Chromatic perceptive field sizes measured at 10 degrees eccentricity along the horizontal and vertical meridians

The different hemifields in the retina are known to vary in photoreceptor density as well as in the number of photoreceptors converging onto one ganglion cell. The effect of these differences among the retinal hemifields at 10 degrees retinal eccentricity was investigated using a color-naming procedure to derive perceptive field sizes for the hue terms of blue, green, yellow, and red. Color-naming data were obtained under two conditions: (1) after a bleach condition, chosen to minimize rod contribution, and (2) after 30 min dark adaptation, chosen to maximize rod contribution. Perceptive field sizes measured in the bleach condition were consistent with degree of neural convergence of cones to ganglion cells across the retina rather than differences in cone density. Rod densities relative to cone densities correlated with the size of perceptive fields in the no-bleach condition, i.e., the greater the rod:cone ratio, the larger the perceptive field.