Wavelength has been shown to be involved in pupillary constriction – although this doesn’t seem to be widely recognized.
This concept proposes it is the integrated response of the rods of the peripheral retina (which we assert is sensitive solely to short wavelength radiation) that controls this function. To corroborate this assertion one asks the question: does wavelength have any effect on pupillary constriction in the eye and, if so, what are the most effective wavelengths? See the paper/website of Drew et al, “Pupillary Response to Chromatic Flicker”, Exp. Brain Res., (2001) 136, pp256-262. They find that hue (color) modulated flicker has a much greater effect on constriction than a luminance modulated signal. Their words: “Red-blue color-paired flicker consistently produced the strongest constrictions. These responses occurred even when the flicker was of a lower luminance, both physically and perceptually, than a preceding non-flickering color, indicating that chromatic rather than luminance-sensitive mechanisms are involved in this response.”???
Additionally, Drew et al point their results to the condition of “photosensitivity…”in which afflicted individuals are abnormally sensitive to particular forms of photic stimulation which can result in seizure attacks…” They cite an event in Japan where 700 children were hospitalized after watching a television program where a particular red-blue flicker signal was displayed. This new model may give some insight into the mechanism involved here… It might be inferred from the geometric model that red wavelengths refracted to the fovea would have a different time constant than a large area, integrated, blue signal attempting to control the mechanical function of modulating the pupil of the eye. One can almost envision the chaotic oscillatory motion of the pupil in this situation attempting to “keep up” with the long wavelength signal disrupting the otherwise coherent interplay of these two signals to the brain.
