Influence of Screen Exposure on Vergence Components from Childhood to Adolescence

The goal of our study is to explore the impact of screen exposure on vergence components in children. Sixty-eight healthy children (aged from 5.4 to 16 years old) were studied. We recorded vergence components (near point of convergence, heterophoria at far and near distances, fusional amplitudes of convergence and divergence at far and near distances, AC/A ratio). We reported the time spent in front of screens at near and far distance per day. NPC value is 1.87 ± 1.05 cm. Phoria at far is -0.29 ± 0.21 pD. Phoria at near is -3.00 ± 0.45 pD. Fusional amplitudes are as follows: convergence at far is 18.72 ± 0.73 pD; convergence at near is 38.16 ± 0.98 pD; divergence at far is 4.76 ± 0.19 pD; divergence at near is 17.01 ± 0.33 pD. AC/A ratio is 2.35 ± 0.08. Amplitude of divergence and convergence at near distance decreased significantly with age, while other vergence components did not vary. The time spent in front of screens at near distance increased significantly with age. There is a significant correlation between the amplitudes of convergence and exposure time to screens (both at near distance). Our study, beside reporting precise normative vergence data in children, suggests that near distance activity could possibly allow older children to have better vergence accuracy at near distance and a smaller range of vergence amplitude as a possible consequence of visual training.