scholarly journals Tracking-Based Interactive Assessment of Saccades, Pursuits, Visual Field, and Contrast Sensitivity in Children With Brain Injury

2021 ◽  
Vol 15 ◽  
Author(s):  
Scott W. J. Mooney ◽  
Nazia M. Alam ◽  
Glen T. Prusky
Keyword(s):  
Eye Movements ◽  
Brain Injury ◽  
Visual Field ◽  
Contrast Sensitivity ◽  
Visual Impairments ◽  
Eye Tracker ◽  
Diverse Range ◽  
Novel Approach ◽  
Visual Tasks ◽  
Cortical Visual Impairment

Visual deficits in children that result from brain injury, including cerebral/cortical visual impairment (CVI), are difficult to assess through conventional methods due to their frequent co-occurrence with cognitive and communicative disabilities. Such impairments hence often go undiagnosed or are only determined through subjective evaluations of gaze-based reactions to different forms, colors, and movements, which limits any potential for remediation. Here, we describe a novel approach to grading visual health based on eye movements and evidence from gaze-based tracking behaviors. Our approach—the “Visual Ladder”—reduces reliance on the user’s ability to attend and communicate. The Visual Ladder produces metrics that quantify spontaneous saccades and pursuits, assess visual field responsiveness, and grade spatial visual function from tracking responses to moving stimuli. We used the Ladder to assess fourteen hospitalized children aged 3 to 18 years with a diverse range of visual impairments and causes of brain injury. Four children were excluded from analysis due to incompatibility with the eye tracker (e.g., due to severe strabismus). The remaining ten children—including five non-verbal children—were tested multiple times over periods ranging from 2 weeks to 9 months, and all produced interpretable outcomes on at least three of the five visual tasks. The results suggest that our assessment tasks are viable in non-communicative children, provided their eyes can be tracked, and hence are promising tools for use in a larger clinical study. We highlight and discuss informative outcomes exhibited by each child, including directional biases in eye movements, pathological nystagmus, visual field asymmetries, and contrast sensitivity deficits. Our findings indicate that these methodologies will enable the rapid, objective classification and grading of visual impairments in children with CVI, including non-verbal children who are currently precluded from most vision assessments. This would provide a much-needed differential diagnostic and prognostic tool for CVI and other impairments of the visual system, both ocular and cerebral.

Residual Vision in Multiple Retinal Locations within a Scotoma: Implications for Blindsight

1997 ◽  
Vol 9 (2) ◽  
pp. 191-202 ◽  
Author(s):  
R. W. Kentridge ◽  
C. A. Heywood ◽  
L. Weiskrantz
Keyword(s):  
Eye Movements ◽  
Visual Field ◽  
Stimulus Display ◽  
Discrimination Performance ◽  
Saccadic Eye Movements ◽  
Lower Visual Field ◽  
Eye Tracker ◽  
Residual Vision ◽  
Fixation Stability ◽  
The Subject

There is an important new proposal that “blindsight”-the ability to detect and identify visual stimuli by forcedchoice guessing and in the absence of conscious awareness when they fall in blind regions of the visual field—is a function of residual “islands” of undamaged visual cortex. This stands in contrast to the widely accepted view that blindsight is exclusively a function of secondary visual pathways. According to the new view, residual vision in blindsight should be patchy. Thus, when apparently wide areas of residual vision in blindsight are found, these may be due to eye-movements that allow stimuli to pass over retinal locations corresponding to islands of sparing. We tested this hypothesis by examining the distribution of residual vision in blindsight when the effects of eye movements on the retinal location of stimuli were minimized. We report a series of experiments that examined twealternate forcedchoice discrimination in the blind field of the subject GY. Using a dual-Purkinje image eye-tracker we applied three methods of minimizing the effects of retinal slippage due to eye-movements on discrimination performance: fixation stability-dependent trials, software image stabilization, and post hoc rejection of trials in which saccadic eye-movements were detected. In the first experiment, GY's discrimination performance was significantly above chance in 8 of 15 locations tested. In the subsequent experiments the subject knew the location of the target in each block of trials, and this resulted in improvements to performance in a further three locations. Increasing the luminance of the stimulus display (while maintaining 95% target contrast), and increasing the temporal discriminability of the forced choice produced performance above chance in all but two of the locations tested. The consistent chance performance observed in two locations in the lower visual field nevertheless implies that GY's blindsight does not extend over the whole of his scotoma. Nevertheless, abolishing, or minimizing, the effects of eye-movements did not result in a loss of detection in all the widely separated regions tested, and we thus conclude that GY's blindsight cannot adequately be explained in terms of islands of spared vision. Islands may account for residual vision in scotomata in some patients, but cannot be a universal account of the phenomenon of blindsight.

Eye tracker outcomes in a randomized trial of 40 sessions of hyperbaric oxygen or sham in participants with persistent post concussive symptoms

2019 ◽  
pp. 299-311
Author(s):  
Paul A. Wetzel ◽  
◽  
Anne S. Lindblad ◽  
Caroline Mulatya ◽  
Mary A. Kannan ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Eye Movements ◽  
Brain Injury ◽  
Hyperbaric Oxygen ◽  
Mild Traumatic Brain Injury ◽  
Smooth Pursuit ◽  
Tracking System ◽  
Eye Tracker ◽  
Normative Study

Purpose: Eye movements may offer a sensitive method to measure response to intervention in mild traumatic brain injury (mTBI). Methods: The Brain Injury and Mechanisms of Action of Hyperbaric Oxygen for Persistent Post-Concussive Symptoms after Mild Traumatic Brain Injury Study (BIMA) randomized 71 participants to 40 sessions of hyperbaric oxygen or sham. A companion normative study (Normal) enrolled 75 participants. An eye tracking system measured left and right eye movements for saccadic and smooth pursuit. At baseline two smooth pursuit tasks, circular and horizontal ramp, and four saccadic tasks, horizontal and vertical step, reading, and memory guided-on tasks differentiated BIMA from Normal participants. The change from baseline in these tasks were measured and compared between interventions and against Normal participants at 13 weeks and six-month follow-up using the two-sample t-test. The Holm-Bonferroni procedure was used to adjust for multiple testing. Results: Change from baseline in eyetracker measures for participants assigned to the hyperbaric oxygen arm did not significantly differ from those assigned to the sham arm at post-randomization time points 13 weeks and six months. Consistent shifts of BIMA participant values toward Normal values at 13 weeks and six months were observed for overall fixation duration, forward saccadic duration, and number of lines read for the reading task, number of misses on the memory guided-on task, and absolute intersaccadic interval velocity and absolute saccadic amplitude on the circular task. The distributions between Normal and BIMA participants were no longer statistically significantly different at 13 weeks and six months post enrollment for these measures. Conclusions: The baseline differences between BIMA and Normal suggest potential vulnerability of the smooth pursuit system and the saccadic system. During the sixmonth follow-up period, improvement toward Normal was seen on some measures in both the hyperbaric oxygen and sham intervention arms without difference between intervention groups. clinicaltrials.gov Identifiers NCT01611194 and NCT01925963

scholarly journals Head and body structure infants’ visual experiences during mobile, naturalistic play

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242009
Author(s):  
Chuan Luo ◽  
John M. Franchak
Keyword(s):  
Eye Movements ◽  
Visual Field ◽  
Field Of View ◽  
Environmental Constraints ◽  
Body Structure ◽  
Eye Tracker ◽  
Physical Relation ◽  
Object Distance ◽  
Object Locations ◽  
The World

Infants’ visual experiences are important for learning, and may depend on how information is structured in the visual field. This study examined how objects are distributed in 12-month-old infants’ field of view in a mobile play setting. Infants wore a mobile eye tracker that recorded their field of view and eye movements while they freely played with toys and a caregiver. We measured how centered and spread object locations were in infants’ field of view, and investigated how infant posture, object looking, and object distance affected the centering and spread. We found that far toys were less centered in infants’ field of view while infants were prone compared to when sitting or upright. Overall, toys became more centered in view and less spread in location when infants were looking at toys regardless of posture and toy distance. In sum, this study showed that infants’ visual experiences are shaped by the physical relation between infants’ bodies and the locations of objects in the world. However, infants are able to compensate for postural and environmental constraints by actively moving their head and eyes when choosing to look at an object.

scholarly journals Teachers’ Professional Vision: Teachers’ Gaze During the Act of Teaching and After the Event

2021 ◽  
Vol 6 ◽  
Author(s):  
Eva Minarikova ◽  
Zuzana Smidekova ◽  
Miroslav Janik ◽  
Kenneth Holmqvist
Keyword(s):  
Eye Movements ◽  
Eye Tracking ◽  
Video Recording ◽  
Professional Vision ◽  
Eye Tracker ◽  
Gaze Behavior ◽  
Quantitative Correlation ◽  
Novel Approach ◽  
Verbal Data ◽  
The Moment

To date most of our knowledge on professional vision has relied on verbal data or questionnaires that used classroom videos as prompts. This has been used to tell us about a teacher’s professional vision. Recently, however, new studies explore professional vision during the act of teaching through the use of mobile eye-tracking. This novel approach poses the question: how do these two “professional visions” differ? Visual attention represented by gaze was used as a proxy to studying professional vision (specifically its noticing component). To achieve this, eye-tracking as a data collection method was used. We worked with three teachers and employed eye-tracking glasses to record teacher eye movements during teaching (4 lessons per teacher; labelled as IN mode). After each lesson, we selected short clips from the lesson recorded by a static camera aimed at pupils and showed them to the same teacher (i.e., providing a similar setting as traditional studies on professional vision) while recording eye movements and gaze behavior data through a screen-based eye-tracker (labelled as ON mode). The two modes differ and due to these differences, comparison is difficult. However, by overlaying them and describing them in detail we want to highlight the exact variance observed. A comparison between IN vs ON condition in terms of dwell time on the same students in either condition was made using both quantitative (correlation) and qualitative (timeline comparison) methods. The findings suggest that the greatest differences in attention given to individual pupils occur when a pupil who was interacted with during the situation is missing from the view in the video recording. Even though individual differences are present in the patterns of gaze in IN and ON modes, the teachers in our sample consistently monitored more pupils more often in the ON mode than in the IN mode. On the other hand, the IN mode was mostly characterized by focused gaze on the pupil that the teacher interacted with in the moment with few side glances. The results aim to open a discussion about our understanding of professional vision in different contexts and about how current research may need to expand its outlook.

Cognitive Processing of Film Cuts Among 4- to 8-Year-Old Children

2012 ◽  
Vol 17 (4) ◽  
pp. 257-265 ◽  
Author(s):  
Carmen Munk ◽  
Günter Daniel Rey ◽  
Anna Katharina Diergarten ◽  
Gerhild Nieding ◽  
Wolfgang Schneider ◽  
...  
Keyword(s):  
Eye Movements ◽  
Cognitive Processing ◽  
Media Literacy ◽  
Age Groups ◽  
Reaction Times ◽  
Time Span ◽  
Short Film ◽  
Calculation Formula ◽  
Eye Tracker ◽  
Chronological Sequence

An eye tracker experiment investigated 4-, 6-, and 8-year old children’s cognitive processing of film cuts. Nine short film sequences with or without editing errors were presented to 79 children. Eye movements up to 400 ms after the targeted film cuts were measured and analyzed using a new calculation formula based on Manhattan Metrics. No age effects were found for jump cuts (i.e., small movement discontinuities in a film). However, disturbances resulting from reversed-angle shots (i.e., a switch of the left-right position of actors in successive shots) led to increased reaction times between 6- and 8-year old children, whereas children of all age groups had difficulties coping with narrative discontinuity (i.e., the canonical chronological sequence of film actions is disrupted). Furthermore, 4-year old children showed a greater number of overall eye movements than 6- and 8-year old children. This indicates that some viewing skills are developed between 4 and 6 years of age. The results of the study provide evidence of a crucial time span of knowledge acquisition for television-based media literacy between 4 and 8 years.

Visual asymmetries during face encoding Increased dwell time and fixations in the upper and left hemifields

2018 ◽  
Author(s):  
Fatima Maria Felisberti
Keyword(s):  
Face Recognition ◽  
Eye Movements ◽  
Visual Field ◽  
Face Processing ◽  
Dwell Time ◽  
The Other ◽  
Environmental Cues ◽  
Reading Habits ◽  
The Right

Visual field asymmetries (VFA) in the encoding of groups rather than individual faces has been rarely investigated. Here, eye movements (dwell time (DT) and fixations (Fix)) were recorded during the encoding of three groups of four faces tagged with cheating, cooperative, or neutral behaviours. Faces in each of the three groups were placed in the upper left (UL), upper right (UR), lower left (LL), or lower right (LR) quadrants. Face recognition was equally high in the three groups. In contrast, the proportion of DT and Fix were higher for faces in the left than the right hemifield and in the upper rather than the lower hemifield. The overall time spent looking at the UL was higher than in the other quadrants. The findings are relevant to the understanding of VFA in face processing, especially groups of faces, and might be linked to environmental cues and/or reading habits.

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