Twilight: Blue light filter

Twilight: Your Solution for Better Sleep and Reduced Eye Strain

Struggling to fall asleep? Do your children become overactive after using tablets before bed? Does evening smartphone or tablet use disrupt your sleep, or worsen migraine sensitivity? Twilight may be the answer.

Emerging research links blue light exposure before sleep to disrupted circadian rhythms and sleep difficulties. The culprit? Melanopsin, a photoreceptor in your eyes sensitive to blue light (460-480nm), which can suppress melatonin production – crucial for healthy sleep cycles. Studies show even a couple of hours of tablet or smartphone use before bed can delay sleep by an hour.

Twilight dynamically adjusts your device's screen to the time of day. After sunset, it filters blue light, replacing it with a soft red filter. The filter's intensity smoothly adapts to your local sunrise and sunset times.

Twilight also works on Wear OS devices.

Key Features & Benefits:

• Improved Sleep: Reduces blue light exposure to promote better sleep.
• Reduced Eye Strain: Protects your eyes with a gentler, red-toned filter.
• Customizable Settings: Adjusts automatically to your location's sunrise/sunset times.
• Wear OS Compatibility: Syncs with your Wear OS device for consistent filtering.
• AMOLED Screen Friendly: Extensive testing shows no sign of AMOLED screen burn-in. May even extend screen lifespan.
• App Integration: Integrates with Tasker and other automation tools (see documentation).
• Smart Light Control: Option to integrate with Philips Hue smart lights to control household lighting.

Learn More:

• Documentation: http://twilight.urbandroid.org/doc/
• Circadian Rhythm Information: http://en.wikipedia.org/wiki/Melatonin, http://en.wikipedia.org/wiki/Melanopsin, http://en.wikipedia.org/wiki/Circadian_rhythms, http://en.wikipedia.org/wiki/Circadian_rhythm_disorder
• Automation: https://sites.google.com/site/twilight4android/automation
• Privacy Information (Accessibility Service): https://twilight.urbandroid.org/is-twilights-accessibility-service-a-thread-to-my-privacy/

Scientific Research References:

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

Experience the difference Twilight can make in your sleep and eye health.