Twilight: Blue light filter

Are you experiencing difficulty falling asleep? Do your kids seem overly stimulated after using their tablets before bedtime? If you're using your smartphone or tablet late in the evening, or if you're light-sensitive during migraines, then [ttpp] could be the perfect solution for you.

Recent studies indicate that exposure to blue light before sleep can disrupt your natural circadian rhythm by interfering with melatonin production — a hormone essential for regulating healthy sleep-wake cycles. This happens due to a specific photoreceptor in your eyes called Melanopsin, which is particularly sensitive to blue light wavelengths between 460-480nm.

Scientific research has shown that reading on a tablet or smartphone for just a couple of hours before bed can delay your sleep onset by nearly an hour. [ttpp] helps reduce this disruption by filtering out harmful blue light from your screen. It applies a soft, soothing red filter that adapts to the time of day based on your local sunrise and sunset times, protecting your eyes naturally without harsh brightness.

You can also enjoy the benefits of [ttpp] on your Wear OS device, ensuring consistent eye protection across all your screens. The app adjusts its filter intensity dynamically throughout the day, offering a seamless experience that aligns with your body's natural rhythm.

Enhanced Features of [ttpp]

• Night Reading Optimization: Twilight provides a more comfortable reading experience at night by dimming the screen far below standard backlight limits, reducing eye fatigue significantly.
• AMOLED Screen Benefits: After extensive testing over five years, we found no signs of screen degradation on AMOLED displays when using Twilight. In fact, by lowering overall light emission and balancing color distribution, it may even extend your screen’s lifespan.

Understanding Circadian Rhythm and Melatonin

To learn more about how melatonin and circadian rhythms affect your sleep patterns, you can explore these resources:

• Melatonin Overview
• Melanopsin Receptor Function
• Circadian Rhythms Explained
• Circadian Rhythm Disorders

Required Permissions

[ttpp] requires several permissions to function effectively:

• Location Access: To determine accurate sunrise and sunset times for your area.
• Running Apps: Allows Twilight to pause automatically within selected apps if desired.
• Write Settings: Enables dynamic control over screen backlight levels.
• Network Access: For integration with smart lighting systems like Philips HUE, shielding your environment from blue light exposure.

Accessibility Service

For full-screen filtering, including lock screen and notifications, [ttpp] may request permission to use the Accessibility Service. Rest assured, this feature is used solely to enhance screen filtering and does not collect any personal data. Learn more about privacy and accessibility here: Twilight & Privacy.

Wear OS Integration

Keep your smartwatch display in sync with your phone's Twilight settings. Control screen filtering directly from a dedicated Wear OS tile for consistent eye comfort across devices.

Automation Support

Advanced users can integrate [ttpp] with automation tools like Tasker. Full documentation on automation options is available here: Twilight Automation Guide.

Scientific Research References

Explore peer-reviewed studies related to blue light exposure and circadian health:

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

Take control of your digital environment and protect your sleep health with [ttpp]. Discover a more natural way to use your devices after dark — your eyes (and your brain) will thank you.