Figure 1.

Spatial contrast sensitivity functions for locations offset by 3° from the horizontal and vertical meridians, fit with the empirical template (equation 1). The size of the symbols was selected to represent approximately ±1 SEM. Filled circles at the top of each graph represent the difference between contrast sensitivities at the innermost and outermost eccentricities for each spatial frequency, to demonstrate the effects of the horizontal shift of the template. In all four graphs, the circles show that the difference increases with spatial frequency in a manner consistent with a horizontal, but not vertical, shift of the template.