Young Children's Larger Measured Visual Field Extent for Flickering Versus Non-Flickering Stimuli: Is It Simply a Preference for Flicker?

Abstract

Abstract: : Purpose. To investigate whether the larger measured visual field extent reported for flickering than for non-flickering stimuli in young children (Delaney et al, OVS, 2001; Mohan et al, ARVO 2002) is due to a simple preference for flickering over non-flickering stimuli that is present irrespective of the location of the stimulus within the visual field. Methods. 30 children (30 months of age) were tested binocularly using paired LED stimuli presented at 18° and at 59° eccentricity along the 45° (upper right) and 135° (upper left) arms of a black, double-arc perimeter. On each presentation, one stimulus flickered at 10 Hz and the other flickered at 40 Hz according to a pseudo-random order, with a total of 16 trials presented at each eccentricity. An observer, concealed behind a black curtain, viewed the child's face. Each trial began with the child fixating centrally, and ended when the observer indicated the direction of the child's first eye movement away from center. The percentage of trials on which the child looked at the 10-Hz stimulus was calculated for each location. Results. Children showed preferential looking toward the 10-Hz stimulus at both the 18° (71.3%, SD 16.0, p<0.001) and the 59° (60.2%, SD 12.4, p<0.001) eccentricities. However, a paired t-test showed that the preference for the 10 Hz stimulus was greater at 59° than at 18° (t(29)=3.14, p<0.01). Conclusions. These results suggest that the larger measured visual field extent that has been reported for flickering than for non-flickering stimuli in young children is not due to a simple preference for flickering stimuli. Sensory or attentional factors in the peripheral visual field also appear to be important.

Keywords: perimetry • visual development: infancy and childhood • visual fields