Vergence dynamics and variability of fixation disparity in children and adults

With dichoptic nonius lines presented repetitively on a computer monitor for only short moments in time (e.g., 80 ms), temporal aspects of vergence can be assessed: the variability of fixation disparity with a stationary central fusion stimulus and the velocity of convergence or divergence changes. Results and test-retest correlations of these psychophysical vergence measures are shown for children and adults. In most children older than about 7 years, the estimation of vergence velocity turned out as well as in adults in terms of amount and reliability.