Effect of retinal location on cone critical flicker frequency

This experiment investigated the differential sensitivity of various areas of the retina using flicker. For 12 subjects testing was carried out in the fovea, and 5 degrees and 6 degrees temporal to the fovea using a wavelength of 555 nm. Testing was done both in the presence of a surround beam and in its absence. In all cases, there was a 2.5- to 4-fold increase in the amount of energy needed to perceive flicker as testing was shifted from the fovea to the periphery. A number of possible explanations are suggested to account for these findings.