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Importance: Occupational therapy practitioners' knowledge of and advocacy for clients with visual symptoms postconcussion can have a considerable impact on recovery. Objective: To compare the frequency of vision symptoms and occupational performance deficits in a sample of participants with and without concussion. Design: Cross-sectional study. Setting: Sports medicine clinic. Participants: Adolescents and adults with concussion (n = 20) and musculoskeletal injuries (n = 19). Outcomes and Measures: Measures included monocular amplitude of accommodation, near point of convergence, Binocular Vision Assessment (BVA) computerized screening for phoria, BVA computerized screening for fusional vergence, the Developmental Eye Movement Test, the Canadian Occupational Performance Measure, and the Convergence Insufficiency Symptom Survey–Concussion Version (CISS–CON). Results: We found significant differences between participants with and without concussion using the CISS–CON (p =.001), positive fusional vergence (p =.02), and near point of convergence (p =.02). Participants with concussion scoring above cutoffs on multiple measures reported poorer performance (p =.005) and satisfaction (p =.004) with valued occupations. Conclusions and Relevance: Concussion has a detrimental effect on vision and occupation, and occupational therapy practitioners are well-positioned to assess and address issues arising from this relationship. Plain-Language Summary: Vision symptoms commonly experienced after a concussion are associated with reduced occupational performance and satisfaction and can have a considerable impact on recovery. Occupational therapy assessment for clients with concussion should include screening for vision difficulties. This study compares the frequency of vision symptoms and occupational performance deficits in a sample of participants with and without concussion. [ABSTRACT FROM AUTHOR]

Psychologists have long been interested in the underlying visual perceptual processes associated with forming responses to certain psychological tests, including the Rorschach Ink Blot Test, which modern users conceptualize as a conceptual problem-solving task. Accordingly, we used eye tracking technology to assess the internal consistency of saccadic responses to both the Rorschach Ink Blot Test and a facial expression task. Internal consistency was highest for eye Fixation Duration (FD) and Saccade Amplitude (SA), and both FD and SA measures in the Rorschach were positively related to the same measures in the facial expression task. Given this high internal consistency of FD and SA for viewing Rorschach ink blots and viewing pictures from well-known collections of facial expressions, and given high correlations between these eye tracking measures across the two tasks, FD and SA may now be used in further studies of eye movements in visuo-attentive psychological/neuropsychological tests (e.g., the Thematic Apperception Test). Reliability of these eye movement measures across tasks enables their use for better understanding of underlying visual processes and improved interpretations of the meaning of behavioral responses to psychological/neuropsychological tests. [ABSTRACT FROM AUTHOR]

In this study, virtual reality technology was used to simulate the virtual scene of three common light environment forms of professional classrooms in universities. The experimental results show that people's environmental perception is related to the average pupil diameter, saccade frequency, high frequency/low frequency (LF/HF) and skin conductance change rate in a combined light environment; moreover, when the colour temperature is 4500 K, the space is brighter, more spacious, more relaxed and the willingness to learn is stronger. In the range of 22.4°C–25°C, temperature does not affect people's perception of the warm feeling of the light environment, while the light colour temperature has a greater impact on people's perception of the warm feeling. The lower the light colour temperature is, the warmer people feel subjectively. However, people's eye movement behaviour and physiological system data have no obvious perception of colour temperature changes. Indoor noise affects the indoor brightness perception to some extent. In the range of 43–46.9 dB, with the increase of noise value, the evaluation score of people's brightness perception basically increases. In terms of learning psychological state, the more comfortable the light environment is, the stronger the willingness to learn and the higher the learning enthusiasm. [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to study consumers' visual attention and emotional experience with clothing design factors and their combinations from the perspective of cognition and emotion and propose an interaction phenomenon to evaluate the combined effect of clothing factors to better guide online clothing design and sales. Design/methodology/approach: An eye movement physiology experiment was conducted, 33 participants screened by questionnaires were invited for this experiment. Hypotheses of visual attention were verified by the FIRST_FIXATION_TIME indicator, DWELL_TIME indicator and FIXATION_COUNT indicator. Hypotheses of emotional experience were verified by the PUPIL_SIZE indicator. Findings: First, on the product list page, it is better to use only the three factors of clothing and a small number of stimulating factors. Second, when the stimulus is consistent with the cognitive task performed by the consumer, the efficiency of the task and the consumer's user experience will be improved. Third, the positive interaction phenomenon of clothing design factors and their combinations could significantly attract consumers' visual attention and improve their emotional experience. Research limitations/implications: This work argues consumer interest and emotional experience with online clothing can be expressed through eye movement physiological indicators, and the concept of interaction was proposed to evaluate the design and display of online clothing. Originality/value: This paper conducted interaction research on online clothing design factors and their combinations from the perspective of cognition and emotion, which provided an objective quantitative method for online clothing designers and online clothing retailers. [ABSTRACT FROM AUTHOR]

Clinical Relevance: The extent of binocular vision dysfunction in elite soccer players needs to be determined as it may impact performance.Background: The purpose of the study was to investigate the prevalence of binocular vision dysfunctions in elite soccer players.Methods: One hundred and seven professional soccer players were evaluated. Refractive error was measured and the following binocular vision parameters were assessed: horizontal and vertical phoria for distance and near vision, the values of break and recovery for negative and positive fusional vergences at distance and near vision, vergence facility at distance and near vision, monocular accommodative facility at near vision, and near point of convergence (break and recovery points). All the athletes were men with a mean age of 24.4 ± 4.8 years.Results: No athlete was diagnosed with divergence excess, divergence insufficiency, or basic exophoria. About 13.0% of the athletes have binocular vision dysfunctions related to esophoria (0.9% with esophoria at near vision and 12.1% with esophoria at distance and near vision). About 10.3% have convergence insufficiency and 2.8% were diagnosed with fusional vergence dysfunction. The only accommodation-related parameter analysed was accommodative infacility, and 6.5% of the athletes had this dysfunction. Vertical phoria was present in 3.7% of the athletes. No statistically significant differences were found based on in athletes with respect to ethnicity, position occupied on the field, age, ametropia or laterality.Conclusion: The overall prevalence of binocular vision dysfunction in elite soccer players was 36.4%. The most prevalent dysfunctions are related to the presence of esophoria (13.0%). The values found point out the need to include binocular vision assessment protocols in the visual assessment routine for athletes. [ABSTRACT FROM AUTHOR]

Lectures constitute a basic component of physiology instruction in scientific and healthcare curricula. Technological progress has allowed a switch from face to face to video lectures, yet there is no evidence of video efficacy in physiology. Because videos increase the cognitive load during a learning task, identifying tools that decrease students' cognitive load during video lectures is critical. Segmenting videos with pauses and inducing joint attention with eye movement modeling examples (EMME) could reduce the cognitive load and improve second-year medical students' learning in physiology video lectures. Second-year medical students were randomized into four groups [EMME + pauses (EMME + P), EMME without pause's (EMME-NoP), pauses only (NoEMME + P), and no EMME and no pause (NoEMME-NoP)], took pretest quizzes, watched a renal physiology video lecture, and answered a cognitive load questionnaire and posttest quizzes on the Moodle learning management system. Student prior knowledge was assessed by a pretest, and learning gains were assessed by the difference between posttest and pretest scores. One hundred ninety-five students completed the experiment. Pauses improved learning gains (P < 0.01) but not EMME (P = 0.11). Student prior knowledge has several interactions with other variables: low-prior knowledge students obtained better learning gains (P < 0.001) and high-prior knowledge students had lower learning gains with EMME (P < 0.05). Our study shows the potential role of tools designed to reduce students' cognitive load during a renal physiology video lecture and the critical need for empirical validation of pedagogical solutions that are adapted to the specificities of physiology lectures. [ABSTRACT FROM AUTHOR]

Among existing accounts of passivisation difficulty, some argue it depends on the predicate semantics (i.e. passives are more difficult with subject-experiencer than agent-patient verbs). Inconsistent with the accounts that predict passive difficulty, Paolazzi et al. (2019) found that passives were read faster than actives at the verb and object by-phrase in a series of self-paced reading experiments, with no modulation of verb type. However, self-paced reading provides limited direct measurement of late revision/interpretive processing. We used modified stimuli from Paolazzi et al. (2019) to re-examine this issue in two eye-tracking while reading experiments. We found that in late measures, passives with subject-experiencer verbs had longer fixation durations than actives at the verb and two subsequent regions but no difference was observed across agent-patient verbs. Subject-experiencer verbs provide a state, but the passive structure requires an event. Thus, the required eventive interpretation is coerced with subject-experiencers (if possible) and induces difficulty. [ABSTRACT FROM AUTHOR]

The author discusses aspects of the article by Smeets and colleagues on stimulus detection, identification and response preparation. He addresses some neurophysiological substrates that may underlie the results of the study by referring to the literature on the neurophysiology of saccadic eye movements. He also mentions that the cellls in the supericial layers receive direct input from the retina and response to visual stimuli in the visual fields.

Data modeling and data processing are important activities in any scientific research. This research focuses on the modeling of data and processing of data generated by a saccadometer. The approach used is based on the relational data model, but the processing and storage of the data is done with client datasets. The experiments were performed with 26 randomly selected files from a total of 264 experimental sessions. The data from each experimental session was stored in three different formats, respectively text, binary and extensible markup language (XML) based. The results showed that the text format and the binary format were the most compact. Several actions related to data processing were analyzed. Based on the results obtained, it was found that the two fastest actions are respectively loading data from a binary file and storing data into a binary file. In contrast, the two slowest actions were storing the data in XML format and loading the data from a text file, respectively. Also, one of the time-consuming operations turned out to be the conversion of data from text format to binary format. Moreover, the time required to perform this action does not depend in proportion on the number of records processed. [ABSTRACT FROM AUTHOR]

This study sought to test the hypothesis that significant differences would be observed in clinical measures, symptoms, and objective assessments of vergence eye movements between children with typically developing convergence insufficiency (TYP-CI) and children with persistent post-concussion symptoms with convergence insufficiency (PPCS-CI). Data from age-matched binocularly normal controls (BNC) were used for comparison. Data from three groups of children 11 to 17 years of age are presented: BNC (N = 11), TYP-CI (N = 10), and PPCS-CI (N = 15). Clinical measures of vergence, accommodation, and symptom severity were collected. Symmetrical 4° disparity vergence eye movements were quantified with an eye tracker integrated into a head-mounted display (Oculus DK2). Peak velocity and final response amplitude of convergence and divergence eye movement responses were assessed. The mean near point of convergence (break) was more receded (worse), the amplitude of accommodation more deficient, and convergent and divergent peak velocities slower in the PPCS-CI group compared with the TYP-CI and BNC groups. These results suggest that PPCS-CI may be a different clinical entity than TYP-CI. Hence, more research is warranted to determine whether the therapeutic interventions that are effective for TYP-CI can also be used for PPCS-CI populations. [ABSTRACT FROM AUTHOR]

Many patients with concussion experience visual symptoms following injury that lead to a diagnosis of convergence insufficiency, accommodative insufficiency, or saccadic dysfunction. However, these diagnostic categories are based on aggregates of clinical tests developed from a non-concussed population and therefore may not accurately describe visual deficits in the concussed population. Thus, we sought to understand individual metrics of visual dysfunction in chronically symptomatic post-concussion patients. This retrospective cross-sectional study included patients examined at the multidisciplinary concussion clinic (MDCC) at Boston Children's Hospital over four years. Patients aged 5-21 years who had a complete assessment of eye alignment, vergence, accommodation, and visual tracking, and had visual acuity better than or equal to 20/30 in each eye were included. Patients with history of amblyopia, strabismus, or ocular pathology were excluded. Chart review yielded 116 patients who met inclusion criteria (median age 15 years, 64% female). The majority of patients (52%) experienced a single concussion and most were sports-related (50%). Clinical data show vergence, accommodation, or visual tracking deficits in 95% of patients. A receded near point of convergence (NPC, 70/116) and reduced accommodative amplitude (63/116) were the most common deficits. Both NPC and accommodative amplitude were significantly correlated with one another (r = -0.5) and with measures of visual tracking (r = -0.34). Patients with chronic post-concussion symptoms show deficits in individual metrics of vergence, accommodation and visual tracking. The high incidence of these deficits, specifically NPC and accommodative amplitude, highlights the need for a detailed sensorimotor evaluation to guide personalized treatment following concussion. [ABSTRACT FROM AUTHOR]

Purpose: To assess pre and post vergence and accommodation parameters after monitored reading on a smartphone device.Methods: This prospective comparative study was performed in a tertiary eye care center for a duration of 6 months (December 2017 - May 2018). A total of 47 healthy emmetropic subjects of age group ranging from 18-30 years were recruited for the study. Participants underwent an initial visual screening protocol, followed by accommodation and vergence parameters assessment. The subjects were given reading text of optotype N6 at 40cm working distance for 30 minutes in a smart phone device. Pre and post measurements were documented.Results: Among 47 subjects there were 17 male and 30 females with mean age group of 21.2+2.06 years. There was a statistically significant worsening of accommodative components (negative & positive relative accommodation, lag of accommodation). In vergence parameters, a statistically significant deterioration of negative (12.8 + 1.65 to 12.38 + 1.93 PD) and positive fusional vergence (15.48 + 1.53 to 16.08 +1.61 PD) was observed. The mean vergence facility also showed a statistically significant change in pre and post task measurements (13.51 + 1.64 to 10.71 + 1.91 cpm (cycles per minute)).Conclusion: The current study investigated that perusing text with a smart phone for 30 minutes shows significant effect on accommodative and vergence components for near task, with greater impact on vergence parameters. Drawn out exposure to digital screens at near, may bring about visual quality dysfunction. [ABSTRACT FROM AUTHOR]

The purpose of the study was to determine the frequency of vision diagnoses after concussion in adolescents and evaluate the sensitivity and specificity of physician-administered screening for detecting convergence and accommodative disorders post-concussion. We enrolled participants 11 to 17 years old, assessed 4 to 12 weeks following a diagnosed concussion. During the initial concussion examination, a sports medicine physician measured the near point of convergence (NPC), monocular accommodative amplitude (AA), and symptoms using the Convergence Insufficiency Symptom Survey (CISS). A comprehensive oculomotor evaluation was performed by an optometrist. One hundred and thirteen adolescents were enrolled, with a mean age of 15.2 years. Seventy-nine of the 113 (70%) participants had at least one oculomotor diagnosis after concussion, with the most common problems being vergence disorders (60%) and accommodative disorders (57%). The most common vergence disorder was convergence insufficiency (35%). Among accommodative disorders, the most common problem was accommodative insufficiency (35%). In all, 47% of the participants had more than one oculomotor diagnosis following concussion. The sensitivity of physician screening using measures of NPC, AA, and CISS for detecting convergence and accommodative insufficiency was 63%, 43%, 48%, respectively. The results of this study provide additional evidence that vision problems are common in adolescents with persistent concussion symptoms in the sub-acute phase 4 to 12 weeks post-concussion, and current physician screening methods using the NPC, AA, or the CISS underperform. Thus, it is prudent that adolescents with post-concussion symptoms lasting more than 4 weeks post injury receive a comprehensive oculomotor examination. [ABSTRACT FROM AUTHOR]

Classic studies of ocular dominance plasticity in early development showed that monocular deprivation suppresses the neural representation and visual function of the deprived eye. However, recent studies have shown that a short period of monocular deprivation (<3 h) in normal adult humans, shifts sensory eye dominance in favor of the deprived eye. How can these opposing effects be reconciled? Here we argue that there are two systems acting in opposition at different time scales. A fast acting, stabilizing, homeostatic system that rapidly decreases gain in the non-deprived eye or increases gain in the deprived eye, and a relatively sluggish system that shifts balance toward the non-deprived eye, in an effort to reduce input of little utility to active vision. If true, then continuous deprivation should produce a biphasic effect on interocular balance, first shifting balance away from the non-deprived eye, then towards it. Here we investigated the time course of the deprivation effect by monocularly depriving typical adults for 10 h and conducting tests of sensory eye balance at six intervening time points. Consistent with previous short-term deprivation work, we found shifts in sensory eye dominance away from the non-deprived eye up until approximately 5 h. We then observed a turning point, with balance shifting back towards the non-deprived eye, -, a biphasic effect. We argue that this turning point marks where the rapid homeostatic response saturates and is overtaken by the slower system responsible for suppressing monocular input of limited utility. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to study online clothing consumers' behaviour and their visual attention mechanism to provide objective and quantitative evidences for the display and sales of online clothing. Design/methodology/approach: Firstly, this paper conducted a Focus Group Methodology and questionnaire survey to obtain concern factors of online clothing. Secondly, the online clothing's bottom-up visual stimulation and consumer's top-down expectations were analysed, and proposed the hypotheses about significant stimulus of clothing and consumer's emotional experience. Thirdly, the online clothing consumer's visual attention rules and related qualitative results were discussed, and proposed visual attention law for online clothing. Finally, took the company's 84th quarter clothing design practices as research projects, all the hypotheses were demonstrated through eye movement physiology experiments, online clothing trial release and node sales data. Findings: Online clothing has unique visual display ways compared with other online products such as online advertising, brands and food packaging. Clothing patterns of unfamiliar (fresh) font shapes are more attractive than the patterns of familiar fonts. The cause of the bottom-up visual attention bias is the contrast between clothing features, not the absolute stimulus intensity of the features themselves. Clothing factors can change their emotional experience from no difference to significant difference under the influence of other clothing factors. Originality/value: Put forward hypotheses of online clothing consumer behaviour and its visual attention mechanism, provided objective and quantitative evidences through eye tracker. [ABSTRACT FROM AUTHOR]

Background: Visual functioning is often affected in persons with aphasia following stroke and other brain injuries. Characterizing the visual functioning of persons with aphasia is imperative in both clinical and research domains; however, visual functioning of persons with aphasia is infrequently assessed or described in either domain. Aims: This study aims to examine the utility of various visual screening measures and document the results of the screening tools for a cohort of persons with aphasia. Methods & Procedures: Twenty-three individuals with chronic aphasia completed a detailed vision screening using a visual case history, the Visual Activities Questionnaire, the McDowell Vision Screening Kit, an Amsler grid, the line bisection task, and the National Institutes of Health Stroke Scale item 3-visual. Outcomes & Results: Two-thirds of the participants reported significant visual histories with only one participant reporting stroke-related visual deficits. On average, the group rated visual difficulty during daily activities as never or rarely occurring, with the least difficulty reported for color discrimination and the most difficulty with visual acuity and visual search, though still only occurring rarely. All participants passed the cover/uncover screening task measuring ocular alignment and motility, the color perception screening task, and several tasks measuring ocular function. Failing scores, however, were assigned for about half of the participants for distance visual acuity, and only three participants for near visual acuity. Visual fields were normal for about two-thirds of the participants and all participants presented with normal visual attention. Conclusions: The results suggest that visual deficits are common in persons with aphasia, but are not necessarily related to the stroke that the person experienced. The results highlight the need to screen the vision of persons with aphasia both for clinical purposes and research protocols to ensure visual deficits are treated, compensated for, or controlled. [ABSTRACT FROM AUTHOR]

This guide describes best practices in using eye tracking technology for research in a variety of disciplines. A basic outline of the anatomy and physiology of the eyes and of eye movements is provided, along with a description of the sorts of research questions eye tracking can address. We then explain how eye tracking technology works and what sorts of data it generates, and provide guidance on how to select and use an eye tracker as well as selecting appropriate eye tracking measures. Challenges to the validity of eye tracking studies are described, along with recommendations for overcoming these challenges. We then outline correct reporting standards for eye tracking studies. [ABSTRACT FROM AUTHOR]

To report convergence excess esotropia (CEET) following 0.01% atropine eye drops (Low dose atropine [LDA]). Children who developed CEET that resolved promptly after discontinuation of LDA are described. Three myopes aged 5.3 ± 1.2 years and mean sphere -4.5D were included. All were operated for intermittent exotropia earlier. Mean esotropia was +28.3PD for near and 10.6PD for distance. LDA induced high AC/A ratio and fusion normalized in 3 weeks after discontinuation of LDA. LDA should be used with caution in patients with esophoria or previously operated for intermittent exotropia. Any evidence of the emergence of a CEET should warrant discontinuation of LDA. [ABSTRACT FROM AUTHOR]

This study investigated the contribution of both physiological and behavioural process data to the comprehension of conflicting digital texts. We measured skin conductance level (SCL) as an index of arousal and the first‐pass and look‐back fixation times as indices of visual behaviour while reading. Forty‐eight seventh graders read four webpages on genetically modified food, and their comprehension of the texts was measured using a short essay. Results showed that the type of webpage did not differentiate the process data. Statistical procedures for the comparison of a series of regression models revealed that SCL and first‐pass fixation time negatively predicted multiple‐text comprehension while also considering the control variables. The more the students were aroused while reading and the longer the processing time during the first encounter with the reading material, the poorer their comprehension of the conflicting texts. However, the interaction of prior knowledge and arousal positively predicted multiple‐text comprehension. A slope analysis revealed that when participants had high prior knowledge and high arousal during reading, their postreading comprehension performance increased. Lay Description: What is already known about this topic Multiple‐text comprehension requires readers to construct both an intertext model and an integrated mental model.The process of reading various texts on the same topic can be traced by physiological and behavioural data.Skin conductance level is an index of physiological arousal.First‐ and second‐pass fixation time are indices of visual behaviour during the immediate and delayed text processing. What this paper adds Physiological arousal per se is negatively associated with the comprehension of various digital texts on the debated topic of genetically modified food.The duration of the first pass is negatively associated with multiple‐text comprehension.The interaction of prior topic knowledge and physiological arousal is positively associated with multiple‐text comprehension.When pre‐existing knowledge is high, multiple‐text comprehension is greater with high arousal. Implications for practice and/or policy Recall of prior knowledge before reading is a beneficial starting point for comprehension processes.Physiological arousal in combination with prior knowledge can reflect interest and enjoyment during reading or less processing effort for comprehension within and across texts.Videos with students' gaze replays can be used to solicit their reflections on the processing behaviour they activated while reading digital texts on the same content, and what processing behaviour is more conducive to successful multiple‐text comprehension. [ABSTRACT FROM AUTHOR]

The hippocampus is the canonical memory system in the brain and is not typically considered part of the visual system. Yet, it sits atop the ventral visual stream and has been implicated in certain aspects of vision. Here I review the place of the hippocampal memory system in vision science. After a brief primer on the local circuity, external connectivity, and computational functions of the hippocampus, I explore what can be learned from each field about the other. I first present four areas of vision science (scene perception, imagery, eye movements, attention) that challenge our current understanding of the hippocampus in terms of its role in episodic memory. In the reverse direction, I leverage this understanding to inform vision science in other ways, presenting a working hypothesis about a unique form of visual representation. This spatiotemporal similarity hypothesis states that the hippocampus represents objects according to whether they co-occur in space and/or time, and not whether they look alike, as elsewhere in the visual system. This tuning may reflect hippocampal mechanisms of pattern separation, relational binding, and statistical learning, allowing the hippocampus to generate visual expectations to facilitate search and recognition. [ABSTRACT FROM AUTHOR]

Ataxia-telangiectasia is the second most common autosomal recessive hereditary ataxia, with an estimated incidence of 1 in 100,000 births. Besides ataxia and ocular telangiectasias, eye movement abnormalities have long been associated with this disorder and is frequently present in almost all patients. A handful of studies have described the phenomenology of ocular motor deficits in ataxia-telangiectasia. Contemporary literature linked their physiology to cerebellar dysfunction and secondary abnormalities at the level of brainstem. These studies, while providing a proof of concept of ocular motor physiology in disease, i.e., ataxia-telangiectasia, also advanced our understanding of how the cerebellum works. Here, we will summarize the clinical abnormalities seen with ataxia-telangiectasia in each subtype of eye movements and subsequently describe the underlying pathophysiology. Finally, we will review how these deficits are linked to abnormal cerebellar function and how it allows better understanding of the cerebellar physiology. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate objective and subjective visual fatigue experienced before and after performing a visual task while using a head-mounted display for virtual reality (VR-HMD) and two-dimensional (2D) display. Binocular fusion maintenance (BFM) was measured using a binocular open-view Shack–Hartmann wavefront aberrometer equipped with liquid crystal shutters. Twelve healthy subjects performed the BFM test and completed a questionnaire regarding subjective symptoms before and after performing a visual task that induces low visually induced motion sickness (VIMS). BFM (p =.87) and total subjective eye symptom scores (p =.38) were not significantly different between both groups, although these values were significantly lower after the visual task than before the task within both groups (p <.05). These findings suggest that visual fatigue after using a VR-HMD is not significantly different from that after using a 2D display in the presence of low-VIMS VR content. Practitioner summary: Objective and subjective evaluation of visual fatigue were not significantly different with the use of a head-mounted display for virtual reality (VR-HMD) and two-dimensional display. These results should be valuable not only to engineers developing VR content but also to researchers involved in the evaluation of visual fatigue using VR-HMD. Abbreviations: VR: virtual reality; VR-HMD: head-mounted display for virtual reality; BFM: binocular fusion maintenance; BWFA: binocular open-view Shack–Hartmann wavefront aberrometer [ABSTRACT FROM AUTHOR]

Background: The frequency of convergence insufficiency was determined in a sample of Chinese high school students. The associations between the frequency of convergence insufficiency, gender, refractive error and accommodative insufficiency were investigated.Methods: This was a single-site, prospective cross-sectional study. In total, 928 eligible teenagers (mean age 15.9 ± 0.8) from a local high school in Guangzhou, Guangdong Province, China participated in this study. Refraction and binocular vision tests were performed on all eligible participants. The following three signs were used to classify participants: sign 1, exophoria at near at least 4▵ greater than at far; sign 2, receded near point of convergence (≥ 6 cm break point); and sign 3, insufficient near positive fusional vergence (that is, failing Sheard's criterion or ≤ 15▵ break point). Diagnostic groups of convergence insufficiency classification were defined as follows: (1) 3-Sign convergence insufficiency (all three signs present); (2) 2-Sign convergence insufficiency (sign 1 plus sign 2 or 3); (3) 1-Sign convergence insufficiency (sign 1 only); and (4) no convergence insufficiency (that is, participants not classified into one of the above groups).Results: The number and frequency of individuals with 3-Sign, 2-Sign, and 1-Sign convergence insufficiency as well as no convergence insufficiency group were 25 (2.7 per cent), 119 (12.8 per cent), 303 (32.6 per cent) and 481 (51.8 per cent), respectively. Gender (χ2  = 36.6, df = 3, p < 0.001), refractive error grouping (χ2  = 37.7, df = 9, p < 0.001) and accommodative insufficiency (χ2  = 15.4, df = 3, p = 0.002) were all significantly associated with convergence insufficiency. Male gender, hyperopia, or accommodative insufficiency were more likely to be classified with 3-Sign convergence insufficiency. The frequency of accommodative insufficiency was 9.5 per cent (88 of 928 participants).Conclusion: Compared to the data from school- and clinic-based populations in the USA and South Africa, the data from this sample of Chinese high school students showed a lower frequency of 3-Sign convergence insufficiency (2.7 per cent). Convergence insufficiency was associated with refractive error, gender and accommodative insufficiency. [ABSTRACT FROM AUTHOR]

Ocular accommodation potentially provides information about depth but there is little evidence that this information is used by the human visual system. We use the hollow-face illusion, an illusion of depth reversal, to investigate whether accommodation is linked to perceived depth. In Experiment 1 accommodation, like vergence, was in front of the physical surface of the mask when the mask was upright and people reported experiencing the illusion. Accommodation to the illusory face did not differ significantly from accommodation to the physically convex back surface of the same mask. Only accommodation to the inverted mask seen as hollow was significantly less and, like the physical surface, beyond the mid-plane of the mask. The effect on accommodation was the same for monocular as binocular viewing, showing that accommodation is not driven by binocular disparities through vergence, although voluntary vergence remains a possibility. In Experiment 2 a projected random dot pattern was used to flip perception between convex and concave in all presentation conditions. Accommodation was again in front of the physical surface when the illusion was experienced. Experiment 3 showed that projected dots are more effective in disambiguating the illusion as concave when they are sharp and provide a good accommodative stimulus than when they are objectively blurred. We interpret Experiments 1 and 2 as showing that accommodation is tied to perceived depth, directly or indirectly, even in a situation where multiple depth cues are available and feedback is not artificially open-looped. Experiment 3 is consistent with accommodation helping to disambiguate depth while not ruling out alternative explanations. [ABSTRACT FROM AUTHOR]

A method of treating divergence excess intermittent exotropia which differs from standard orthoptics is presented. Training is not done at the objective angle; ARC is ignored; diplopia awareness is not cultivated; stereoscopic targets are introduced before flat fusion or simultaneous perception targets; little emphasis is placed on developing base-out prism vergence ranges; monocular skills and accommodative facility are developed; and plus adds are utilized. The rationale for this approach is developed. [ABSTRACT FROM AUTHOR]

Background: There is no consensus on the precise method of measuring amplitude of accommodation (AA) in routine clinical examination. In addition, studies have queried the use of Hofstetter's equation for computing the expected AA for different populations. This study was designed to compare four subjective methods of AA measurement in children and results from each method with Hofstetter's calculated average AA. Methods: An evenly distributed sample of 103 children aged 6-17 years attending schools in Benin City participated in this study. Amplitude of accommodation measurements--push-up (PU), push-down PD), minus lens to blur (MLB), and modified push-up (MPU)--were carried out in children with emmetropia. The values obtained for each method were compared with Hofstetter's calculated average values. Agreement among each method was investigated using Bland- Altman plots. Results: The means ± SD obtained for the right eye of subjects in Diopters (D) were: PU (12.69 ± 3.16), PD (12.50 ± 2.95), MLB (11.83 ± 2.99), and MPU (11.88 ± 2.88). Using the t-test, significant differences were found between all groups except the MLB and MPU pair. Hofstetter's calculated average differed significantly from results obtained using each method (P<0.0001). Bland-Altman plots showed levels of agreement between the PU and PD and the MLB and MPU methods. Conclusion: Given the difference in results between some of the measurement techniques and with Hofstetter's calculated average AA values, caution should be taken when making decisions concerning AA measurements and accommodative anomalies in school children aged 6-17 years in Benin-city, Nigeria. [ABSTRACT FROM AUTHOR]

Background: To evaluate the impact of treatment of symptomatic convergence insufficiency using office-based vergence/accommodative therapy on reading skills in children.Methods: Children (n = 44) ages nine to 17 years with symptomatic convergence insufficiency were administered the following four reading tests: Wechsler Individual Achievement Test II; Test of Word Reading Efficiency; Test of Silent Word Reading Fluency; and the Gray Oral Reading Test, at baseline and eight weeks after completion of a 16-week program of office-based vergence/accommodative therapy. To determine whether significant change occurred with therapy, change in performance was compared to zero. Treatment response was determined using a composite score of symptoms and signs at the conclusion of treatment and at the 24-week outcome visit. Participants were classified as early responders, late responders, or non-responders based upon whether criteria for successful treatment were met at the completion of 16 weeks of treatment, at the 24-week outcome visit, or not met at either visit, respectively.Results: After treatment for convergence insufficiency, statistically significant improvements were found for reading comprehension (mean = 4.2, p = 0.009) and the reading composite score (mean = 2.4, p = 0.016) as measured by the Wechsler Individual Achievement Test at the 24-week visit. These improvements were related to the clinical treatment outcome measures (p = 0.011) with the largest improvements occurring in those who were early responders to treatment. Reading speed (words per minute) increased significantly on the Gray Oral Reading Test (p < 0.0001). No significant improvements were observed for single word reading or reading fluency as measured by the Test of Word Reading Efficiency, the Test of Silent Word Reading Fluency or the Gray Oral Reading Test.Conclusion: Improvements in reading comprehension and reading composite were found after office-based vergence/accommodative therapy, with the greatest improvements in those who responded early to treatment. [ABSTRACT FROM AUTHOR]

Background: Convergence insufficiency (CI) is a common binocular vision disorder which often causes symptoms when doing near work. However, the best screening test for CI is unknown. The purpose of this study was to evaluate the ability of common tests of binocular and accommodative function to identify children with CI in a school screening setting.Methods: Children aged nine to 14 were invited to participate. Positive fusional vergences, near point of convergence (NPC), accommodative amplitude, accommodative facility, Modified Thorington, and the Convergence Insufficiency Symptom Survey were evaluated.Results: Of the 282 children tested, approximately 20 per cent had 2-3 signs of CI. One half of 2-3 signs of CI and 66 per cent of three signs of CI subjects were symptomatic. Approximately 61 per cent of subjects with symptomatic 2-3 signs of CI had an accompanying low accommodative amplitude. The largest area under the receiver operating characteristic curve was obtained using NPC break measurements. NPC break ≥ 6 cm for CI and NPC break ≥ 7 cm for symptomatic CI were the cut points that maximised the sum of sensitivity and specificity.Conclusion: NPC break performed best in identifying children with CI. [ABSTRACT FROM AUTHOR]

Background: Ocular dominance can be defined as the preference of an individual for viewing with one eye over the other for particular visual tasks. It is relevant to monovision contact lens wear, cataract surgery and sports vision. Clinically, the measurement of ocular dominance is typically done at an arbitrary distance using a sighting test, such as the hole-in-card method that has a binary outcome. We investigated the effect of test distance on ocular dominance measured using a binocular sighting test that provided a continuous measurement of dominance.Methods: Ten participants with normal binocular vision took part in this study. Their binocular sighting ocular dominance and phorias were measured at one, two, four, eight and 10 metres. During the dominance tests participants made a binocular alignment judgment and then were asked to indicate the relative alignment of each eye using a visual analogue scale as a reference.Results: Eight participants had strong ocular dominance (five right, three left). For these participants, there was a significant increase in the magnitude of dominance with increasing test distance (p < 0.001). This could not be fully explained by changes in convergence demand. Two participants showed very weak ocular dominance across all test distances (p > 0.05), despite changes in convergence demand.Conclusion: When ocular dominance is present, its magnitude varies significantly with test distance. This has significant implications for the accurate measurement of ocular dominance in the clinic and may reflect the neural processes that influence eye preference. [ABSTRACT FROM AUTHOR]

Temporal summation is an important feature of the visual system which combines visual signals that arrive at different times. Previous research estimated complete summation to last for 100ms for stimuli judged "just detectable." We measured the full range of temporal summation for much weaker stimuli using a new paradigm and a novel light source, developed in the field of quantum optics for generating small numbers of photons with precise timing characteristics and reduced variance in photon number. Dark-adapted participants judged whether a light was presented to the left or right of their fixation in each trial. In Experiment 1, stimuli contained a stream of photons delivered at a constant rate while the duration was systematically varied. Accuracy should increase with duration as long as the later photons can be integrated with the proceeding ones into a single signal. The temporal integration window was estimated as the point that performance no longer improved, and was found to be 650ms on average. In Experiment 2, the duration of the visual stimuli was kept short (100ms or <30ms) while the number of photons was varied to explore the efficiency of summation over the integration window compared to Experiment 1. There was some indication that temporal summation remains efficient over the integration window, although there is variation between individuals. The relatively long integration window measured in this study may be relevant to studies of the absolute visual threshold, i.e., tests of single-photon vision, where "single" photons should be separated by greater than the integration window to avoid summation. [ABSTRACT FROM AUTHOR]

Humans and many other species sense visual information with varying spatial resolution across the visual field (foveated vision) and deploy eye movements to actively sample regions of interests in scenes. The advantage of such varying resolution architecture is a reduced computational, hence metabolic cost. But what are the performance costs of such processing strategy relative to a scheme that processes the visual field at high spatial resolution? Here we first focus on visual search and combine object detectors from computer vision with a recent model of peripheral pooling regions found at the V1 layer of the human visual system. We develop a foveated object detector that processes the entire scene with varying resolution, uses retino-specific object detection classifiers to guide eye movements, aligns its fovea with regions of interest in the input image and integrates observations across multiple fixations. We compared the foveated object detector against a non-foveated version of the same object detector which processes the entire image at with homogeneous high spatial resolution. We evaluated the accuracy of the foveated and non-foveated object detectors identifying 20 different objects classes in scenes from a standard computer vision data set (the PASCAL VOC 2007 dataset). We show that the foveated object detector can approximate the performance of the object detector with homogeneous high spatial resolution processing while bringing significant computational cost savings. Additionally, we assessed the impact of foveation on the computation of bottom-up saliency. An implementation of a simple foveated bottom-up saliency model with eye movements showed agreement in the selection of top salient regions of scenes with those selected by a non-foveated high resolution saliency model. Together, our results might help explain the evolution of foveated visual systems with eye movements as a solution that preserves perceptual performance in visual search while resulting in computational and metabolic savings to the brain. [ABSTRACT FROM AUTHOR]

One of the fundamental challenges of visual cognition is how our visual systems combine information about an object's features with its spatial location. A recent phenomenon related to object-location binding, the 'spatial congruency bias,' revealed that two objects are more likely to be perceived as having the same identity or features if they appear in the same spatial location, versus if the second object appears in a different location. The spatial congruency bias suggests that irrelevant location information is automatically encoded with and bound to other object properties, biasing perceptual judgments. Here we further explored this new phenomenon and its role in object-location binding by asking what happens when an object moves to a new location: Is the spatial congruency bias sensitive to spatiotemporal contiguity cues, or does it remain linked to the original object location? Across four experiments, we found that the spatial congruency bias remained strongly linked to the original object location. However, under certain circumstances-for instance, when the first object paused and remained visible for a brief time after the movement-the congruency bias was found at both the original location and the updated location. These data suggest that the spatial congruency bias is based more on low-level visual information than on spatiotemporal contiguity cues, and reflects a type of object-location binding that is primarily tied to the original object location and that may only update to the object's new location if there is time for the features to be re-encoded and rebound following the movement. [ABSTRACT FROM AUTHOR]

When acting in a complex visual environment, it is essential to be able to flexibly allocate attention to parts of the visual scene that may contain goal-relevant information. The paper by Jia et al. provides novel evidence that our brains sequentially sample different objects in a visual scene. The results were obtained using “temporal response functions,” in which unique electroencephalographic (EEG) signals corresponding to the processing of 2 continuously presented objects were isolated in an object-specific way. These response functions were dominated by 10-Hz alpha-band activity. Crucially, the different objects were sequentially sampled at a rate of about 2 Hz. These findings provide important neurophysiological insights into how our visual system operates in complex environments. [ABSTRACT FROM AUTHOR]

An anaphylactic shock is a time-critical emergency situation. The decision-making during emergencies is an important responsibility but difficult to study. Eye-tracking technology allows us to identify visual patterns involved in the decision-making. The aim of this pilot study was to evaluate two training models for the recognition and treatment of anaphylaxis by laypeople, based on expert assessment and eye-tracking technology. A cross-sectional quasi-experimental simulation study was made to evaluate the identification and treatment of anaphylaxis. 50 subjects were randomly assigned to four groups: three groups watching different training videos with content supervised by sanitary personnel and one control group who received face-to-face training during paediatric practice. To evaluate the learning, a simulation scenario represented by an anaphylaxis’ victim was designed. A device capturing eye movement as well as expert valuation was used to evaluate the performance. The subjects that underwent paediatric face-to-face training achieved better and faster recognition of the anaphylaxis. They also used the adrenaline injector with better precision and less mistakes, and they needed a smaller number of visual fixations to recognise the anaphylaxis and to make the decision to inject epinephrine. Analysing the different video formats, mixed results were obtained. Therefore, they should be tested to evaluate their usability before implementation. [ABSTRACT FROM AUTHOR]

Recent corpus studies of eye-movements in reading revealed a substantial increase in saccade amplitudes and fixation durations as the eyes move over the first words of a sentence. This start- up effect suggests a global oculomotor program, which operates on the level of an entire line, in addition to the well-established local programs operating within the visual span. The present study investigates the nature of this global program experimentally and examines whether the start-up effect is predicated on generic visual or specific linguistic characteristics and whether it is mainly reflected in saccade amplitudes, fixation durations or both measures. Eye movements were recorded while 38 participants read (a) normal sentences, (b) sequences of randomly shuffled words and (c) sequences of z-strings. The stimuli were, therefore, similar in their visual features, but varied in the amount of syntactic and lexical information. Further, the stimuli were composed of words or strings that either varied naturally in length (Nonequal condition) or were all restricted to a specific length within a sentence (Equal). The latter condition constrained the variability of saccades and served to dissociate effects of word position in line on saccade amplitudes and fixation durations. A robust start-up effect emerged in saccade amplitudes in all Nonequal stimuli, and-in an attenuated form-in Equal sentences. A start-up effect in single fixation durations was observed in Nonequal and Equal normal sentences, but not in z-strings. These findings support the notion of a global oculomotor program in reading particularly for the spatial characteristics of motor planning, which rely on visual rather than linguistic information. [ABSTRACT FROM AUTHOR]

Background: This population-based, cross-sectional study was designed to determine normative data for binocular vision and accommodative testing in rural and urban populations of Tamil Nadu.Methods: A sample of 936 was determined, based on a previous pilot study. The epidemiological field work included a comprehensive eye examination and a binocular vision and accommodative assessment carried out in a total of four public schools, two each in the rural and urban arms of Chennai. An overall sample of 3,024 children between seven and 17 years of age was screened in the four schools and 920 children were included in the study.Results: We found significant differences in expected values from the current clinical criteria for near point of convergence (NPC) with penlight, distance and near horizontal phorias, vergence facility, accommodation convergence/accommodation (AC/A) ratio, accommodative amplitudes, monocular and binocular accommodative facility (t-test: p < 0.001). The mean and standard deviation break/recovery values for NPC (in centimetres) with an accommodative target and penlight with red filter was 3 ± 3/4 ± 4 and 7 ± 5/10 ± 7, respectively. The mean accommodative amplitudes for the population could be estimated from the linear regression equation 16 - 0.3 × (age). The vergence facility was 12 ± 4 cycles/minute and 14 ± 4 cycles/minute in the seven to 10 and 11 to 17 age groups, respectively. Monocular accommodative facility was 11 ± 4 cycles/minute and 14 ± 5 cycles/minute and binocular accommodative facility was 10 ± 4 cycles/minute and 14 ± 5 cycles/minute in the seven to 12 and 13 to 17 age groups, respectively. The mean calculated AC/A ratio was 5.4 ± 0.6/1.Conclusion: The normative data for vergence and accommodative parameters for the Indian children between seven and 17 years of age are reported. The developmental trend of accommodation and vergence differences and significant differences in cut-off between the current data and available literature are reported. These differences have clinical implications for the interpretation, diagnosis and management of anomalies of binocular vision. [ABSTRACT FROM AUTHOR]

Purpose: The aim was to determine the distribution of the near point of convergence (NPC) and its association with age, gender and refractive errors through a population-based study.Methods: In this cross-sectional study, samples were randomly selected from the population of Mashhad city in the northeast of Iran through stratified cluster sampling. In each of the 120 randomly selected clusters, 10 households were systematically chosen. Examinations included visual acuity testing, refractive and binocular vision examination. NPC was measured using a 6/12 single target on a Gulden fixation stick. Positive and negative fusional vergences were measured by the step method at far and near fixation distances.Results: Of the 4,453 invitees, 3,132 people participated (response rate of 70.4 per cent) and after applying the exclusion criteria, analysis was conducted on data from 2,433 individuals whose mean age was 31.2 ± 15.1 years (range: 10 to 86 years). Mean NPC was 8.59 ± 4.82 cm (range: 2 to 40 cm) in the total sample, 6.95 ± 3.87 cm in the 10-19 years age group and 13.06 ± 5.2 cm in those over 70 years. The relationships of NPC with the variables ages, gender and refractive errors (spherical equivalent) was assessed in a multiple linear regression model. Based on this model, older age (p < 0.001, coefficient = 0.106), male gender (p = 0.002, coefficient = 0.608) maintained a significant correlation with NPC, while the association with refractive error was no longer significant (p = 0.109, coefficient = 0.128) after adjusting for age and gender.Conclusion: This is the first population-based study to examine the normal ranges of NPC and also the first to describe normal values in a presbyopic population. The results of this study indicate an age-related change in NPC. These changes should be noted in the interpretation of tests for the diagnosis and treatment of problems with binocular vision. [ABSTRACT FROM AUTHOR]

Background: Visual symptoms and dysfunctions may be a part of the long-term issues following mild traumatic brain injury. These issues may have an impact on near work and reading, and thus affect activities of daily life and the ability to return to work. The purpose of the study was to assess the effect of spectacle treatment on near work-related visual symptoms, visual function and reading performance in patients with persisting symptoms after mild traumatic brain injury.Methods: Eight patients with persisting symptoms after mild traumatic brain injury and anomalies of binocular function were included. Binocular function, visual symptoms and reading performance were assessed before and after spectacle treatment. Reading eye movements were recorded with eye tracking.Results: Four patients showed a considerable symptom reduction along with minor improvement in clinical visual measures. Reading performance improved in four patients; however, the relationship to symptom reduction was inconsistent. The improvement was correlated to reduced average number of fixations per word (r = -0.89, p = 0.02), reduced proportion of regressive saccades (r = -0.93, p = 0.01) and a significant increase of mean progressive saccade length (p = 0.03).Conclusion: This pilot study found that spectacle treatment, specifically directed at optimising near task visual function, significantly reduced symptoms in 50 per cent of patients and improved reading performance in 50 per cent. While promising, lack of placebo control and lack of correlation between reading performance and symptom improvements means we cannot decipher mechanisms without further study. [ABSTRACT FROM AUTHOR]

A paucity of research exists to investigate whether the normal aging process influences the ability to adapt disparity vergence and phoria. Vergence eye movements and dissociated phoria were recorded from 49 healthy subjects (ages 20-70years) using an objective eye movement tracking system. Four-degree vergence responses were modified using a double-step protocol. Dynamics of vergence were quantified via peak velocity. The phoria adaptation experiment measured the magnitude (net change in phoria level) and rate (magnitude divided by the time constant) of phoria adaption during 5min of sustained fixation on a binocular target (40cm/8.44° from midline). The magnitude of phoria adaptation decreased as a function of age (r=-0.33; p=0.04). The ability to adapt vergence peak velocity and the rate of phoria adaptation showed no significant age-related influence (p>0.05). The data suggest that the ability to modify the disparity vergence system and the rate of phoria adaptation are not dependent on age; whereas, the magnitude of phoria adaptation decreases as part of the normal adult aging process. These results have clinical and basic science implications because one should consider age when assessing the changes in the magnitude of phoria adaptation which can be abnormal in those with oculomotor dysfunctions. [ABSTRACT FROM AUTHOR]

Children with a progressing myopia exhibit an abnormal pattern of high accommodative lags coupled with high accommodative convergence (AC/A) and high accommodative adaptation. This is not predicted by the current models of accommodation and vergence. Reduced accommodative plant gain and reduced sensitivity to blur have been suggested as potential causes for this abnormal behavior. These etiologies were tested by altering parameters (sensory, controller and plant gains) in the Simulink model of accommodation. Predictions were then compared to the static and dynamic blur accommodation (BA) measures taken using a Badal optical system on 12 children (6 emmetropes and 6 myopes, 8-13years) and 6 adults (20-35years). Other critical parameters such as CA/C, AC/A, and accommodative adaptation were also measured. Usable BA responses were classified as either typical or atypical. Typical accommodation data confirmed the abnormal pattern of myopia along with an unchanged CA/C. Main sequence relationship remained invariant between myopic and nonmyopic children. An overall reduction was noted in the response dynamics such as peak velocity and acceleration with age. Neither a reduced plant gain nor reduced blur sensitivity could predict the abnormal accommodative behavior. A model adjustment reflecting a reduced accommodative sensory gain (ASG) coupled with an increased AC cross-link gain and reduced vergence adaptive gain does predict the empirical findings. Empirical measures also showed a greater frequency of errors in accommodative response generation (atypical responses) in both myopic and control children compared to adults. [ABSTRACT FROM AUTHOR]

The purpose of this study is to examine the potential relationship between tonic accommodation (TA), near work induced TA-adaptation and the steady state closed-loop accommodation response (AR). Forty-two graduate students participated in the study. Various aspects of their accommodation system were objectively measured using an open-field infrared auto-refractor (Grand Seiko WAM-5500). Tonic accommodation was assessed in a completely dark environment. The association between TA and closed-loop AR was assessed using linear regression correlations and t-test comparisons. Initial mean baseline TA was 1.84diopter (D) (SD±1.29D) with a wide distribution range (-0.43D to 5.14D). For monocular visual tasks, baseline TA was significantly correlated with the closed-loop AR. The slope of the best fit line indicated that closed-loop AR varied by approximately 0.3D for every 1D change in TA. This ratio was consistent across a variety of viewing distances and different near work tasks, including both static targets and continuous reading. Binocular reading conditions weakened the correlation between baseline TA and AR, although results remained statistically significant. The 10min near reading task with a 3D demand did not reveal significant near work induced TA-adaptation for either monocular or binocular conditions. Consistently, the TA-adaptation did not show any correlation with AR during reading. This study found a strong association between open-loop TA and closed-loop AR across a variety of viewing distances and different near work tasks. Difference between the correlations under monocular and binocular reading condition suggests a potential role for vergence compensation during binocular closed-loop AR. [ABSTRACT FROM AUTHOR]

Saccade latencies are known to increase for targets presented close to fixation. Recently, it was shown that not only target eccentricity, but the size of a proximal saccade target also plays a crucial role: latencies increase rapidly with increasing target size. Interestingly, these latency increases are greater than those typically found for other supra-threshold manipulations of target properties. Here we evaluate to what extent this phenomenon is distinct from known delays in saccade initiation and whether the phenomenon is truly related to the size of a proximal target. In Experiment 1 we focus on the importance of the required amplitude. Employing a saccade adaptation paradigm we find that the required amplitude is not a determining factor. Focusing on the role of size, in Experiment 2, we find that while latency increases are strongest for targets elongated in the direction of the fovea, elongations perpendicular to this direction also lead to an increase in latencies. Finally, in Experiment 3 we verify that the latency increases are driven by the properties of the saccade target rather than visual input in general. Together these experiments provide converging evidence that the current phenomenon is both novel and a consequence of the relation between proximal target size and its eccentricity. [ABSTRACT FROM AUTHOR]

Increasing time-on-task leads to fatigue and, as shown by previous research, differentially affects the deployment of visual attention towards the left and the right visual space. In healthy participants, an increasing rightward bias is commonly observed with increasing time-on-task. Yet, it is unclear whether specific mechanisms involved in the spatial deployment of visual attention are differentially affected by increasing time-on-task. The aim of the present study was to investigate whether prolonged time-on-task would affect a specific mechanism of visuospatial attentional deployment, namely attentional disengagement, in an asymmetrical fashion. For this purpose, we administered to healthy participants a prolonged gap/overlap saccadic paradigm, with left- and right-sided target stimuli. This oculomotor paradigm allowed to quantify disengagement costs according to the direction of the subsequent attentional shifts, and to evaluate the temporal development of disengagement costs with increasing time-on-task. Our results show that, with increasing time-on-task, participants demonstrated significantly lower disengagement costs for rightward compared to leftward saccades. These effects were specific, since concurring side differences of saccadic latencies were found for overlap trials (requiring attentional disengagement), but not for gap trials (requiring no or less attentional disengagement). Moreover, the results were paralleled by a non-lateralised decrease in saccadic peak velocity with increasing time-on-task, a common finding indicating an increasing level of fatigue. Our findings support the idea that non-spatial attentional aspects, such as fatigue due to increasing time-on-task, can have a substantial influence on the spatial deployment of visual attention, in particular on its disengagement, depending on the direction of the subsequent attentional shift. [ABSTRACT FROM AUTHOR]

Recent work has shown that attentional deficits following stroke can be modulated by motivational stimulation, particularly anticipated monetary reward. Here we examined the effects of anticipated reward on the pathological attentional blink (AB), an index of temporal selective attention, which is prolonged in patients with right hemisphere damage and a history of left neglect. We specifically compared the effects of reward versus feedback-without-reward on the AB in 17 patients. We found that the patients all manifested impaired performance compared to healthy controls and that reward modulated the pathological blink in the patient group, but only in the second experimental session. When the performance of patients whose neglect had recovered was compared with that of patients who had ongoing or persistent neglect, reward appeared to only influence the AB in the former. These results have implications for our understanding of motivation-attention interactions following right hemisphere stroke, and how they may impact upon recovery from spatial neglect. [ABSTRACT FROM AUTHOR]

The evolution of the human eye's unique high contrast morphology allows people to communicate with a simple look. Yet overt looking is not always preferred in social situations. Do covert shifts in attention – those that occur without a concomitant shift of the eyes or head – support this need? In the present field study, we discretely recorded pedestrians' looks to a confederate who performed an action - raising his hand to the side of his head and saying ‘Hey’ into a phone (private action), or raising his hand to the side of his head in greeting (i.e. a static wave) and saying ‘Hey’ (public action). Critically, pedestrians were not looking at the confederate at the start of the action. Despite this, pedestrians looked more in response to the public action (wave) than private action (phone). We argue that the observed difference in looking responses must be due to pedestrians first attending to the confederate covertly in order to assess the intention of his action, and only signaling this attention with a look when socially appropriate (e.g. to respond to a public action). Though the functional utility of covert attention has rarely been considered outside of controlled laboratory tasks, these results provide the first demonstration that covert attention plays a critical role in guiding appropriate social looking behaviour. [ABSTRACT FROM AUTHOR]

Purpose: To characterise the effects on accommodation and binocular vision in young adults of 2 distance centre multifocal soft contact lenses (MFSCLs), differing in add power.Methods: Twenty-four young adult myopes (18-28 years; 20 females, 4 males) had baseline visual acuity, accommodation, near phoria, fixation disparity and stereopsis data collected with single vision (SV) SCLs. The same set of measurements was repeated immediately after subjects were fitted with each of two MFSCLs (with either +1.50 or +3.00 D add), and after 2 weeks of daily wear in each case. The order of testing was randomised and a one-week washout period was allowed between the first and second MFSCL trials.Results: Differences in distance and near acuities with MFSCLs compared to SVSCLs were small and clinically insignificant. Compared to responses with SVSCLs, MFSCLs increased accommodative lags with this change reaching statistical significance for the +1.50 D add lens. Furthermore, both MFSCLs induced significant shifts in near phorias in the exo direction. Finally, there were no significant differences in stereopsis and fixation disparity with MFSCLs compared to SVSCLs.Conclusion: Differences in acuities, accommodation accuracy and binocular posture with MFSCLs compared to SVSCLs were clinically small and mostly not significant. These results predict good tolerance of MFSCLs in young patients fitted with them for myopia control. [ABSTRACT FROM AUTHOR]

Maddox proposed that the perceived nearness of a target could influence the ocular vergence response. Proximal inputs have been used to refer to all static and dynamic cues to depth other than disparity and blur. In this paper, we review a number of studies in which proximal influences have been assessed. While general agreement exists that proximal contributions are significant when blur and disparity cues are absent (open-loop conditions), there are conflicting reports on the role of proximal vergence and accommodation under closed-loop conditions. [ABSTRACT FROM AUTHOR]

Natural vision is characterized by alternating sequences of rapid gaze shifts (saccades) and fixations. During fixations, microsaccades and slower drift movements occur spontaneously, so that the eye is never motionless. Theoretical models of fixational eye movements predict that microsaccades are dynamically coupled to slower drift movements generated immediately before microsaccades, which might be used as a criterion to distinguish microsaccades from small voluntary saccades. Here we investigate a sequential scanning task, where participants generate goal-directed saccades and microsaccades with overlapping amplitude distributions. We show that properties of microsaccades are correlated with precursory drift motion, while amplitudes of goal-directed saccades do not dependent on previous drift epochs. We develop and test a mathematical model that integrates goal-directed and fixational eye movements, including microsaccades. Using model simulations, we reproduce the experimental finding of correlations within fixational eye movement components (i.e., between physiological drift and microsaccades) but not between goal-directed saccades and fixational drift motion. These results lend support to a functional difference between microsaccades and goal-directed saccades, while, at the same time, both types of behavior may be part of an oculomotor continuum that is quantitatively described by our mathematical model. [ABSTRACT FROM AUTHOR]

Background: Several tests are available to optometrists for investigating accommodation and vergence. This study sought to investigate the agreement between clinical and laboratory methods and to clarify which components are actually measured when tonic and cross-link of accommodation and vergence are assessed.Methods: Tonic vergence, tonic accommodation, accommodative vergence (AC/A) and vergence accommodation (CA/C) were measured using several tests. Clinical tests were compared to the laboratory assessment, the latter being regarded as an absolute reference. The repeatability of each test and the degree of agreement between the tests were quantified using Bland-Altman analysis.Results: The values obtained for each test were found to be stable across repetitions; however, in most cases, significant differences were observed between tests supposed to measure the same oculomotor component. Tonic and cross-link components cannot be easily assessed because proximal and instrumental responses interfere with the assessment. Other components interfere with oculomotor assessment. Specifically, accommodative divergence interferes with tonic vergence estimation and the type of accommodation considered in the AC/A ratio affects its magnitude. Results on clinical tonic accommodation and clinical CA/C show that further investigation is needed to clarify the limitations associated with the use of difference of Gaussian as visual targets to open the accommodative loop.Conclusions: Although different optometric tests of accommodation and vergence rely on the same basic principles, the results of this study indicate that clinical and laboratory methods actually involve distinct components. These differences, which are induced by methodological choices, must be taken into account, when comparing studies or when selecting a test to investigate a particular oculomotor component. [ABSTRACT FROM AUTHOR]