John P. Hanifin

TL;DR: The results suggest that, in humans, a single photopigment may be primarily responsible for melatonin suppression, and its peak absorbance appears to be distinct from that of rod and cone cellphotopigments for vision.

TL;DR: These mechanistic studies are the first to provide a rational biological explanation for the increased breast cancer risk in female night shift workers and show that the tumor growth response to exposure to light during darkness is intensity dependent and that the human nocturnal, circadian melatonin signal not only inhibits human breast cancer growth but that this effect is extinguished by short-term ocular exposure to bright, white light at night.

TL;DR: It is demonstrated that increasing irradiances of narrowband blue-appearing light can elicit increasing plasma melatonin suppression in healthy subjects, and narrow bandwidth blue LED light may be stronger than 4,000 K white fluorescent light for suppressing melatonin.

TL;DR: The aim of this work was to quantify the sensitivity of human volunteers to monochromatic 420-nm light for plasma melatonin suppression and clarify the visible short-wavelength sensitivity of the humanmelatonin suppression action spectrum.

TL;DR: Acute, light-induced suppression of melatonin is proving to be a powerful tool for clarifying how elements of ocular and neural physiology influence the interaction between light and the secretion ofmelatonin from the human pineal gland.