Saccades In Children Research Articles

Characterization of vision in pediatric retinoblastoma survivors beyond visual acuity

Retinoblastoma (RB) and its associated treatments can significantly impact visual acuity. However, little is known regarding other measures of vision, such as contrast sensitivity or saccades. The aim of this study was to describe contrast sensitivity and saccades in children treated for retinoblastoma. This cross-sectional study included children aged 5-17 years who had completed treatment for RB. Visual acuity, saccades via fixation analysis, and contrast sensitivity by Cardiff contrast sensitivity were assessed, and multivariable linear regression was performed. Eleven children were enrolled (mean age, 10.7 ± 3.9 years). Treatment included enucleation (8 children [73%]) and chemotherapy (10 [91%]). Of the 11, one participant was unable to complete testing of saccades, and another was unable to complete contrast sensitivity testing. Decreased saccade parameters (velocity, latency, or accuracy) and impaired contrast sensitivity were observed in all 10 participants who underwent visual testing. Multivariable analysis revealed that worse logMAR visual acuity (B, -4.54 [-6.8, -2.2]; P = 0.004) and bilateral disease (B, -3.9 [-6.4, -1.4]; P = 0.009) were associated with worse contrast sensitivity. Germline disease was associated with decreased vertical saccade accuracy (P = 0.02). Decreased contrast sensitivity and impaired saccades were universally observed in this cohort of RB survivors. Comprehensive visual evaluation should be considered for all RB survivors to provide optimal rehabilitative services for these patients.

Objective and Subjective Evaluation of Saccadic Eye Movements in Healthy Children and Children with Neurodevelopmental Disorders: A Pilot Study

The objective of this study was to characterize saccades in children with neurodevelopmental disorders (NDDG, 17 children, age: 7–12 years) and compare them with a control group (CG, 15 children, age: 7–12 years), comparing the outcomes obtained with a subjective score system (Northeastern State University College of Optometry’s Oculomotor test, NSUCO) with the objective analysis obtained through a commercially available Eye Tracker (Tobii Eye X, Tobii, Stockholm, Sweden) and a specialized software analysis (Thomson Software Solutions, Welham Green, UK). Children from the NDDG obtained significantly lower NSUCO scores (p < 0.001) compared with CG. Concerning eye tracking analyses, we found a significantly higher number of hypometric saccades in NDGG (p ≤ 0.044). Likewise, we found a significantly higher percentage of regressions in the NDDG for a time interval of presentation of stimuli of 1 s (p = 0.012). Significant correlations were found between different NSUCO scores and percentage of regressions, number of saccades completed and number of hypometric saccades. The presence of hypometric saccades and regressions seems to be a differential characteristic sign of children with neurodevelopmental disorders that can be detected using an objective eye tracking analysis, but also using the subjective test NSUCO that can be easily implemented in all clinical settings.

Латентный период зрительновызванных саккад у детей 2–9 лет

Латентный период зрительновызванных саккад у детей 2–9 лет

A Normative Study of Objective Measures of Disparity Vergence and Saccades in Children 9 to 17 Years Old

This study establishes normative data for objective outcome measures of vergence and saccade eye movements for the pediatric population. These data should facilitate future clinical trial design. This study was designed to establish normative data for objective measures of disparity vergence and saccades in children between the ages 9 and 17 years using an objective binocular eye movement tracking system. Participants (aged 9 to 17 years) had a vision examination including refraction, accommodative, and binocular vision testing. Eligibility criteria included 20/25 visual acuity with best correction, normal accommodation, and binocular vision. The ISCAN RK-826PCI binocular tracking system (ISCAN, Woburn, MA) was used to objectively record horizontal, symmetrical disparity vergence, and saccadic eye movements. Parameters assessed included peak velocity, time to peak velocity, latency, and response amplitude for both disparity vergence and saccades. One hundred eighteen participants were recruited (54.94% female; mean age, 13.5 years), and 77.1% (91/118) of the participants completed the assessment with usable data. A sample of the normative data included peak velocity (°/s), which had a mean ± standard deviation of 25.4 ± 2.9, 22.0 ± 3.0, 225 ± 16.7, and 332.5 ± 20.5 for 4° convergence, 4° divergence, 5° saccades, and 10° saccades, respectively. The mean ± standard deviation for the latency (seconds) measures were 0.28 ± 0.1, 0.28 ± 0.16, 0.23 ± 0.05, and 0.23 ± 0.05 for 4° convergence, 4° divergence, 5° saccades, and 10° saccades, respectively. Normative data enable researchers to have benchmark results for comparison with patient populations with binocular dysfunction. These objective disparity vergence measures can serve as outcome measures in future clinical trials to assess the effectiveness of therapeutic interventions by determining whether post-treatment results are similar to normal data.

Visual working memory performance based on fixations and saccades in children with and without specific learning disorder: An eye-tracking study

Visual working memory performance based on fixations and saccades in children with and without specific learning disorder: An eye-tracking study

Predictive saccades in children and adults: A combined fMRI and eye tracking study.

Saccades were assessed in 21 adults (age 24 years, SD = 4) and 15 children (age 11 years, SD = 1), using combined functional magnetic resonance imaging (fMRI) and eye-tracking. Subjects visually tracked a point on a horizontal line in four conditions: time and position predictable task (PRED), position predictable (pPRED), time predictable (tPRED) and visually guided saccades (SAC). Both groups in the PRED but not in pPRED, tPRED and SAC produced predictive saccades with latency below 80 ms. In task versus group comparisons, children’s showed less efficient learning compared to adults for predictive saccades (adults = 48%, children = 34%, p = 0.05). In adults brain activation was found in the frontal and occipital regions in the PRED, in the intraparietal sulcus in pPRED and in the frontal eye field, posterior intraparietal sulcus and medial regions in the tPRED task. Group–task interaction was found in the supplementary eye field and visual cortex in the PRED task, and the frontal cortex including the right frontal eye field and left frontal pole, in the pPRED condition. These results indicate that, the basic visuomotor circuitry is present in both adults and children, but fine-tuning of the activation according to the task temporal and spatial demand mature late in child development.

Saccadic Adaptation in 10-41 Month-Old Children.

When saccade amplitude becomes systematically inaccurate, adaptation mechanisms gradually decrease or increase it until accurate saccade targeting is recovered. Adaptive shortening and adaptive lengthening of saccade amplitude rely on separate mechanisms in adults. When these adaptation mechanisms emerge during development is poorly known except that adaptive shortening processes are functional in children above 8 years of age. Yet, saccades in infants are consistently inaccurate (hypometric) as if adaptation mechanisms were not fully functional in early childhood. Here, we tested reactive saccade adaptation in 10–41 month-old children compared to a group of 20–30 year-old adults. A visual target representing a cartoon character appeared at successive and unpredictable locations 10° apart on a computer screen. During the eye movement toward the target, it systematically stepped in the direction opposite to the saccade to induce an adaptive shortening of saccade amplitude (Experiment 1). In Experiment 2, the target stepped in the same direction as the ongoing saccade to induce an adaptive lengthening of saccade amplitude. In both backward and forward adaptation experiments, saccade adaptation was compared to a control condition where there was no intrasaccadic target step. Analysis of baseline performance revealed both longer saccade reaction times and hypometric saccades in children compared to adults. In both experiments, children on average showed gradual changes in saccade amplitude consistent with the systematic intrasaccadic target steps. Moreover, the amount of amplitude change was similar between children and adults for both backward and forward adaptation. Finally, adaptation abilities in our child group were not related to age. Overall the results suggest that the neural mechanisms underlying reactive saccade adaptation are in place early during development.

Up/down anisotropies of vertical saccades in healthy children depending on the mode and the depth of execution

While the overall development of saccades in children has recently gained increasing interest, the precise characteristics of vertical saccades remain understudied. The few adult studies existing showed up/down anisotropies on various parameters. This study focuses on the development of vertical saccades and their interaction with vergence movements, according to the mode of initiation of the saccades (automatic and controlled). Eighty six children (9.57±3.15years) performed vertical saccades with an eccentricity of 7.5°, at 40cm and at 150cm viewing distance, in a gap paradigm – automatic saccades – and in an overlap paradigm – more voluntary or controlled saccades. Task and direction effects: latency was overall longer in the overlap than in the gap task, duration was longer for upward than downward saccades, conjugate vertical drift was larger after upward than downward saccades, horizontal vergence was higher during and after downward than upward saccades. Age effects: For upward saccades, amplitude, mean and peak velocity of upward saccades increased with age, while the vertical conjugate drift after downward saccades at far distance decreased with age; for downward saccades in the overlap task, the horizontal convergence increased with age concomitantly with an increase of the duration. The results are discussed in the context of hypothetical differential circuits of automatic and controlled saccades maturing progressively in children and interacting with direction (up/down). We suggest that the up/down asymmetries, more pronounced in the overlap task, are built progressively in mutual interaction with a perceptive peripheral bias, up being perceived as far and down as near.

Abnormal Fixational Eye Movements in Amblyopia.

PurposeFixational saccades shift the foveal image to counteract visual fading related to neural adaptation. Drifts are slow eye movements between two adjacent fixational saccades. We quantified fixational saccades and asked whether their changes could be attributed to pathologic drifts seen in amblyopia, one of the most common causes of blindness in childhood.MethodsThirty-six pediatric subjects with varying severity of amblyopia and eleven healthy age-matched controls held their gaze on a visual target. Eye movements were measured with high-resolution video-oculography during fellow eye-viewing and amblyopic eye-viewing conditions. Fixational saccades and drifts were analyzed in the amblyopic and fellow eye and compared with controls.ResultsWe found an increase in the amplitude with decreased frequency of fixational saccades in children with amblyopia. These alterations in fixational eye movements correlated with the severity of their amblyopia. There was also an increase in eye position variance during drifts in amblyopes. There was no correlation between the eye position variance or the eye velocity during ocular drifts and the amplitude of subsequent fixational saccade. Our findings suggest that abnormalities in fixational saccades in amblyopia are independent of the ocular drift.DiscussionThis investigation of amblyopia in pediatric age group quantitatively characterizes the fixation instability. Impaired properties of fixational saccades could be the consequence of abnormal processing and reorganization of the visual system in amblyopia. Paucity in the visual feedback during amblyopic eye-viewing condition can attribute to the increased eye position variance and drift velocity.

Up/Down Anisotropies of Vertical Saccades in Healthy Children From 6 to 10 Years of Age

Although the overall development of saccades in children has recently gained increasing interest, the precise characteristics of vertical saccades remain understudied. This study focused on the development of vertical saccades and their interaction with vergence movements. Thirty-one children (mean age: 7.33 ± 0.21 years) performed vertical saccades with an eccentricity of 7.5° at 40 and 150 cm viewing distance, in a simultaneous paradigm (simultaneous offset of central dot and onset of peripheral target). The results revealed shorter latency, more vertical conjugate postsaccadic drift after upward saccades, and less horizontal vergence during and after upward saccades in children. Furthermore, the intrasaccadic convergence decreased progressively with children's age for upward saccades. Relative to adult behavior, children present more hypometric saccades, longer latencies, higher vertical disconjugacy, and a different pattern of horizontal vergence during vertical saccades. This result suggests that up/down asymmetries are built progressively in mutual interaction with a perceptive peripheral bias such as up being perceived as far and down as near.

Vertical saccades in children: a developmental study

There are no studies exploring the development of vertical saccades in large populations of children. In this study, we examined the development of vertical saccades in sixty-nine children. Binocular eye movements were recorded using an infrared video oculography system [Mobile EBT(®), e(ye)BRAIN], and movements from both eyes had been analyzed. The gain and the peak velocity of vertical saccades show an up-down asymmetry. Latency value decreases with the age of children, and it does not depend on the direction of the saccades; in contrast, the gain and the peak velocity values of vertical saccades are stable during childhood. We suggest that the up-down asymmetry is developed early, or is innate, in humans. Latencies of vertical saccades develop with the age of children, in relationship with the development of the cortical network responsible for the saccade preparation. In contrast, the precision and the peak velocity are not age-dependent as they are controlled by the cerebellum and brainstem structures.

Saccadic eye movements in children: a developmental study

To our knowledge, there are no studies exploring the development of voluntary and reflexive saccades in children using different types of paradigms to investigate horizontal saccades. In the present study, we examined the development of horizontal saccades in children aged 6-15 years. Binocular eye movements were recorded using an infrared video-oculography system (mobileEBT(®), e(ye)BRAIN) in seventy-two children (aged 6-15). Several paradigms were used to stimulate reflexive and voluntary horizontal saccades: gap, step and overlap paradigms. Horizontal anti-saccades were also examined. In all paradigms, the latency of saccades decreased with the age of children and it did not depend on the direction of the saccades (left/right); the error rate in the anti-saccade task decreased with age; the gain of horizontal saccades improved with age; the peak velocity of horizontal saccades was stable throughout childhood. We conclude that saccadic performances are influenced by age and cortical circuits responsible for the preparation of reflexive or voluntary saccades are completed at 12 years old. These data could be used as reference values for further studies dealing with pathologic development.

Binocular coordination of saccades in children with vertigo: Dependency on the vergence state

The present study examines the quality of binocular coordination of saccades at far and near distance in 15 children with symptoms of vertigo headache and equilibrium disorders; these children show normal vestibular function but abnormal convergence eye movements (e.g., long time preparation, slow execution and poor accuracy, see Bucci, Kapoula, Yang, Bremond-Gignac, & Wiener-Vacher, 2004a, 2004b). The results show normal binocular saccade coordination at far distance, but large abnormal disconjugacy for saccades at near distance. During combined saccade–vergence movements (studied in six of these children), convergence remains abnormally slow. This supports the interpretation according to which poor binocular yoking of the saccades is linked to the reduced ability to produce fast convergence during the saccade; a learning mechanism based on rapid vergence would help to reduce the abducting–adducting asymmetry of the saccades. An alternative interpretation would be reduced learning ability for monocular adjustment of the saccade signals.

Saccades in children

Saccades are necessary for optimal vision. Little is known about saccades in children. We recorded saccades using an infrared eye tracker in 39 children, aged 8–19 years. Participants made saccades to visual targets that stepped 10° or 15° horizontally and 5° or 10° vertically at unpredictable time intervals. Saccadic latency decreased significantly with increasing age, while saccadic gain and peak velocity did not vary with age. Saccadic gains and peak velocities in children are similar to reported adult values. This implies maturity of the neural circuits responsible for making saccades accurate and fast. Saccade latency decreases as the brain matures.

Saccades in children with spina bifida and Chiari type II malformation

Saccades are essential for optimal visual function. Chiari type II malformation (CII) is a congenital anomaly of the cerebellum and brainstem, associated with spina bifida. To investigate the effects of CII on saccades and correlate saccadic parameters with brain MRI measurements. Saccades were recorded in 21 participants with CII, aged 8 to 19, using an infrared eye tracker. Thirty-nine typically developing children served as controls. Participants made saccades to horizontal and vertical target steps. Nineteen participants with CII had MRI. Regression analyses were used to investigate the effects of spinal lesion level, number of shunt revisions, presence of nystagmus, and midsagittal MRI measurements on saccades. Saccadic amplitude gains, asymptotic peak velocities, and latencies did not differ between the control and CII groups (p > 0.01). No significant differences were found between saccadic gains, asymptotic peak velocities or latencies, and spinal lesion level, number of shunt revisions, presence of nystagmus, or MRI measurements. Saccades were normal in most participants with Chiari II malformation (CII). Neural coding of saccades is robust and is typically not affected by the anatomic deformity of CII.

Influence of gap and overlap paradigms on saccade latencies and vergence eye movements in seven-year-old children

The latency of eye movements is influenced by the fixation task; when the fixation stimulus is switched off before the target presentation (gap paradigm) the latency becomes short and express movements occur. In contrast, when the fixation stimulus remains on when the target appears (overlap paradigm), eye movement latency is longer. Several previous studies have shown increased rates of express saccades in children; however the presence of an express type of latency for vergence and combined movements in children has never been explored. The present study examines the effects of the gap and the overlap paradigms on horizontal saccades at far (150 cm) and at close (20 cm) viewing distances, on vergence along the median plane, and on saccades combined with convergence or divergence in 15 normal seven-year-old children. The results show that the gap paradigm produced shorter latency for all eye movements than the overlap paradigm, but the difference was only significant for saccades at close viewing distances, for divergence (pure and combined), and for saccades combined with vergence. The gap paradigm produced significantly higher rates of express latencies for saccades at close viewing distances, for divergence, and for saccades combined with divergence; in contrast, the frequencies of express latencies for saccades at far viewing distances and for convergence (pure or combined) were similar in the gap and the overlap paradigms. Interestingly, the rate of anticipatory latencies (<80 ms) was particularly high for divergence in the gap paradigm. Our collective findings suggest that the initiation of saccades at close viewing distances and of divergence is more reflexive, particularly in the gap paradigm. The finding of frequent anticipatory divergence that occurs at similar rates for seven-year-old children (this study) and for adults (Coubard et al., 2004, Exp Brain Res 154:368-381) indicates that predictive initiation of divergence is dominant.

OPL018 Saccades in children

OPL018 Saccades in children

Association of binocular lower visual field impairment, impaired simultaneous perception, disordered visually guided motion and inaccurate saccades in children with cerebral visual dysfunction-a retrospective observational study.

The principal pathways serving higher visual function comprise the dorsal stream and the ventral stream. The dorsal stream runs between the occipital lobes and the parietal lobes and subserves the ability to process the whole visual scene and carry out visually guided movement. The ventral stream runs between the occipital lobes and temporal lobe tissue and primarily subserves visual recognition and memory. These tissues are susceptible to dysfunction in children with brain damage. We report a series of 40 children in whom damage to the brain has led to a common symptom complex affecting vision. Lower visual field loss was frequently elicited. This was associated with impaired ability to make accurate visually guided movement (particularly of the lower limbs) accompanied by impaired simultaneous perception, and in some cases, with inaccurate saccades and in others, impaired perception of movement. These features are consistent with parietal/dorsal stream dysfunction. Difficulty recognising faces and problems with route finding (which are ventral stream functions) were also present in a number of the children. These visual difficulties can be manifest in the presence of normal visual acuity. Recognition of these problems leads to understanding of the child's visual difficulties and facilitates adaptation of curriculum delivery at school.

Abnormalities of voluntary saccades in Gilles de la Tourette's syndrome: pathophysiological consideration

Gilles de la Tourette's syndrome (TS) is a neurobehavioral disorder. Although the etiology and the pathophysiology of TS are still unknown, the involvement of the basal ganglia has long been postulated. On the other hand, saccadic eye movement was shown to be a useful measure to assess order and disorder of the function of the basal ganglia. To investigate the dysfunction of the basal ganglia of TS, we examined voluntary saccades in children with TS in comparison with the saccades in age-matched control children. Two kinds of saccades, visually-guided saccades (VGS) and memory-guided (MGS) saccades were evaluated. During the MGS, distracted saccades (DS), which indicate the distractibility, were examined. The results revealed the abnormalities in the parameters of the MGS, i.e. longer latencies and hypometric amplitudes, and decrease in the frequency of MGS. Whereas, the frequency of DS, the saccade to the predicted cue was significantly lower in younger patients (6−<9-years) than normal, but it was higher in the older TS children (9−<12-years). In addition, some of the patients showed large involuntary saccades, usually associated with eye blinks, during the task performance. These results suggest that in TS the basal ganglia fails to disinhibit the saccade neuron in the superior colliculus with the input of the frontal eye field to the striatum, and later allow the neurons to evoke non-goal directed saccades. In reference to abnormal saccades in other basal ganglia disorders with dopamine deficiency and to animal experiments with MPTP monkeys, these findings postulate primary hypodopaminergic state followed by upward regulation of dopamine receptors later in TS.

Adaptive control of saccades in children with dancing eye syndrome.

Adaptive control of saccades in children with dancing eye syndrome.