Overhead lights, TVs, phones, and tablets all emit blue light. Just like blue light from the sun, blue light makes our bodies think that it is daytime. Therefore, exposure to blue light is a good thing in the morning, and during the day when you want to be awake and alert. However, it is detrimental before bed, when we want our bodies to start winding down. These glasses can be worn during the evening to block blue light and help improve sleep.