Blue light from the phone is a cause of eye fatigue. It disturbs your sleep and harms your eye health. The night shift function has been scientifically proven to reduce blue light. By adjusting the screen to soft light, it relieves eye fatigue, helps you sleep well and improves your vision health. 100% FREE and effective for eye care! Features √ Night filter shifts your screen to natural warm light √ Help you gain one more hour of sleep √ Protect your eyes for 24 hours with the auto-timer √ Help maintain healthy eye habits √ Save your battery by 15% √ Get better sleep by reducing blue light √ Ease eye fatigue with just one tap √ Many colors to choose from WHAT IS BLUE LIGHT? Blue light is the visible light spectrum (380-550nm) for circadian regulation. It contains more energy than other visible light types, so it may damage your retinal cells. WHY SHOULD I USE BLUE LIGHT FILTER? Research shows that exposure to blue light imposes serious threats to retinal neurons, causes eye strain, dry eyes, and inhibits the secretion of melatonin, a hormone that influences circadian rhythms. With our night shift function, your vision health will be greatly improved. CAN BLUE LIGHT FILTER IMPROVE MY SLEEP? Yes. Natural exposure to blue light during the daylight hours boosts people's energy, alertness and mood; however, it will disturb your sleep at night.(from wiki) Blue light filter can effectively reduce blue light from the screen and help you get better sleep. RELEVANT SCIENTIFIC STUDIES  1. Steven W. Lockley, George C. Brainard, Charles A. Czeisler. “High Sensitivity of the Human Circadian Melatonin Rhythm to Resetting by Short Wavelength Light”. J Clin Endocrinol Metab. 2003 Sep;88(9):4502-5. 2. Burkhart K, Phelps JR. “AMBER LENSES TO BLOCK BLUE LIGHT AND IMPROVE SLEEP: A RANDOMIZED TRIAL”. Chronobiol Int. 2009 Dec;26(8):1602-12. 3. ----“Effects of blue lights technology”. https://en.wikipedia.org/wiki/Effects_of_blue_lights_technology 4. “How exposure to blue light affects your brain and body”. Nature Neuroscience; Harvard Health Publications; ACS, Sleep Med Rev, American Macular Degeneration Foundation; European Society of Cataract and Refractive Surgeons; JAMA Neurology