Ocular Metrics Research Articles

Synchronization-based fusion of EEG and eye blink signals for enhanced decoding accuracy

Decoding locomotor tasks is crucial in cognitive neuroscience for understanding brain responses to physical tasks. Traditional methods like EEG offer brain activity insights but may require additional modalities for enhanced interpretative precision and depth. The integration of EEG with ocular metrics, particularly eye blinks, presents a promising avenue for understanding cognitive processes by combining neural and ocular behaviors. However, synchronizing EEG and eye blink activities poses a significant challenge due to their frequently inconsistent alignment. Our study with 35 participants performing various locomotor tasks such as standing, walking, and transversing obstacles introduced a novel methodology, pcEEG+, which fuses EEG principal components (pcEEG) with aligned eye blink data (syncBlink). The results demonstrated that pcEEG+ significantly improved decoding accuracy in locomotor tasks, reaching 78% in some conditions, and surpassed standalone pcEEG and syncBlink methods by 7.6% and 22.7%, respectively. The temporal generalization matrix confirmed the consistency of pcEEG+ across tasks and times. The results were replicated using two driving simulator datasets, thereby confirming the validity of our method. This study demonstrates the efficacy of the pcEEG+ method in decoding locomotor tasks, underscoring the importance of temporal synchronization for accuracy and offering a deeper insight into brain activity during complex movements.

Driving performance and ocular activity following acute administration of 10 mg methylphenidate: A randomised, double-blind, placebo-controlled study.

Methylphenidate is a routinely prescribed treatment for attention-deficit/hyperactivity disorder with misuse potential owing to its perceived performance-enhancing and euphoric properties. Although clinically effective, there is limited understanding of how methylphenidate affects safety-sensitive tasks such as driving when used by healthy individuals. Explore the acute effects of 10 mg methylphenidate on driving performance and gaze behaviour. Twenty-five fully licensed, healthy adults (mean age = 33.5 ± 7.8 years, 64% male) took part in two 40-min simulated highway drives with simultaneous eye movements monitored using a proprietary automotive-grade driver monitoring system (Seeing Machines). Driving performance was assessed using the standard deviation of lateral position, standard deviation of speed and steering variability. Visual scanning efficiency was determined using ocular metrics, such as fixation duration and rate, gaze transition entropy, and stationary gaze entropy, were assessed to determine visual scanning efficiency. Methylphenidate significantly improved driving performance by reducing lane weaving and speed variation, particularly in the latter half of the drive. Although a significant reduction in fixation duration was observed, all other ocular metrics remained unchanged. Methylphenidate mitigates performance decrements typically associated with prolonged and monotonous driving. The absence of pronounced oculomotor effects suggests that a single 10 mg dose of methylphenidate has no deleterious impact on visual scanning behaviour during driving tasks with low-to-moderate cognitive demand. Future research should investigate the effects of methylphenidate under various dosing and driving conditions to better understand its impact. ACTRN12620000499987.

Influence of punishments associated with task outcomes in physical and mental efforts performed by semi-elite soccer players during training tasks

ABSTRACT Punishing application associated with the task outcomes is a familiar strategy used by soccer coaches during training, but it has been mainly remained in the research background. To date, no previous studies have addressed the effects of punishments on soccer players’ physical and mental efforts during on-field training sessions. Voluntarily, 40 semi-elite male soccer players from two Spanish teams of the same club participated in the study (M age = 22.90 yrs, SD = 5.60 yrs), performing two training sessions with the same tasks, but different in the use or non-use of punishments associated with the task outcomes. Physical load was registered using Polar Team and Ratio of Perceived Exertion. Mental load was estimated by the NASA-Task Load Index and mental fatigue was collected using a Visual Analogue Scale. A portable eye tracker was used to seek the effects of punishment manipulation on ocular metrics. After training, players achieved higher values of peak and mean heart rate, peak and mean speed, distance/minute, and number of sprints at the session with punishments, compared to the session without them. The punishments also influenced participants’ eye movement metrics because changes were found in pupil diameter, latency and velocity of saccades, and number of saccades and blinks when compared to the two training sessions. However, no differences were found between sessions for subjective mental load and fatigue variables. These findings have practical implications to the design of soccer training tasks because this emotional constraint influenced the physical load and objective mental load of the soccer players, but not their subjective measures of mental load and fatigue.

Serum lipid and lipoprotein profiles and their association with intraocular pressure in primary open-angle glaucoma: an observational cross-sectional study in the Chinese population

BackgroundGlaucoma is a leading cause of vision impairment and permanent blindness. Primary open-angle glaucoma (POAG) is a prominent type of primary glaucoma; however, its cause is difficult to determine. This study aimed to analyze the serum lipid profile of Chinese POAG patients and assess its correlation with intraocular pressure (IOP).MethodsThe study included 1,139, 1,248, and 356 Chinese individuals with POAG, primary angle closure glaucoma (PACG), and controls, respectively. Peripheral whole blood samples were collected at the time of diagnosis. Enzymatic colorimetry was used to determine serum levels of different lipids: high-density lipoproteins (HDL), low-density lipoproteins (LDL), triglycerides, cholesterol, and very low-density lipoproteins (VLDL). Additionally, immunoturbidimetry was used to quantify serum levels of apolipoproteins A (APOA), B (APOB), E (APOE), and lipoprotein A [Lp(a)], while intraocular pressure (IOP) was measured in all patients with POAG.ResultsAfter adjusting for age and sex, patients with POAG exhibited elevated serum levels of VLDL, APOA, and APOE but mitigated cholesterol levels compared with the control participants. Significantly lower serum triglyceride, VLDL, and Lp(a) levels were found in patients with PACG than in control participants. Serum cholesterol (P = 0.019; β = -0.75, 95% confidence interval [CI]: -1.38 – -0.12) and HDL levels (P < 0.001; β = -2.91, 95% CI: -4.58 – -1.25) were inversely linked to IOP in patients with POAG, after adjusting for age, sex, and ocular metrics. In addition, serum Lp(a) levels were correlated with the average IOP (P = 0.023; β = -0.0039, 95% CI: -0.0073 – -0.006) and night peak (P = 0.027; β = -0.0061, 95% CI: -0.0113 – -0.0008) in patients with POAG.ConclusionsSignificantly different serum lipid and lipoprotein profiles were observed in POAG and PACG patients. This study highlighted the differences in serum lipid and lipoprotein levels among Chinese POAG patients and their relationship with IOP and IOP fluctuation. Serum lipid and lipoprotein profiles should be considered while evaluating glaucoma risk.

Quantifying ocular microcirculation in hypertension patients with carotid artery stenosis.

Carotid artery stenosis (CAS) is one of the most common macrovascular complications of hypertension. The ophthalmic artery springs from the internal carotid artery; however, the effect of CAS on ocular microcirculation has not been quantified in hypertension patients. This study aimed to quantify ocular microcirculation metrics in hypertension with CAS (HCAS) patients and to explore the relationship between micro- and macroangiopathy in hypertension. All participants (community-based) underwent detailed assessments, including carotid ultrasonography, optical coherence tomography angiography (OCTA), and enhanced depth imaging (EDI)-OCT. CAS was diagnosed using carotid ultrasonography. Retinal microcirculation metrics, including vessel density (VD), skeleton density (SD), fractal dimension (FD), and foveal avascular zone (FAZ), were quantified using OCTA and ImageJ software. Choroidal microcirculation metrics, including subfoveal choroidal thickness (SFCT), luminal area (LA), and choroidal vascularity index (CVI), were quantified using EDI-OCT and ImageJ. Retinal vessel caliber metrics, including central retinal artery equivalent (CRAE), central retinal vein equivalent (CRVE), and artery/vein ratio (AVR), were calculated using revised formulas. The above metrics were compared among the HCAS group, hypertension with no CAS (HNCAS) group, and healthy control group. The mutual effects between ocular metrics and CAS were evaluated using regression analyses. In a comparison of the HCAS vs. HNCAS groups, retinal metrics including VD, SD, FD, and choroidal metrics including CVI and LA were significantly decreased in the HCAS group (all p < 0.05); however, FAZ, SFCT, and retinal vessel caliber metrics including CRAE, CRVE, and AVR were comparable between groups (all p > 0.05). In a comparison of HNCAS and the healthy control group, VD, SD, and CRAE showed that AVR was significantly decreased in the HNCAS group (all p < 0.05); meanwhile, choroidal metrics were comparable between groups (all p > 0.05). Linear regression analyses showed that intima-media thickness (IMT) (p = 0.01) and peak systolic velocity (PSV) (p = 0.002) were negatively related to retinal VD in hypertension patients. Logistic regression analyses disclosed that older age (p < 0.001), smoking history (p = 0.002), lower VD (p = 0.04), SD (p = 0.02), and CVI (p < 0.001) were related to the presence of CAS in hypertension patients. CAS in hypertension-induced hypoperfusion in retinal and choroidal microcirculation and the decreased retinal VD and choroidal CVI were significantly associated with the presence of CAS in patients with hypertension, suggesting that hypertension macro- and microangiopathy were mutually affected and share the common pathophysiology. Furthermore, OCT could be a useful tool to assess hypertension patient's CAS risk profiles in a non-invasive way.

Parallel comparison of ocular metrics in non-human primates with high myopia by LS900, ultrasonography and MRI-based 3D reconstruction

We investigate the ocular dimensions and shape by using Lenstar900 (LS900), A-scan ultrasonography, and Magnetic Resonance Imaging (MRI) in highly myopic Macaca fascicularis. The ocular dimensions data of LS900, A-scan ultrasonography and MRI was assessed from 8 eyes (4 adult male cynomolgus macaque) with extremely high myopia (≤-1000DS) and compared by means of coefficients of concordance and 95% limits of agreement. Multiple regression analysis was performed to explore the associations between ocular biometry, volume, refraction and inter-instrument discrepancies. Test-retest reliability of three measurements of ocular parameters at two time points was almost equal (intraclass correlation = 0.831 to 1.000). The parallel-forms reliability of three measurements was strong for vitreous chamber depth (VCD) (coefficient of concordance = 0.919 to 0.981), moderate for axial length (AL) (coefficient of concordance = 0.486 to 0.981), and weak for anterior chamber depth (ACD) (coefficient of concordance = 0.267 to 0.621) and lens thickness (LT) (coefficient of concordance = 0.035 to 0.631). The LS900 and MRI systematically underestimated the ACD and LT comparing to A-scan ultrasonography (P < 0.05). Notably, the average AL on LS900 displayed a significant correlation with those on MRI (r = 0.978, P < 0.001) and A-scan ultrasonography (r = 0.990, P < 0.001). Almost 4/5 eyeballs were prolate. The mean eyeball volume positively correlated with AL (r = 0.782, P = 0.022), the width (r = 0.945, P = 0.000), and the length (r = 0.782, P = 0.022) of eyeball, while negatively correlated with SER (r = −0.901, P = 0.000). In conclusion, there was a high inter-instrument concordance for VCD with LS900, A-scan ultrasonography and MRI, while ACD and LT were underestimated with LS900 compared to A-scan ultrasonography, and the LS900 and A-scan ultrasonography could reliably measure the AL. MRI further revealed an equatorial globe shape in extremely myopic non-human primates.

Comment on: influence of the time-task constraint on ocular metrics of semi-elite soccer

ABSTRACT This letter offers a constructive review of the article ‘Influence of the time-task constraint on ocular metrics of semi-elite soccer’ by Luis-del Campo et al. (2023), focusing on methodological considerations and avenues for future research enhancement. The study investigates the impact of task constraints on eye-tracking metrics among semi-elite soccer players, aiming to gauge mental workload during training sessions. While the study presents valuable insights, there are opportunities for methodological refinement. Suggestions include emphasizing sample size determination, randomization of the experimental conditions, and employing robust statistical analyses to mitigate potential biases. Moreover, future studies could benefit from integrating external load measures alongside heart rate monitoring to comprehensively assess training task variations. Despite these considerations, the study underscores the promising application of eye-tracking techniques in evaluating mental workload during soccer training, paving the way for further exploration and refinement of methodologies to enhance player performance assessment and training optimization in the field.

Corneal densitometry in Chinese adults with healthy corneas: associations with sex, age, ocular metrics, and optical characteristics

BackgroundStandardized corneal densitometry (CD) values in large samples of healthy Chinese individuals are scarce. Therefore, we aimed to determine the standard CD values using a Scheimpflug camera in healthy corneas, investigate the correlations of sex, age, and ocular parameters with corneal density, and explore the impact of corneal density on the forward scattering and optical quality of the eye.MethodsThis retrospective observational study involved 990 healthy Chinese individuals, including 494 males and 496 females (mean age: 23.88 ± 6.90 years). The CD values at various depths and radial areas of 0–12 mm were measured using a Scheimpflug camera. Densitometric measurements were expressed in standardized grayscale units (GSU). The optical scatter index (OSI), modulation transfer function cutoff values (MTFcutoff), and Strehl’s ratio (SR) were also determined using an optical quality analysis system.ResultsThe average CD within a 12 mm diameter area was 16.26 ± 1.35 GSU. The highest and lowest optical densities at different depths were observed in the anterior (21.41 ± 2.16 GSU) and posterior (12.00 ± 1.01 GSU) layers, respectively (P < 0.001). Similarly, the maximum and minimum optical densities at different radial areas were observed in the 10–12 mm (14.09 ± 0.93 GSU) and 2–6 mm (25.93 ± 4.77 GSU) circles, respectively (P < 0.001). There was no significant difference in the average CD within a 12 mm diameter area between males and females (P > 0.05). However, upon adjusting for age, central corneal thickness (CCT), corneal curvature, white-to-white (WTW) corneal diameter, and axial length, females exhibited a greater average CD within the 12 mm diameter and in the 6–10 mm and 10–12 mm circles than males. Age-related changes in CD were evident, except in the 2–6 mm circle. CCT, corneal curvature, WTW corneal diameter, and partial depth correlated with CD in the radial area, and CD in different areas correlated with the OSI, MTFcutoff, and SR (P < 0.05).ConclusionsThis study provides the normative CD measurement data of Chinese adults with healthy corneas, emphasizing the significance of sex, age, CCT, corneal curvature, and WTW corneal diameter in CD evaluation. Notably, elevated CD can lead to increased forward scattering within the eye, thereby affecting the optical quality.

A Morphometric Study of the Pars Plana of the Ciliary Body in Human Cadaver Eyes.

This study aimed to determine the pars plana length in postmortem human eyes using advanced morphometric techniques and correlate demographics to ocular metrics such as age, sex, ethnicity, and axial length. Between February and July 2005, we conducted a cross-sectional observational study on 46 human cadaver eyes deemed unsuitable for transplant by the SBO Eye Bank. The morphometric analysis was performed on projected images using a surgical microscope and a video-microscopy system with a 20.5:1 correction factor. The pars plana length was measured three times per quadrant, with the final value being the mean of these measurements. Of the 46 eyes collected, 9 were unsuitable for the study due to technical constraints in conducting intraocular measurements. Overall, the average axial length was 25.20 mm. The average pars plana length was 3.8 mm in all quadrants, with no measurements below 2.8 mm or above 4.9 mm. There were no statistically significant variations across quadrants or with age, sex, axial length, or laterality. Accurately defining the pars plana dimensions is crucial for safely accessing the posterior segment of the eye and minimizing complications during intraocular procedures, such as intravitreal injections and vitreoretinal surgeries.

(083) Visual Attention, Affective, and Sexual Responses Toward a Sexualized Video Game Female Character

Abstract Introduction Psychological models theorizing human sexual response have consistently stressed the role of cognitive factors, namely attention to sexual cues, as a precursor of sexual arousal. Specifically, laboratory studies have focused on (visual)attention as a trigger and maintenance factor of sexual arousal and interest; these studies suggest that sexual stimuli, e.g., stimuli displaying human-realistic nudity and/or sexual intercourse, capture more attention, prompting a sexual response. These studies have settled the basis for psychological interventions in sexual dysfunctions. However, contemporary generations were (sexually)educated and are a product of the digital era, where human-realistic sexual stimuli are no longer the only features people use to induce a sexual response. Female video game characters have “ascended” to the status of sexual stimuli. Animated sexual features are replacing human-realistic ones to induce a sexual response. Yet, sexology research still supports its assumptions on people’s responses to “old fashion” sexual stimuli. Objective Given the lack of laboratory studies using animated sexual features as a frame to study human sexual response - being, therefore, aligned to current preferences regarding what constitutes a sexual stimulus – the current study was aimed at testing the effects of being exposed to a sexualized as compared to a non-sexualized female video game character on men’s (visual)attention, affective and sexual responses. It further tested if the propensity to get sexually aroused predicts men’s responses to sexually animated cues. Methods 46 men (Mage = 25, SD = 8.71) were exposed to the following 2-minute video clips/experimental conditions: 1) a sexualized female video game character, i.e., the character is fighting against a non-human male character, using nothing more than a tie, short bikini; 2) a non-sexualized female character fighting, and wearing a common, practical, outfit, with no evidence of nudity. The video clips were presented in a counterbalanced fashion. The female characters were equal, except for the woman’s clothing and display of nudity. Objective proxies of sexual arousal and interest were captured by an eye tracker (pupil size and dwell time to the sexual features, respectively). Self-reported attention, affective, and sexual responses were also measured. Furthermore, the propensity for sexual excitation was included as a trait sexual dimension. Results As expected, participants reported being more distracted and sexually aroused during the sexualized experimental condition. Similarly, ocular metrics revealed that during the sexualized condition, participants paid less attention to the game/dangerous cues and spent more time looking at the woman’s body and buttocks. No effects were found regarding pupil size. Findings regarding sexual excitation as a sexual trait showed that the propensity to get sexually aroused predicted increased visual attention, i.e., more interest, to the buttocks of the sexualized female character. Conclusions Findings suggest that sexualized female video game characters mimic the effects of human-realistic sex stimuli. Findings add to the understanding of cognitive and emotional processes involved in the human sexual response considering the new trends regarding what constitutes sexual stimuli. They further contribute to the discussion on sexual preferences diversity, with a special emphasis on the current digital culture. Disclosure No.

Evaluating the efficacy of Rho kinase inhibitor eye drops in the management of corneal edema: A single-center retrospective cohort study.

This study aimed to evaluate the efficacy of ripasudil in managing various corneal edema conditions. This single-center retrospective analysis was conducted at Hadassah Medical Center and involved 16 patients with 17 eyes. Patients were selected based on diagnostic criteria, primarily corneal edema. The conditions were as follows, listed by frequency: postcataract surgery (31.25%), postpenetrating keratoplasty (25%), post-Descemet's membrane endothelial keratoplasty (18.75%), Fuchs' endothelial corneal dystrophy (12.5%), status post-Ahmed glaucoma valve (6.25%), and status posttrabeculectomy (6.25%). The treatment regimen involved topical administration of ripasudil hydrochloride hydrate (Glanatec® 0.4%), administered three times a day or tailored to condition severity. Efficacy was assessed using pre- and posttreatment measurements of best-corrected visual acuity (BCVA), central corneal thickness (CCT), and endothelial cell count (ECC), along with slit-lamp and optical coherence tomography examinations. The average duration of ripasudil treatment was approximately 4.9 ± 2.2 months. Significant improvements were observed in BCVA, changing from a pretreatment value of 1.106 ± 0.817 logMAR to a posttreatment value of 0.56 ± 0.57 logMAR (P = 0.0308). CCT also showed a significant reduction, from 619.50 ± 56.36 μm pretreatment to 572.5 ± 75.48 μm posttreatment (P = 0.0479). ECC showed a marginal but not statistically significant increase, from 849.00 ± 570.72 cells/mm² pretreatment to 874.75 ± 625.59 cells/mm² posttreatment (P = 0.9010). The study provides robust evidence supporting the use of ripasudil in managing corneal edema. Significant improvements in key ocular metrics such as BCVA and CCT were observed, enhancing the overall quality of life for patients suffering from various forms of corneal edema.

Expertise differences in cognitive interpreting: A meta-analysis of eye tracking studies across four decades.

This meta-analytic research delves into the influence of expertise on cognitive interpreting, emphasizing time efficiency, accuracy, and cognitive effort, in alignment with prevailing expertise theories that link professional development and cognitive efficiency. The study assimilates empirical data from 18 eye-tracking studies conducted over the past four decades, encompassing a sample of 1581 interpreters. The objective is to elucidate the role of expertise in interpretative performance while tracing the evolution of these dynamics over time. Findings suggest that expert interpreters outperform novices in time efficiency and accuracy and exhibit lower cognitive effort, especially in sight and consecutive interpreting. This effect is particularly pronounced in the English-Chinese language pair and with the use of E-prime and Tobii eye-tracking systems. Further, fixation count and pupil size are essential metrics impacting cognitive effort. These findings have vital implications for interpreter training programs, suggesting a focus on expertise development to enhance efficiency and accuracy, reduce cognitive load, and emphasize the importance of sight interpreting as a foundational skill. The selection of technology and understanding of specific ocular metrics also emerged as essential for future research and practical applications in the interpreting industry. This article is categorized under: Psychology > Theory and Methods Linguistics > Cognitive.

On the potential of pupil size as a metric of physical fatigue during a repeated handle push/pull task

Force output and muscle activity represent the gold standards for measuring physical fatigue. This study explores using ocular metrics for tracking changes in physical fatigue during the completion of a repeated handle push/pull task. Participants completed this task over three trials, and pupil size was recorded by means of a head-mounted eye-tracker. Blink frequency was also measured. Force impulse and maximum peak force were used as ground-truth measures of physical fatigue. As expected, a reduction in peak force and impulse was observed over time as participants became more fatigued. More interestingly, pupil size was also found to decrease from trial 1 through trial 3. No changes in blink rate were found with increasing physical fatigue. While exploratory in nature, these findings add to the sparse literature exploring the use of ocular metrics in Ergonomics. They also advance the use of pupil size as a possible future alternative for physical fatigue detection.

Comparison of pain perception in patients undergoing manual cataract surgery versus refractive laser-assisted cataract surgery

ObjectifsMesurer la perception de la douleur pendant la chirurgie manuelle de la cataracte comparativement à la chirurgie de la cataracte au laser femtoseconde (CCLF) de même que la perception de la douleur chez des patients qui font l'objet d'une anesthésie à 2 moments différents de la CCLF. Nous avons également évalué les facteurs liés à la perception de la douleur dans ces différents groupes. NatureÉtude comparative de cohorte prospective portant sur une démarche chirurgicale choisie par les patients. ParticipantsPatients devant subir une chirurgie de la cataracte bilatérale séquentielle retardée dans un centre de chirurgie ambulatoire en Ontario. MéthodesLes patients ont été répartis en 3 groupes : une cohorte devant subir une chirurgie manuelle de la cataracte (n = 30) et 2 cohortes devant subir une CCLF, dont l'une soumise à une neuroleptanalgésie tout juste avant le drapage opératoire en vue de la phacoémulsification (cohorte CCLF standard; n = 38) et l'autre, à une neuroleptanalgésie avant le recours au laser femtoseconde (cohorte CCLF hâtive; n = 35). Les paramètres de mesure comprenaient les scores de douleur sur une échelle visuelle analogique au jour postopératoire 0 et à la semaine postopératoire 1. Au nombre des paramètres secondaires, citons les scores d'anxiété, les scores de coopération de la part des patients selon le chirurgien ou l'anesthésiologiste, les variables oculaires et les signes vitaux peropératoires. RésultatsOn n'a pas noté de différence significative quant à la perception de la douleur au jour postopératoire 0 et à la semaine postopératoire 1 entre la cohorte chirurgie manuelle de la cataracte et la cohorte CCLF standard (p = 0,94 et p = 0,72, respectivement), ni entre la cohorte CCLF hâtive et la cohorte CCLF standard (p = 0,76 et p = 0,67, respectivement). Les scores de douleur des patients étaient plus élevés pendant l'intervention touchant le deuxième œil que pendant l'intervention touchant le premier œil. ConclusionsLe type de chirurgie de la cataracte de même que le moment où a lieu l'anesthésie dans le cas de la CCLF n'ont pas d'incidence sur la perception de la douleur en période postopératoire. L'intervention touchant le deuxième œil est associée à des scores de douleur plus élevés que l'intervention touchant le premier œil.

Influence of the time-task constraint on ocular metrics of semi-elite soccer players

ABSTRACT This study novelty aimed to investigate the influence of manipulating the available time to perform the training tasks on soccer players´ ocular metrics, following training. Specifically, pupillary response (pupil diameter) and saccadic features (latency, accuracy, velocity, and number) were measured with a portable eye tracker following training to reflect the mental load accumulated by players during the training sessions. Nine semi-elite soccer players performed two training sessions, based on large-sided games, on an artificial grass field. These two sessions were composed of the same tasks but varying the required time to complete the task goals (Session 1: No time limitations to perform the tasks; Session 2: Limited time to perform the tasks). The participants performed, before (pre-test) and after (post-test) each training session, a prosaccade task in a room near the playing field. Findings revealed a differentiated effect of the available time to complete the training tasks on ocular metrics because significant differences were found in all variables after training (p < .001 for pupil diameter; p < .01 for saccade accuracy and number of saccades; p < .05 for saccade velocity and latency). Ocular metrics could be a promising tool to evaluate mental load following practice because they were sensitive to the time-task constraint, providing researchers a valuable information for a better planning of the mental workload when designed training tasks.

Distracted worker: Using pupil size and blink rate to detect cognitive load during manufacturing tasks

This study sets out to extend the use of blink rate and pupil size to the assessment of cognitive load of completing common automotive manufacturing tasks. Nonoptimal cognitive load is detrimental to safety. Existing occupational ergonomics approaches come short of measuring dynamic changes in cognitive load during complex assembling tasks. Cognitive demand was manipulated by having participants complete two versions of the n-back task (easy, hard). Two durations of the physical task were also considered (short, long). Pupil size and blink rate increased under greater cognitive task demand. High cognitive load also resulted in longer task completion times, and higher ratings of mental and temporal demand, and effort. This exploratory study offers relevant insights on the use of ocular metrics for cognitive load assessment in occupational ergonomics. While the existing eye-tracking technology may yet limit their adoption in the field, they offer advantages over the more popular expert-based and self-reported techniques in measuring changes in cognitive load during dynamic tasks.

Quantifying Workload and Stress in Intensive Care Unit Nurses:PreliminaryEvaluation Using ContinuousEye-Tracking.

(1) To assess mental workloads of intensive care unit (ICU) nurses in 12-hour working shifts (days and nights) using eye movement data; (2) to explore the impact of stress on the ocular metrics of nurses performing patient care in the ICU. Prior studies have employed workload scoring systems or accelerometer data to assess ICU nurses' workload. This is the first naturalistic attempt to explore nurses' mental workload using eye movement data. Tobii Pro Glasses 2 eye-tracking and Empatica E4 devices were used to collect eye movement and physiological data from 15 nurses during 12-hour shifts (252 observation hours). We used mixed-effect models and an ordinal regression model with a random effect to analyze the changes in eye movement metrics during high stress episodes. While the cadence and characteristics of nurse workload can vary between day shift and night shift, no significant difference in eye movement values was detected. However, eye movement metrics showed that the initial handoff period of nursing shifts has a higher mental workload compared with other times. Analysis of ocular metrics showed that stress is positively associated with an increase in number of eye fixations and gaze entropy, but negatively correlated with the duration of saccades and pupil diameter. Eye-tracking technology can be used to assess the temporal variation of stress and associated changes with mental workload in the ICU environment. A real-time system could be developed for monitoring stress and workload for intervention development.

Fixation and Blink Eye Movement Behavior in Dyslexic and Non-Dyslexic English Readers

This study identifies eye movement differences amongst dyslexic and non-dyslexic groups during varying visual reading stimuli. Four ocular metrics are investigated: fixation duration, regression count, blink count and blink duration. In this study, 24 participants were divided into two groups dyslexic (n = 11) and non-dyslexic (n = 13) to read an electronic reading stimulus under different visual typographic conditions. A t-test analysis of each group was conducted for each ocular metric. Significant differences were observed amongst three of the four ocular metrics: fixation duration (p 0.001), regression count (p p p

Exploring Hypersexuality Pathways From Eye Movements: The Role of (Sexual) Impulsivity

BackgroundImpulsivity is regarded as a key factor underpinning hypersexuality like-conditions. However, impulsivity is a multifaceted construct, and existing research has not been capturing such complexity, which includes the effects of domain-general and domain-specific impulsivity in hypersexuality. AimThe aim of this study was to test the predictive role of specific impulsivity domains, ie, domain-general and domain-specific, in hypersexuality and its associated consequences. MethodsFifty-five men and 58 women went through an emotional Go/-no-Go task (including sexual, high-valence positive, and neutral pictures), aimed at capturing domain-general and domain-specific impulsivity. Ocular metrics were further considered in order to increase the validity of the experimental task, and provide a metric of attention capturing. The study was carried out in a community sample. OutcomesSelf-reported (general)impulsivity and commission errors toward high-valence positive and sexual pictures (signaling domain-general and domain-specific impulsivity, respectively) were settled as independent variables, along with Time to First Fixation to stimuli, capturing early/uncontrolled attention. Scores on hypersexuality and negative consequences emerging from hypersexual behavior were settled as outcome variables. ResultsSelf-reported (general)impulsivity was the only predictor of hypersexuality scores, while negative consequences were best accounted by higher fixation time to sexual pictures. In all, findings did not support the role of domain-specific impulsivity (ie, sexual impulsivity) in hypersexuality. Clinical TranslationFindings tentatively suggest that hypersexuality, as captured at the community level, may be best positioned within the general spectrum of psychopathology, thus influencing educational and clinical intervention protocols aimed at addressing hypersexuality related complaints. Protocols would be expected to primarily target general psychopathology phenomena, rather than specific sexual aspects. Strengths & LimitationsThis study implemented an innovative approach to capture different impulsivity domains, thus adding to previous literature in the field. However, the current study precludes the generalization of findings to clinical samples, where psychological comorbidities are expected to impact results. Further, findings must be read with caution given to limited effect sizes. ConclusionWhile hypersexuality was related to self-reported (general) impulsivity, findings on the negative consequences associated with hypersexual behavior mirrored response patterns found in depression. Such evidence aligns with the assumption that hypersexuality related phenomena might be better positioned in the psychopathology domain, rather than simply framed as a specific sexual problem.Carvalho J, Rosa PJ, Štulhofer A. Exploring Hypersexuality Pathways From Eye Movements: The Role of (Sexual) Impulsivity. J Sex Med 2021;18:1607–1614.

Ocular measures during associative learning predict recall accuracy

The ability to form associations between stimuli and commit those associations to memory is a cornerstone of human cognition. Dopamine and noradrenaline are critical neuromodulators implicated in a range of cognitive functions, including learning and memory. Eye blink rate (EBR) and pupil diameter have been shown to index dopaminergic and noradrenergic activity. Here, we examined how these ocular measures relate to accuracy in a paired-associate learning task where participants (N = 73) learned consistent object-location associations over eight trials consisting of pre-trial fixation, encoding, delay, and retrieval epochs. In order to examine how within-subject changes and between-subject changes in ocular metrics related to accuracy, we mean centered individual metric values on each trial based on within-person and across-subject means for each epoch. Within-participant variation in EBR was positively related to accuracy in both encoding and delay epochs: faster EBR within the individual predicted better retrieval. Differences in EBR across participants was negatively related to accuracy in the encoding epoch and in early trials of the pre-trial fixation: faster EBR, relative to other subjects, predicted poorer retrieval. Visual scanning behavior in pre-trial fixation and delay epochs was also positively related to accuracy in early trials: more scanning predicted better retrieval. We found no relationship between pupil diameter and accuracy. These results provide novel evidence supporting the utility of ocular metrics in illuminating cognitive and neurobiological mechanisms of paired-associate learning.