Application Description

Are you struggling to fall asleep at night? Do your children become hyperactive after using tablets before bedtime? If you use smartphones or tablets in the evening or are sensitive to light during migraines, Twilight might be the solution for you!

Recent research indicates that exposure to blue light before sleep can disrupt your natural circadian rhythm, making it harder to fall asleep. This is due to a photoreceptor in your eyes called Melanopsin, which is sensitive to blue light in the 460-480nm range. This light can suppress the production of Melatonin, a crucial hormone for maintaining healthy sleep-wake cycles. Studies have shown that reading on a tablet or smartphone for a couple of hours before bed can delay sleep by about an hour.

The Twilight app adjusts your device's screen to the time of day by filtering out blue light after sunset and applying a soothing red filter. This filter's intensity is smoothly adjusted based on your local sunset and sunrise times, protecting your eyes and enhancing your sleep quality. Twilight is also compatible with Wear OS devices.

For more information, visit the Twilight documentation.

Get More from Twilight

1. Bed Reading: Twilight provides a more comfortable reading experience at night by allowing the screen backlight to be dimmed far below the standard settings, making it easier on your eyes.

2. AMOLED Screens: Our tests on AMOLED screens over five years show no signs of depletion or over-burning. When properly configured, Twilight reduces light emission and distributes light more evenly across the screen, potentially extending the life of your AMOLED screen.

Learn more about circadian rhythms and the role of melatonin at these resources:

• Melatonin
• Melanopsin
• Circadian Rhythms
• Circadian Rhythm Disorder

Permissions

Twilight requires certain permissions to function effectively:

• Location: To determine your local sunset and sunrise times.
• Running Apps: To pause Twilight in specific apps.
• Write Settings: To adjust the screen backlight.
• Network: To connect with smart lighting systems like Philips HUE to reduce blue light in your home environment.

Accessibility Service

To filter notifications and the lock screen, Twilight may request the activation of its Accessibility Service. This service is used solely to enhance screen filtering and does not collect any personal information. For more details, visit Twilight's privacy policy.

Wear OS

Twilight syncs with your Wear OS device, allowing you to manage the filter settings directly from a "Wear OS Tile".

Automation

For more advanced users, Twilight supports automation with tools like Tasker. Learn more at Twilight's automation page.

Related Scientific Research

Twilight's development is supported by extensive research, including:

• "Amplitude Reduction and Phase Shifts of Melatonin, Cortisol and Other Circadian Rhythms after a Gradual Advance of Sleep and Light Exposure in Humans" by Derk-Jan Dijk et al., 2012
• "Exposure to Room Light before Bedtime Suppresses Melatonin Onset and Shortens Melatonin Duration in Humans" by Joshua J. Gooley et al., 2011
• "Effect of Light on Human Circadian Physiology" by Jeanne F. Duffy and Charles A. Czeisler, 2009
• "Efficacy of a single sequence of intermittent bright light pulses for delaying circadian phase in humans" by Claude Gronfier et al., 2009
• "Intrinsic period and light intensity determine the phase relationship between melatonin and sleep in humans" by Kenneth P. Wright et al., 2009
• "The Impact of Sleep Timing and Bright Light Exposure on Attentional Impairment during Night Work" by Nayantara Santhi et al., 2008
• "Short-Wavelength Light Sensitivity of Circadian, Pupillary, and Visual Awareness in Humans Lacking an Outer Retina" by Farhan H. Zaidi et al., 2007

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