Having trouble sleeping? If you use your phone around your bedtime, that could be why. Electronic devices emit blue light. It's part of any bright, white light, like the sun. Ashley McCain, a UW Medicine optometrist, explains that, while you could switch your device to “night mode,” it's better to not to use it before going to bed.

There is also concern about whether blue light harms the eyes. McCain says more research needs to be done. If you spend a lot of time on computers or smartphones, your sore, tired, or dry eyes could result from digital eye strain.

"People generally don't blink as much, and strain their eyes to adjust for the contrast from the blue light when looking at screens," McCain observed. While glasses with yellow tints or coatings might help block blue light and improve contrast, the best thing to do is take breaks. A good rule of thumb is 20-20-20: Every 20 minutes, look 20 feet away for 20 seconds.