Twilight Circadian Rhythm Control


If you’ve ever felt that stabbing pain in your eye balls when you pick up your phone or tablet late at night to check a notification then Twilight is an app to try out. Twilight goes further than existing auto brightness control apps by filtering out blue light from your display, a key factor in sleep cycle control.

If you or your kids have trouble getting to sleep at night after using bright phone/tablet displays then Twilight may be a solution. A growing body of research suggests that exposure to blue light before sleep may distort your natural (circadian) rhythm and cause inability to fall asleep. Photoreceptors called Melanopsin in the eye are sensitive to a narrow band of blue light in the 460-480nm range. These in turn suppress Melatonin production – a hormone responsible for healthy sleep-wake cycles. Scientific studies have shown an average person can delay natural sleep by about an hour after reading on a tablet or smart phone for a couple of hours before bed time.

Twilight screenshots

The Twilight app makes your device screen adapt to the time of the day. It filters the blue spectrum on your phone or tablet after sunset and protects your eyes with a soft and pleasant red filter. The filter intensity is smoothly adjusted to the sun cycle based on your local sunset and sunrise times. Settings are available for color temperature, intensity, dim, location, status and a few more pro settings via an upgrade/donation. Developer Urbandroid has also created previously the Sleep as Android app that has reached over a million downloads.