Home vision therapy and prism prescription in presbyopic persons with convergence insufficiency: study protocol for a randomized controlled trial.

BACKGROUND: Convergence insufficiency is a common issue in the field of binocular vision. Various treatment options have been suggested for managing this condition, but their efficacy in individuals with presbyopia remains unclear. The objective of this study is to compare the effectiveness of home-based vision therapy and prism prescription, in presbyopic patients with convergence insufficiency. METHODS/DESIGN: It is a randomized, prospective, double-blind clinical trial, with total of 150 participants randomly assigned to the three groups. The Control Group will receive a new near glasses as a conventional prescription, along with aimless and random eye movement exercises that do not have any convergence or accommodation effects. The Home Vision Therapy Group will receive new near glasses with accommodative and convergence eye exercises. The Prism Group will receive a near prismatic glasses prescribed using the Sheard's criterion. All treatments will be administered for a period of 2 months, and measurements of the modified convergence insufficiency symptoms survey (CISS), near point convergence, near phoria, and positive fusional vergence will be taken at baseline, one month later, and at the end of the treatment. DISCUSSION: We aim to identify which component - either the prism prescription or the home vision therapy - is more effective in improving binocular abilities and reducing patients' symptom scores. TRIAL REGISTRATION: ClinicalTrials.gov NCT05311917 with last update on 04/22/2023.

Multifractal characterization of nystagmus eye movements.

In this work, we investigate the multifractal properties of eye movement dynamics of children with infantile nystagmus, particularly the fluctuations of its velocity. The eye movements of three children and one adult with infantile nystagmus were evaluated in a simple task in comparison with 28 children with no ocular pathologies. Four indices emerge from the analysis: the classical Hurst exponent, the singularity strength corresponding to the maximum of the singularity spectrum, the asymmetry of the singularity spectrum, and the multifractal strength, each of which characterizes a particular aspect of eye movement dynamics. Our findings indicate that, when compared to children with no ocular pathologies, patients with infantile nystagmus present lower values of all indices. Except for the multifractal strength, the difference in the remaining indices is statistically significant. To test whether the characterization of patients with infantile nystagmus in terms of multifractality indices allows them to be distinguished from children without ocular pathologies, we performed an unsupervised clustering analysis and classified the subjects using supervised clustering techniques. The results indicate that these indices do, indeed, distinctively characterize the eye movements of patients with infantile nystagmus.

Influence of training and expertise on deep neural network attention and human attention during a medical image classification task.

In many different domains, experts can make complex decisions after glancing very briefly at an image. However, the perceptual mechanisms underlying expert performance are still largely unknown. Recently, several machine learning algorithms have been shown to outperform human experts in specific tasks. But these algorithms often behave as black boxes and their information processing pipeline remains unknown. This lack of transparency and interpretability is highly problematic in applications involving human lives, such as health care. One way to "open the black box" is to compute an artificial attention map from the model, which highlights the pixels of the input image that contributed the most to the model decision. In this work, we directly compare human visual attention to machine visual attention when performing the same visual task. We have designed a medical diagnosis task involving the detection of lesions in small bowel endoscopic images. We collected eye movements from novices and gastroenterologist experts while they classified medical images according to their relevance for Crohn's disease diagnosis. We trained three state-of-the-art deep learning models on our carefully labeled dataset. Both humans and machine performed the same task. We extracted artificial attention with six different post hoc methods. We show that the model attention maps are significantly closer to human expert attention maps than to novices', especially for pathological images. As the model gets trained and its performance gets closer to the human experts, the similarity between model and human attention increases. Through the understanding of the similarities between the visual decision-making process of human experts and deep neural networks, we hope to inform both the training of new doctors and the architecture of new algorithms.

Reduced spatial attentional distribution in older adults.

Older adults show decline in visual search performance, but the underlying cause remains unclear. It has been suggested that older adults' altered performance may be related to reduced spatial attention to peripheral visual information compared with younger adults. In this study, 18 younger (M = 21.6 years) and 16 older (M = 69.1 years) participants performed pop-out and serial visual search tasks with variously sized gaze-contingent artificial central scotomas (3°, 5°, or 7° diameter). By occluding central vision, we measured how attention to the periphery was contributing to the search performance. We also tested the effect of target eccentricity on search times and eye movements. We hypothesized that, if attention is reduced primarily in the periphery in older adults, we would observe longer search times for more eccentric targets and with central occlusion. During the pop-out search, older adults showed a steeper decline in search performance with increasing eccentricity and central scotoma size compared with younger adults. In contrast, during the serial search, older adults had longer search times than younger adults overall, independent of target eccentricity and scotoma size. Longer search times were attributed to higher cost-per-item slopes, indicating increased difficulty in simultaneously processing complex symbols made up of separable features in aging, possibly stemming from challenges in spatially binding individual features. Altogether, our findings point to fewer attentional resources of simultaneous visual processing to distribute over space or separable features of objects, consistent with decreased dorsal visual stream functioning in aging.

Randomness impacts the building of specific priors, visual exploration, and perception in object recognition.

Recognising objects is a vital skill on which humans heavily rely to respond quickly and adaptively to their environment. Yet, we lack a full understanding of the role visual information sampling plays in this process, and its relation to the individual's priors. To bridge this gap, the eye-movements of 18 adult participants were recorded during a free-viewing object-recognition task using Dots stimuli1. Participants viewed the stimuli in one of three orders: from most visible to least (Descending), least visible to most (Ascending), or in a randomised order (Random). This dictated the strength of their priors along the experiment. Visibility order influenced the participants' recognition performance and visual exploration. In addition, we found that while orders allowing for stronger priors generally led participants to visually sample more informative locations, this was not the case of Random participants. Indeed, they appeared to behave naïvely, and their use of specific object-related priors was fully impaired, while they maintained the ability to use general, task-related priors to guide their exploration. These findings have important implications for our understanding of perception, which appears to be influenced by complex cognitive processes, even at the basic level of visual sampling during object recognition.

Eye blinks as a visual processing stage.

Humans blink their eyes frequently during normal viewing, more often than it seems necessary for keeping the cornea well lubricated. Since the closure of the eyelid disrupts the image on the retina, eye blinks are commonly assumed to be detrimental to visual processing. However, blinks also provide luminance transients rich in spatial information to neural pathways highly sensitive to temporal changes. Here, we report that the luminance modulations from blinks enhance visual sensitivity. By coupling high-resolution eye tracking in human observers with modeling of blink transients and spectral analysis of visual input signals, we show that blinking increases the power of retinal stimulation and that this effect significantly enhances visibility despite the time lost in exposure to the external scene. We further show that, as predicted from the spectral content of input signals, this enhancement is selective for stimuli at low spatial frequencies and occurs irrespective of whether the luminance transients are actively generated or passively experienced. These findings indicate that, like eye movements, blinking acts as a computational component of a visual processing strategy that uses motor behavior to reformat spatial information into the temporal domain.

EEG complexity measures for detecting mind wandering during video-based learning.

This study explores the efficacy of various EEG complexity measures in detecting mind wandering during video-based learning. Employing a modified probe-caught method, we recorded EEG data from participants engaged in viewing educational videos and subsequently focused on the discrimination between mind wandering (MW) and non-MW states. We systematically investigated various EEG complexity metrics, including metrics that reflect a system's regularity like multiscale permutation entropy (MPE), and metrics that reflect a system's dimensionality like detrended fluctuation analysis (DFA). We also compare these features to traditional band power (BP) features. Data augmentation methods and feature selection were applied to optimize detection accuracy. Results show BP features excelled (mean area under the receiver operating characteristic curve (AUC) 0.646) in datasets without eye-movement artifacts, while MPE showed similar performance (mean AUC 0.639) without requiring removal of eye-movement artifacts. Combining all kinds of features improved decoding performance to 0.66 mean AUC. Our findings demonstrate the potential of these complexity metrics in EEG analysis for mind wandering detection, highlighting their practical implications in educational contexts.

Why did Rubens add a parrot to Titian's The Fall of Man? A pictorial manipulation of joint attention.

Almost 400 years ago, Rubens copied Titian's The Fall of Man, albeit with important changes. Rubens altered Titian's original composition in numerous ways, including by changing the gaze directions of the depicted characters and adding a striking red parrot to the painting. Here, we quantify the impact of Rubens's choices on the viewer's gaze behavior. We displayed digital copies of Rubens's and Titian's artworks-as well as a version of Rubens's painting with the parrot digitally removed-on a computer screen while recording the eye movements produced by observers during free visual exploration of each image. To assess the effects of Rubens's changes to Titian's composition, we directly compared multiple gaze parameters across the different images. We found that participants gazed at Eve's face more frequently in Rubens's painting than in Titian's. In addition, gaze positions were more tightly focused for the former than for the latter, consistent with different allocations of viewer interest. We also investigated how gaze fixation on Eve's face affected the perceptual visibility of the parrot in Rubens's composition and how the parrot's presence versus its absence impacted gaze dynamics. Taken together, our results demonstrate that Rubens's critical deviations from Titian's painting have powerful effects on viewers' oculomotor behavior.

ERG Responses in Albinism, Idiopathic Infantile Nystagmus, and Controls.

Purpose: Our primary aim was to compare adult full-field ERG (ffERG) responses in albinism, idiopathic infantile nystagmus (IIN), and controls. A secondary aim was to investigate the effect of within-subject changes in nystagmus eye movements on ffERG responses. Methods: Dilated Ganzfeld flash ffERG responses were recorded using DTL electrodes under conditions of dark (standard and dim flash) and light adaptation in 68 participants with albinism, 43 with IIN, and 24 controls. For the primary aim, the effect of group and age on ffERG responses was investigated. For the secondary aim, null region characteristics were determined using eye movements recorded prior to ffERG recordings. ffERG responses were recorded near and away from the null regions of 18 participants also measuring the success rate of recordings. Results: For the primary aim, age-adjusted photopic a- and b-wave amplitudes were consistently smaller in IIN compared with controls (P < 0.0001), with responses in both groups decreasing with age. In contrast, photopic a-wave amplitudes increased with age in albinism (P = 0.0035). For the secondary aim, more intense nystagmus significantly reduced the success rate of measurable responses. Within-subject changes in nystagmus intensity generated small, borderline significant differences in photopic b-wave peak times and a-and b-wave amplitudes under scotopic conditions with standard flash. Conclusions: Age-adjusted photopic ffERG responses are significantly reduced in IIN adding to the growing body of evidence of retinal abnormalities in IIN. Differences between photopic responses in albinism and controls depend on age. Success at obtaining ffERG responses could be improved by recording responses at the null region.

A multimodal physiological dataset for driving behaviour analysis.

Physiological signal monitoring and driver behavior analysis have gained increasing attention in both fundamental research and applied research. This study involved the analysis of driving behavior using multimodal physiological data collected from 35 participants. The data included 59-channel EEG, single-channel ECG, 4-channel EMG, single-channel GSR, and eye movement data obtained via a six-degree-of-freedom driving simulator. We categorized driving behavior into five groups: smooth driving, acceleration, deceleration, lane changing, and turning. Through extensive experiments, we confirmed that both physiological and vehicle data met the requirements. Subsequently, we developed classification models, including linear discriminant analysis (LDA), MMPNet, and EEGNet, to demonstrate the correlation between physiological data and driving behaviors. Notably, we propose a multimodal physiological dataset for analyzing driving behavior(MPDB). The MPDB dataset's scale, accuracy, and multimodality provide unprecedented opportunities for researchers in the autonomous driving field and beyond. With this dataset, we will contribute to the field of traffic psychology and behavior.

Spontaneous perspective-taking in real-time language comprehension: evidence from eye-movements and grain of coordination.

Linguistic communication requires interlocutors to consider differences in each other's knowledge (perspective-taking). However, perspective-taking might either be spontaneous or strategic. We monitored listeners' eye movements in a referential communication task. A virtual speaker gave temporally ambiguous instructions with scalar adjectives ("big" in "big cubic block"). Scalar adjectives assume a contrasting object (a small cubic block). We manipulated whether the contrasting object (a small triangle) for a competitor object (a big triangle) was in common ground (visible to both speaker and listener) or was occluded so it was in the listener's privileged ground, in which case perspective-taking would allow earlier reference-resolution. We used a complex visual context with multiple objects, making strategic perspective-taking unlikely when all objects are in the listener's referential domain. A turn-taking, puzzle-solving task manipulated whether participants could anticipate a more restricted referential domain. Pieces were either confined to a small area (requiring fine-grained coordination) or distributed across spatially distinct regions (requiring only coarse-grained coordination). Results strongly supported spontaneous perspective-taking: Although comprehension was less time-locked in the coarse-grained condition, participants in both conditions used perspective information to identify the target referent earlier when the competitor contrast was in privileged ground, even when participants believed instructions were computer-generated.

Multifaceted Interactions of Stereoacuity, Inter-Ocular Suppression, and Fixation Eye Movement Abnormalities in Amblyopia and Strabismus.

Purpose: Amblyopic and strabismus subjects experience inter-ocular suppression, impaired stereoacuity, and increased fixation instability. The purpose of the study was to investigate factors affecting suppression and stereoacuity and examine their relationship to fixation eye movement (FEM) abnormalities. Methods: We recruited 14 controls and 46 amblyopic subjects (anisometropic = 18, strabismic = 14, and mixed = 14) and 11 subjects with strabismus without amblyopia. We utilized the dichoptic motion coherence test to quantify suppression, and stereoacuity was assessed using the Titmus Fly test. We recorded FEMs using high-resolution video-oculography and classified subjects that did not have nystagmus (n = 27) versus those with nystagmus (n = 32; fusion maldevelopment nystagmus [FMN], n = 10) and nystagmus that did not meet the criteria of FMN (n = 20). We also recorded FEMs under dichoptic viewing (DcV) at varied fellow eye (FE) contrasts and computed the amplitude and velocity of the fast and slow FEMs and vergence instability. Results: Inter-ocular suppression and stereoacuity deficits were closely correlated with an amblyopic eye (AE), visual acuity, and strabismus angle. Subjects with nystagmus displayed more pronounced stereoacuity deficits than those without nystagmus. Strabismic subjects with and without amblyopia, who demonstrated a fixation switch at 100% FE contrast, had lower inter-ocular suppression than subjects lacking a fixation switch under DcV. Amplitude of fast FEMs and velocity of slow FEMs, and vergence instability were increased as the FE contrast was lowered in both amblyopic and strabismic subjects. Conclusions: The current study highlights the intricate relationships between AE visual acuity, eye deviation, and FEM abnormalities on suppression and stereoacuity deficits and underscores the need to evaluate FEM abnormalities while assessing dichoptic treatment outcomes.

The effect of quiet eye training on golf putting performance in pressure situation.

To explores the effect and mechanism of quiet eye training on the accuracy of golfers´ putts in pressure situations and provides methods and basis for targeted attention training and control. 22 young golfers in China golf team aged from 13 to 18 were randomly assigned to the experimental group (quiet eye training group) and the control group (technical guidance group) according to gender. Both groups of participants underwent two consecutive weeks of push training (3 sets per day, 20 golf putts per set, rest for 3 min between sets) separately in accordance with the guidance of a professional psychological research group and an expert coach. Eye tracking technology, biofeedback technology, and subjective evaluation methods were used to test and analyze the push process of the two groups of participants before and after training under pressure situations (Eye movement behaviors and the heart rate were recorded by ASL Mobile Eye-XG and NeXus-2 biofeedback, pressure and state anxiety were evaluated by self-rating pressure scale and S-AI. Golf putting performance was recorded by a research graduate assistant). A higher hit ratio as well as lower pressure and SAI level was founded in quiet eye training group in the pressure situation, the quiet eye movement time and total fixation time was longer than technical group. The quiet eye training group has a better putting performance. Quiet eye training can improve the golf putting performance in pressure situations. After quiet eye training, the state anxiety decreased, the quiet eye movement time and the total fixation time increased in pressure situations.

Decision-making processes in perceptual learning depend on effectors.

Visual perceptual learning is traditionally thought to arise in visual cortex. However, typical perceptual learning tasks also involve systematic mapping of visual information onto motor actions. Because the motor system contains both effector-specific and effector-unspecific representations, the question arises whether visual perceptual learning is effector-specific itself, or not. Here, we study this question in an orientation discrimination task. Subjects learn to indicate their choices either with joystick movements or with manual reaches. After training, we challenge them to perform the same task with eye movements. We dissect the decision-making process using the drift diffusion model. We find that learning effects on the rate of evidence accumulation depend on effectors, albeit not fully. This suggests that during perceptual learning, visual information is mapped onto effector-specific integrators. Overlap of the populations of neurons encoding motor plans for these effectors may explain partial generalization. Taken together, visual perceptual learning is not limited to visual cortex, but also affects sensorimotor mapping at the interface of visual processing and decision making.

[Research progress on the relationship between neural synchronization activity and memory consolidation during non-rapid eye movement sleep].

Neural synchronization activity is considered a key aspect of information processing in the nervous system. Local synchronization within different frequency ranges and inter-regional synchronization are ubiquitous and related to various behavioral and cognitive functions. As memory is a higher cognitive function of the brain, the formation and consolidation of memory are closely related to neural synchronization activity. This article provides an overview of the research progress on the relationship between neural synchronization activity and memory consolidation, focusing primarily on the neuro-oscillatory activities across multiple brain regions during non-rapid eye movement (NREM) sleep in vivo, as well as the synchronous burst activity in cultured neural networks in vitro. Finally, we analyzed the existing issues in current research and provided a perspective on future relevant studies.

Quantitative Foveal Structural Metrics as Predictors of Visual Acuity in Human Albinism.

Purpose: To assess the degree to which quantitative foveal structural measurements account for variation in best-corrected visual acuity (BCVA) in human albinism. Methods: BCVA was measured and spectral domain optical coherence tomography (SD-OCT) images were acquired for 74 individuals with albinism. Categorical foveal hypoplasia grades were assessed using the Leicester Grading System for Foveal Hypoplasia. Foveal anatomical specialization (foveal versus parafoveal value) was quantified for inner retinal layer (IRL) thickness, outer segment (OS) length, and outer nuclear layer (ONL) thickness. These metrics, participant sex, and age were used to build a multiple linear regression of BCVA. This combined linear model's predictive properties were compared to those of categorical foveal hypoplasia grading. Results: The cohort included three participants with type 1a foveal hypoplasia, 23 participants with type 1b, 33 with type 2, ten with type 3, and five with type 4. BCVA ranged from 0.08 to 1.00 logMAR (mean ± SD: 0.53 ± 0.21). IRL ratio, OS ratio, and ONL ratio were measured in all participants and decreased with increasing severity of foveal hypoplasia. The best-fit combined linear model included all three quantitative metrics and participant age expressed as a binary variable (divided into 0-18 years and 19 years or older; adjusted R2 = 0.500). This model predicted BCVA more accurately than a categorical foveal hypoplasia model (adjusted R2 = 0.352). Conclusions: A quantitative model of foveal specialization accounts for more variance in BCVA in albinism than categorical foveal hypoplasia grading. Other factors, such as optical aberrations and eye movements, may account for the remaining unexplained variance.

Gaze-contingent processing improves mobility, scene recognition and visual search in simulated head-steered prosthetic vision.

Objective.The enabling technology of visual prosthetics for the blind is making rapid progress. However, there are still uncertainties regarding the functional outcomes, which can depend on many design choices in the development. In visual prostheses with a head-mounted camera, a particularly challenging question is how to deal with the gaze-locked visual percept associated with spatial updating conflicts in the brain. The current study investigates a recently proposed compensation strategy based on gaze-contingent image processing with eye-tracking. Gaze-contingent processing is expected to reinforce natural-like visual scanning and reestablished spatial updating based on eye movements. The beneficial effects remain to be investigated for daily life activities in complex visual environments.Approach.The current study evaluates the benefits of gaze-contingent processing versus gaze-locked and gaze-ignored simulations in the context of mobility, scene recognition and visual search, using a virtual reality simulated prosthetic vision paradigm with sighted subjects.Main results.Compared to gaze-locked vision, gaze-contingent processing was consistently found to improve the speed in all experimental tasks, as well as the subjective quality of vision. Similar or further improvements were found in a control condition that ignores gaze-dependent effects, a simulation that is unattainable in the clinical reality.Significance.Our results suggest that gaze-locked vision and spatial updating conflicts can be debilitating for complex visually-guided activities of daily living such as mobility and orientation. Therefore, for prospective users of head-steered prostheses with an unimpaired oculomotor system, the inclusion of a compensatory eye-tracking system is strongly endorsed.

Different extrapolation of moving object locations in perception, smooth pursuit, and saccades.

The ability to accurately perceive and track moving objects is crucial for many everyday activities. In this study, we use a "double-drift stimulus" to explore the processing of visual motion signals that underlie perception, pursuit, and saccade responses to a moving object. Participants were presented with peripheral moving apertures filled with noise that either drifted orthogonally to the aperture's direction or had no net motion. Participants were asked to saccade to and track these targets with their gaze as soon as they appeared and then to report their direction. In the trials with internal motion, the target disappeared at saccade onset so that the first 100 ms of the postsaccadic pursuit response was driven uniquely by peripheral information gathered before saccade onset. This provided independent measures of perceptual, pursuit, and saccadic responses to the double-drift stimulus on a trial-by-trial basis. Our analysis revealed systematic differences between saccadic responses, on one hand, and perceptual and pursuit responses, on the other. These differences are unlikely to be caused by differences in the processing of motion signals because both saccades and pursuits seem to rely on shared target position and velocity information. We conclude that our results are instead due to a difference in how the processing mechanisms underlying perception, pursuit, and saccades combine motor signals with target position. These findings advance our understanding of the mechanisms underlying dissociation in visual processing between perception and eye movements.

Performance of the Action Observation-Based Brain-Computer Interface in Stroke Patients and Gaze Metrics Analysis.

Brain-computer interfaces (BCIs) are anticipated to improve the efficacy of rehabilitation for people with motor disabilities. However, applying BCI in clinical practice is still a challenge due to the great diversity of patients. In the current study, a novel action observation (AO) based BCI was proposed and tested on stroke patients. Ten non-hemineglect patients and ten hemineglect patients were recruited. Four AO stimuli were designed, each presenting a decomposed action to complete the reach-and-grasp task. EEG data and eye movement data were collected. Eye movement data was utilized to analyze the reasons for individual differences in BCI performance. Task discriminative component analysis was utilized to perform online target detection. The results showed that the designed AO-based BCI could simultaneously induce steady state motion visual evoked potential (SSMVEP) from the occipital region and sensory motor rhythm from the sensorimotor region in stroke patients. The average online detection accuracy among the four AO stimuli reached 67% within 3 s in the non-hemineglect group, while the accuracy only reached 35% in the hemineglect group. Gaze metrics showed that the average total duration of fixations during the stimulus phase in the hemineglect group was only 1.31 s ± 0.532 s which was significantly lower than that in the non-hemineglect group. The results indicated that hemineglect patients have difficulty gazing at the AO stimulus, resulting in poor detection performance and weak desynchronization in the sensorimotor region. Furthermore, the degree of neglect is inversely proportional to the target detection accuracy in hemineglect stroke patients. In addition, the gaze metrics associated with cognitive load were significantly correlated with the accuracy in non-hemineglect patients. It indicated the cognitive load may affect the AO-based BCI. The current study will expedite the clinical application of AO-based BCI.

Toward viewing behavior for aerial scene categorization.

Previous work has demonstrated similarities and differences between aerial and terrestrial image viewing. Aerial scene categorization, a pivotal visual processing task for gathering geoinformation, heavily depends on rotation-invariant information. Aerial image-centered research has revealed effects of low-level features on performance of various aerial image interpretation tasks. However, there are fewer studies of viewing behavior for aerial scene categorization and of higher-level factors that might influence that categorization. In this paper, experienced subjects' eye movements were recorded while they were asked to categorize aerial scenes. A typical viewing center bias was observed. Eye movement patterns varied among categories. We explored the relationship of nine image statistics to observers' eye movements. Results showed that if the images were less homogeneous, and/or if they contained fewer or no salient diagnostic objects, viewing behavior became more exploratory. Higher- and object-level image statistics were predictive at both the image and scene category levels. Scanpaths were generally organized and small differences in scanpath randomness could be roughly captured by critical object saliency. Participants tended to fixate on critical objects. Image statistics included in this study showed rotational invariance. The results supported our hypothesis that the availability of diagnostic objects strongly influences eye movements in this task. In addition, this study provides supporting evidence for Loschky et al.'s (Journal of Vision, 15(6), 11, 2015) speculation that aerial scenes are categorized on the basis of image parts and individual objects. The findings were discussed in relation to theories of scene perception and their implications for automation development.