Twilight 12.11

Twilight is a free application for Android-based mobile devices that adapts the screen of your device to the time of day, filtering out the blue spectrum on your phone or tablet after sunset and protects your eyes with a soft and pleasant red filter. The intensity of the filter is smoothly adjusted relative to the solar cycle and is based on the time of local sunset and sunrise.

Recent studies prove that the perception of blue light before going to bed can upset your natural (circadian) rhythms and cause you to be unable to fall asleep.

The reason is in the photoreceptors of the eyes, called Melanopsin. This receptor is sensitive to a narrow band of blue in the range of 460-480 nm, which affects the production of Melatonin, the hormone responsible for your healthy sleep-wake cycles.

In experimental scientific studies, an average person was shown reading from a smartphone or tablet for several hours before going to bed, which caused a delay in sleep for about an hour.