As if you needed another reason to put down your phone, it turns out the blue light emitted by your cellphone and computer screens can not only make it harder to fall asleep at night, it could be damaging your skin, too.

Blue light, the kind emitted from screens, is a type of high energy visible light, or HEV. While blue light is strongest from environmental sources like the sun, there are studies that show electronic screens can have similar effects.

But first, its important to note that the light from your screen isnt as harmful as a day spent at the pool. The sun is still the biggest enemy when it comes to long term dangers like DNA damage and skin cancer.

Blue light causes a slightly different type of damage. It causes generation of reactive oxygen species which damages collagen, causes wrinkling, pigment changes and laxity, said Michele Farber, a dermatologist at Schweiger Dermatology Group in New York. The sun, on the other hand, causes photoaging to a greater degree than blue light, and can also induce skin cancers, she said.

Blue light hasnt been shown to cause skin cancer. In fact, in medical settings its used to prevent skin cancer . But cosmetic dermatologist Kenneth Mark , who has practices in New York and Colorado, warned that blue light can increase signs of aging, such as hyperpigmentation, collagen breakdown, redness, inflammation, swelling/edema and oxidative stress in the form of free radicals.

Blue light has been shown to generate reactive oxygen species, causing damage to collagen, inflammation and pigment changes, noted Farber.

Blue lights sleep-disrupting qualities have a direct effect on skin, too: Watching TV and using our phones at night also disrupts our sleep-wake cycle, and lack of sleep also results in hormone fluctuations that can flare skin conditions and can accelerate aging, Farber said.

Even exposure time as short as an hour can cause oxidative stress in skin cells that leads to aging. Other studies show that humans are exposed to enough blue light in the course of a normal day to decrease carotenoids (an antioxidant) in skin, which increases free radicals (which can cause skin damage).