Twilight may be a solution for you!
Recent research suggests that exposure to blue light before sleep can distort your natural (circadian) rhythm and cause inability to fall asleep.
The cause is the photoreceptor in your eyes, called melanopsin. This receptor is sensitive to a narrow band of blue light in the 460-480nm range which can suppress the production of melatonin - a hormone responsible for your healthy sleep-wake cycles.
In experimental scientific studies it was shown that a person average reading on a tablet or smart phone for a couple of hours before bedtime can find their delayed sleep about an hour.
Reading Room: Twilight is nicer on the eyes for night reading. Especially as it is able to reduce the backlight of the screen well below the capacity of backligt controls on your screen
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