Human Eye Movements Research Articles

Biometric Measurement of Anterior Segment: A Review.

Biometric measurement of the anterior segment is of great importance for the ophthalmology, human eye modeling, contact lens fitting, intraocular lens design, etc. This paper serves as a comprehensive review on the historical development and basic principles of the technologies for measuring the geometric profiles of the anterior segment. Both the advantages and drawbacks of the current technologies are illustrated. For in vivo measurement of the anterior segment, there are two main challenges that need to be addressed to achieve high speed, fine resolution, and large range imaging. One is the motion artefacts caused by the inevitable and random human eye movement. The other is the serious multiple scattering effects in intraocular turbid media. The future research perspectives are also outlined in this paper.

Optimised multi‐wavelet domain for decomposed electrooculogram‐based eye movement classification

The human eye movement tracking is possible with the assistance of the electrooculography (EOG) signals. The human eye tracking system allows researchers to analyse the participant's eye movements during certain activities. This study offers the EOG signals to control the human–computer interface systems with the help of Empirical Mean Curve Decomposition (EMCD) decomposition model. At first, the input EOG signal is provided as input to the EMCD decomposition model, later the resultant signal is given to principal component analysis for dimensional reduction, and then the dimensional reduced signal is offered to multi-wavelet decomposition model. The resultant dimensionally reduced multi-wavelet decomposed signal is passed to the proposed Feature Mapping (FM) model, using the k-means clustering model. Then, the Grey Wolf Optimization (GWO) algorithm is utilised to tune the margin. Next to mapping, the obtained features are provided to the nearest neighbour classifier, to obtain the eye movement. Next to the implementation, the proposed method is compared with the existing methods, and it is witnessed that the proposed methodology gives the superior performance in correspondence with accuracy, sensitivity, specificity, precision, false positive rate, false negative rate, negative predictive value, false discovery rate, F1 score and Mathews correlation coefficient.

Two Distinct Types of Eye-Head Coupling in Freely Moving Mice

SummaryAnimals actively interact with their environment to gather sensory information. There is conflicting evidence about how mice use vision to sample their environment. During head restraint, mice make rapid eye movements coupled between the eyes, similar to conjugate saccadic eye movements in humans. However, when mice are free to move their heads, eye movements are more complex and often non-conjugate, with the eyes moving in opposite directions. We combined head and eye tracking in freely moving mice and found both observations are explained by two eye-head coupling types, associated with vestibular mechanisms. The first type comprised non-conjugate eye movements, which compensate for head tilt changes to maintain a similar visual field relative to the horizontal ground plane. The second type of eye movements was conjugate and coupled to head yaw rotation to produce a “saccade and fixate” gaze pattern. During head-initiated saccades, the eyes moved together in the head direction but during subsequent fixation moved in the opposite direction to the head to compensate for head rotation. This saccade and fixate pattern is similar to humans who use eye movements (with or without head movement) to rapidly shift gaze but in mice relies on combined head and eye movements. Both couplings were maintained during social interactions and visually guided object tracking. Even in head-restrained mice, eye movements were invariably associated with attempted head motion. Our results reveal that mice combine head and eye movements to sample their environment and highlight similarities and differences between eye movements in mice and humans.

Lack of Torsion in the Type-III Duane Retraction Syndrome (DRS-III) Affected Left Eye During Dix -Hallpike Test

Abstract Background Duane retraction syndrome (DRS) is a congenital cranial dysinnervation disorder (CCDD) of ocular movements, characterized by deficits in horizontal duction associated with narrowing of palpebral fissure, retraction of eye globe on attempted adduction and occasionally accompanied by upshoot or downshoot of the eye globe. It is caused by congenital absence of sixth cranial nerve, which results in fibrotic changes in the extraocular muscles leading to an abnormal ocular motility--a concept known as CCDD. Depending on whether only abduction/adduction or both are affected, DRS has been classified into three types designated as type-I, type-II and type-III. The torsional movements of the affected eye in DRS have not been reported to be deficient hitherto, which could be due to difficulties in the routine bedside evaluation of such movements. Case Presentation An unusual case of a patient of left unilateral type-III DRS is reported, who presented with a short history of vertigo on getting up from supine to sitting position and on assuming right lateral recumbent position. The diagnostic right Dix-Hallpike test (DHT) revealed upbeating torsional geotropic positioning nystagmus in the normal right eye and upbeating positioning nystagmus without torsional component in the abnormal left eye and this clinical finding was video recorded. Conclusion The observed lack of incyclotorsion of the left eye, affected with DRS-III during right Dix-Hallpike positioning, is primarily due to the absence of initial slow-phase excyclotorsional component. If the slow phase of VOR does not occur, then the fast-phase VOR, which is a refixation saccade, will be lacking too. An anastomosis, either in the lateral wall of the cavernous sinus or within the orbit, between the trochlear nerve and fibers of the oculomotor nerve can lead to simultaneous co-contraction of the inferior and superior oblique muscles. This is the most probable explanation for such finding of asymmetrical absence of torsional component in the left eye affected by DRS-III, during right Dix -Hallpike positioning. Thus, the recording of eye movements (voluntary and involuntary) opened a window into the brain to conceptualize neural and mechanical factors influencing the human eye movements.

Fast calculation method with saccade suppression for a computer-generated hologram based on Fresnel zone plate limitation.

The computer-generated hologram (CGH) is an ideal 3D technology that can satisfy all the physiological factors of the human eye (such as binocular parallax, focus adjustment and convergence etc.) by simulating the recording part of traditional optical holography with a computer. CGH has a lot of advantages such as being able to be used for animation. However, it also has many disadvantages, and one of them is the large amount of calculation. A saccade is one of a very rapid movement of human eye, and also, it is an ability of the eye to quickly and accurately move from one target to another. This is very critical for reading and involves very precise and specific eye movements. Saccades normally happen at a frequency of 2 - 8 times per second in daily life without our being conscious, and their peak angular speed can reach 900 degrees/second. However, saccades can also be initiated by an expected stimulus such as looking from one object to another, and they last from 20 - 200 ms depending on their amplitude. In addition, our visual information is suppressed while saccade occurs. In this paper, to realize the fast calculation of CGHs, a new method is proposed that uses saccades to reduce the amount of CGH calculation without any negative effects on observers viewing CGH reconstruction images. We increased high-speed calculation by at least 4 times through Fresnel zone plate limitation and 4.64 times through saccade suppression.

Optimal time task in saccadic eye movement

This article is devoted to fast goal-directed human eye movements. Such movements are described in few ways. One of them is the time-optimal problem model. It this work, the saccade – fast single conformable ballistic eye movement, is under consideration. Saccadic eye trajectory is described by time-optimal task solution. Differential equations system are based on pendulum model. It defines control moment applied from extraocular muscles to eye globe and movement of it. Main feature of the system is all values in suggested system have physical meaning and were found in published experimental investigations. Consideration of the moment applied from extraocular muscles to eye glob as control is main difference of the system from other models for eye movement in submitted works. In this case, the open-loop system has two real roots and one zero. The particular case of the ratio of real roots of 1:3 is analyzed in the article. As a result of modelling, trajectory characteristics closed to the saccades observed in experimental studies is obtained. On the basis of the constructed model, the parameters of the synthesized saccades were compared with the parameters obtained on the experimental sample. The obtained models can be used both for problems of physiology and medicine, and for constructing virtual reality environments. For example, when developing 3D interfaces, the use of a mathematical model makes it possible to optimize the elements arrangement using game theory.

Unbalancing the Attentional Priority Map via Gaze-Contingent Displays Induces Neglect-Like Visual Exploration.

Selective spatial attention is a crucial cognitive process that guides us to the behaviorally relevant objects in a complex visual world by using exploratory eye movements. The spatial location of objects, their (bottom-up) saliency and (top-down) relevance is assumed to be encoded in one “attentional priority map” in the brain, using different egocentric (eye-, head- and trunk-centered) spatial reference frames. In patients with hemispatial neglect, this map is supposed to be imbalanced, leading to a spatially biased exploration of the visual environment. As a proof of concept, we altered the visual saliency (and thereby attentional priority) of objects in a naturalistic scene along a left-right spatial gradient and investigated whether this can induce a bias in the exploratory eye movements of healthy humans (n = 28; all right-handed; mean age: 23 years, range 19–48). We developed a computerized mask, using high-end “gaze-contingent display (GCD)” technology, that immediately and continuously reduced the saliency of objects on the left—“left” with respect to the head (body-centered) and the current position on the retina (eye-centered). In both experimental conditions, task-free viewing and goal-driven visual search, this modification induced a mild but significant bias in visual exploration similar to hemispatial neglect. Accordingly, global eye movement parameters changed (reduced number and increased duration of fixations) and the spatial distribution of fixations indicated an attentional bias towards the right (rightward shift of first orienting, fixations favoring the scene’s outmost right over left). Our results support the concept of an attentional priority map in the brain as an interface between perception and behavior and as one pathophysiological ground of hemispatial neglect.

Dog eye movements are slower than human eye movements.

Eye movement of a species reflects the visual behavior strategy that it has adapted to during its evolution. What are eye movements of domestic dogs (Canis lupus familiaris) like? Investigations of dog eye movements per se have not been done, despite the increasing number of visuo-cognitive studies in dogs using eye-tracking systems. To fill this gap, we have recorded dog eye movements using a video-based eye-tracking system, and compared the dog data to that of humans. We found dog saccades follow the systematic relationships between saccade metrics previously shown in humans and other animal species. Yet, the details of the relationships, and the quantities of each metric of dog saccades and fixations differed from those of humans. Overall, dog saccades were slower and fixations were longer than those of humans. We hope our findings contribute to existing comparative analyses of eye movement across animal species, and also to improvement of algorithms used for classifying eye movement data of dogs.

Interpretable Global-Local Dynamics for the Prediction of Eye Fixations in Autonomous Driving Scenarios

Human eye movements while driving reveal that visual attention largely depends on the context in which it occurs. Furthermore, an autonomous vehicle which performs this function would be more reliable if its outputs were understandable. Capsule Networks have been presented as a great opportunity to explore new horizons in the Computer Vision field, due to their capability to structure and relate latent information. In this article, we present a hierarchical approach for the prediction of eye fixations in autonomous driving scenarios. Context-driven visual attention can be modeled by considering different conditions which, in turn, are represented as combinations of several spatio-temporal features. With the aim of learning these conditions, we have built an encoder-decoder network which merges visual features’ information using a global-local definition of capsules. Two types of capsules are distinguished: representational capsules for features and discriminative capsules for conditions. The latter and the use of eye fixations recorded with wearable eye tracking glasses allow the model to learn both to predict contextual conditions and to estimate visual attention, by means of a multi-task loss function. Experiments show how our approach is able to express either frame-level (global) or pixel-wise (local) relationships between features and contextual conditions, allowing for interpretability while maintaining or improving the performance of black-box related systems in the literature. Indeed, our proposal offers an improvement of 29% in terms of information gain with respect to the best performance reported in the literature.

Analysis of Motion and Internal Loading in Redundantly Actuated Human Eyeball

The 3-DOF rotational motion of the human eyeball is created by using six extraocular muscles. For the force-redundant system of the human eyeball, a load distribution algorithm is proposed to investigate the dynamics and intrinsic load distribution of the eyeball. Initially, the role of each extraocular muscle is explained by describing the anatomy of the human eye. Furthermore, activity of each muscle group is analyzed to create six primitive motions of the human eye. Moreover, the dynamic model of the human eye is developed to simulate the human eye motion. Finally, a load distribution algorithm is newly developed and it is found that asymmetric arrangement of six extraocular muscles with respect to the eye axis enables the human eye not only to create the motion using minimum number of extraocular muscles, but also to ensure stability in other directions by providing antagonistic internal loading. Surprisingly, it is also found that all six primitive motions of the eyeball require three independent muscles, which is different from clinical observation so far.

Visual Scanpath Prediction Using IOR-ROI Recurrent Mixture Density Network.

A visual scanpath represents the human eye movements when scanning the visual field for acquiring and receiving visual information. Predicting visual scanpaths when a certain stimulus is presented plays an important role in modeling overt human visual attention and search behavior. In this paper, we presented an 'Inhibition of Return - Region of Interest' (IOR-ROI) recurrent mixture density network based framework learning to produce human-like visual scanpaths under task-free viewing conditions. The proposed model simultaneously predicts a sequence of ordered fixation positions and their corresponding fixation durations. Our model integrates bottom-up features and semantic features extracted by convolutional neural networks. Then the integrated feature maps are fed into the IOR-ROI Long Short-Term Memory (LSTM) which is the core component of the proposed model. The IOR-ROI LSTM is a dual LSTM unit, i.e., the IOR-LSTM and the ROI-LSTM, capturing IOR dynamics and gaze shift behavior simultaneously. IOR-LSTM simulates the visual working memory to adaptively maintain and update visual information regarding previously fixated regions. ROI-LSTM is responsible for predicting the next possible ROIs given the spatially inhibited image feature maps on the feature-wise basis. Fixation duration is predicted by a regression neural network given the viewing history and image feature maps corresponding to currently fixated ROI. Considering the eye movement pattern variations among subjects, a mixture density network is adopted to model the next fixation distribution as Gaussian mixtures and the fixation duration is also modeled using Gaussian distribution. Our model is evaluated on the OSIE and MIT low resolution eye-tracking datasets and experimental results indicate that the proposed method can achieve superior performance in predicting visual scanpaths. The code will be publicly available on URL: https://github.com/sunwj/scanpath.

Optimal Control of Eye Movements During Visual Search

In this paper, we study the problem of an optimal oculomotor control during the execution of visual search tasks. We introduce a computational model of human eye movements, which takes into account various constraints of the human visual and oculomotor systems. In the model, the choice of the subsequent fixation location is posed as a problem of a stochastic optimal control, which relies on reinforcement learning methods. We show that if biological constraints are taken into account, the trajectories simulated under a learned policy share both basic statistical properties and a scaling behavior with human eye movements. We validated our model simulations with human psychophysical eye-tracking experiments.

P.846 Genetic haplotype of the glymphatic-associated water channel aquaporin 4 modulates slow waves in human non-rapid eye movement sleep

Although osteoid osteomas have traditionally been treated by surgical excision, radiofrequency ablation (RFA) has gained favor as a less invasive procedure. However, RFA is contraindicated for osteoid osteomas close to the skin or crucial neurovascular structures, and is not covered by national health insurance in Japan. The aim of the present study was to evaluate the efficacy of surgical excision of osteoid osteomas using intraoperative navigation.We performed a retrospective review of five patients with osteoid osteoma who underwent a mini-open excision using O-arm/Stealth navigation at our institution. The osteoid osteomas were excised using a cannulated cutter or curetted out with the assistance of navigation.Complete excision was achieved in all patients, which was confirmed by pathological examination. The mean skin incision was 2.1 cm (range, 1.5 to 3.0 cm) and the mean duration required for setup three-dimensional image was 15 min (range, 12 to 20 min). Although the mean visual analog scale score was 7 (range, 4 to 8) before surgery, all patients experienced relief from their characteristic pain immediately after surgery, with the mean scores of 2.2 (range, 1 to 3) and 0 at 2 days and 4 weeks after surgery, respectively. There was no intra-operative complication related to the navigation and no recurrence was observed during the mean follow-up period of 25 months (range, 13 to 33 months).Mini-open excision using intraoperative O-arm/Stealth navigation is a safe and accurate procedure for patients with osteoid osteoma, which could cover the limitation of RFA.

Using the eye-tracking method to study consumer online health information search behaviour

Purpose The purpose of this paper is to introduce eye tracking as a method for capturing direct and indirect measures of online human information search behaviour. The unique contribution of eye-tracking data in studying information behaviour is examined in the context of health information research. Design/methodology/approach The need for multiple methods of data collection when examining human online health information behaviour is described and summarised. The nature of human eye movements in information use and reading is outlined and the emergence and application of contemporary eye-tracking technology are explained. Findings The paper summarises key contributions and insights that eye tracking has provided across multiple studies, with examples of both direct data on fixations and gaze durations as well as theoretical assessments of relevance and knowledge gain. Originality/value The paper provides a basic introduction to the application of a unique method for information research in general and online health information search in particular and provides readers with an awareness of how such data are captured and interpreted.

Eye movement control in Chinese reading: A cross-sectional study.

The present study explored the age-related changes of eye movement control in reading-that is, where to send the eyes and when to move them. Different orthographies present readers with somewhat different problems to solve, and this might, in turn, be reflected in different patterns of development of reading skill. Participants of different developmental levels (Grade 3, N = 30; Grade 5, N = 27 and adults, N = 27) were instructed to read sentences for comprehension while their eye movements were recorded. Contrary to previous findings that have been well documented indicating early maturation of saccade generation in English, current results showed that saccade generation among Chinese readers was still under development at Grade 5, although immediate lexical processing was relatively well-established. The distinct age-related changes in eye movements are attributable to certain linguistic properties of Chinese including the lack of interword spaces and word boundary uncertainty. The present study offers an example of how human eye movement adapts to the orthographic environment. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Abstract goal representation in visual search by neurons in the human pre-supplementary motor area.

The medial frontal cortex is important for goal-directed behaviours such as visual search. The pre-supplementary motor area (pre-SMA) plays a critical role in linking higher-level goals to actions, but little is known about the responses of individual cells in this area in humans. Pre-SMA dysfunction is thought to be a critical factor in the cognitive deficits that are observed in diseases such as Parkinson's disease and schizophrenia, making it important to develop a better mechanistic understanding of the pre-SMA's role in cognition. We simultaneously recorded single neurons in the human pre-SMA and eye movements while subjects performed goal-directed visual search tasks. We characterized two groups of neurons in the pre-SMA. First, 40% of neurons changed their firing rate whenever a fixation landed on the search target. These neurons responded to targets in an abstract manner across several conditions and tasks. Responses were invariant to motor output (i.e. button press or not), and to different ways of defining the search target (by instruction or pop-out). Second, ∼50% of neurons changed their response as a function of fixation order. Together, our results show that human pre-SMA neurons carry abstract signals during visual search that indicate whether a goal was reached in an action- and cue-independent manner. This suggests that the pre-SMA contributes to goal-directed behaviour by flexibly signalling goal detection and time elapsed since start of the search, and this process occurs regardless of task. These observations provide insights into how pre-SMA dysfunction might impact cognitive function.

Detection of object displacement during a saccade is prioritized by the oculomotor system.

The human eye-movement system is equipped with a sophisticated updating mechanism that can adjust for large retinal displacements produced by saccadic eye movements. The nature of this updating mechanism is still highly debated. Previous studies have demonstrated that updating can occur very rapidly and is initiated before the start of a saccade. In the present study, we used saccade curvature to demonstrate that the oculomotor system is tuned for detecting object displacements during saccades. Participants made a sequence of saccades while ignoring an irrelevant distractor. Curvature of the second saccade relative to the distractor was used to estimate the time course of updating. Saccade curvature away from the presaccadic location of the distractor emerged as early as 80 ms after the first saccade when the distractor was displaced during a saccade. This is about 50 ms earlier than when a distractor was only present before a saccade, only present after a saccade, or remained stationary across a saccade. This shows that the oculomotor system prioritizes detection of object displacements during saccades, which may be useful for guiding corrective saccades. The results also challenge previous views by demonstrating the additional role of postsaccadic information in updating target-distractor competition across saccades.

Responses of neurons in macaque MT to unikinetic plaids.

Response properties of MT neurons are often studied with "bikinetic" plaid stimuli, which consist of two superimposed sine wave gratings moving in different directions. Oculomotor studies using "unikinetic plaids" in which only one of the two superimposed gratings moves suggest that the eyes first move reflexively in the direction of the moving grating and only later converge on the perceived direction of the moving pattern. MT has been implicated as the source of visual signals that drives these responses. We wanted to know whether stationary gratings, which have little effect on MT cells when presented alone, would influence MT responses when paired with a moving grating. We recorded extracellularly from neurons in area MT and measured responses to stationary and moving gratings, and to their sums: bikinetic and unikinetic plaids. As expected, stationary gratings presented alone had a very modest influence on the activity of MT neurons. Responses to moving gratings and bikinetic plaids were similar to those previously reported and revealed cells selective for the motion of plaid patterns and of their components (pattern and component cells). When these neurons were probed with unikinetic plaids, pattern cells shifted their direction preferences in a way that revealed the influence of the static grating. Component cell preferences shifted little or not at all. These results support the notion that pattern-selective neurons in area MT integrate component motions that differ widely in speed, and that they do so in a way that is consistent with an intersection-of-constraints model.NEW & NOTEWORTHY Human perceptual and eye movement responses to moving gratings are influenced by adding a second, static grating to create a "unikinetic" plaid. Cells in MT do not respond to static gratings, but those gratings still influence the direction selectivity of some MT cells. The cells influenced by static gratings are those tuned for the motion of global patterns, but not those tuned only for the individual components of moving targets.

A visual interactive reading system based on eye tracking technology to improve digital reading performance

Purpose Developing attention-aware systems and interfaces based on eye tracking technology could revolutionize mainstream human–computer interaction to make the interaction between human beings and computers more intuitive, effective and immersive than can be achieved traditionally using a computer mouse. This paper aims to propose an eye-controlled interactive reading system (ECIRS) that uses human eyes instead of the traditional mouse to control digital text to support screen-based digital reading. Design/methodology/approach This study uses a quasi-experimental design to examine the effects of an experimental group and a control group of learners who, respectively, used the ECIRS and a mouse-controlled interactive reading system (MCIRS) to conduct their reading of two types of English-language text online – pure text and Q&A-type articles on reading comprehension, cognitive load, technology acceptance, and reading behavioural characteristics. Additionally, the effects of learners with field-independent (FI) and field-dependence (FD) cognitive styles who, respectively, used the ECIRS and MCIRS to conduct their reading of two types of English-language text online – pure text and Q&A-type articles on reading comprehension are also examined. Findings Analytical results reveal that the reading comprehension of learners in the experimental group significantly exceeded those in the control group for the Q&A article, but the difference was insignificant for the pure text article. Moreover, the ECIRS improved the reading comprehension of field-independent learners more than it did that of field-dependent learners. Moreover, neither the cognitive loads of the two groups nor their acceptance of the technology differed significantly, whereas the reading time of the experimental group significantly exceeded that of the control group. Interestingly, for all articles, the control group of learners read mostly from top to bottom without repetition, whereas most of the learners in the experimental group read most paragraphs more than once. Clearly, the proposed ECIRS supports deeper digital reading than does the MCIRS. Originality/value This study proposes an emerging ECIRS that can automatically provide supplementary information to a reader and control a reading text based on a reader’s eye movement to replace the widely used mouse-controlled reading system on a computer screen to effectively support digital reading for English language learning. The implications of this study are that the highly interactive reading patterns of digital text with ECIRS support increase motivation and willingness to learn while giving learners a more intuitive and natural reading experience as well as reading an article online with ECIRS support guides learners’ attention in deeper digital reading than does the MCIRS because of simultaneously integrating perceptual and cognitive processes of selection, awareness and control based on human eye movement.

Visual Saliency Prediction Based on Deep Learning

Human eye movement is one of the most important functions for understanding our surroundings. When a human eye processes a scene, it quickly focuses on dominant parts of the scene, commonly known as a visual saliency detection or visual attention prediction. Recently, neural networks have been used to predict visual saliency. This paper proposes a deep learning encoder-decoder architecture, based on a transfer learning technique, to predict visual saliency. In the proposed model, visual features are extracted through convolutional layers from raw images to predict visual saliency. In addition, the proposed model uses the VGG-16 network for semantic segmentation, which uses a pixel classification layer to predict the categorical label for every pixel in an input image. The proposed model is applied to several datasets, including TORONTO, MIT300, MIT1003, and DUT-OMRON, to illustrate its efficiency. The results of the proposed model are quantitatively and qualitatively compared to classic and state-of-the-art deep learning models. Using the proposed deep learning model, a global accuracy of up to 96.22% is achieved for the prediction of visual saliency.