Acuity for vertical (black symbols), horizontal (white symbols), and oblique (gray symbols) gratings for children in the non-astigmatic (NonA, n=468), hyperopic astigmatism (HA, n=152), and myopic/mixed astigmatism (M/MA, n=166) groups. Bars indicate ± 1 SEM. For all three orientations, mean acuity in the NonA group was significantly better than mean acuity in the HA and M/MA groups (ps < 0.001). In comparison to results from the NonA group, both the HA and M/MA groups showed evidence of MA (ps < 0.001), with the HA group showing better acuity for horizontal than for vertical gratings, and the M/MA group showing better acuity for vertical than for horizontal gratings.