Up/down anisotropies of vertical saccades in healthy children from 6 to 10 years of age.

Purpose: Although the overall development of saccades in children has recently gained increasing interest, the precise characteristics of vertical saccades remain understudied. This study focused on the development of vertical saccades and their interaction with vergence movements.

Methods: Thirty-one children (mean age: 7.33 ± 0.21 years) performed vertical saccades with an eccentricity of 7.5° at 40 and 150 cm viewing distance, in a simultaneous paradigm (simultaneous offset of central dot and onset of peripheral target).

Results: The results revealed shorter latency, more vertical conjugate postsaccadic drift after upward saccades, and less horizontal vergence during and after upward saccades in children. Furthermore, the intrasaccadic convergence decreased progressively with children's age for upward saccades. Relative to adult behavior, children present more hypometric saccades, longer latencies, higher vertical disconjugacy, and a different pattern of horizontal vergence during vertical saccades.

Conclusions: This result suggests that up/down asymmetries are built progressively in mutual interaction with a perceptive peripheral bias such as up being perceived as far and down as near.