partly determined by the driver’s working memory capacity.

Vision Bus Aotearoa: a platform for strengthening eye health teaching, research and community partnership

ABSTRACT Clinical Relevance Vision Bus Aotearoa is a fully equipped mobile eye health clinic designed to provide a novel platform for undergraduate optometry clinical training, community eye health research and deliver services to underserved communities. Background Aotearoa New Zealand has inequitable access to eye health care. Vision Bus Aotearoa aims to work in partnership with communities to provide comprehensive mobile primary eye health care services while training optometry students, and integrating community eye health research. Methods A description is provided of the governance model which has been involved throughout the project. Results The process of vehicle manufacture, clinical set-up, funding models and service delivery are described. The aims of the project are detailed in terms of optometry teaching, clinical services in partnership with communities, and research integration and implementation. Conclusion Vision Bus Aotearoa represents a valuable opportunity to deliver mobile eye health care to historically underserved communities, enhance undergraduate optometry teaching and to provide a unique platform for community eye health research.

Prevalence of hypertensive retinopathy among the known diabetics in a community-based setting using a non-mydriatic fundus camera

Hypertension is a leading cause of morbidity and mortality and is associated with the risk of cardiovascular, cerebrovascular disease, and target organ damage. The risk increases exponentially in individuals with diabetes. Hypertensive retinopathy is a marker for target organ damage, so screening for hypertensive retinopathy helps in cardiovascular risk stratification. This study was conducted with an objective to screen for hypertensive retinopathy among known diabetics using a portable non-mydriatic fundus camera to ascertain its prevalence. The study was conducted in three selected field practice areas of the Department of Community Medicine. A house-to-house survey was performed using a predesigned, pretested questionnaire among 302 known diabetics. The study participants were subjected to visual acuity examination using Snellen's chart and retinal fundus examination using a portable non-mydriatic Bosch Mobile Eye Care Solutions fundus camera. The fundus images were transferred to a laptop and were reviewed and graded by an experienced Ophthalmologist. Among the 302 participants studied, 60 were diagnosed with hypertensive retinopathy. The prevalence of hypertensive retinopathy among diabetic patients was 19.9 % (95% CI: 15.7% - 24.6%). The prevalence was found to be higher in ** (21.8%; 95% CI: 16% - 28.6%) as compared to ** (17.5%; 95% CI: 11.8% - 24.6%). Early detection of hypertensive retinopathy with cardiovascular risk stratification and initiation of prompt treatment among the high-risk individuals will help reduce the morbidity caused due to end-organ damage and premature mortality to a greater extent and will pave the way forward to achieving sustainable developmental goals.

Tracking visual attention during learning of complex science concepts with augmented 3D visualizations

The main purpose of the study was to explore how different augmented 3D visualizations may affect the learning of complex science concepts using the eye tracking method. An Augmented Reality (AR) learning system incorporated with different 3D visualizations was developed to assist conceptual learning in the topic of “molecular shapes.” Learners' visual attention during the AR learning was recorded using a mobile eye tracking system. Participants were 32 10th grade students. Pre- and post-tests were used to assess students' learning achievements. Learners were grouped into low and high achievers according to the posttest result. To analyze the associations between learners' visual attentions and learning achievements, correlation, t-test, correlation, and regression analyses were applied. Additionally, we conducted lag sequential analysis (LSA) to compare the visual transitions of different groups of achievers. The results showed that learners’ conceptual understanding was improved after the AR learning activity. Among the different 3D visualizations, learners attended more to the static and dynamic types in the basic learning stage and to the static and interactive types in the advanced learning stage. Attention to the 3D static model was found to associate more to the attention to the interactive type. The correlation and regression analyses found that the cognitive effort to integrate information about the static 3D model was the key predictor for the learning achievement. LSA showed that high achievers displayed a higher chance of looking back to the static 3D model from other AOIs. The visual pattern analysis suggested that a guidance to connect information delivered by the static and the animated visual representations is necessary for complex conceptual learning.

Eye-Head-Body Coordination in the Motor-Memory Trade-off

Previous studies have demonstrated that people trade off between expending motor effort and memorization effort when completing a copying task that requires looking in different directions to gather information. When information is easy to gather with minimal movement, people choose to look more frequently and rely on less on memorization, however, they reduce motor effort and rely on memory more when looking requires larger (and more effortful) shifts of gaze. This paper investigated the eye-head-body movements that guided looking as well as participants’ trade-off between using motor effort and memory in a copying task. We add to prior work by characterizing the coordination between eyes, head, and body required to look at targets at different angles. In the task, participants copied models onto a board while wearing a mobile eye tracker that measured eye rotations and motion sensors that measured head rotations. We manipulated the angle of the model relative to the participant and the memorization difficulty of the models. Results showed that eye movements contributed more to small gaze shifts but the head and body contributed more as the angle of the target increased (requiring larger amplitude shifts of gaze). Participants chose to look frequently when models were adjacent to the workspace, but chose to rely more on memory for models that required greater shifts of gaze. Memorization difficulty affected the trade-off such that participants used more memory when the models were easy to remember. We discuss how participants’ decisions to look versus remember may depend on the contribution of eyes, head, and body to shift gaze by varying amplitudes.

Enhancing User Experience in Fashion m-Retail: Mapping Shopping User Journey Using Google Analytics, Eye Tracking Technology and Retrospective Think Aloud Interview

With increased mobile traffic to fashion retailers’ websites, conversion rates are lower than for desktop users. Mobile consumers more readily abandon retailers if not satisfied with their shopping experience. There is a dearth of literature involving Google Analytics to analyze digital consumer shopping behavior and customer journeys. Retailers need to innovate the ways they approach the vast amount of digital analytics data. This research highlights the need for continuous auditing of Google Analytics data to ensure retailers understand the behavior of their mobile consumers and respond to their needs accordingly. A multi-method research design incorporated mobile fashion consumer data from Google Analytics, innovative mobile eye tracking technology and retrospective think aloud. A comparison of consumer shopping journeys showed that a Digital User Journey Mapping Framework based on eye tracking data can be used to audit Google Analytics datasets and to understand what elements of the fashion retailer’s website consumers prefer to interact with. Retrospective think aloud interviews complementing eye tracking experiments define how digital user experience can be improved in fashion m-retail. The shopping journey map framework can be used for mobile fashion consumer behavior analysis, auditing Google Analytics datasets and enhancing digital user experience.

Generating accurate 3D gaze vectors using synchronized eye tracking and motion capture.

Assessing gaze behavior during real-world tasks is difficult; dynamic bodies moving through dynamic worlds make gaze analysis difficult. Current approaches involve laborious coding of pupil positions. In settings where motion capture and mobile eye tracking are used concurrently in naturalistic tasks, it is critical that data collection be simple, efficient, and systematic. One solution is to combine eye tracking with motion capture to generate 3D gaze vectors. When combined with tracked or known object locations, 3D gaze vector generation can be automated. Here we use combined eye and motion capture and explore how linear regression models generate accurate 3D gaze vectors. We compare spatial accuracy of models derived from four short calibration routines across three pupil data inputs: the efficacy of calibration routines was assessed, a validation task requiring short fixations on task-relevant locations, and a naturalistic object interaction task to bridge the gap between laboratory and "in the wild" studies. Further, we generated and compared models using spherical and Cartesian coordinate systems and monocular (left or right) or binocular data. All calibration routines performed similarly, with the best performance (i.e., sub-centimeter errors) coming from the naturalistic task trials when the participant is looking at an object in front of them. We found that spherical coordinate systems generate the most accurate gaze vectors with no differences in accuracy when using monocular or binocular data. Overall, we recommend 1-min calibration routines using binocular pupil data combined with a spherical world coordinate system to produce the highest-quality gaze vectors.

Evaluating the integration of eye-tracking and motion capture technologies: Quantifying the accuracy and precision of gaze measures.

Integrating mobile eye tracking and optoelectronic motion capture enables point of gaze to be expressed within the laboratory co-ordinate system and presents a method not commonly applied during research examining dynamic behaviors, such as locomotion. This paper examines the quality of gaze data collected through the integration. Based on research suggesting increased viewing distances are associated with reduced data quality; the accuracy and precision of gaze data as participants (N = 11) viewed floor-based targets at distances of 1–6 m was investigated. A mean accuracy of 2.55 ± 1.12° was identified, however, accuracy and precision measures (relative to targets) were significantly (p < .05) reduced at greater viewing distances. We then consider if signal processing techniques may improve accuracy and precision, and overcome issues associated with missing data. A 4th-order Butterworth lowpass filter with cut-off frequencies determined via autocorrelation did not significantly improve data quality, however, interpolation via Quintic spline was sufficient to overcome gaps of up to 0.1 s. We conclude the integration of gaze and motion capture presents a viable methodology in the study of human behavior and presents advantages for data collection, treatment, and analysis. We provide considerations for the collection, analysis, and treatment of gaze data that may help inform future methodological decisions.

A Multi-Modal Gait Database of Natural Everyday-Walk in an Urban Environment

Human gait data have traditionally been recorded in controlled laboratory environments focusing on single aspects in isolation. In contrast, the database presented here provides recordings of everyday walk scenarios in a natural urban environment, including synchronized IMU−, FSR−, and gaze data. Twenty healthy participants (five females, fifteen males, between 18 and 69 years old, 178.5 ± 7.64 cm, 72.9 ± 8.7 kg) wore a full-body Lycra suit with 17 IMU sensors, insoles with eight pressure sensing cells per foot, and a mobile eye tracker. They completed three different walk courses, where each trial consisted of several minutes of walking, including a variety of common elements such as ramps, stairs, and pavements. The data is annotated in detail to enable machine-learning-based analysis and prediction. We anticipate the data set to provide a foundation for research that considers natural everyday walk scenarios with transitional motions and the interaction between gait and gaze during walking.

Do pupillary responses during authentic slot machine use reflect arousal or screen luminance fluctuations? A proof-of-concept study.

Modern slot machines are among the more harmful forms of gambling. Psychophysiological measures may provide a window into mental processes that underpin these harms. Here we investigated pupil dilation derived from eye tracking as a means of capturing changes in sympathetic nervous system arousal following outcomes on a real slot machine. We hypothesized that positively reinforcing slot machine outcomes would be associated with increases in arousal, reflected in larger pupil diameter. We further examined the contribution of game luminance fluctuations on pupil diameter. In Experiment 1A, experienced slot machine gamblers (N = 53) played a commercially-available slot machine in a laboratory for 20 minutes while wearing mobile eye tracking glasses. Analyses differentiated loss outcomes, wins, losses-disguised-as-wins, and (free-spin) bonus features. Bonus features were associated with rapid increases in pupil diameter following the onset of outcome-related audiovisual feedback, relative to losses. In Experiment 1B, luminance data were extracted from captured screen videos (derived from Experiment 1A) to characterize on-screen luminance changes that could modulate pupil diameter. Bonus features and wins were associated with pronounced and complex fluctuations in screen luminance (≈50 L and ≈25L, respectively). However, the pupil dilation that was observed to bonus features in Experiment 1A coincided temporally with only negligible changes in screen luminance, providing partial evidence that the pupil dilation to bonus features may be due to arousal. In Experiment 2, 12 participants viewed pairs of stimuli (scrambled slot machine images) at luminance difference thresholds of ≈25L, ≈50L, and ≈100L. Scrambled images presented at luminance differences of ≈25L and greater were sufficient to cause pupillary responses. Overall, pupillometry may detect event-related changes in sympathetic nervous system arousal following gambling outcomes, but researchers must pay careful attention to substantial in-game luminance changes that may confound arousal-based interpretations.

External focus facilitates cognitive stability and promotes motor performance of an interceptive task in children

ABSTRACT Recent evidence suggests that one of the benefits of external focus is facilitating task focus. To this extent, an external focus might influence cognitive function. To help elucidate the underlying mechanisms of attentional focus instructions, the aim of this study was to examine the influence of attentional focus instructions on cognitive stability and task focus, as indicated by the number of eye blinks, during an interceptive timing task with children who are at a crucial stage of motor coordination development. Twenty-four children (M age = 10.4 ± 0.9 years) performed a forehand drag shot with a floorball stick to hit a tennis ball at a target in each of three different attentional focus conditions: external focus “focus on the blade of the stick”, internal focus “focus on their hands”, and control (no focus instructions). A mobile eye tracker was used to record the number of eye blinks from the moment that the tennis ball was released by an experimenter from the top of a boccia ramp to the moment of the initial movement of the floorball stick. Results showed that the accuracy of hits was significantly better in the external focus relative to the internal focus condition. Also, the number of eye blinks was significantly lower in the external focus relative to the internal focus and control conditions. Findings suggest that improved cognitive stability and task focus may underlie the improved performance associated with an external focus in a visually demanding motor task in children.

Investigating visual expertise in sculpture: A methodological approach using eye tracking.

Research on visual expertise has progressed significantly due to the availability of eye tracking tools. However, attempts to bring together research on expertise and eye tracking methodology provoke several challenges, because visual information processes should be studied in authentic and domain-specific environments. Among the barriers to designing appropriate research are the proper definition of levels of expertise, the tension between internal (experimental control) and external (authentic environments) validity, and the appropriate methodology to study eye movements in a three-dimensional environment. This exploratory study aims to address these challenges and to provide an adequate research setting by investigating visual expertise in sculpting. Eye movements and gaze patterns of 20 participants were investigated while looking at two sculptures in a museum. The participants were assigned to four different groups based on their level of expertise (laypersons, novices, semi-experts, experts). Using mobile eye tracking, the following parameters were measured: number of fixations, duration of fixation, dwell time in relevant areas, and revisits in relevant areas. Moreover, scan paths were analysed using the eyenalysis approach. Conclusions are drawn on both the nature of visual expertise in sculpting and the potential (and limitations) of empirical designs that aim to investigate expertise in authentic environments.

Adolescents reading texts in LexiaD, a dyslexia-specific Cyrillic font: A mobile eye-tracking study

Recently, LexiaD, a dyslexia-specific Cyrillic font, was tested alongside the widely used Arial font in an experiment during which adolescents with and without dyslexia silently read sentences on a computer screen (Alexeeva et al., 2022). LexiaD showed a worse performance than Arial at the beginning of the experiment, but by the end of it, LexiaD demonstrated a positive effect in feature extraction and similar performance in lexical access, text integration, and global reading processing. We suggest that Arial’s initial advantage can be explained either by its familiarity or by its design features. The current study aims to test these assumptions in adolescents without dyslexia by comparing LexiaD with two popular fonts familiar to adolescents: Times New Roman and Roboto (a default font for the Google applications that is similar to Arial). Participants silently read printed versions of three texts (one in each of the three fonts) while their eye movements were recorded using a mobile eye tracker (Pupil Core glasses). In reading speed measures, Roboto outperformed LexiaD, whereas we found no evidence that Times New Roman’s performance was better than that of LexiaD. Moreover, there was no evidence that the control fonts differed in terms of subjective font familiarity. Therefore, we speculate that it was the design features that contributed the most to Arial becoming a facilitating font in the previous experiment. A study that investigates the efficiency of LexiaD, Arial/Roboto, and Times New Roman in a less experienced group (with participants less accustomed to particular fonts) is required to replicate our results. Involving people with dyslexia in future studies is extremely important.

A Spiral into the Mind

Comparing mobile eye tracking data from multiple participants without information about areas of interest (AOIs) is challenging because of individual timing and coordinate systems. We present a technique, the gaze spiral, that visualizes individual recordings based on image content of the stimulus. The spiral layout of the slitscan visualization is used to create a compact representation of scanpaths. The visualization provides an overview of multiple recordings even for long time spans and helps identify and annotate recurring patterns within recordings. The gaze spirals can also serve as glyphs that can be projected to 2D space based on established scanpath metrics in order to interpret the metrics and identify groups of similar viewing behavior. We present examples based on two egocentric datasets to demonstrate the effectiveness of our approach for annotation and comparison tasks. Our examples show that the technique has the potential to let users compare even long-term recordings of pervasive scenarios without manual annotation.

Beyond the smartphone's mere presence effect: A quantitative mobile eye tracking study on the visual and internal distraction potential of smartphones

Smartphones are a daily companion and ensure users' constant connectedness. In the context of focused work, however, smartphone presence may be problematic. Previous research has shown that even the mere presence of smartphones is distracting. The present study reexamined the smartphone's mere presence effect on performance. In addition, we investigated whether the mere presence of smartphones is visually distracting or creates smartphone-related thoughts. In a laboratory experiment, we compared participants (N = 103) with their smartphone present versus absent. Using mobile eye tracking glasses, we tracked how often people looked at their smartphone while performing cognitive and reading tasks. Our study could not replicate the negative effect of smartphone presence on performance. Results revealed that people rarely looked at their smartphones during the tasks. However, smartphones drew users' visual attention during breaks and transitions between tasks. We also showed that smartphone presence increased smartphone vigilance but had no effect on task performance. Our study contributes to understanding the underlying mechanisms of the smartphone's mere presence effects on performance. With this study, we extend previous research by showing that people can regulate their visual attention to smartphones.

Adaptations in Visual Search Behaviour as a Function of Expertise in Rugby Union Players Completing Attacking Scenarios.

The current study investigated the adaptations which occur in visual search behaviour as a function of expertise in rugby union players when completing attacking scenarios. Ten experienced players (EP) and ten novice players (NP) completed 2 vs. 1 attacking game scenarios. Starting with the ball in hand and wearing a mobile eye tracker throughout, participants were required to score a try against a defender. The scenarios allowed for a pass to their supporting player (Spin Pass or Switch) or trying to run past the defender (Take-Player-On or Dummy Switch). No between group differences were found in fixating on the supporting attacking player (p > 0.05). However, EP increased the length (p = 0.008) and frequency (p = 0.004) looking at the area immediately ahead of the supporting player, particularly when executing a spin pass. NP fixated longer (p = 0.005) and more frequently (p = 0.032) at the defender, whilst EP fixated more frequently in the space the supporting player would run into in Switch and Dummy Switch scenarios (p = 0.025). More successful passes were completed and tries scored by EP compared to NP (p = 0.001). Differences in visual search behaviour between experienced and NP suggest that the experts extract information from areas directly related to guiding the motor action; the space immediately ahead of the support player to pass the ball in. Contrastingly, novices use a more allocentric perspective where the actions from the defender are used to guide their motor actions.