Quantification of gaze reaction time in infants with Pediatric Perimeter

Purpose We quantified the eye/head (gaze) reaction time in infants to establish a normative database for the Pediatric Perimeter device. Additionally, we tested the hypothesis that gaze reaction time will reduce with age. Methods A cross-sectional study was conducted. Healthy infants between 3 to 10 months of age were recruited. Peripheral visual field stimuli (hemifield and quadrant stimuli) were presented in the Pediatric Perimeter device. Infant's gaze to these stimuli was observed, documented in real time, and video recorded for offline analysis. Results A total of 121 infants were tested in three age group bins [3-5 months, n = 44; >5-7 months, n = 30 and >7-10 months, n = 47]. Overall, 3-5 months old had longer reaction time when compared to the older infants particularly for stimuli presented in the quadrants (Kruskal- Wallis, p<0.038). A significantly asymmetric difference (p = 0.025) in reaction time was observed between the upper (median = 820ms, IQR = 659-1093ms) and lower quadrants (median = 601ms, IQR = 540-1052ms) only for the 3-5 months old infants. Conclusion This study provides the normative gaze reaction time of healthy infants. With increase in age, there is reduction in reaction time and disappearance of reaction time asymmetry in quadrant stimuli. The longer reaction time for upward gaze could be due to delayed maturation of neural mechanisms and/or decreased visual attention.