Size and sensitivity (M- and F-) scaling of π4 and π5
Steven L. Buck, Kathleen Bonnelle, Paul Zohn, Roger Knight · Annual Meeting Optical Society of America · 1988
Our previous work has shown no difference in spectral sensitivity (other than effects of macular pigment) but reduced overall sensitivity at 7° compared to fovea for both π4 and π5 detection mechanisms.1 We show here that this difference can be explained only by a combination of size and sensitivity scaling, analogous to M and F scaling.