In general, being on your phone at night can be a terrible idea. The smartphone's screen emits blue light so your brain gets confused and stops producing melatonin, the hormone that tells your body it’s time to go to sleep. If you must use your phone at night, there are some things you can do.
What Is Night Shift?
The Night Shift feature on iPhones will automatically adjust the screen’s colors to warmer hues after dark and sunset. It became a part of the iOS 9.2 operating system and the feature will use the iPhone's Geo-location and clock to determine when sunset is in the area and then adjust the screen's colors. Apple introduced the feature since studies show that the exposure to light at nighttime, especially blue light, can interfere with sleep. While this feature does seem to have benefits and there may be some anecdotal evidence, there is no conclusive evidence to show that it filters out all the harmful blue light. It's also hard to know how much of the blue light it is filtering out. Using Night Shift is a step in the right direction but you want to still use additional protection.
In order to set up Night Shift, there are two things that you can do. You can open the control center on the phone and then press the brightness control to tap the sun icon and turn it on or off. You can also go to settings, and display and brightness. On this screen, you can schedule a time for Night Shift to automatically turn on. The feature will default from sunset to sunrise if you don't choose specific times.
What Is a Blue Light Filter?
A blue light filter will decrease the amount of blue light that is displayed on the screen. A blue light filter can be found in blue light blocking glasses. A blue light filter or glasses can decrease how much blue light you are exposed to on a daily basis and can help mitigate the negative effects of too much blue light.
What Is the Difference between the Two?
Night Shift is a good idea if you have the option for it on your phone. Since many people like to stare at their phone during the night time when they are trying to fall asleep, this may help. However, Night Shift is only going to help with the harmful effects of blue light at night since this is when the filter turns on. If you want to protect your eyes from blue light all the time, especially when you are looking at other devices such as your computer, you should also be using blue light filters.
What You Should Know about Blue Light
You should know that blue light is everywhere. Sunlight is actually the main source of blue light and being outdoors during the day is when you get a lot of exposure to blue light. However, there are also many man-made sources of blue light, which include LED lighting and digital screens. While the amount of blue light that is emitted from these devices is just a fraction of what is emitted by the sun, the time on these devices and the proximity of the screens to your face have many health care professionals and eye doctors concerned about the long-term effects of blue light.
The Human Eye and Blue Light
The human eye is not all that good at blocking blue light. The anterior structures of the eye, which include the lens and cornea, are effective at blocking UV light from reaching the light sensitive retina. However, virtually all blue light passes the cornea and the lens and reaches the retina. Since blue light reaches all the way to the retina, one of the concerns is macular degeneration. This can lead to permanent vision loss. More research is needed to determine how much blue light is too much but this is where the concern comes from.
Blue light does contribute to digital eye strain. Since the blue light scatters easier than other types of visible light, it can't be easily focused. When you are staring at digital devices, you are unfocused and this contributes to the digital eye strain. Blue light blockers can increase the contrast significantly and can increase your comfort when looking at devices.