scholarly journals Changes in Eye Movement Amplitude after Conjunctivo-Limbal Autograft in Patients with Recurrent Pterygium, Ocular Motility Restriction

2021 ◽  
Vol 62 (1) ◽  
pp. 36-45
Author(s):  
Hye Jin Hong ◽  
Min Gu Huh ◽  
Dae Jin Park
Keyword(s):  
Eye Movement ◽  
Ocular Motility ◽  
Movement Amplitude ◽  
Recurrent Pterygium

scholarly journals Maxwellian Eye Fixation during Natural Scene Perception

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Jean Duchesne ◽  
Vincent Bouvier ◽  
Julien Guillemé ◽  
Olivier A. Coubard
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Scene Perception ◽  
Random Motion ◽  
Natural Scenes ◽  
Movement Amplitude ◽  
Natural Scene ◽  
Eye Fixation ◽  
Free Viewing ◽  
Natural Scene Perception

When we explore a visual scene, our eyes make saccades to jump rapidly from one area to another and fixate regions of interest to extract useful information. While the role of fixation eye movements in vision has been widely studied, their random nature has been a hitherto neglected issue. Here we conducted two experiments to examine the Maxwellian nature of eye movements during fixation. In Experiment 1, eight participants were asked to perform free viewing of natural scenes displayed on a computer screen while their eye movements were recorded. For each participant, the probability density function (PDF) of eye movement amplitude during fixation obeyed the law established by Maxwell for describing molecule velocity in gas. Only the mean amplitude of eye movements varied with expertise, which was lower in experts than novice participants. In Experiment 2, two participants underwent fixed time, free viewing of natural scenes and of their scrambled version while their eye movements were recorded. Again, the PDF of eye movement amplitude during fixation obeyed Maxwell’s law for each participant and for each scene condition (normal or scrambled). The results suggest that eye fixation during natural scene perception describes a random motion regardless of top-down or of bottom-up processes.

scholarly journals Auditory Electrooculogram-based Communication System for ALS Patients in Transition from Locked-in to Complete Locked-in State

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Alessandro Tonin ◽  
Andres Jaramillo-Gonzalez ◽  
Aygul Rana ◽  
Majid Khalili-Ardali ◽  
Niels Birbaumer ◽  
...  
Keyword(s):  
Eye Movement ◽  
Communication System ◽  
Movement Control ◽  
Movement Amplitude ◽  
Gaze Fixation ◽  
System A ◽  
Complete Paralysis ◽  
One Year ◽  
Als Patients

AbstractPatients in the transition from locked-in (i.e., a state of almost complete paralysis with voluntary eye movement control, eye blinks or twitches of face muscles, and preserved consciousness) to complete locked-in state (i.e., total paralysis including paralysis of eye-muscles and loss of gaze-fixation, combined with preserved consciousness) are left without any means of communication. An auditory communication system based on electrooculogram (EOG) was developed to enable such patients to communicate. Four amyotrophic lateral sclerosis patients in transition from locked-in state to completely locked-in state, with ALSFRS-R score of 0, unable to use eye trackers for communication, learned to use an auditory EOG-based communication system. The patients, with eye-movement amplitude between the range of ±200μV and ±40μV, were able to form complete sentences and communicate independently and freely, selecting letters from an auditory speller system. A follow-up of one year with one patient shows the feasibility of the proposed system in long-term use and the correlation between speller performance and eye-movement decay. The results of the auditory speller system have the potential to provide a means of communication to patient populations without gaze fixation ability and with low eye-movement amplitude range.

Ocular Motility Testing in Children

2022 ◽  
pp. 97-125
Author(s):  
M. H. Esther Han
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Management Plan ◽  
Ocular Motility ◽  
Developmental Approach ◽  
The Central Nervous System ◽  
Movement Function ◽  
Reading To Learn ◽  
Objective Tests ◽  
Vision Therapy

The purpose of this chapter is to provide the main indications, background, and procedures when assessing eye movement function in the pediatric patient. The assessment of extraocular motility function includes version and ductions using the H pattern test in order to determine the presence of underaction or overactions of the extraocular muscles (EOM). EOM testing detects abnormalities in the structural and neurological integrity caused by an acquired or congenital disease of the central nervous system. Deficits in eye movement function can also contribute to poor academic performance which requires a developmental approach to the assessment of saccadic and pursuit eye movements to determine if a referral for optometric vision therapy is indicated. For the older child who is reading to learn, an assessment of reading eye movements using objective tests, such as the Visagraph and/or the ReadAlyzer, will guide the direction of the management plan.

Apparent Dissociation Between Saccadic Eye Movements and the Firing Patterns of Premotor Neurons and Motoneurons

1999 ◽  
Vol 82 (5) ◽  
pp. 2808-2811 ◽  
Author(s):  
Leo Ling ◽  
Albert F. Fuchs ◽  
James O. Phillips ◽  
Edward G. Freedman
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
High Frequency ◽  
Action Potentials ◽  
Saccadic Eye Movements ◽  
Line Of Sight ◽  
Movement Amplitude ◽  
Burst Neurons ◽  
Premotor Neurons ◽  
Motoneuron Activity

Saccadic eye movements result from high-frequency bursts of activity in ocular motoneurons. This phasic activity originates in premotor burst neurons. When the head is restrained, the number of action potentials in the bursts of burst neurons and motoneurons increases linearly with eye movement amplitude. However, when the head is unrestrained, the number of action potentials now increase as a function of the change in the direction of the line of sight during eye movements of relatively similar amplitudes. These data suggest an apparent uncoupling of premotor neuron and motoneuron activity from the resultant eye movement.

Stimulation-Evoked Eye Movements With and Without the Lateral Rectus Muscle Pulley

2003 ◽  
Vol 90 (6) ◽  
pp. 3809-3815 ◽  
Author(s):  
Diana M. Dimitrova ◽  
Mary S. Shall ◽  
Stephen J. Goldberg
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Rectus Muscle ◽  
Lateral Rectus ◽  
Physiological Data ◽  
Movement Amplitude ◽  
Lateral Rectus Muscle ◽  
Before And After ◽  
Orbital Tissue ◽  
Orbital Layer

Recent studies have suggested that extraocular muscle (EOM) pulleys, composed of collagen, elastin, and smooth muscle, are among the tissues surrounding the eye. High-resolution magnetic-resonance imaging appears to indicate that the pulleys serve to both constrain and alter the pulling paths of the EOMs. The active pulley hypothesis suggests that the orbital layer of the EOMs inserts on the pulley and serves to control it. Based on anatomical data, the active pulley hypothesis also suggests that the orbital layer does not rotate the eye within the orbit; this is done by the global layer of the muscle. However, no physiological data exist to confirm this hypothesis. Here we used stimulation-evoked eye movements in anesthetized monkeys and cats before and after destruction of the lateral rectus muscle pulley by removal of the lateral bony orbit and adjacent orbital tissue. The absence of these structures resulted in increased lateral, in the primate, and medial, in the cat, eye-movement amplitude and velocity. Vertical eye movements in the cat were not significantly affected. The results indicate that these increases, confined to horizontal eye-movement amplitude and velocity, may be attributed to passive properties within the orbit. In relation to the active pulley hypothesis, we could discern no clear impact (in terms of amplitude or velocity profile of the movements) of lateral eye exposure that could be directly attributable to the active lateral pulley system.

Alexander's Law Revisited

2008 ◽  
Vol 19 (08) ◽  
pp. 630-638 ◽  
Author(s):  
Gary P. Jacobson ◽  
Devin L. McCaslin ◽  
David M. Kaylie
Keyword(s):  
Eye Movement ◽  
Vestibular System ◽  
Case Reports ◽  
Spontaneous Nystagmus ◽  
Ocular Motility ◽  
Vestibular Evoked Myogenic Potential ◽  
Data Collection And Analysis ◽  
Alexander’S Law ◽  
Neuro Imaging ◽  
Case Data

Background: It is a common occurrence in the balance function laboratory to evaluate patients in the post-acute period following unilateral vestibular system impairment. It is important to be able to differentiate spontaneous nystagmus (SN) emanating from peripheral vestibular system impairments from asymmetric gaze-evoked nystagmus (GEN) that originates from central ocular motility impairment. Purpose: To describe the three elements of Alexander's Law (AL) that have been used to define SN from unilateral peripheral impairment. Additionally, a fourth element is described (i.e., augmentation of spontaneous nystagmus from unilateral peripheral vestibular system impairment) that differentiates nystagmus of peripheral vestibular system origin from nystagmus that originates from a central eye movement disorder. Research Design: Case reports Study Sample: Case data were obtained from two patients both showing a nystagmus that followed AL. Intervention: None Data Collection And Analysis: Videonystagmography (VNG), rotational, vestibular evoked myogenic potential (VEMP), and neuro-imaging studies were presented for each patient. Results: The nystagmus in Case 1 occurred as a result of a unilateral, peripheral, vestibular system impairment. The nystagmus was direction-fixed and intensified in the vision-denied condition. The nystagmus in Case 2, by appearance identical to that in Case 1, was an asymmetric gaze-evoked nystagmus originating from a space-occupying lesion in the cerebello-pontine angle. Unlike Case 1, the nystagmus did not augment in the vision-denied condition. Conclusions: Although nystagmus following AL usually occurs in acute peripheral vestibular system impairment, it can occur in cases of central eye movement impairment. The key element is whether the SN that follows AL is attenuated or augmented in the vision-denied condition. The SN from a unilateral peripheral vestibular system impairment should augment in the vision denied condition. An asymmetric GEN will either not augment, decrease in magnitude, or disappear entirely, in the vision-denied condition.

Updating Visual Memory Across Eye Movements for Ocular and Arm Motor Control

2008 ◽  
Vol 100 (5) ◽  
pp. 2507-2514 ◽  
Author(s):  
Aidan A. Thompson ◽  
Denise Y. P. Henriques
Keyword(s):  
Eye Movements ◽  
Eye Movement ◽  
Smooth Pursuit ◽  
Visual Information ◽  
Visual Memory ◽  
Target Location ◽  
Spatial Updating ◽  
Spatial Representations ◽  
Movement Amplitude ◽  
Background Motion

Remembered object locations are stored in an eye-fixed reference frame, so that every time the eyes move, spatial representations must be updated for the arm-motor system to reflect the target's new relative position. To date, studies have not investigated how the brain updates these spatial representations during other types of eye movements, such as smooth-pursuit. Further, it is unclear what information is used in spatial updating. To address these questions we investigated whether remembered locations of pointing targets are updated following smooth-pursuit eye movements, as they are following saccades, and also investigated the role of visual information in estimating eye-movement amplitude for updating spatial memory. Misestimates of eye-movement amplitude were induced when participants visually tracked stimuli presented with a background that moved in either the same or opposite direction of the eye before pointing or looking back to the remembered target location. We found that gaze-dependent pointing errors were similar following saccades and smooth-pursuit and that incongruent background motion did result in a misestimate of eye-movement amplitude. However, the background motion had no effect on spatial updating for pointing, but did when subjects made a return saccade, suggesting that the oculomotor and arm-motor systems may rely on different sources of information for spatial updating.

scholarly journals Detection of third and sixth cranial nerve palsies with a novel method for eye tracking while watching a short film clip

2015 ◽  
Vol 122 (3) ◽  
pp. 707-720 ◽  
Author(s):  
Uzma Samadani ◽  
Sameer Farooq ◽  
Robert Ritlop ◽  
Floyd Warren ◽  
Marleen Reyes ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Eye Tracking ◽  
Eye Movement ◽  
Mass Effect ◽  
Ocular Motility ◽  
Pathological Conditions ◽  
Healthy Control ◽  
The Subject ◽  
Spatial Calibration ◽  
Normal Controls

OBJECT Automated eye movement tracking may provide clues to nervous system function at many levels. Spatial calibration of the eye tracking device requires the subject to have relatively intact ocular motility that implies function of cranial nerves (CNs) III (oculomotor), IV (trochlear), and VI (abducent) and their associated nuclei, along with the multiple regions of the brain imparting cognition and volition. The authors have developed a technique for eye tracking that uses temporal rather than spatial calibration, enabling detection of impaired ability to move the pupil relative to normal (neurologically healthy) control volunteers. This work was performed to demonstrate that this technique may detect CN palsies related to brain compression and to provide insight into how the technique may be of value for evaluating neuropathological conditions associated with CN palsy, such as hydrocephalus or acute mass effect. METHODS The authors recorded subjects' eye movements by using an Eyelink 1000 eye tracker sampling at 500 Hz over 200 seconds while the subject viewed a music video playing inside an aperture on a computer monitor. The aperture moved in a rectangular pattern over a fixed time period. This technique was used to assess ocular motility in 157 neurologically healthy control subjects and 12 patients with either clinical CN III or VI palsy confirmed by neuro-ophthalmological examination, or surgically treatable pathological conditions potentially impacting these nerves. The authors compared the ratio of vertical to horizontal eye movement (height/width defined as aspect ratio) in normal and test subjects. RESULTS In 157 normal controls, the aspect ratio (height/width) for the left eye had a mean value ± SD of 1.0117 ± 0.0706. For the right eye, the aspect ratio had a mean of 1.0077 ± 0.0679 in these 157 subjects. There was no difference between sexes or ages. A patient with known CN VI palsy had a significantly increased aspect ratio (1.39), whereas 2 patients with known CN III palsy had significantly decreased ratios of 0.19 and 0.06, respectively. Three patients with surgically treatable pathological conditions impacting CN VI, such as infratentorial mass effect or hydrocephalus, had significantly increased ratios (1.84, 1.44, and 1.34, respectively) relative to normal controls, and 6 patients with supratentorial mass effect had significantly decreased ratios (0.27, 0.53, 0.62, 0.45, 0.49, and 0.41, respectively). These alterations in eye tracking all reverted to normal ranges after surgical treatment of underlying pathological conditions in these 9 neurosurgical cases. CONCLUSIONS This proof of concept series of cases suggests that the use of eye tracking to detect CN palsy while the patient watches television or its equivalent represents a new capacity for this technology. It may provide a new tool for the assessment of multiple CNS functions that can potentially be useful in the assessment of awake patients with elevated intracranial pressure from hydrocephalus or trauma.

Screen Time and Developmental Eye Movement Testing in Middle School Students

2021 ◽  
pp. 107-116
Keyword(s):  
Middle School ◽  
Middle School Students ◽  
Eye Movement ◽  
Screen Time ◽  
Smart Devices ◽  
Ocular Motility ◽  
School Students ◽  
Significant Difference ◽  
Current Sample ◽  
Oculomotor Function

Background: Screen time continues to increase among children and youth, yet little is known about its potential effects on oculomotor development and function. The aims of the current study were to (a) compare oculomotor function in children today to those tested before smartphone use and (b) explore correlations between screen time use and oculomotor function among children today. Method: A retrospective comparison was conducted comparing normative data published in the Developmental Eye Movement (DEM) Test manual in 1990, prior to the invention of smart devices, to data collected in 2020. Correlations between screen time and DEM variables were also explored within the current sample. Results: Sixty middle school students reported spending on average 45.5 hours/week on screens with approximately 18.5 hours/week on iPhones, 14.5 hours/week on television and 10.5 hours/week on computers. Surprisingly, DEM performance was not significantly improved in the current sample compared to the historical sample. There were also no significant correlations between any screen time variables and oculomotor metrics within the current sample. Conclusion: Despite the significant increase in screen time usage since 1990, DEM performance was replicable among 6th, 7th, and 8th grader students tested 30 years later. A statistically significant difference was found among 7th graders on DEM Vertical, where the 2020 students performed slower however, this difference may not be clinically significant. Importantly, DEM Ratio, a key variable for identifying ocular motility dysfunction (OMD), was also not significantly different between 1990 and 2020. Moreover, screen time in the current sample did not correlate with any DEM variables. This study provides preliminary evidence indicating that as measured by the DEM Test, increased screen time may not affect ocular motility. Further research is warranted using more finite methods for measuring saccade and smooth pursuit eye movements during the use of screened devices.

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