Exposure to light through the eyes helps regulate the body’s sleep/wake cycle by affecting the pineal gland’s secretion of melatonin.
This hormone is produced at night and promotes drowsiness; exposure to light, notably blue light, suppresses it.
This is one way sunlight contributes to alertness, and why lack of light at night helps increase sleepiness.
download this free app http://stereopsis.com/flux/ to regualte the ‘blue light’ to an ‘amber’ on your ipad, desktop, or smartphone screen.
Krista Lynn Reid