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T McCarthy, EL Irving; Effect of Stimulus Type on Eye Movement Performance and Dynamics in Young Children . Invest. Ophthalmol. Vis. Sci. 2002;43(13):4666.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To determine if age appropriate pictures elicit superior performance on saccade and pursuit tasks in children compared with conventional dots or spots of light. Methods: Eye position data was collected from 27 children ranging in age from 3 to 12 years using the El-Mar 2020, video-based eye tracker, sampling at 120Hz. Participants were instructed to follow a dot or picture as it jumped (saccades) or traveled (pursuits) across the screen. The order of stimulus presentation was randomized for the collection of saccade and pursuit recordings. Saccades differed in jump size, ranging from 5-30 degrees in the horizontal direction. Pursuit velocities ranged from 5-30 degrees/second along the horizontal meridian. All targets subtended approximately 1 degree and were viewed from a distance of 2 metres. The saccadic latency, accuracy, peak velocity, and response rate were determined as was pursuit gain. Results: Younger subjects more frequently (60% increase for 3 & 4 yr olds) made saccades in response to pictures than to dots. As well saccadic amplitude gains were higher (0.93 vs. 0.83 in children <7 yrs) for all step sizes with pictures and latencies were shorter (236msec vs. 298msec) compared with dots. The peak velocity vs. amplitude relationship was very similar for the two stimulus types. Pursuit gain was higher (1.01 vs. 0.82 in children ≤7yrs) for picture stimuli over a range of target velocities. Between 7 and 9 years of age, performance between the two stimuli becomes similar for all parameters tested with the exception of saccadic latency, which remains shorter for pictures even in the oldest children tested. Conclusion: In order to achieve optimum eye movement performance in young children it is important to use age appropriate meaningful targets. Studies, which do not use such targets, will underestimate the oculomotor capabilities of this population.
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