Search

In this article, we discuss operationalizations and examples of experimental design in eye-tracking research. First, we distinguish direct operationalization for entities like saccades, which are closely aligned with their original concepts, and indirect operationalization for concepts not directly measurable, such as attention or mind-wandering. The latter relies on selecting a measurable proxy. Second, we highlight the variability in algorithmic operationalizations and emphasize that changing parameters can affect outcome measures. Transparency in reporting these parameters and algorithms is crucial for comparisons across studies. Third, we provide references to studies for common operationalizations in eye-tracking research and discuss key operationalizations in reading research. Fourth, the IO-model is introduced as a tool to help researchers operationalize difficult concepts. Finally, we present three example experiments with useful methods for eye-tracking research, encouraging readers to consider these examples for inspiration in their own experiments., Competing Interests: Declarations. Ethics approval: Not applicable. Consent to participate: Not applicable. Consent for publication: Not applicable. Competing interests: RA is since 2017 an employee of Tobii AB. The other authors declare no competing interests. Open Practices Statement: There are no data or code associated with the present article., (© 2025. The Author(s).)

We built a novel setup to record large gaze shifts (up to 140 ∘ ). The setup consists of a wearable eye tracker and a high-speed camera with fiducial marker technology to track the head. We tested our setup by replicating findings from the classic eye-head gaze shift literature. We conclude that our new inexpensive setup is good enough to investigate the dynamics of large eye-head gaze shifts. This novel setup could be used for future research on large eye-head gaze shifts, but also for research on gaze during e.g., human interaction. We further discuss reference frames and terminology in head-free eye tracking. Despite a transition from head-fixed eye tracking to head-free gaze tracking, researchers still use head-fixed eye movement terminology when discussing world-fixed gaze phenomena. We propose to use more specific terminology for world-fixed phenomena, including gaze fixation, gaze pursuit, and gaze saccade., (© 2024. The Author(s).)

A guideline is proposed that comprises the minimum items to be reported in research studies involving an eye tracker and human or non-human primate participant(s). This guideline was developed over a 3-year period using a consensus-based process via an open invitation to the international eye tracking community. This guideline will be reviewed at maximum intervals of 4 years., (© 2023. The Author(s).)

Blinks, the closing and opening of the eyelids, are used in a wide array of fields where human function and behavior are studied. In data from video-based eye trackers, blink rate and duration are often estimated from the pupil-size signal. However, blinks and their parameters can be estimated only indirectly from this signal, since it does not explicitly contain information about the eyelid position. We ask whether blinks detected from an eye openness signal that estimates the distance between the eyelids (EO blinks) are comparable to blinks detected with a traditional algorithm using the pupil-size signal (PS blinks) and how robust blink detection is when data quality is low. In terms of rate, there was an almost-perfect overlap between EO and PS blink (F1 score: 0.98) when the head was in the center of the eye tracker's tracking range where data quality was high and a high overlap (F1 score 0.94) when the head was at the edge of the tracking range where data quality was worse. When there was a difference in blink rate between EO and PS blinks, it was mainly due to data loss in the pupil-size signal. Blink durations were about 60 ms longer in EO blinks compared to PS blinks. Moreover, the dynamics of EO blinks was similar to results from previous literature. We conclude that the eye openness signal together with our proposed blink detection algorithm provides an advantageous method to detect and describe blinks in greater detail., (© 2024. The Author(s).)

We present a deep learning method for accurately localizing the center of a single corneal reflection (CR) in an eye image. Unlike previous approaches, we use a convolutional neural network (CNN) that was trained solely using synthetic data. Using only synthetic data has the benefit of completely sidestepping the time-consuming process of manual annotation that is required for supervised training on real eye images. To systematically evaluate the accuracy of our method, we first tested it on images with synthetic CRs placed on different backgrounds and embedded in varying levels of noise. Second, we tested the method on two datasets consisting of high-quality videos captured from real eyes. Our method outperformed state-of-the-art algorithmic methods on real eye images with a 3-41.5% reduction in terms of spatial precision across data sets, and performed on par with state-of-the-art on synthetic images in terms of spatial accuracy. We conclude that our method provides a precise method for CR center localization and provides a solution to the data availability problem, which is one of the important common roadblocks in the development of deep learning models for gaze estimation. Due to the superior CR center localization and ease of application, our method has the potential to improve the accuracy and precision of CR-based eye trackers., (© 2023. The Author(s).)

According to the proposal for a minimum reporting guideline for an eye tracking study by Holmqvist et al. (2022), the accuracy (in degrees) of eye tracking data should be reported. Currently, there is no easy way to determine accuracy for wearable eye tracking recordings. To enable determining the accuracy quickly and easily, we have produced a simple validation procedure using a printable poster and accompanying Python software. We tested the poster and procedure with 61 participants using one wearable eye tracker. In addition, the software was tested with six different wearable eye trackers. We found that the validation procedure can be administered within a minute per participant and provides measures of accuracy and precision. Calculating the eye-tracking data quality measures can be done offline on a simple computer and requires no advanced computer skills., (© 2023. The Author(s).)

Background and Aim: The aim of the present article was to elaborate on a research approach and method called 'lifeworld hermeneutics'. Significant to lifeworld hermeneutics is that interpretation is the main methodological instrument for explaining and understanding existential research questions and lived experiences. From a caring science perspective, this often refers to research that aims to gain a deeper understanding of existential phenomena and issues, such as existential meaning of health, well-being, homelessness, lostness, suffering and ageing, as well as what it means to experience unhealthiness and illness, the need for care, and caring that responds to such needs., Design: Theoretical paper., Result: The article briefly covers ontology and epistemology that clarifies the meaning and importance of a lifeworld hermeneutic attitude. This is followed by suggestions for how to perform a lifeworld hermeneutic study, expressed in relation to methodological principles for the interpretation, validation and structuring of interpretations. Thereafter, follow reflections on how to use theoretical or philosophical support to develop and deepen existential interpretations. The findings of lifeworld hermeneutic research consist of existential interpretations where the researcher, with an open and pliable attitude towards the phenomenon and the aim of the study, clarifies, explains and suggests new ways of understanding participants' lived experiences; the researcher should maintain such an attitude towards their understanding of the phenomenon as well., Conclusion: The lifeworld hermeneutical approach and method described in this article makes it possible to further deepen the understanding and knowledge about existential issues that is relevant for caring and caring science., (© 2023 The Authors. Scandinavian Journal of Caring Sciences published by John Wiley & Sons Ltd on behalf of Nordic College of Caring Science.)

There is an abundance of commercial and open-source eye trackers available for researchers interested in gaze and eye movements. Which aspects should be considered when choosing an eye tracker? The paper describes what distinguishes different types of eye trackers, their suitability for different types of research questions, and highlights questions researchers should ask themselves to make an informed choice., Competing Interests: Declarations. Competing Interests: RA is since 2017 an employee of Tobii AB. The other authors declare no competing interests. Open Practices Statement: There are no data or code associated with the present article., (© 2025. The Author(s).)

Researchers using eye tracking are heavily dependent on software and hardware tools to perform their studies, from recording eye tracking data and visualizing it, to processing and analyzing it. This article provides an overview of available tools for research using eye trackers and discusses considerations to make when choosing which tools to adopt for one's study., Competing Interests: Declarations. Competing interests: RA is since 2017 an employee of Tobii AB. The other authors declare no conflicts of interest. Ethics approval: Not applicable. Consent to participate: Not applicable. Consent for publication: Not applicable. Open Practices Statement: There are no data or code associated with the present article., (© 2025. The Author(s).)

Irrespective of the precision, the inaccuracy of a pupil-based eye tracker is about 0.5 ∘ . This paper delves into two factors that potentially increase the inaccuracy of the gaze signal, namely, 1) Pupil-size changes and the pupil-size artefact (PSA) and 2) the putative inability of experienced individuals to precisely refixate a visual target. Experiment 1 utilizes a traditional pupil-CR eye tracker, while Experiment 2 employs a retinal eye tracker, the FreezeEye tracker, eliminating the pupil-based estimation. Results reveal that the PSA significantly affects gaze accuracy, introducing up to 0.5 ∘ inaccuracies during calibration and validation. Corrections based on the relation between pupil size and apparent gaze shift substantially reduce inaccuracies, underscoring the PSA's influence on eye-tracking quality. Conversely, Experiment 2 demonstrates humans' precise refixation abilities, suggesting that the accuracy of the gaze signal is not limited by human refixation inconsistencies., Competing Interests: Declarations. Competing interests: RA is since 2017 an employee of Tobii AB. MNo, AS and MS are co-owners and RK is an employee of Inoko Vision. Ethics approval: This research project does not belong to the regimen of the Dutch Act on Medical Research Involving Human Subjects, and therefore there is no need for approval of a Medical Ethics Committee. However, the present study is approved by the Ethics Committee of the Faculty of Social and Behavioural Sciences of Utrecht University and filed under number 24-0055 (Experiment 1) and 24-0060 (Experiment 2). Consent to participate: Participants were authors on the paper gave consent to participate. Consent for publication: Not applicable. Open Practices Statement: There are no data associated with the present article., (© 2024. The Author(s).)

Eye tracking technology has become increasingly prevalent in scientific research, offering unique insights into oculomotor and cognitive processes. The present article explores the relationship between scientific theory, the research question, and the use of eye-tracking technology. It aims to guide readers in determining if eye tracking is suitable for their studies and how to formulate relevant research questions. Examples from research on oculomotor control, reading, scene perception, task execution, visual expertise, and instructional design are used to illustrate the connection between theory and eye-tracking data. These examples may serve as inspiration to researchers new to eye tracking. In summarizing the examples, three important considerations emerge: (1) whether the study focuses on describing eye movements or uses them as a proxy for e.g., perceptual, or cognitive processes, (2) the logical chain from theory to predictions, and (3) whether the study is of an observational or idea-testing nature. We provide a generic scheme and a set of specific questions that may help researchers formulate and explicate their research question using eye tracking., Competing Interests: Declarations. Competing interests: RA is since 2017 an employee of Tobii AB. The other authors declare no competing interests. Ethics approval: Not applicable. Consent to participate: Not applicable. Consent for publication: Not applicable. Open practices statement: There are no data or code associated with the present article., (© 2024. The Author(s).)

When lab resources are shared among multiple research projects, issues such as experimental integrity, replicability, and data safety become important. Different research projects often need different software and settings that may well conflict with one another, and data collected for one project may not be safeguarded from exposure to researchers from other projects. In this paper we provide an infrastructure design and an open-source tool, labManager, that render multi-user lab facilities in the behavioral sciences accessible to research projects with widely varying needs. The solutions proposed ensure ease of management while simultaneously offering maximum flexibility by providing research projects with fully separated bare metal environments. This solution also ensures that collected data is kept separate, and compliant with relevant ethical standards and regulations such as General Data Protection Regulation (GDPR) legislation. Furthermore, we discuss preconditions for running shared lab facilities and provide practical advice., (© 2024. The Author(s).)

In human interactions, gaze may be used to acquire information for goal-directed actions, to acquire information related to the interacting partner's actions, and in the context of multimodal communication. At present, there are no models of gaze behavior in the context of vision that adequately incorporate these three components. In this study, we aimed to uncover and quantify patterns of within-person gaze-action coupling, gaze-gesture and gaze-speech coupling, and coupling between one person's gaze and another person's manual actions, gestures, or speech (or exogenous attraction of gaze) during dyadic collaboration. We showed that in the context of a collaborative Lego Duplo-model copying task, within-person gaze-action coupling is strongest, followed by within-person gaze-gesture coupling, and coupling between gaze and another person's actions. When trying to infer gaze location from one's own manual actions, gestures, or speech or that of the other person, only one's own manual actions were found to lead to better inference compared to a baseline model. The improvement in inferring gaze location was limited, contrary to what might be expected based on previous research. We suggest that inferring gaze location may be most effective for constrained tasks in which different manual actions follow in a quick sequence, while gaze-gesture and gaze-speech coupling may be stronger in unconstrained conversational settings or when the collaboration requires more negotiation. Our findings may serve as an empirical foundation for future theory and model development, and may further be relevant in the context of action/intention prediction for (social) robotics and effective human-robot interaction., Competing Interests: Declarations. Competing Interests: The authors report that there are no competing interests to declare. Ethics Approval: This study was performed in line with the principles of the Declaration of Helsinki. The study was approved by the Ethics Committee of the Faculty of Social and Behavioural Sciences of Utrecht University (protocol number 22-0206) Consent to Participate: All participants gave written informed consent. Consent for Publication: The authors affirm that human research participants provided informed consent for publication of the videos available at https://osf.io/2q6f4/. Open Practices Statement: Data files and example videos are available at https://osf.io/2q6f4/. The experiment and analyses were not preregistered., (© 2024. The Author(s).)

Background: White noise stimulation has demonstrated efficacy in enhancing working memory in children with ADHD. However, its impact on other executive functions commonly affected by ADHD, such as inhibitory control, remains largely unexplored. This research aims to explore the effects of two types of white noise stimulation on oculomotor inhibitory control in children with ADHD., Method: Memory guided saccade (MGS) and prolonged fixation (PF) performance was compared between children with ADHD ( N  = 52) and typically developing controls (TDC, N  = 45), during auditory and visual white noise stimulation as well as in a no noise condition., Results: Neither the auditory nor the visual white noise had any beneficial effects on performance for either group., Conclusions: White noise stimulation does not appear to be beneficial for children with ADHD in tasks that target oculomotor inhibitory control. Potential explanations for this lack of noise benefit will be discussed., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: In attention-deficit/hyperactivity disorder (ADHD), poor inhibitory control is one of the main characteristics, with oculomotor inhibition impairments being considered a potential biomarker of the disorder. While auditory white noise has demonstrated the ability to enhance working memory in this group, visual white noise is still unexplored and so are the effects of both types of white noise stimulation on oculomotor inhibition., Objective: This crossover study aims to explore the impact of auditory and visual white noise on oculomotor inhibition in children with ADHD and typically developing (TD) children. The study will investigate the impact of different noise levels (25% and 50% visual, 78 dB auditory), and performance will be evaluated both with and without noise stimulation. We hypothesize that exposure to white noise will improve performance in children with ADHD and impair the performance for TD children., Methods: Memory-guided saccades and prolonged fixations, known for their sensitivity in detecting oculomotor disinhibition in ADHD, will be used to assess performance. Children diagnosed with ADHD, withdrawing from medication for 24 hours, and TD children without psychiatric disorders were recruited for the study., Results: Data collection was initiated in October 2023 and ended in February 2024. A total of 97 participants were enrolled, and the first results are expected between September and November 2024., Conclusions: This study will examine whether cross-modal sensory stimulation can enhance executive function, specifically eye movement control, in children with ADHD. In addition, the study will explore potential differences between auditory and visual noise effects in both groups. Our goal is to identify implications for understanding how noise can be used to improve cognitive performance., Trial Registration: ClinicalTrials.gov NCT06057441; https://clinicaltrials.gov/study/NCT06057441., International Registered Report Identifier (irrid): DERR1-10.2196/56388., (©Erica Jostrup, Marcus Nyström, Pia Tallberg, Göran Söderlund, Peik Gustafsson, Emma Claesdotter-Knutsson. Originally published in JMIR Research Protocols (https://www.researchprotocols.org), 15.08.2024.)

Much of the Earth's biosphere has been appropriated for the production of harvestable biomass in the form of food, fuel and fibre. Here we show that the simplification and intensification of these systems and their growing connection to international markets has yielded a global production ecosystem that is homogenous, highly connected and characterized by weakened internal feedbacks. We argue that these features converge to yield high and predictable supplies of biomass in the short term, but create conditions for novel and pervasive risks to emerge and interact in the longer term. Steering the global production ecosystem towards a sustainable trajectory will require the redirection of finance, increased transparency and traceability in supply chains, and the participation of a multitude of players, including integrated 'keystone actors' such as multinational corporations. This Perspective examines the global production ecosystem through the lenses of connectivity, diversity and feedback, and proposes measures that will increase its stability and sustainability., Author(s): M. Nyström [sup.1] , J.-B. Jouffray [sup.1] [sup.2] , A. V. Norström [sup.1] , B. Crona [sup.1] [sup.2] , P. Søgaard Jørgensen [sup.1] [sup.2] , S. R. Carpenter [sup.3] [...]

Background: Lynch syndrome (LS) is one of the most common hereditary cancer syndromes worldwide. Dominantly inherited mutation in one of four DNA mismatch repair genes combined with somatic events leads to mismatch repair deficiency and microsatellite instability (MSI) in tumours. Due to a high lifetime risk of cancer, regular surveillance plays a key role in cancer prevention; yet the observation of frequent interval cancers points to insufficient cancer prevention by colonoscopy-based methods alone. This study aimed to identify precancerous functional changes in colonic mucosa that could facilitate the monitoring and prevention of cancer development in LS., Methods: The study material comprised colon biopsy specimens (n = 71) collected during colonoscopy examinations from LS carriers (tumour-free, or diagnosed with adenoma, or diagnosed with carcinoma) and a control group, which included sporadic cases without LS or neoplasia. The majority (80%) of LS carriers had an inherited genetic MLH1 mutation. The remaining 20% included MSH2 mutation carriers (13%) and MSH6 mutation carriers (7%). The transcriptomes were first analysed with RNA-sequencing and followed up with Gorilla Ontology analysis and Reactome Knowledgebase and Ingenuity Pathway Analyses to detect functional changes that might be associated with the initiation of the neoplastic process in LS individuals., Findings: With pathway and gene ontology analyses combined with measurement of mitotic perimeters from colonic mucosa and tumours, we found an increased tendency to chromosomal instability (CIN), already present in macroscopically normal LS mucosa. Our results suggest that CIN is an earlier aberration than MSI and may be the initial cancer driving aberration, whereas MSI accelerates tumour formation. Furthermore, our results suggest that MLH1 deficiency plays a significant role in the development of CIN., Interpretation: The results validate our previous findings from mice and highlight early mitotic abnormalities as an important contributor and precancerous marker of colorectal tumourigenesis in LS., Funding: This work was supported by grants from the Jane and Aatos Erkko Foundation, the Academy of Finland (330606 and 331284), Cancer Foundation Finland sr, and the Sigrid Jusélius Foundation. Open access is funded by Helsinki University Library., Competing Interests: Declaration of interests Minna Nyström is a member of the board of directors and a shareholder in LS CancerDiag Ltd. No disclosures were reported by the other authors., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Estimating the gaze direction with a digital video-based pupil and corneal reflection (P-CR) eye tracker is challenging partly since a video camera is limited in terms of spatial and temporal resolution, and because the captured eye images contain noise. Through computer simulation, we evaluated the localization accuracy of pupil-, and CR centers in the eye image for small eye rotations (≪ 1 deg). Results highlight how inaccuracies in center localization are related to 1) how many pixels the pupil and CR span in the eye camera image, 2) the method to compute the center of the pupil and CRs, and 3) the level of image noise. Our results provide a possible explanation to why the amplitude of small saccades may not be accurately estimated by many currently used video-based eye trackers. We conclude that eye movements with arbitrarily small amplitudes can be accurately estimated using the P-CR eye-tracking principle given that the level of image noise is low and the pupil and CR span enough pixels in the eye camera, or if localization of the CR is based on the intensity values in the eye image instead of a binary representation., (© 2022. The Author(s).)

Eye trackers are applied in many research fields (e.g., cognitive science, medicine, marketing research). To give meaning to the eye-tracking data, researchers have a broad choice of classification methods to extract various behaviors (e.g., saccade, blink, fixation) from the gaze signal. There is extensive literature about the different classification algorithms. Surprisingly, not much is known about the effect of fixation and saccade selection rules that are usually (implicitly) applied. We want to answer the following question: What is the impact of the selection-rule parameters (minimal saccade amplitude and minimal fixation duration) on the distribution of fixation durations? To answer this question, we used eye-tracking data with high and low quality and seven different classification algorithms. We conclude that selection rules play an important role in merging and selecting fixation candidates. For eye-tracking data with good-to-moderate precision (RMSD < 0.5 ∘ ), the classification algorithm of choice does not matter too much as long as it is sensitive enough and is followed by a rule that selects saccades with amplitudes larger than 1.0 ∘ and a rule that selects fixations with duration longer than 60 ms. Because of the importance of selection, researchers should always report whether they performed selection and the values of their parameters., (© 2021. The Author(s).)

Introduction: A large body of research has established a consensus that racial discrimination in CV screening occurs and persists. Nevertheless, we still know very little about how recruiters look at the CV and how this is connected to the discriminatory patterns. This article examines the way recruiters view and select CVs and how they reason about their CV selection choices, as a first step in unpacking the patterns of hiring discrimination. Specifically, we explore how race and ethnicity signaled through the CV matter, and how recruiters reason about the choices they make., Methods: We recorded data from 40 respondents (20 pairs) who are real-life recruiters with experiences in recruitment of diverse employees in three large Swedish-based firms in the finance and retail sector in two large cities. The participating firms all value diversity, equity and inclusion in their recruitment. Their task was to individually rate 10 fictious CVs where race (signaled by face image) and ethnicity (signaled by name) were systematically manipulated, select the top three candidates, and then discuss their choices in pairs to decide on a single top candidate. We examined whether respondents' choices were associated with the parts of the CV they looked at, and how they reasoned and justified their choices through dialog., Results: Our results show that non-White CVs were rated higher than White CVs. While we do not observe any statistically significant differences in the ratings between different racial groups, we see a statistically significant preference for Chinese over Iraqi names. There were no significant differences in time spent looking at the CV across different racial groups, but respondents looked longer at Polish names compared to Swedish names when presented next to a White face. The dialog data reveal how respondents assess different CVs by making assumptions about the candidates' job and organizational fit through limited information on the CVs, especially when the qualifications of the candidates are evaluated to be equal., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Osanami Törngren, Schütze, Van Belle and Nyström.)

The Anthropocene is characterized by accelerating change and global challenges of increasing complexity. Inspired by what some have called a polycrisis, we explore whether the human trajectory of increasing complexity and influence on the Earth system could become a form of trap for humanity. Based on an adaptation of the evolutionary traps concept to a global human context, we present results from a participatory mapping. We identify 14 traps and categorize them as either global, technology or structural traps. An assessment reveals that 12 traps (86%) could be in an advanced phase of trapping with high risk of hard-to-reverse lock-ins and growing risks of negative impacts on human well-being. Ten traps (71%) currently see growing trends in their indicators. Revealing the systemic nature of the polycrisis, we assess that Anthropocene traps often interact reinforcingly (45% of pairwise interactions), and rarely in a dampening fashion (3%). We end by discussing capacities that will be important for navigating these systemic challenges in pursuit of global sustainability. Doing so, we introduce evolvability as a unifying concept for such research between the sustainability and evolutionary sciences. This article is part of the theme issue 'Evolution and sustainability: gathering the strands for an Anthropocene synthesis'.

How well can modern wearable eye trackers cope with head and body movement? To investigate this question, we asked four participants to stand still, walk, skip, and jump while fixating a static physical target in space. We did this for six different eye trackers. All the eye trackers were capable of recording gaze during the most dynamic episodes (skipping and jumping). The accuracy became worse as movement got wilder. During skipping and jumping, the biggest error was 5.8 ∘ . However, most errors were smaller than 3 ∘ . We discuss the implications of decreased accuracy in the context of different research scenarios., (© 2022. The Author(s).)

Previous work has shown that exposure to auditory white noise (WN) can improve cognitive performance in children with ADHD, but it is unknown whether this improvement generalizes to other sensory modalities. To address this knowledge gap, we tested the effect of Stochastic Vestibular Stimulation (SVS) on cognitive performance and reaction time (RT) variability in two groups: children with ADHD and typically developing children (TDC). Children with ADHD (N=42) and TDC (N=28) performed three cognitive tasks (Spanboard, Word Recall and N-back tasks) at two different occasions, with and without exposure to SVS, in a double blinded design. The results showed no main effects of SVS on neither performance nor RT variability for children in any of the groups, and no interactions between SVS and group. Based on these results we conclude that, using our stimulation protocol, the positive effects of WN exposure on cognition in children with ADHD do not generalize to Stochastic Vestibular Stimulation., (© 2023. The Author(s).)

The Tobii Pro TX300 is a popular eye tracker in developmental eye-tracking research, yet it is no longer manufactured. If a TX300 breaks down, it may have to be replaced. The data quality of the replacement eye tracker may differ from that of the TX300, which may affect the experimental outcome measures. This is problematic for longitudinal and multi-site studies, and for researchers replacing eye trackers between studies. We, therefore, ask how the TX300 and its successor, the Tobii Pro Spectrum, compare in terms of eye-tracking data quality. Data quality-operationalized through precision, accuracy, and data loss-was compared between eye trackers for three age groups (around 5-months, 10-months, and 3-years). Precision was better for all gaze position signals obtained with the Spectrum in comparison to the TX300. Accuracy of the Spectrum was higher for the 5-month-old and 10-month-old children. For the three-year-old children, accuracy was similar across both eye trackers. Gaze position signals from the Spectrum exhibited lower proportions of data loss, and the duration of the data loss periods tended to be shorter. In conclusion, the Spectrum produces gaze position signals with higher data quality, especially for the younger infants. Implications for data analysis are discussed., (© 2021 The Authors. Infancy published by Wiley Periodicals LLC on behalf of International Congress of Infant Studies.)

Background: Although autologous fat grafting is considered a successful method for the management of contour deformities, the fat graft could potentially induce cancer reappearance by fueling dormant breast cancer cells. Our aim was to characterize the role of adipose-derived stem cells on active and dormant breast cancer cell growth., Methods: Cobalt chloride was used to induce dormancy in MCF-7 cancer cells. Proliferation of active and dormant cancer cells was determined in the presence of adipose-derived stem cells. A proteome array was used to detect cancer-related protein expression in the cell-conditioned medium. The migration of cancer cells was measured in response to conditioned medium from the adipose-derived stem cells., Results: The adipose-derived stem cells showed variable effects on active MCF-7 cells growth and inhibited MCF-7 proliferation after the withdrawal of cobalt chloride. Of the 84 different proteins measured in the conditioned medium, only tenascin-C was differentially expressed in the co-cultures. MCF-7 cells alone did not express tenascin-C, whereas co-cultures between MCF-7 and adipose-derived stem cells expressed more tenascin-C versus adipose-derived stem cells alone. The conditioned medium from co-cultures significantly increased the migration of the cancer cells., Conclusions: Adipose-derived stem cells themselves neither increased the growth or migration of cancer cells, suggesting that autologous fat grafting may be oncologically safe if reconstruction is postponed until there is no evidence of active disease. However, interactions between adipose-derived stem cells and MCF-7 cancer cells could potentially lead to the production of factors, which further promote cancer cell migration., Competing Interests: Declaration of Competing Interest None of the authors has a financial interest in any of the products, devices, or drugs mentioned in this manuscript., (Copyright © 2023 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.)