The physiology is that there are blue sensitive ganglia in the retina, not part of the visual system but instead part of autonomic systems (pupil dilation, melanin production). People wear blue blockers in the evening to (supposedly) fall asleep more easily. And it probably works for some people, although cortisol levels seem more important than melatonin for getting to sleep.
Personally, I find phosphatidyl serine, which depresses the active form of cortisol, effective for going to sleep at an unaccustomed time (jet lag).