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Latency of Visually Guided Saccades in Children Aged 2–9 Years

A great number of studies on saccades in children deal with neuropathology, while much less is known about saccades in healthy children. This research aimed to explore the yearly latency and the gap-effect characteristics of horizontal and vertical (both centrifugal and centripetal) visually guided saccades in healthy children. The study involved 418 subjects aged between 2 and 9 years. This age range was chosen due to the fact that during this postnatal period the processes of neuronal differentiation are most intensive. The RED250mobile eye tracker was used to record saccadic eye movements. The target saccade amplitude was 4.5° in response to dot stimuli in the Step and Gap paradigms. A correlation was found between the child ʼ s age and the parameters of centripetal saccades, while no age effect was identified for centrifugal saccades between 2 and 9 years. The parameters of centrifugal saccades remain stable between the age of 2 and 9 years. The vertical and horizontal saccades showed no statistically significant differences in latency and gap-effect. This indicates a parallel development of structures mediating vertical and horizontal saccades between 2 and 9 years. Asymmetry was observed in the groups of 7–9-year-olds (in vertical centrifugal saccades) and in 6-year-olds (horizontal saccades). This asymmetry could be caused by the heterochronic development of different oculomotor areas in the brain. Our results can contribute to the study of age-related saccadic dynamics and help to create a saccadic control database.