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Vision Research 1990End-point nystagmus (EPN) and ocular drift during eccentric fixation were investigated in five normal subjects. All had EPN during prolonged eccentric fixation, two had...
End-point nystagmus (EPN) and ocular drift during eccentric fixation were investigated in five normal subjects. All had EPN during prolonged eccentric fixation, two had sustained EPN within a few seconds of fixating an eccentric target. Our data show that the occurrence of EPN was determined by the velocity of slow phase ocular drift. Drift velocities greater than 1 deg/sec elicited sustained EPN or fatigue EPN while drift velocities lower than 0.3 deg/sec did not elicit EPN. Slow phase drift velocity increased with eccentricity and fixation duration and decreased with visual feedback. Computer simulations and theoretical analysis suggest that the reduction in drift eye movement velocity during fixation of a visible target, as compared to drift eye movement velocity during attempted fixation of a remembered target in darkness, is mainly due to the smooth pursuit system.
Topics: Adult; Dark Adaptation; Eye Movements; Feedback; Female; Fixation, Ocular; Humans; Male; Mathematics; Models, Biological; Neural Pathways; Nystagmus, Physiologic
PubMed: 2385927
DOI: 10.1016/0042-6989(90)90055-p -
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 -
The Laryngoscope Apr 1999Characteristics of static positional nystagmus (SPN) (i.e., persistency, direction fixed, direction changing) are observed in both peripheral and central disturbances...
OBJECTIVE
Characteristics of static positional nystagmus (SPN) (i.e., persistency, direction fixed, direction changing) are observed in both peripheral and central disturbances and possess no localizing value for vestibular lesions. Our objective was to investigate whether the ocular fixation test as applied to SPN could assist in localizing vestibular lesions.
STUDY DESIGN
A 3-year prospective study that included 43 patients with SPN.
METHODS
All patients underwent a standard vestibular test battery and cerebral imaging (7, computed tomography scan; 36, magnetic resonance imaging). The ocular fixation index (OFI) was calculated by the ratio of the mean slow component velocity of SPN (measured with red light-emitting diode fixation) to that measured in darkness, multiplied by 100. An OFI less than 50 was considered normal.
RESULTS
In 33 of 35 patients whose OFI was less than 50, the cerebral imaging was normal and a peripheral vestibular lesion was diagnosed (two benign tumors of the fourth ventricle were missed). In all eight patients whose OFI was greater than 50, the cerebral imaging was abnormal and a central vestibular lesion was noted.
CONCLUSIONS
These results indicate that the visual suppression of SPN does, indeed, permit the localization of vestibular lesions. The predictive value of the ocular fixation test on the origin of SPN is greater than 94% for peripheral lesions and 100% for central disorders.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Electronystagmography; Female; Fixation, Ocular; Humans; Male; Middle Aged; Nystagmus, Physiologic; Posture; Prospective Studies; Vestibular Function Tests
PubMed: 10201749
DOI: 10.1097/00005537-199904000-00016 -
Journal of Neuro-ophthalmology : the... Dec 2019
Topics: Adult; Aniseikonia; Diplopia; Fixation, Ocular; Humans; Vision, Binocular
PubMed: 31790371
DOI: 10.1097/WNO.0000000000000867 -
Psychonomic Bulletin & Review Oct 2020Humans tend to shift attention according to others' eye-gaze direction. This is a core ability as it permits to create pervasive relationships among individuals and with... (Review)
Review
Humans tend to shift attention according to others' eye-gaze direction. This is a core ability as it permits to create pervasive relationships among individuals and with the environment around them. In the beginning, this form of social orienting was considered a reflexive phenomenon, but in recent years evidence has shown that it is also permeable to several social factors related to the observer, the individual depicted in the cueing face, and the relationship between them. The major goal of this work is to provide a comprehensive overview concerning the role that social variables can play in shaping covert gaze cueing in healthy adults, critically examining both the modulatory social factors for which evidence is more robust and those for which evidence is mixed. When available, overt attention studies will also be discussed. Finally, a novel theoretical framework linking these social and attention domains will be also introduced.
Topics: Adult; Attention; Cues; Fixation, Ocular; Humans; Social Perception; Visual Perception
PubMed: 32291650
DOI: 10.3758/s13423-020-01730-x -
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 -
Journal of Neuroscience Methods Sep 2003Patterns of ocular fixation in free-viewing tasks reflect aspects of visual attention and cognition. To quantify these patterns, fixations must be identified in raw eye...
Patterns of ocular fixation in free-viewing tasks reflect aspects of visual attention and cognition. To quantify these patterns, fixations must be identified in raw eye movement data by applying explicit spatial and temporal thresholds. A temporal threshold of 200 ms is commonly used in clinical visuocognitive research, despite having been originally derived from a study of eye movements in reading. We systematically explored temporal fixation thresholds below 200 ms, using biologically relevant (human face) and abstract (complex geometric) stimuli. Short fixations (<200 ms) significantly altered spatiotemporal patterns of fixation for both the face and geometric stimuli, by increasing the number of fixations and the scanpath length. A threshold of 100 ms was found to discriminate fixations from other oculomotor activity effectively, and was consistent with current physiological and visuocognitive models. Statistical examination of fixation duration data for each subject suggested the median was a less biased and more robust measure of central tendency than the mean.
Topics: Adult; Analysis of Variance; Cognition; Female; Fixation, Ocular; Humans; Male; Middle Aged; Photic Stimulation; Sensory Thresholds; Time Factors; Visual Perception
PubMed: 12948551
DOI: 10.1016/s0165-0270(03)00151-1 -
Medical Science Monitor : International... Jun 2008Visual field (VF) examinations provide important information about diagnosis and follow-up in many ocular and visual pathway disorders. Previous studies have shown that...
BACKGROUND
Visual field (VF) examinations provide important information about diagnosis and follow-up in many ocular and visual pathway disorders. Previous studies have shown that fixation stability can be measured very exactly around the center of the fixation point with SLO. The importance of measuring fixation during microperimetry in the absence of field defects is to learn more about the normal fixation pattern. This is of interest since changes in fixation pattern due to pathology can occur prior to detectable changes in the macula or visual pathway.
MATERIAL/METHODS
Thirty-one adult subjects with healthy eyes were recruited from the staff of the Section of Ophthalmology and Vision, Department of Clinical Neuroscience, Karolinska Institutet. The fixation pattern in one randomly selected eye from each subject was investigated with the SLO using the fixation control function in the microperimetry technique.
RESULTS
The results showed that the fixation pattern had a mean center of gravity located at a mean absolute distance of 0.27 degrees from the fixation point (FP) and a directional predominance of the fixation pattern was found in that the fixations were more frequently distributed vertically than horizontally.
CONCLUSIONS
The computerized fixation control when performing microperimetry with the SLO provides information about the fixation pattern which cannot be obtained with standard clinical perimetry techniques.
Topics: Adult; Female; Fixation, Ocular; Fundus Oculi; Health; Humans; Lasers; Male; Ophthalmoscopes; Visual Field Tests
PubMed: 18509274
DOI: No ID Found -
Revue Medicale Suisse Nov 2011
Topics: Communication Barriers; Eye; Female; Fixation, Ocular; Humans; Kinesics; Office Visits; Physician-Patient Relations
PubMed: 22400369
DOI: No ID Found -
Vision Research Jan 2013People can direct their gaze at a visual target for extended periods of time. Yet, even during fixation the eyes make small, involuntary movements (e.g. tremor, drift,... (Comparative Study)
Comparative Study
People can direct their gaze at a visual target for extended periods of time. Yet, even during fixation the eyes make small, involuntary movements (e.g. tremor, drift, and microsaccades). This can be a problem during experiments that require stable fixation. The shape of a fixation target can be easily manipulated in the context of many experimental paradigms. Thus, from a purely methodological point of view, it would be good to know if there was a particular shape of a fixation target that minimizes involuntary eye movements during fixation, because this shape could then be used in experiments that require stable fixation. Based on this methodological motivation, the current experiments tested if the shape of a fixation target can be used to reduce eye movements during fixation. In two separate experiments subjects directed their gaze at a fixation target for 17s on each trial. The shape of the fixation target varied from trial to trial and was drawn from a set of seven shapes, the use of which has been frequently reported in the literature. To determine stability of fixation we computed spatial dispersion and microsaccade rate. We found that only a target shape which looks like a combination of bulls eye and cross hair resulted in combined low dispersion and microsaccade rate. We recommend the combination of bulls eye and cross hair as fixation target shape for experiments that require stable fixation.
Topics: Eye Movements; Fixation, Ocular; Form Perception; Humans; Photic Stimulation
PubMed: 23099046
DOI: 10.1016/j.visres.2012.10.012