Developmental characteristics of visual cognitive function during childhood according to exploratory eye movements

To evaluate the development of visual cognitive function in childhood, we examined exploratory eye movements in 84 healthy subjects viewing picture-based stimuli. Age-defined groups included 4- to 6-year-olds, 7-year-olds, 10-year-olds, 14-year-olds, 16-year-olds, and adults. In each group, 7 subjects were male and 7 were female. Exploratory eye movements, recorded as gaze points using an eye-mark recorder, were analyzed in terms of the total number of gaze points (TNGP); total eye-scanning length of gaze points (TESL); total number of gaze points on the left (l TNGP) and right (r TNGP) of the screen; and responsive search score (RSS) on the left (l RSS) and right (r RSS) of the screen. Both the TESL and TNGP increased significantly with age. The TESL and TNGP of 16-year-olds and adults viewing a repeat-comparison figure were significantly greater than when viewing a comparison figure. During the repeat-comparisons, the TNGP in 4- to 6-year-olds was greater on the right than the left; the opposite was true in 16-year-olds and adults. The RSS in 4- to 10-year-olds was greater on the right than the left; 16-year-olds and adults showed the reverse findings. Thus, in the repeat-comparison task, TNGP, TESL, TNGP, and RSS differences between left and right visual fields are useful biologic markers for estimating the development of visual cognitive function.