bluuebunny/crossref_metadata_2025 huggingface dataset:
Microsaccade-induced prolongation of saccade latencies depends on microsaccade amplitude
Authors: Rolfs Martin , Laubrock Jochen , Kliegl Reinhold
Published: February 2021

Fixations consist of small movements including microsaccades, i.e., rapid flicks in eye position that replace the retinal image by up to 1 degree of visual angle. Recently, we showed in a delayed-saccade task (1) that the rate of microsaccades decreased in the course of saccade preparation and (2) that microsaccades occurring around the time of a go signal were associated with prolonged saccade latencies (Rolfs et al., 2006). A re-analysis of the same data set revealed a strong dependence of these findings on microsaccade amplitude. First, microsaccade amplitude dropped to a minimum just before the generation of a saccade. Second, the delay of response saccades was a function of microsaccade amplitude: Microsaccades with larger amplitudes were followed by longer response latencies. These finding were predicted by a recently proposed model that attributes microsaccade generation to fixation-related activity in a saccadic motor map that is in competition with the generation of large saccades (Rolfs et al., 2008). We propose, therefore, that microsaccade statistics provide a behavioral correlate of fixation-related activity in the oculomotor system.
Multimodal Comprehension of Language and Graphics: Graphs with and without annotations
Authors: Acarturk Cengiz , Habel Christopher , Cagiltay Kursat , Alacam Ozge
Published: February 2021

An experimental investigation into interaction between language and information graphics in multimodal documents served as the basis for this study. More specifically, our purpose was to investigate the role of linguistic annotations in graph-text documents. Participants were presented with three newspaper articles in the following conditions: one text-only, one text plus non-annotated graph, and one text plus annotated graph. Results of the experiment showed that, on one hand, annotations play a bridging role for integration of information contributed by different representational modalities. On the other hand, linguistic annotations have negative effects on recall, possibly due to attention divided by the different parts of a document.
Schedule of the 13th European Conference on Eye Movements 2005
Authors: Groner Marina , Groner Rudolf , Müri R. , Koga Kazuo , Raess Simon , P. P
Published: February 2021

This document contains the schedule of the 13th European Conference on Eye Movements, August 14-18 2005 in Bern, Switzerland
Abstracts of the 14th European Conference on Eye Movements 2007
Authors: Kliegl Reinhold , Engbert R.
Published: February 2021

The European Conference on Eye Movements, ECEM2007, is the 14th in a series of international scientific conferences dedicated to transdisciplinary research on eye movements. The series was initiated in 1981 by Rudolf Groner in Bern and is organized every second year by a group of European scientists active in eye movement research. This meeting in Potsdam is the third one in Germany, after Göttingen in 1987 and Ulm in 1997.

The broad range of topics of the ECEM conferences attracts scientists from psychology, cognitive and visual neuroscience, computer science and related disciplines with interests from basic research to medical and applied aspects. Some 400 scientists from 27 countries, literally from around the world, have registered as participants of ECEM2007 and submitted over 300 oral and poster presentations.
Eye tracking in Educational Science: Theoretical frameworks and research agendas
Authors: Jarodzka Halszka , Holmqvist Kenneth , Gruber Hans
Published: February 2021

Eye tracking is increasingly being used in Educational Science and so has the interest of the eye tracking community grown in this topic. In this paper we briefly introduce the discipline of Educational Science and why it might be interesting to couple it with eye tracking research. We then introduce three major research areas in Educational Science that have already successfully used eye tracking: First, eye tracking has been used to improve the instructional design of computer-based learning and testing environments, often using hyper- or multimedia. Second, eye tracking has shed light on expertise and its development in visual domains, such as chess or medicine. Third, eye tracking has recently been also used to promote visual expertise by means of eye movement modeling examples. We outline the main educational theories for these research areas and indicate where further eye tracking research is needed to expand them.
How a distractor influences fixations during the exploration of natural scenes
Authors: Devillez Hélène , Guérin-Dugué Anne , Guyader Nathalie
Published: February 2021

The distractor effect is a well-established means of studying different aspects of fixation pro-gramming during the exploration of visual scenes. In this study, we present a task-irrelevant distractor to participants during the free exploration of natural scenes. We investigate the con-trol and programming of fixations by analyzing fixation durations and locations, and the link between the two. We also propose a simple mixture model evaluated using the Expectation-Maximization algorithm to test the distractor effect on fixation locations, including fixations which did not land on the distractor. The model allows us to quantify the influence of a visual distractor on fixation location relative to scene saliency for all fixations, at distractor onset and during all subsequent exploration. The distractor effect is not just limited to the current fixa-tion, it continues to influence fixations during subsequent exploration. An abrupt change in the stimulus not only increases the duration of the current fixation, it also influences the location of the fixation which occurs immediately afterwards and to some extent, in function of the length of the change, the duration and location of any subsequent fixations. Overall, results from the eye movement analysis and the statistical model suggest that fixation durations and locations are both controlled by direct and indirect mechanisms.
The effect of magnification and contrast on reading performance in different types of simulated low vision
Authors: Christen Michael , Abegg Mathias
Published: February 2021

Low vision therapy, such as magnifiers or contrast enhancement, is widely used. Scientific evidence proving its efficacy is scarce however. The objective of this study was to investigate whether the benefits of magnification and contrast enhancement depended on the origin of low vision. For this purpose we measured reading speed with artificially induced low vision in 12 healthy subjects in conditions of a simulated central scotoma, blurred vision and oscillopsia. Texts were either blurred, set in motion or blanked at the gaze position by using eye tracking and gaze contingent display. The simulated visual impairment was calibrated such that all types of low vision caused equal reading impairment. We then tested the effect of magnification and contrast enhancement among the different types of low vision. We found that reading speed improved with increasing magnification and with higher contrast in all conditions. The effect of magnification was significantly different in the three low vision conditions: The gain from magnification was highest in simulated blur and least in central scotoma. Magnification eventually led to near normal reading speed in all conditions. High contrast was less effective than high magnification and the effect of contrast enhancement was similar in all low vision conditions. From these results we conclude that the type of low vision determines the benefit that can be expected from magnification. Contrast enhancement leads to similar improved reading speed in all low vision types. We provide evidence that supports the use of low vision aids.
Negative versus positive priming: When are distractors inhibited?
Authors: Van der Stigchel Stefan
Published: February 2021

Visual attention is guided by the history of selections in previous trials, an effect usually referred to as intertrial priming. The aim of the present study was to investigate whether such priming in visual search is due to a strengthening of the target signal, or the suppression of the distractor signal. In two experiments, we examined the deviation of saccade endpoints in situations in which the target and distractors were presented in relative close proximity. We found both negative and positive priming, irrespective of whether the repeating feature was relevant or irrelevant. This finding is in contrast to previous results with this paradigm, based on which we concluded that visual priming is strictly the result of boosting perceptual target signals. Based on the differences between these experiments, we conclude that the number of distractors is essential in observing negative priming. We propose that negative priming is solely observed when multiple distractors result in either strong inhibition of distractor features, or strong adaptation to them. Whereas positive priming seems to be a robust mechanism, negative priming is only present if there are multiple distractors.
Ways of improving the precision of eye tracking data: Controlling the influence of dirt and dust on pupil detection
Authors: Fuhl Wolfgang , Hospach Dennis , Kübler Thomas C. , Rosenstiel Wolfgang , Bringmann Oliver , Kasneci Enkelejda
Published: February 2021

Eye-tracking technology has to date been primarily employed in research. With recent advances in aordable video-based devices, the implementation of gaze-aware smartphones, and marketable driver monitoring systems, a considerable step towards pervasive eye-tracking has been made. However, several new challenges arise with the usage of eye-tracking in the wild and will need to be tackled to increase the acceptance of this technology. The main challenge is still related to the usage of eye-tracking together with eyeglasses, which in combination with reflections for changing illumination conditions will make a subject "untrackable". If we really want to bring the technology to the consumer, we cannot simply exclude 30% of the population as potential users only because they wear eyeglasses, nor can we make them clean their glasses and the device regularly. Instead, the pupil detection algorithms need to be made robust to potential sources of noise. We hypothesize that the amount of dust and dirt on the eyeglasses and the eye-tracker camera has a significant influence on the performance of currently available pupil detection algorithms. Therefore, in this work, we present a systematic study of the eect of dust and dirt on the pupil detection by simulating various quantities of dirt and dust on eyeglasses. Our results show 1) an overall high robustness to dust in an o-focus layer. 2) the vulnerability of edge-based methods to even small in-focus dust particles. 3) a trade-o between tolerated particle size and particle amount, where a small number of rather large particles showed only a minor performance impact.
Eye tracking and visualization. Introduction to the Special Thematic Issue
Authors: Burch Michael , Chuang Lewis L. , Duchowski Andrew , Daniel Weiskopf , Groner Rudolf
Published: February 2021

There is a growing interest in eye tracking technologies applied to support traditional visualization techniques like diagrams, charts, maps, or plots, either static, animated, or interactive ones. More complex data analyses are required to derive knowledge and meaning from the data. Eye tracking systems serve that purpose in combination with biological and computer vision, cognition, perception, visualization,  human-computer-interaction, as well as usability and user experience research. The 10 articles collected in this thematic special issue provide interesting examples how sophisticated methods of data analysis and representation enable researchers to discover and describe fundamental spatio-temporal regularities in the data. The human visual system, supported by appropriate visualization tools, enables the human operator to solve complex tasks, like understanding and interpreting three-dimensional medical images, controlling air traffic by radar displays, supporting instrument flight tasks, or interacting with virtual realities. The development and application of new visualization techniques is of major importance for future technological progress.
Gaze Self-Similarity Plot - A New Visualization Technique
Authors: Kasprowski Pawel , Harezlak Katarzyna
Published: February 2021

Eye tracking has become a valuable way for extending knowledge of human behavior based on visual patterns. One of the most important elements of such an analysis is the presentation of obtained results, which proves to be a challenging task. Traditional visualization techniques such as scan-paths or heat maps may reveal interesting information, nonetheless many useful features are still not visible, especially when temporal characteristics of eye movement is taken into account. This paper introduces a technique called gaze self-similarity plot (GSSP) that may be applied to visualize both spatial and temporal eye movement features on the single two-dimensional plot. The technique is an extension of the idea of recurrence plots, commonly used in time series analysis. The paper presents the basic concepts of the proposed approach (two types of GSSP) complemented with some examples of what kind of information may be disclosed and finally showing areas of the GSSP possible applications.
Visual Analytics of Gaze Data with Standard Multimedia Player
Authors: Schöning Julius , Gundler Christopher , Heidemann Gunther , König Peter , Krumnack Ulf
Published: February 2021

With the increasing number of studies, where participants’ eye movements are tracked while watching videos, the volume of gaze data records is growing tremendously. Unfortunately, in most cases, such data are collected in separate files in custom-made or proprietary data formats. These data are difficult to access even for experts and effectively inaccessible for non-experts. Normally expensive or custom-made software is necessary for their analysis. We address this problem by using existing multimedia container formats for distributing and archiving eye-tracking and gaze data bundled with the stimuli data. We define an exchange format that can be interpreted by standard multimedia players and can be streamed via the Internet. We convert several gaze data sets into our format, demonstrating the feasibility of our approach and allowing to visualize these data with standard multimedia players. We also introduce two VLC player add-ons, allowing for further visual analytics. We discuss the benefit of gaze data in a multimedia container and explain possible visual analytics approaches based on our implementations, converted datasets, and first user interviews.
Eye movement planning on Single-Sensor-Single-Indicator displays is vulnerable to user anxiety and cognitive load
Authors: Allsop Jonathan , Gray Rob , Bülthoff Heinrich , Chuang Lewis
Published: February 2021

In this study, we demonstrate the effects of anxiety and cognitive load on eye movement planning in an instrument flight task adhering to a single-sensor-single-indicator data visualisation design philosophy. The task was performed in neutral and anxiety conditions, while a low or high cognitive load, auditory n-back task was also performed. Cognitive load led to a reduction in the number of transitions between instruments, and impaired task performance. Changes in self-reported anxiety between the neutral and anxiety conditions positively correlated with changes in the randomness of eye movements between instruments, but only when cognitive load was high. Taken together, the results suggest that both cognitive load and anxiety impact gaze behavior, and that these effects should be explored when designing data visualization displays.
Scan path visualization and comparison using visual aggregation techniques
Authors: Peysakhovich Vsevolod , Hurter Christophe
Published: February 2021

We demonstrate the use of different visual aggregation techniques to obtain non-cluttered visual representations of scanpaths. First, fixation points are clustered using the mean-shift algorithm. Second, saccades are aggregated using the Attribute-Driven Edge Bundling (ADEB) algorithm that handles a saccades direction, onset timestamp, magnitude or their combination for the edge compatibility criterion. Flow direction maps, computed during bundling, can be visualized separately (vertical or horizontal components) or as a single image using the Oriented Line Integral Convolution (OLIC) algorithm. Furthermore, cosine similarity between two flow direction maps provides a similarity map to compare two scanpaths. Last, we provide examples of basic patterns, visual search task, and art perception. Used together, these techniques provide valuable insights about scanpath exploration and informative illustrations of the eye movement data.
One page of text: Eye movements during regular and thorough reading, skimming, and spell checking.
Authors: Strukelj Alexander , Niehorster Diederick C
Published: February 2021

Eye movements during regular reading, thorough reading, skimming, and spell checking of single pages of text were measured, to investigate how high-level reading tasks elicited by instructions affect reading behavior. Word frequency and word length effects were found. All results were compared to regular reading. Thorough reading involved longer total reading times and more rereading, and resulted in higher comprehension scores. Skimming involved longer saccades, shorter average fixation durations, more word skipping, shorter total reading times evenly distributed across the page, and resulted in lower comprehension scores. Spell checking involved shorter saccades, longer average fixation durations, less word skipping, longer total reading times evenly distributed across the entire page, and resulted in lower comprehension scores. Replicating local effects shows that paragraphs maintain sufficient experimental rigor, while also enabling reading analyses from a global perspective. Compared to regular reading, thorough reading was more elaborate and less uniform, skimming was faster and more uniform, and spell checking was slower and more uniform.
Pupillary dilation response reflects surprising moments in music
Authors: Liao Hsin-I , Makoto Yoneya , Kashino Makio , Furukawa Shigeto
Published: February 2021

There are indications that the pupillary dilation response (PDR) reflects surprising moments in an auditory sequence such as the appearance of a deviant noise against repetitively presented pure tones (Liao, Yoneya, Kidani, Kashino, & Furukawa, 2016), and salient and loud sounds that are evaluated by human participants subjectively (Liao, Kidani, Yoneya, Kashino, & Furukawa, 2016). In the current study, we further examined whether the reflection of PDR in auditory surprise can be accumulated and revealed in complex and yet structured auditory stimuli, i.e., music, and when the surprise is defined subjectively. Participants listened to 15 excerpts of music while their pupillary responses were recorded. In the surprise-rating session, participants rated how surprising an instance in the excerpt was, i.e., rich in variation versus monotonous, while they listened to it. In the passive-listening session, they listened to the same 15 excerpts again but were not involved in any task. The pupil diameter data obtained from both sessions were time-aligned to the rating data obtained from the surprise-rating session. Results showed that in both sessions, mean pupil diameter was larger at moments rated more surprising than unsurprising. The result suggests that the PDR reflects surprise in music automatically.
Synchronizing eye tracking and optical motion capture: How to bring them together
Authors: Burger Birgitta , Puupponen Anna , Jantunen Tommi
Published: February 2021

Both eye tracking and motion capture technologies are nowadays frequently used in human sciences, although both technologies are usually used separately. However, measuring both eye and body movements simultaneously would offer great potential for investigating cross- modal interaction in human (e.g. music and language-related) behavior. Here we combined an Ergoneers Dikablis head mounted eye tracker with a Qualisys Oqus optical motion cap- ture system. In order to synchronize the recordings of both devices, we developed a gener- alizable solution that does not rely on any (cost-intensive) ready-made / company-provided synchronization solution. At the beginning of each recording, the participant nods quickly while fixing on a target while keeping the eyes open – a motion yielding a sharp vertical displacement in both mocap and eye data. This displacement can be reliably detected with a peak-picking algorithm and used for accurately aligning the mocap and eye data. This method produces accurate synchronization results in the case of clean data and therefore provides an attractive alternative to costly plug-ins, as well as a solution in case ready-made synchronization solutions are unavailable.
Eye-hand synchronisation in xylophone performance: Two case-studies with african and western percussionists
Authors: Marandola Fabrice
Published: February 2021

This article is the result of a first foray into xylophone performance with percussionists from Canada and Cameroon. It proposes to use the combination of Eye-Stroke Span (ESS), Fix- ation-Duration and Note-Pattern indexes to analyze free-score and performance oriented musical tasks, instead of eye-hand span or awareness span for sight-reading and score-based eye-tracking research in music. Based on measurements realized with a head-mounted eye- tracker system, the research examines gaze-movements related to eye-hand synchronization in xylophone performance with musicians coming from three different ethnic groups from Cameroon (Bedzan Pygmies, Tikar and Eton) and classically trained Western percussionists (Canada). Increases in tempo are found to involve a diminution of the number of fixations, but not proportionally, as well as changes in lateral gaze shifts. Fixation-Duration and Note- Pattern are closely related but not identical, while ESS is relatively more independent. These gaze patterns are consistent within individuals, but not across individuals. Cameroonian mu- sicians tend to look away from their instrument, interacting with their peers or with the au- dience. When they look at their keyboard, preliminary measures of ESS were found similar to the ESS of Western performers.
An investigation of the distribution of gaze estimation errors in head mounted gaze trackers using polynomial functions
Authors: Mardanbegi Diako , Kurauchi Andrew T. N. , Morimoto Carlos H.
Published: February 2021

Second order polynomials are commonly used for estimating the point-of-gaze in head-mounted eye trackers. Studies in remote (desktop) eye trackers show that although some non-standard 3rd order polynomial models could provide better accuracy, high-order polynomials do not necessarily provide better results. Different than remote setups though, where gaze is estimated over a relatively narrow field-of-view surface (e.g. less than 30x20 degrees on typical computer displays), head-mounted gaze trackers (HMGT) are often desired to cover a relatively wider field-of-view to make sure that the gaze is detected in the scene image even for extreme eye angles. In this paper we investigate the behavior of the gaze estimation error distribution throughout the image of the scene camera when using polynomial functions. Using simulated scenarios, we describe effects of four different sources of error: interpolation, extrapolation, parallax, and radial distortion. We show that the use of third order polynomials result in more accurate gaze estimates in HMGT, and that the use of wide angle lenses might be beneficial in terms of error reduction.
Eye-tracking en masse: Group user studies, lab infrastructure, and practices
Authors: Bielikova Maria , Konopka Martin , Simko Jakub , Moro Robert , Tvarozek Jozef , Hlavac Patrik , Kuric Eduard
Published: February 2021

The costs of eye-tracking technologies steadily decrease. This allows research institutions to obtain multiple eye-tracking devices. Already, several multiple eye-tracker laboratories have been established. Researchers begin to recognize the subfield of group eye-tracking. In comparison to the single-participant eye-tracking, group eye-tracking brings new technical and methodological challenges. Solutions to these challenges are far from being established within the research community. In this paper, we present the Group Studies system, which manages the infrastructure of the group eye-tracking laboratory at the User Experience and Interaction Research Center (UXI) at the Slovak University of Technology in Bratislava. We discuss the functional and architectural characteristics of the system. Furthermore, we illustrate our infrastructure with one of our past studies. With this paper, we also publish the source code and the documentation of our system to be re-used.
Using Eye-Movement Events to Determine the Mental Workload of Surgical Residents
Authors: Menekşe Dalveren Gonca Gökçe , Cagiltay Nergiz Ercil
Published: February 2021

These days, eye-tracking is one of the promising technologies used in different fields. However, studies involving eye-tracking are rare in the field of endo-neurosurgery. This study aims to use this technology to promote our understanding of the effect related to computer-based instructional materials on mental workload of surgical residents. Four computer-based simulation scenarios are developed, two of them were designed as general models and the other two as simulated surgical models. During these surgical procedures, in real settings, surgical residents need to use their both hands simultaneously to control the endoscope and the operational tool in a coordinated fashion. Therefore, to shed light on the participants’ behaviors, these scenarios are performed with dominant-hand, non-dominant hand and, finally with both-hands. Twenty-three residents’ eye-movements were recorded while performing the scenarios. According to the results of this study, when performing the simulated surgical models, an increase in the participants’ mental workload was recorded when compared to the other scenarios. Accordingly, it can be concluded that the eye-movements of surgical residents can provide insights about the anticipated level of difficulty about the skill-based tasks. This information might be very critical to properly design and organize instructional materials for endo-neurosurgery, and also to better guide and evaluate the progress of trainees in computer simulation-based skill training environments.
A single-camera gaze tracking system under natural light
Authors: Xiao Feng , Zheng Dandan , Huang Kejie , Qiu Yue , Shen Haibin
Published: February 2021

Gaze tracking is a human-computer interaction technology, and it has been widely studied in the academic and industrial fields. However, constrained by the performance of the specific sensors and algorithms, it has not been popularized for everyone. This paper proposes a single-camera gaze tracking system under natural light to enable its versatility. The iris center and anchor point are the most crucial factors for the accuracy of the system. The accurate iris center is detected by the simple active contour snakuscule, which is initialized by the prior knowledge of eye anatomical dimensions. After that, a novel anchor point is computed by the stable facial landmarks. Next, second-order mapping functions use the eye vectors and the head pose to estimate the points of regard. Finally, the gaze errors are improved by implementing a weight coefficient on the points of regard of the left and right eyes. The feature position of the iris center achieves an accuracy of 98.87% on the GI4E database when the normalized error is lower than 0.05. The accuracy of the gaze tracking method is superior to the-state-of-the-art appearance-based and feature-based methods on the EYEDIAP database.
Eye-hand coordination patterns of intermediate and novice surgeons in a simulation-based endoscopic surgery training environment
Authors: Topalli Damla , Cagiltay Nergiz Ercil
Published: February 2021

Endoscopic surgery procedures require specific skills, such as eye-hand coordination to be developed. Current education programs are facing with problems to provide appropriate skill improvement and assessment methods in this field. This study aims to propose objective metrics for hand-movement skills and assess eye-hand coordination. An experimental study is conducted with 15 surgical residents to test the newly proposed measures. Two computer-based both-handed endoscopic surgery practice scenarios are developed in a simulation environment to gather the participants’ eye-gaze data with the help of an eye tracker as well as the related hand movement data through haptic interfaces. Additionally, participants’ eye-hand coordination skills are analyzed. The results indicate higher correlations in the intermediates’ eye-hand movements compared to the novices. An increase in intermediates’ visual concentration leads to smoother hand movements. Similarly, the novices’ hand movements are shown to remain at a standstill. After the first round of practice, all participants’ eye-hand coordination skills are improved on the specific task targeted in this study. According to these results, it can be concluded that the proposed metrics can potentially provide some additional insights about trainees’ eye-hand coordination skills and help instructional system designers to better address training requirements.
Use of eye tracking for assessment of electronic navigation competency in maritime training
Authors: Atik Oguz , Arslan Omer
Published: February 2021

The purpose of this study is to experiment an assessment method using eye tracking technology in simulator based electronic navigation training of ship officers who play a critical role in maritime accidents. The maritime industry focuses on human factor developing and improving regulations, training requirements and technology to prevent marine casualties. The mandatory use of simulations in maritime training as per international regulations includes competency assessment as a vital process. The study involves capturing and analyzing eye movement data from ship officers with sea experience in simulation exercises for assessing competency.  A system including an eye tracking analysis software and eye tracking glasses is used for the study. Inferential and descriptive analysis were both used to validate the results. Significant differences were found between electronic navigation competencies of expert and novice ship officers. The results show that the eye tracking technology is a valuable tool for assessment of electronic navigation competency. Comparing novice and expert ship officers’ data proves that eye tracking provides in-depth data which is not obtainable by the available observation methods used in simulation training. The findings show that eye tracking provides the assessor novel data, such as focus of attention, which enables evaluation of the cognitive process and competency. The study, therefore, contributes to maritime education aiming to improve the effectiveness of simulator based maritime training which is vital for maritime safety. It also contributes to scientific research on eye movement in maritime field by proposing the integration of eye tracking in competency assessment in electronic navigation training as a part of simulation based maritime education.
Improving the pilot selection process by using eye-tracking tools
Authors: Vlačić Slaviša Ivan , Knežević Aleksandar Zdravko , Mandal Saptarshi , Rođenkov Sanja , Vitsas Panos
Published: February 2021

This paper improves the understanding of the use of eye-tracking tools in the pilot selection process.  Research of eye movement and attention distribution of candidate pilots may provide the capability for visual behavior prediction in more demanding flight training phases. The research included psychological testing, flight screening of subjects and their achievements in a flight simulator in combination with an eye-tracking device. Participants were divided into three categories: high performance, average performance, and low performance and separately regarded through psychological testing results and flight screening results. An eye-tracking device tracked visual behavior of subjects through the scope and speed of visual perception. The number of fixations and revisits recorded during the simulated visual flight conditions measured the difference in visual response between subjects. Comparison of results showed a positive correlation with psychological test results. Correlation with flight screening selection was not confirmed. We used the new network-based approach with three target importance measures to overcome the shortcomings of traditional eye movement metrics. The results of the adopted network approach presented in the form of graphs and analysis of normalized importance measures showed that it was possible to extract specific saccade strategy for each participant. Discovered differences between them positively detected week ones. In this way, Eye-tracking tools can potentially improve the pilot selection process and complement other tests and assessment methods.
Eye tracking use in researching driver distraction: A scientometric and qualitative literature review approach
Authors: Cvahte Ojsteršek Tina , Topolšek Darja
Published: February 2021

Many factors affect road safety, but research constantly shows that drivers are the major cause of critical situations that could potentially lead to a traffic accident in road traffic. Visual information is a crucial part of input information into the driving process; therefore, distractions of overt visual attention can potentially have a large impact on driving safety. Modern eye tracking technology enables researchers to gain precise insight into the direction and movement of a driver’s gaze during various distractions. As this is an evolving and currently very relevant field of road safety research, the present paper sets out to analyse the current state of the research field and the most relevant publications that use eye tracking for research of distractions to a driver’s visual attention. With the use of scientometrics and a qualitative review of the 139 identified publications that fit the inclusion criteria, the results revealed a currently expanding research field. The narrow research field is interdisciplinary in its core, as evidenced by the dispersion of publication sources and research variables. The main research gaps identified were performing research in real conditions, including a wider array of distractions, a larger number of participants, and increasing interdisciplinarity of the field with more author cooperation outside of their primary co-authorship networks.
Dynamics of the disparity vergence fusion sustain component
Authors: Semmlow John L. , Yaramothu Chang , Alvarez Tara L.
Published: February 2021

The stereotypical vergence response to a step stimulus consists of two dynamic components: a high velocity fusion initiating component followed by a slower component that may mediate sustained fusion.  The initial component has been well-studied and is thought to be controlled by an open-loop mechanism. Less is known about the slow, or fusion sustaining component except that it must be feedback controlled to achieve the positional precision of sustained fusion.  Given the delays in disparity vergence control, a feedback control system is likely to exhibit oscillatory behavior.  Vergence responses to 4 deg step changes in target position were recorded in eight subjects. The slow component of each response was isolated manually using interactive graphics and the frequency spectrum determined.  The frequency spectra of all isolated slow vergence movements showed a large low frequency peak between 1.0 and 2.0 Hz and one or more higher frequency components.  The higher frequency components were found to be harmonics of the low frequency oscillation.  A feedback model of the slow component was developed consisting of a time delay, an integral/derivative controller and an oculomotor plant based on Robinson’s model.  Model simulations showed that a direction dependent asymmetry in the derivative element was primarily responsible for the higher frequency harmonic components. Simulations also showed that the base frequencies are primarily dependent on the time delay in the feedback control system. The fact that oscillatory behavior was found in all subjects provides strong support that the slow, fusion sustaining component is mediated by a feedback system.
Variance components affecting the repeatability of the alternating cover test
Authors: Paulus Marius M. , Straube Andreas , Eggert Thomas
Published: February 2021

In within-subject and within-examiner repeated measures designs, measures of heterophoria with the manual prism cover test achieve standard deviations between 0.5 and 0.8 deg. We addressed the question how this total noise is composed of variable errors related to the examiner (measurement noise), to the size of the heterophoria (heterophoria noise), and to the availability of sensory vergence cues (stimulus noise).
We developed an automated alternating cover test (based on a combination of VOG and shutter glasses) which minimizes stimulus noise and has a defined measurement noise (sd=0.06 deg). In a within-subject design, 19 measures were taken within 1.5 min and multiple such blocks were repeated either across days or across 45 min. Blocks were separated by periods of binocular viewing. The standard deviation of the heterophoria across blocks from different days or from the same day (sd=0.33 deg) was 6 times larger than expected based on the standard deviation within the block.
The results show that about 42% of the inter-block variance with the manual prism cover test was related to variability of the heterophoria and not to measurement noise or stimulus noise. The heterophoria noise across blocks was predominantly induced during the inter-mediate binocular viewing periods.
The Effect of target speed and verbal instruction on NPC measures in a young, healthy, and active population
Authors: McGinnis Ian , Tierney Ryan , Mansell Jamie , Phillips Jacqueline
Published: February 2021

Purpose: Evaluate the effect of target speed and verbal instruction on near point of convergence (NPC) measurements in a young, healthy, and active population. Methods: NPC was measured in 20 individuals with three target speeds and two sets of verbal instruction. The target speeds used were 1 cm/s, 3 cm/s, 5 cm/s, and participant self-paced. The verbal instruction given was either to indicate when the target became “double” or “blurry”. Results: Paired-samples t-tests revealed significant differences between 5 cm/s (5.44 ± 2.01) and 1 cm/s (6.72 ± 2.39, p = .003), 3 cm/s (6.10 ± 2.36, p = .030) and self-paced (6.63 ± 2.26, p = .005). A significant difference (p < .001) was also found between the “double” (6.72 ± 2.39) and “blurry” (10.82 ± 3.08) conditions Conclusion: For young, healthy and active individuals, target speed and verbal instruction matter when measuring NPC.
Effects of visual blur on microsaccades during visual exploration
Authors: Tang Sherry , Skelly Peggy , Otero-Millan Jorge , Jacobs Jonathan , Murray Jordan , Shaikh Aasef G. , Ghasia Fatema F.
Published: February 2021

Microsaccades shift the image on the fovea and counteract visual fading. They also serve as an optimal sampling strategy while viewing complex visual scenes. Microsaccade production relies on the amount of retinal error or acuity demand of a visual task. The goal of this study was to assess the effects of blur induced by uncorrected refractive error on visual search. Eye movements were recorded in fourteen healthy subjects with uncorrected and corrected refractive error while they performed a) visual fixation b) blank-scene viewing c) visual search (spot the difference) tasks. Microsaccades, saccades, correctly identified differences and reaction times were analyzed. The frequency of microsaccades and correctly identified differences were lower in the uncorrected refractive error during visual search. No similar change in microsaccades was seen during blank-scene viewing and gaze holding tasks. These findings suggest that visual blur, hence the precision of an image on the fovea, has an important role in calibrating the amplitude of microsaccades during visual scanning.
What makes a microsaccade? A review of 70 years research prompts a new detection method
Authors: Hauperich Anna-Katharina , Young Laura K. , Smithson Hannah E.
Published: February 2021

We have developed a new method for detecting microsaccades in eye-movement data. The impetus was the review of the literature on microsaccades presented in this paper, which revealed (1) large changes in the size and speed of reported microsaccades over the last 70 years and (2) references to monocular microsaccades, which have recently been shown to be artefacts of analysis methods (Nyström et al, 2017; Fang et al, 2018). The changes in reported microsaccade characteristics, such as size and speed, must be due to experimental factors, such as methods of recording and analysis, and different levels of experience of the participants in the task: They cannot represent a change in the fundamental characteristics of microsaccades. In this paper we present a review of reported microsaccade properties between the 1940s and today and we determine the range within which certain physical parameters of microsaccades are thought to occur. These parameters drive our new microsaccade detection method. We have validated this method on two datasets of binocular eye-movements recorded using video-based systems: one from within our lab, and one from Nyström et al, 2017. We have additionally applied our method to eye-movement data collected using an adaptive optics scanning laser ophthalmoscope (AOSLO), to show its adaptability to a fundamentally different method of data capture. This confirmed that the microsaccade detection method produces microsaccade detection rates within expected limits across very different methods of recording. Our new microsaccade detection method is easy to implement and intuitive to understand, and affords researchers flexibility in adjusting it to their experimental set-up.
Microsaccades in applied environments: Real-world applications of fixational eye movement measurements
Authors: Alexander Robert G , Macknik Stephen L , Martinez-Conde Susana
Published: February 2021

Across a wide variety of research environments, the recording of microsaccades and other fixational eye movements has provided insight and solutions into practical problems. Here we review the literature on fixational eye movements—especially microsaccades—in applied and ecologically-valid scenarios. Recent technical advances allow noninvasive fixational eye movement recordings in real-world contexts, while observers perform a variety of tasks. Thus, fixational eye movement measures have been obtained in a host of real-world scenarios, such as in connection with driver fatigue, vestibular sensory deprivation in astronauts, and elite athletic training, among others. Here we present the state of the art in the practical applications of fixational eye movement research, examine its potential future uses, and discuss the benefits of including microsaccade measures in existing eye movement detection technologies. Current evidence supports the inclusion of fixational eye movement measures in real-world contexts, as part of the development of new or improved oculomotor assessment tools. The real-world applications of fixational eye movement measurements will only grow larger and wider as affordable high-speed and high-spatial resolution eye trackers become increasingly prevalent.
Saccadic intrusions in amyotrophic lateral sclerosis (ALS)
Authors: Becker Wolfgang , Gorges Martin , Lulé Dorothée , Pinkhardt Elmar , Ludolph Albert Christian , Kassubek Jan
Published: February 2021

The attempt to steadily fixate at a small visual object is continuously interrupted by a variety of fixational eye movements comprising, among others, a continuum of saccadic intrusions (SI) which ranges in size from microsaccades with amplitudes ≤0.25° to larger refixation saccades of up to about 2°. The size and frequency of SI varies considerably among individuals and is known to increase in neurodegenerative diseases such as neurodegenerative parkinsonism and amyotrophic lateral sclerosis (ALS). However, studies of ALS disagree whether also the frequency of SI increases. We undertook an analysis of SI in 119 ALS patients and 47 age-matched healthy controls whose eye movements during fixation and tests of executive functions (e.g antisaccades) had been recorded by video-oculography according to standardised procedures. SI were categorised according to their spatio-temporal patterns as stair case, back-and-forth and square wave jerks (a subcategory of back-and-forth). The SI of patients and controls were qualitatively similar (same direction preferences, similar differences between patterns), but were enlarged in ALS. Notably however, no increase of SI frequency could be demonstrated. Yet, there were clear correlations with parameters such as eye blink rate or errors in a delayed saccade task that suggest an impairment of inhibitory mechanisms, in keeping with the notion of a frontal dysfunction in ALS. However, it remains unclear how the impairment of inhibitory mechanisms in ALS could selectively increase the amplitude of intrusions without changing their frequency of occurrence.
Eyes Wide Shut: Gaze dynamics without vision,
Authors: Martinez-Conde Susana , Buchsbaum Bradley , Ghasia Fatema , Van Ede Freek , Macknik Stephen L.
Published: February 2021

Video stream: https://vimeo.com/365522806
The human ability for visualization extends far beyond the physical items that surround us. We are able to dismiss the constant influx of photons hitting our retinas, and instead picture the layout of our kindergarten classroom, envision the gently swaying palm trees of our dream vacation, or foresee the face of a yet-to-be-born child. As we inspect imaginary objects and people with our mind’s eye, our corporeal eyeballs latch onto the fantasy. Research has found that our eyes can move as if seeing, even when there is nothing to look at. Thus, gaze explorations in the absence of actual vision have been reported in many contexts, including in visualization and memory tasks, and perhaps even during REM sleep. This symposium will present the manifold aspects of gaze dynamics in conditions when the visual input is impoverished or altogether absent. Presentations will address the characteristics of large and small eye movements during imagined and remembered scenes, the impact of visual field deficits on oculomotor control, and the role of eye movements in the future development of neural prosthetics for the blind.
Beyond the lab ?
Authors: Kasneci Enkelejda
Published: February 2021

Keynote by Enkelejda Kasneci at the 20th European Conference on Eye Movement Research (ECEM) in Alicante, 18.8.2019,
Video stream of presentation: https://vimeo.com/356314274