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Eye (London, England) Dec 2011To define factors that determine the location and stability of fixation in patients with neovascular age-related macular degeneration (NV-AMD) treated with intravitreal...
AIMS
To define factors that determine the location and stability of fixation in patients with neovascular age-related macular degeneration (NV-AMD) treated with intravitreal ranibizumab injections.
METHODS
The location and stability of fixation using microperimetry were determined in 77 eyes treated with ranibizumab for NV-AMD for at least 12 months. All patients were treated with three injections of ranibizumab 0.5 mg, 1 month apart and retreated according to predefined criteria. The fixation parameters were correlated to the visual acuity, and quantitative measures on OCT.
RESULTS
The location of fixation was predominantly central in 52.6%, poor central fixation in 9.2%, and predominantly eccentric fixation in 38.2%. The fixation was stable in 65%, relatively unstable in 25%, and unstable in 10%. Visual acuity was the only factor that determined the stability and location of fixation. The characteristics of fixation were not related to the macular thickness or volume as measured by OCT.
CONCLUSIONS
Better visual outcome ensures central and stable fixation. Quantitative measures of OCT parameters do not determine fixation. Further studies on morphological features of the macula may provide some insight into the determinants of fixation.
Topics: Aged; Angiogenesis Inhibitors; Antibodies, Monoclonal, Humanized; Female; Fixation, Ocular; Humans; Immunologic Factors; Intravitreal Injections; Macular Degeneration; Male; Middle Aged; Ranibizumab; Tomography, Optical Coherence; Visual Acuity
PubMed: 21921956
DOI: 10.1038/eye.2011.223 -
Child Development Nov 2017The present article shows that infant and dyad differences in hand-eye coordination predict dyad differences in joint attention (JA). In the study reported here, 51...
The present article shows that infant and dyad differences in hand-eye coordination predict dyad differences in joint attention (JA). In the study reported here, 51 toddlers ranging in age from 11 to 24 months and their parents wore head-mounted eye trackers as they played with objects together. We found that physically active toddlers aligned their looking behavior with their parent and achieved a substantial proportion of time spent jointly attending to the same object. However, JA did not arise through gaze following but rather through the coordination of gaze with manual actions on objects as both infants and parents attended to their partner's object manipulations. Moreover, dyad differences in JA were associated with dyad differences in hand following.
Topics: Attention; Child, Preschool; Female; Fixation, Ocular; Hand; Humans; Infant; Male; Motor Activity; Parent-Child Relations; Psychomotor Performance
PubMed: 28186339
DOI: 10.1111/cdev.12730 -
Journal of Vision Apr 2024We obtain large amounts of external information through our eyes, a process often considered analogous to picture mapping onto a camera lens. However, our eyes are never...
We obtain large amounts of external information through our eyes, a process often considered analogous to picture mapping onto a camera lens. However, our eyes are never as still as a camera lens, with saccades occurring between fixations and microsaccades occurring within a fixation. Although saccades are agreed to be functional for information sampling in visual perception, it remains unknown if microsaccades have a similar function when eye movement is restricted. Here, we demonstrated that saccades and microsaccades share common spatiotemporal structures in viewing visual objects. Twenty-seven adults viewed faces and houses in free-viewing and fixation-controlled conditions. Both saccades and microsaccades showed distinctive spatiotemporal patterns between face and house viewing that could be discriminated by pattern classifications. The classifications based on saccades and microsaccades could also be mutually generalized. Importantly, individuals who showed more distinctive saccadic patterns between faces and houses also showed more distinctive microsaccadic patterns. Moreover, saccades and microsaccades showed a higher structure similarity for face viewing than house viewing and a common orienting preference for the eye region over the mouth region. These findings suggested a common oculomotor program that is used to optimize information sampling during visual object perception.
Topics: Humans; Saccades; Male; Female; Adult; Fixation, Ocular; Young Adult; Visual Perception; Photic Stimulation; Pattern Recognition, Visual
PubMed: 38656530
DOI: 10.1167/jov.24.4.20 -
Psychological Bulletin Jul 2007During social interactions, people's eyes convey a wealth of information about their direction of attention and their emotional and mental states. This review aims to... (Review)
Review
During social interactions, people's eyes convey a wealth of information about their direction of attention and their emotional and mental states. This review aims to provide a comprehensive overview of past and current research into the perception of gaze behavior and its effect on the observer. This encompasses the perception of gaze direction and its influence on perception of the other person, as well as gaze-following behavior such as joint attention, in infant, adult, and clinical populations. Particular focus is given to the gaze-cueing paradigm that has been used to investigate the mechanisms of joint attention. The contribution of this paradigm has been significant and will likely continue to advance knowledge across diverse fields within psychology and neuroscience.
Topics: Attention; Cognition; Cues; Female; Fixation, Ocular; Humans; Individuality; Male; Social Behavior; Social Perception; Visual Perception
PubMed: 17592962
DOI: 10.1037/0033-2909.133.4.694 -
The Journal of Neuroscience : the... Jun 2009To explore the visible world, human beings and other primates often rely on gaze shifts. These are coordinated movements of the eyes and head characterized by...
To explore the visible world, human beings and other primates often rely on gaze shifts. These are coordinated movements of the eyes and head characterized by stereotypical metrics and kinematics. It is possible to determine the rules that the effectors must obey to execute them rapidly and accurately and the neural commands needed to implement these rules with the help of optimal control theory. In this study, we demonstrate that head-fixed saccades and head-free gaze shifts obey a simple physical principle, "the minimum effort rule." By direct comparison with existing models of the neural control of gaze shifts, we conclude that the neural circuitry that implements the minimum effort rule is one that uses inhibitory cross talk between independent eye and head controllers.
Topics: Animals; Attention; Biomechanical Phenomena; Fixation, Ocular; Head Movements; Humans; Models, Neurological; Orientation; Time Factors
PubMed: 19535584
DOI: 10.1523/JNEUROSCI.5518-08.2009 -
Vision Research May 2015Humans have two, frontally placed eyes and during reading oculomotor and sensory processes are needed to combine the two inputs into a unified percept of the text....
Humans have two, frontally placed eyes and during reading oculomotor and sensory processes are needed to combine the two inputs into a unified percept of the text. Generally, slight vergence errors, i.e., fixation disparities, occur but do not cause double vision since disparate retinal inputs fall into Panum's fusional area, that is, a range of disparity wherein sensory fusion of the two retinal images is achieved. In this study, we report benchmark data with respect to the mean magnitude and range of vertical compared to horizontal fixation disparities for natural reading. Our data clearly fit to an elliptical pattern of Panum's fusional area that corresponds with theoretical estimates. Furthermore, when we examined disparity-driven vergence adjustments during fixations by comparing monocular with binocular reading conditions, we found that only horizontal fixation disparities increased significantly under conditions of monocular stimulation. Also, no significant vertical fine-tuning (vergence adjustment) was observed for vergence eye movements during reading fixations. Thus, horizontal and vertical fixation disparities and vergence adjustments during reading showed quite different characteristics, and this dissociation is directly related to the functional role of vergence adjustments: vertical fusion - and vertical vergence - subserve the maintenance of a single percept and stereopsis by keeping the eyes in register and allowing for horizontal fusional processes to successfully operate over a vertically aligned input. A reliable and stable vertical alignment is, thus, a pre-requisite over which horizontal fusional responses (and depth perception) can work most efficiently - even in a task like reading.
Topics: Adolescent; Adult; Convergence, Ocular; Female; Fixation, Ocular; Humans; Male; Reading; Vision Disparity; Vision, Binocular; Young Adult
PubMed: 25839421
DOI: 10.1016/j.visres.2015.03.008 -
Current Biology : CB Jun 2008
Topics: Animal Communication; Animals; Fixation, Ocular; Humans; Imitative Behavior; Language Development; Primates; Visual Perception
PubMed: 18522809
DOI: 10.1016/j.cub.2008.03.015 -
PloS One 2013In human vision, acuity and color sensitivity are greatest at the center of fixation and fall off rapidly as visual eccentricity increases. Humans exploit the high...
In human vision, acuity and color sensitivity are greatest at the center of fixation and fall off rapidly as visual eccentricity increases. Humans exploit the high resolution of central vision by actively moving their eyes three to four times each second. Here we demonstrate that it is possible to classify the task that a person is engaged in from their eye movements using multivariate pattern classification. The results have important theoretical implications for computational and neural models of eye movement control. They also have important practical implications for using passively recorded eye movements to infer the cognitive state of a viewer, information that can be used as input for intelligent human-computer interfaces and related applications.
Topics: Cognition; Eye Movements; Fixation, Ocular; Humans; Photic Stimulation; Psychomotor Performance; Reading; Visual Perception
PubMed: 23734228
DOI: 10.1371/journal.pone.0064937 -
Journal of Vision Feb 2014Microsaccades, small involuntary eye movements that occur once or twice per second during attempted visual fixation, are relevant to perception, cognition, and...
Microsaccades, small involuntary eye movements that occur once or twice per second during attempted visual fixation, are relevant to perception, cognition, and oculomotor control and present distinctive characteristics in visual and oculomotor pathologies. Thus, the development of robust and accurate microsaccade-detection techniques is important for basic and clinical neuroscience research. Due to the diminutive size of microsaccades, however, automatic and reliable detection can be difficult. Current challenges in microsaccade detection include reliance on set, arbitrary thresholds and lack of objective validation. Here we describe a novel microsaccade-detecting method, based on unsupervised clustering techniques, that does not require an arbitrary threshold and provides a detection reliability index. We validated the new clustering method using real and simulated eye-movement data. The clustering method reduced detection errors by 62% for binocular data and 78% for monocular data, when compared to standard contemporary microsaccade-detection techniques. Further, the clustering method's reliability index was correlated with the microsaccade-detection error rate, suggesting that the reliability index may be used to determine the comparative precision of eye-tracking devices.
Topics: Cluster Analysis; Fixation, Ocular; Humans; Photic Stimulation; Reproducibility of Results; Saccades; Visual Perception
PubMed: 24569984
DOI: 10.1167/14.2.18 -
PloS One 2012Although most instances of object recognition during natural viewing occur in the presence of saccades, the neural correlates of objection recognition have almost...
Although most instances of object recognition during natural viewing occur in the presence of saccades, the neural correlates of objection recognition have almost exclusively been examined during fixation. Recent studies have indicated that there are post-saccadic modulations of neural activity immediately following eye movement landing; however, whether post-saccadic modulations affect relatively late occurring cognitive components such as the P3 has not been explored. The P3 as conventionally measured at fixation is commonly used in brain computer interfaces, hence characterizing the post-saccadic P3 could aid in the development of improved brain computer interfaces that allow for eye movements. In this study, the P3 observed after saccadic landing was compared to the P3 measured at fixation. No significant differences in P3 start time, temporal persistence, or amplitude were found between fixation and saccade trials. Importantly, sensory neural responses canceled in the target minus distracter comparisons used to identify the P3. Our results indicate that relatively late occurring cognitive neural components such as the P3 are likely less sensitive to post saccadic modulations than sensory neural components and other neural activity occurring shortly after eye movement landing. Furthermore, due to the similarity of the fixation and saccade P3, we conclude that the P3 following saccadic landing could possibly be used as a viable signal in brain computer interfaces allowing for eye movements.
Topics: Eye Movements; Female; Fixation, Ocular; Humans; Male; Photic Stimulation; Saccades
PubMed: 23144959
DOI: 10.1371/journal.pone.0048761