For distant stimuli, there were significant main effects of task (
P = 0.001, better accuracy, i.e., mean closer to −0.50 D, in the THTR and AATR conditions than in the VV condition), amount of astigmatism (
P < 0.001, all pairwise comparisons significant, with best accuracy in the no/low astigmatism group and poorest accuracy in the high astigmatism group), and amount of accommodative demand (
P < 0.001, subjects with lower demand more accurate) (
Table 3;
Fig. 2). In addition, there were significant interactions between task and amount of astigmatism (
P = 0.003), amount of accommodative demand and amount of astigmatism (
P < 0.001), and task and amount of accommodative demand (
P < 0.001). Post hoc analyses indicated that in all three astigmatism groups, accuracy was better in the two text-reading conditions (THTR, AATR) than in the VV condition (
Table 3, right columns). However, as astigmatism increased, the difference in accuracy between the text-reading conditions and the VV condition increased. There were no subjects who met the criteria for the high astigmatism and low-demand group. However, in both no/low and moderate astigmatism groups, accuracy was better in subjects with low accommodative demand, but the difference in accuracy between low- and high-demand subjects increased with increasing astigmatism (difference of 0.32 vs. 0.90 D in no/low versus moderate astigmatism groups, respectively) (
Table 3, bottom section). Finally, for both the low- and high-demand groups, there were significant differences in M
nc for all pairwise comparisons between tasks, with greater differences in accuracy between the text-reading (THTR, AATR) and VV conditions. However, reduced accuracy in the VV condition (compared with text-reading conditions) was greater in the high-demand group than in the low-demand group.