Reading this article is causing damage to your eyes and face—and you don’t even realize it.

On average, people spend four or more hours a day on their phones. For some, their jobs require them to use a lot of screen time, but let’s face it, most of the time people are on their phones just for using any and every form of social media. The screens on phones, however, project a light called blue light, and this seemly harmless light actually causes damage every single time it’s used.

Blue light, in short terms, is a high energy wavelength on the light spectrum. Humans see blue light mainly through sunlight, but now with technology being everywhere a person goes, he is also exposed to blue light through screens that have any type of LED and HEV lighting. The most common source of blue light is our phones.

When people come into contact with the blue light emitting from their phones, it literally pierces through their eye and reaches the thin layer of tissue on the back of their eye called the retina. Blue light piercing through eyes can cause major eye strain and even serious eye diseases.

Not only does blue light cause damage to the eyes, but it also affects the face and brain. Blue light stops the production of melatonin, a hormone to help people sleep. Blue light actually stops the secretion of melatonin twice as long as any other light, as stated by an article from Harvard Health Publishing. For some, this may come as shock; blue light can cause damage to the skin causing color changes, inflammation, and aging. The high energy wavelength can cause a lifetime of damage when being looked at or a prolonged time. Thus, those who are all about skincare may want to watch their screen time.

Yes, blue light has some bad effects, but there is still hope for the eyes and skin. On Apple phones, there is a feature on the brightness called Night Shift. This feature turns the phone screen into a yellow-orange color, instead of the blue. The Night Shift mode emits less blue light, and gives off a light that is less harmful and damaging; it’s especially useful at night before going to sleep.

With there being risks and preventions for blue light, people still may not care about the warning signs and take up most of their time on their phones. Like most teens, Raina Kunder, 11, uses her phone daily and shares her input after recently discovering the effects of blue light: “Blue light is unavoidable; people don’t pay attention to the risks. Even with people knowing about the risks, they still won’t be able to put their phones down, but I—for sure—will start to use night shift more often and limit my screen time.”