Non-astigmatic children's contrast sensitivities differ from anisotropic patterns of adults

Monocular contrast thresholds were estimated for horizontal (H), vertical (V) and left and right diagonal 10 c/deg sinusoidal gratings for non-astigmatic children (4:10--11:2 yr) and adults using yes-no signal detection (YN) methods. Some children were also tested with two-interval forced-choice (2IFC). Younger children were less likely to have the typical adult pattern of anisotropic sensitivity, favoring H and V, while 10--11 yr olds had more adult-like anisotropy. Within all age groups patterns of anisotropy varied considerably. Deviation of adults from the typical pattern may be related to small amounts of astigmatism in their untested eyes. 4- and 5-yr olds were confused by 2IFC. For children 6 yr and older, 2IFC and YN threshold estimates were equivalent, but 2IFC required less testing time.