Quantitative Characterization of Smooth Pursuit Eye Movements in School-Age Children Using a Child-Friendly Setup

Oculomotor deficits in children with sensory processing difficulties

Background

Atypically developing children often present with a variety of sensory processing difficulties which have been proposed to reflect abnormal development of pathways integrating sensation and action. A brain system in which the process of sensorimotor integration is particularly well understood is the oculomotor system, but no studies to date have used computerised eye tracking to assess eye movements in children with sensory processing difficulties.

Method

Ten children with sensory processing difficulties completed a battery of oculomotor tasks comprising pro-saccades, anti-saccades, smooth pursuit tracking and sustained fixation. Eye movements were recorded using a high-resolution eye tracker.

Results

Compared to age-matched controls, children with sensory processing difficulties were found to make more directional errors in the anti-saccade task and less-accurate smooth pursuit and sustained fixation.

Conclusion

Consistent differences were found in oculomotor ability in children with sensory processing difficulties which are likely to impact children's ability to process and respond to visual information within home and school contexts. Further research is needed to understand the relationship between oculomotor deficits in children with sensory processing difficulties and the presence/absence of neurodevelopmental diagnoses. Eye tracking may be of value in the future for assessment and objective evaluation of interventions for sensory processing difficulties such as sensory integration therapy.

Oculomotor, vestibular, reaction time, and cognitive (OVRT-C) responses in 7- to 17-year-old children

Several aspects of oculomotor, vestibular, reaction time, and cognitive (OVRT-C) abilities improve throughout childhood at varying rates and become adult-like at different ages. However, developmental testing of these abilities often focuses on limited age ranges and does not elucidate clear developmental trajectories. The present study utilized high-resolution eye-tracking to evaluate 40 children aged 7-17 years on a comprehensive battery of OVRT-C tests to better understand how and when these abilities develop across childhood. As expected, mean responses on OVRT-C tests showed consistent improvement as subject age increased. We report a high prevalence of saccadic intrusions during smooth pursuit in children and adolescents, more self-paced saccades in older children, decreased auditory and visual RT with age, and fewer errors on the anti-saccade test in older children. We also used the Akaike information criterion (AIC) and Bayesian information criterion (BIC) modelling to determine whether a two- or three age group division would be most appropriate for each OVRT-C test. For all key OVRT-C metrics, our data support a separation of children into two age groups as opposed to three. While the age group divide varied by OVRT-C test, these data suggest these abilities mature at differing rates, and optimal separations into two age groups rather than three may reflect a slowing of rapid development as OVRT-C performance becomes more adult-like.

A Platform for Tracking Surgeon and Observer Gaze as a Surrogate for Attention in Ophthalmic Surgery

Purpose

To develop and validate a platform that can extract eye gaze metrics from surgeons observing cataract and vitreoretinal procedures and to enable post hoc data analysis to assess potential discrepancies in eye movement behavior according to surgeon experience.

Design

Experimental, prospective, single-center study.

Participants

Eleven ophthalmic surgeons observing deidentified vitreoretinal and cataract surgical procedures performed at a single university-based medical center.

Methods

An open-source platform was developed to extract gaze coordinates and metrics from ophthalmic surgeons via a computer vision algorithm in conjunction with a neural network to track and segment instruments and tissues, identifying areas of attention in the visual field of study subjects. Eleven surgeons provided validation data by watching videos of 6 heterogeneous vitreoretinal and cataract surgical phases.

Main Outcome Measures

Accuracy and distance traveled by the eye gaze of participants and overlap of the participants' eye gaze with instruments and tissues while observing surgical procedures.

Results

The platform demonstrated repeatability of > 94% when acquiring the eye gaze behavior of subjects. Attending ophthalmic surgeons and clinical fellows exhibited a lower overall cartesian distance traveled in comparison to resident physicians in ophthalmology (P < 0.02). Ophthalmology residents and clinical fellows exhibited more fixations to the display area where surgical device parameters were superimposed than attending surgeons (P < 0.05). There was a trend toward gaze overlap with the instrument tooltip location among resident physicians in comparison to attending surgeons and fellows (41.42% vs. 34.8%, P > 0.2). The number and duration of fixations did not vary substantially among groups (P > 0.3).

Conclusions

The platform proved effective in extracting gaze metrics of ophthalmic surgeons. These preliminary data suggest that surgeon gaze behavior differs according to experience.

Global-local consistency benefits memory-guided tracking of a moving target

INTRODUCTION

Previous findings have demonstrated that several Gestalt principles do facilitate VSTM performance in change detection tasks. However, few studies have investigated the role of and time-course of global-local consistency in motion perception.

METHODS

Participants were required to track a moving target surrounded by three different backgrounds: blank, inconsistent, or consistent. Global-local objects were be bound to move together (covariation). During the PMT, participants had to follow the moving target with their eyes and react as fast as possible when the target had just vanished behind the obstruction or would arrive at a predetermined point of interception. Variable error (VE) and constant error (CE) of estimated time-to-contact (TTC) and gain of smooth pursuit eye movements were calculated in various conditions and analyzed qualitatively.

RESULTS

Experiment 1 established the basic finding that VSTM performance could benefit from global-local consistency. Experiment 2 extended this finding by eye-tracking device. Both in visible phase and in occluded phase, CEs were smaller for the target in a consistent background than for the target in an inconsistent background and for the target in a blank background, with both differences significant (ps < .05). However, the difference in VE among three conditions was not significant. At early stage (100-250 ms), later stage (2750-3000 ms), and termination stage (5750-6000 ms) of smooth pursuit, the velocity gains were higher in the trials with consistent backgrounds than in the trials with inconsistent backgrounds and blank backgrounds (ps < .001). With the exception of 100-250 ms phase, the means did not differ between the inconsistent background and the blank background trials (ps > .1).

CONCLUSIONS

Global-local consistency could be activated within the first few hundred milliseconds to prioritize the deployment of attention and eye movement to component target. Meanwhile, it also removes ambiguity from motion tracking and TTC estimation under some unpredictable conditions, leading to the consistency advantage during smooth-pursuit termination phase. Global-local consistency may act as an important information source to TTC estimation and oculomotor response in PMT.

Traumatic Brain Injury in Children: Do the Eyes Have It? The Orthoptic Evaluation of Traumatic Brain Injury

Because the neuropathological changes caused by mild traumatic brain injury (mTBI) more often manifest as functional impairments than structural abnormalities, the clinical diagnosis of mTBI may rely too heavily on a combination of history and self-reported symptoms. The mechanism of injury in mild traumatic brain injury (mTBI) predicts that supranuclear pathways controlling eye movement systems would be vulnerable to damage, and diagnostic tests of these systems would be high-yield. In fact, tests of oculomotor function have proven to be highly sensitive in detecting neurological soft signs, but may require expensive, specialized equipment. Fortunately, Certified Orthoptists (COs) are skilled at the evaluation of accommodative dysfunction, abnormalities of saccades, smooth pursuit, and vestibular eye movements, and vergence errors using standard ophthalmic equipment. Because COs are accustomed to adapting the sensorimotor exam to infants and pre-verbal children, they are able to modify or design objective methods, the results of which may be difficult for the patient with a functional overlay to decipher and deceive. When the patient with a history of mTBI presents to the ophthalmologist with visual symptoms and a normal routine eye exam, it is important to order a sensorimotor examination by a CO to confirm the diagnosis.