Other than sun, TV screens, computer screens, tablets and smartphone screens all produce blue light. Blue light has a very short wavelength. Since shorter the wavelength, higher the energy, the incidence of blue lights to our eyes, tricks our brain to think that it's a daytime.
Looking at computer or smartphone screens at daytime is not the problem. The real issue is our brain tricked by the screens that it's a bright day even if it is 2 AM and the body is tired as hell. The blue light from these screens makes us feel active at night which might make us not able to sleep. A lot of research has led to this conclusion and researchers has recommended to not use cell phones or any other devices with bright screens or even bright white room lights. People should dim everything in their room with warm colours at night. Colours with warm temperatures do exactly opposite to what the blue light does. It is said to make the eyes lazy, which is better for a good sleep.
But in this tech-savvy world, no one likes to stay away from their phones even for a minute. People these days wake up with their phones and goes to sleep with their phones. This has hugely hampered the sleep quality of millions of people using the smartphone and it is really important for them to understand what are they doing to themselves using the smartphones at night.
Since warm light helps in gaining quality sleep. Smartphones have been coming with a feature that reduces blue light. iPhone, the leading smartphone brand announced a feature called night shift since ios 9.3. Android phones have been having this feature way before than iPhone. There are tons of apps that are available in the play store to block blue light from the smartphone screen. One app that is best in doing so is an app available in the Google Play Store is Opti Care - Blue Light Filter.
Opti Care - Blue Light Filter is an ultimate app to protect your eyes from the harmful blue light as well as it has a feature that reminds you to take eye breaks from time to time. It provides you with very customizable overlay. You can change the temperature of the overlay, control the intensity and apply a dark overlay to make it seem like the brightness is below the system allows. You can manually toggle the blue light ON or OFF or, you can make it turn ON after the sunset and to automatically turn OFF in the morning. The other feature, which is the eye break reminder feature helps you avoid eye stress while looking at the screen. By default, it is set to the 20-20-20 rule, which is thought be the perfect break rule for the eye according to the researchers. 20-20-20 rule means, Every 20 minutes, look 20ft. away for 20 seconds. Which I think provides enough exercise to the eye.
Some other good apps are Twilight, f.lux.
