Visual accommodation variations during trans-atlantic cockpit duties

Twenty airline pilots measured their near point of accommodation employing a modified Princes' Rule. Measurements were performed periodically travelling east- and west-bound. Five clerical control subjects performed the same measurements over 2 consecutive days. The ranges of variability of the nearpoint of accommodation were compared between the two groups, directions and days. No statistically significant differences in the variability of accommodation were found in the comparisons.