scholarly journals Fixational eye movement waveforms in amblyopia: Characteristics of fast and slow eye movements

2019 ◽  
Vol 12 (6) ◽  
Author(s):  
Sarah Linda Kang ◽  
Sinem B. Beylergil ◽  
Jorge Otero-Millan ◽  
Aasef Shaikh ◽  
Fatema Ghasia
Keyword(s):  
Visual Acuity ◽  
Eye Movements ◽  
Eye Movement ◽  
Treatment Effectiveness ◽  
Eye Diseases ◽  
Fixational Eye Movements ◽  
Fixation Stability ◽  
Slow Eye Movements ◽  
Fixational Saccades ◽  
The Impact

Fixational eye movements comprise of fast microsaccades alternating with slow inter-saccadic drifts. These physiologic eye movements play an important role in visual perception.  Amblyopic patients are known to have fixation instability, particularly of the amblyopic eye. We examined eye movement abnormalities that contribute to this instability. We found that fixation stability is affected by the presence of fusion maldevelopment nystagmus (FMN). However, some amblyopes can have nystagmus without nasally directed slow phases and reversal in direction of the quick phase on ocular occlusion, features seen in FMN. In patients without nystagmus, we found increased amplitude of fixational saccades and inter-saccadic drifts. We categorized amblyopia patients by type (anisometropic, strabismic, or mixed) and eye movement waveform (no nystagmus, nystagmus without FMN, and FMN). We found specific fast and slow eye movement abnormalities of the fellow and amblyopic eye during fellow, amblyopic and both eyes viewing conditions across eye movement waveforms and types of amblyopia. These eye movement abnormalities can serve as biomarkers that can predict the impact of amblyopia as measured by visual acuity and stereopsis. Evaluation of fixational eye movements in amblyopia could be important to diagnose these common eye diseases and predict treatment effectiveness. 

scholarly journals Fixation eye movement abnormalities and stereopsis recovery following strabismus repair

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Talora L. Martin ◽  
Jordan Murray ◽  
Kiran Garg ◽  
Charles Gallagher ◽  
Aasef G. Shaikh ◽  
...  
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Functional Improvement ◽  
Slow Phase ◽  
Fixational Eye Movements ◽  
Movement Characteristics ◽  
Adaptive Mechanisms ◽  
Before And After ◽  
Gaze Holding ◽  
Fixational Saccades

AbstractWe evaluated the effects of strabismus repair on fixational eye movements (FEMs) and stereopsis recovery in patients with fusion maldevelopment nystagmus (FMN) and patients without nystagmus. Twenty-one patients with strabismus, twelve with FMN and nine without nystagmus, were tested before and after strabismus repair. Eye-movements were recorded during a gaze-holding task under monocular viewing conditions. Fast (fixational saccades and quick phases of nystagmus) and slow (inter-saccadic drifts and slow phases of nystagmus) FEMs and bivariate contour ellipse area (BCEA) were analyzed in the viewing and non-viewing eye. Strabismus repair improved the angle of strabismus in subjects with and without FMN, however patients without nystagmus were more likely to have improvement in stereoacuity. The fixational saccade amplitudes and intersaccadic drift velocities in both eyes decreased after strabismus repair in subjects without nystagmus. The slow phase velocities were higher in patients with FMN compared to inter-saccadic drifts in patients without nystagmus. There was no change in the BCEA after surgery in either group. In patients without nystagmus, the improvement of the binocular function (stereopsis), as well as decreased fixational saccade amplitude and intersaccadic drift velocity, could be due, at least partially, to central adaptive mechanisms rendered possible by surgical realignment of the eyes. The absence of improvement in patients with FMN post strabismus repair likely suggests the lack of such adaptive mechanisms in patients with early onset infantile strabismus. Assessment of fixation eye movement characteristics can be a useful tool to predict functional improvement post strabismus repair.

scholarly journals Fixational eye movements abnormalities and rate of visual acuity and stereoacuity improvement with part time patching

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Matteo Scaramuzzi ◽  
Jordan Murray ◽  
Paolo Nucci ◽  
Aasef G. Shaikh ◽  
Fatema F. Ghasia
Keyword(s):  
Visual Acuity ◽  
Eye Movements ◽  
Eye Movement ◽  
Duration Of Treatment ◽  
Fixational Eye Movements ◽  
Infantile Nystagmus ◽  
Part Time ◽  
Stereo Acuity ◽  
Clinical Subtype

AbstractResidual amblyopia is seen in 40% of amblyopic patients treated with part-time patching. Amblyopic patients with infantile onset strabismus or anisometropia can develop fusion maldevelopment nystagmus syndrome (FMNS). The purpose of this study was to understand the effects of presence of FMNS and clinical subtype of amblyopia on visual acuity and stereo-acuity improvement in children treated with part-time patching. Forty amblyopic children who had fixation eye movement recordings and at least 12 months of follow-up after initiating part-time patching were included. We classified amblyopic subjects per the fixational eye movements characteristics into those without any nystagmus, those with FMNS and patients with nystagmus without any structural anomalies that do not meet the criteria of FMNS or idiopathic infantile nystagmus. We also classified the patients per the clinical type of amblyopia. Patching was continued until amblyopia was resolved or no visual acuity improvement was noted at two consecutive visits. Children with anisometropic amblyopia and without FMNS have a faster improvement and plateaued sooner. Regression was only seen in patients with strabismic/mixed amblyopia particularly those with FMNS. Patients with FMNS had improvement in visual acuity but poor stereopsis with part-time patching and required longer duration of treatment.

scholarly journals Influence of eye diseases on the mortality rate of the population

2018 ◽  
Vol 11 (1) ◽  
pp. 47-53
Author(s):  
Andrey V Zolotarev ◽  
Elena V Karlova ◽  
Elena V Miroshnichenko
Keyword(s):  
Quality Of Life ◽  
Visual Acuity ◽  
Mortality Rate ◽  
Life Expectancy ◽  
Eye Diseases ◽  
Review Of Literature ◽  
The Impact

Evaluating of the correlation between quality of life, life expectancy and mortality rate is an important problem of modern ophthalmology. Many researchers note that eye pathology, which leads to a visual acuity decrease and blindness, has a significant impact on the mortality rate of the population. This review of literature is dedicated to studies examining the impact of eye diseases on the mortality rate of the population. (For citation: Zolotarev AV, Karlova EV, Miroshnichenko EV. Influence of eye diseases on the mortality rate of the population. ­Oph­thal­mology Journal. 2018;11(1):47-53. doi: 10.17816/OV11147-53).

scholarly journals Pursuit disorder and saccade dysmetria after caudal fastigial inactivation in the monkey

2018 ◽  
Vol 120 (4) ◽  
pp. 1640-1654 ◽  
Author(s):  
Clara Bourrelly ◽  
Julie Quinet ◽  
Laurent Goffart
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Visual Target ◽  
Fastigial Nucleus ◽  
Gaze Direction ◽  
Moving Target ◽  
Horizontal Meridian ◽  
Pursuit Eye Movements ◽  
Neural Processes ◽  
Slow Eye Movements

The caudal fastigial nuclei (cFN) are the output nuclei by which the medio-posterior cerebellum influences the production of saccadic and pursuit eye movements. We investigated the consequences of unilateral inactivation on the pursuit eye movement made immediately after an interceptive saccade toward a centrifugal target. We describe here the effects when the target moved along the horizontal meridian with a 10 or 20°/s speed. After muscimol injection, the monkeys were unable to track the present location of the moving target. During contralesional tracking, the velocity of postsaccadic pursuit was reduced. This slowing was associated with a hypometria of interceptive saccades such that gaze direction always lagged behind the moving target. No correlation was found between the sizes of saccade undershoot and the decreases in pursuit speed. During ipsilesional tracking, the effects on postsaccadic pursuit were variable across the injection sessions, whereas the interceptive saccades were consistently hypermetric. Here also, the ipsilesional pursuit disorder was not correlated with the saccade hypermetria either. The lack of correlation between the sizes of saccade dysmetria and changes of postsaccadic pursuit speed suggests that cFN activity exerts independent influences on the neural processes generating the saccadic and slow eye movements. It also suggests that the cFN is one locus where the synergy between the two motor categories develops in the context of tracking a moving visual target. We explain how the different fastigial output channels can account for these oculomotor tracking disorders. NEW & NOTEWORTHY Inactivation of the caudal fastigial nucleus impairs the ability to track a moving target. The accuracy of interceptive saccades and the velocity of postsaccadic pursuit movements are both altered, but these changes are not correlated. This absence of correlation is not compatible with an impaired common command feeding the circuits producing saccadic and pursuit eye movements. However, it suggests an involvement of caudal fastigial nuclei in their synergy to accurately track a moving target.

scholarly journals Linking individual differences in fixational eye movements and visual acuity

2021 ◽  
Vol 21 (9) ◽  
pp. 2763
Author(s):  
Ashley Clark ◽  
Janis Intoy ◽  
Martina Poletti
Keyword(s):  
Visual Acuity ◽  
Individual Differences ◽  
Eye Movements ◽  
Fixational Eye Movements

scholarly journals Microsaccades in applied environments: Real-world applications of fixational eye movement measurements

2020 ◽  
Vol 12 (6) ◽  
Author(s):  
Robert G Alexander ◽  
Stephen L Macknik ◽  
Susana Martinez-Conde
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Athletic Training ◽  
Real World ◽  
High Speed ◽  
Sensory Deprivation ◽  
Assessment Tools ◽  
Current Evidence ◽  
Fixational Eye Movements ◽  
Real World Applications

Across a wide variety of research environments, the recording of microsaccades and other fixational eye movements has provided insight and solutions into practical problems. Here we review the literature on fixational eye movements—especially microsaccades—in applied and ecologically-valid scenarios. Recent technical advances allow noninvasive fixational eye movement recordings in real-world contexts, while observers perform a variety of tasks. Thus, fixational eye movement measures have been obtained in a host of real-world scenarios, such as in connection with driver fatigue, vestibular sensory deprivation in astronauts, and elite athletic training, among others. Here we present the state of the art in the practical applications of fixational eye movement research, examine its potential future uses, and discuss the benefits of including microsaccade measures in existing eye movement detection technologies. Current evidence supports the inclusion of fixational eye movement measures in real-world contexts, as part of the development of new or improved oculomotor assessment tools. The real-world applications of fixational eye movement measurements will only grow larger and wider as affordable high-speed and high-spatial resolution eye trackers become increasingly prevalent.

scholarly journals Reading Specific Small Saccades Predict Individual Phonemic Awareness and Reading Speed

2021 ◽  
Vol 15 ◽  
Author(s):  
Samy Rima ◽  
Michael C. Schmid
Keyword(s):  
Eye Movements ◽  
Short Story ◽  
Phonemic Awareness ◽  
Developmental Dyslexia ◽  
Reading Skill ◽  
Fundamental Aspect ◽  
Fixational Eye Movements ◽  
Free Viewing ◽  
Wide Range ◽  
Fixational Saccades

Small fixational eye-movements are a fundamental aspect of vision and thought to reflect fine shifts in covert attention during active viewing. While the perceptual benefits of these small eye movements have been demonstrated during a wide range of experimental tasks including during free viewing, their function during reading remains surprisingly unclear. Previous research demonstrated that readers with increased microsaccade rates displayed longer reading speeds. To what extent increased fixational eye movements are, however, specific to reading and might be indicative of reading skill deficits remains, however, unknown. To address this topic, we compared the eye movement scan paths of 13 neurotypical individuals and 13 subjects diagnosed with developmental dyslexia during short story reading and free viewing of natural scenes. We found that during reading only, dyslexics tended to display small eye movements more frequently compared to neurotypicals, though this effect was not significant at the population level, as it could also occur in slow readers not diagnosed as dyslexics. In line with previous research, neurotypical readers had twice as many regressive compared to progressive microsaccades, which did not occur during free viewing. In contrast, dyslexics showed similar amounts of regressive and progressive small fixational eye movements during both reading and free viewing. We also found that participants with smaller fixational saccades from both neurotypical and dyslexic samples displayed reduced reading speeds and lower scores during independent tests of reading skill. Slower readers also displayed greater variability in the landing points and temporal occurrence of their fixational saccades. Both the rate and spatio-temporal variability of fixational saccades were associated with lower phonemic awareness scores. As none of the observed differences between dyslexics and neurotypical readers occurred during control experiments with free viewing, the reported effects appear to be directly related to reading. In summary, our results highlight the predictive value of small saccades for reading skill, but not necessarily for developmental dyslexia.

ORIENTATION IN SPACE, VESTIBULAR FUNCTION AND OCULAR TRACKING IN THE CHANGED GRAVITATIONAL ENVIRONMENT

2020 ◽  
Vol 54 (6) ◽  
pp. 50-57
Author(s):  
L.N. Kornilova ◽  
Keyword(s):  
Eye Movements ◽  
Spatial Perception ◽  
Sensory Deprivation ◽  
Space Station ◽  
Vestibular Function ◽  
Sensory Stimulation ◽  
The Body ◽  
Fixational Eye Movements ◽  
Ocular Tracking ◽  
The Impact

The paper reports results of the author's sensorimotor physiology studies made under the guidance of I.B.Kozlovskaya. The vestibular function and ocular tracking tests were performed by more than 100 cosmonauts prior to and after long-term missions to the Mir and International space station. Fifty two of them implemented these tests between mission days 129 to 215. We studies orientation illusions, spontaneous eye movements, static vestibulo-ocular response to head turns (static otolith-cervical reflex), dynamic vestibulo-ocular reactions to the head roll about the body axis, precision of fixational eye movements, and smooth tracking. Results of testing in the real changed gravity were compared with the data from 7 to 21-day simulation studies in horizontal dry immersion. The tests revealed 4 forms of vestibular disorders characterized by disturbances of spatial perception, orientation illusions, inversions of vection illusions, weakening of static and strengthening of dynamic vestibulo-ocular reactions, a new visual tracking strategy termed a saccadic approximation, that is the gaze approaches or tracks a target using a series of saccadic movements. In addition, the tests made it possible to specify the impact of afferentation deficit (sensory deprivation) on accuracy of ocular and ocular-manual tracking and validate additional sensory stimulation as a method to counteract the effects of sensory deprivation in real and simulated microgravity.

The impact of audio on the reading of intralingual versus interlingual subtitles: Evidence from eye movements

2021 ◽  
pp. 1-33
Author(s):  
Sixin Liao ◽  
Lili Yu ◽  
Jan-Louis Kruger ◽  
Erik D. Reichle
Keyword(s):  
Second Language ◽  
Eye Movements ◽  
Eye Movement ◽  
Information Sources ◽  
Lexical Processing ◽  
Auditory Information ◽  
Video Content ◽  
Video Presentation ◽  
Chinese Speakers ◽  
The Impact

Abstract This study investigated how semantically relevant auditory information might affect the reading of subtitles, and if such effects might be modulated by the concurrent video content. Thirty-four native Chinese speakers with English as their second language watched video with English subtitles in six conditions defined by manipulating the nature of the audio (Chinese/L1 audio vs. English/L2 audio vs. no audio) and the presence versus absence of video content. Global eye-movement analyses showed that participants tended to rely less on subtitles with Chinese or English audio than without audio, and the effects of audio were more pronounced in the presence of video presentation. Lexical processing of subtitles was not modulated by the audio. However, Chinese audio, which presumably obviated the need to read the subtitles, resulted in more superficial post-lexical processing of the subtitles relative to either the English or no audio. On the contrary, English audio accentuated post-lexical processing of the subtitles compared with Chinese audio or no audio, indicating that participants might use English audio to support subtitle reading (or vice versa) and thus engaged in deeper processing of the subtitles. These findings suggest that, in multimodal reading situations, eye movements are not only controlled by processing difficulties associated with properties of words (e.g., their frequency and length) but also guided by metacognitive strategies involved in monitoring comprehension and its online modulation by different information sources.

scholarly journals Characteristics of fixational eye movements in amblyopia: Limitations on fixation stability and acuity?

2015 ◽  
Vol 114 ◽  
pp. 87-99 ◽  
Author(s):  
Susana T.L. Chung ◽  
Girish Kumar ◽  
Roger W. Li ◽  
Dennis M. Levi
Keyword(s):  
Eye Movements ◽  
Fixational Eye Movements ◽  
Fixation Stability
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