Sunlight is the main source of blue light, and being outdoors during daylight is where we get most of our exposure to it. But there are also many man-made, indoor sources of blue light, including fluorescent and LED lighting and flat-screen televisions.Most notably, the display screens of computers, tablets, smartphones and other digital devices emit significant amounts of blue light.
Because blue light scatters more easily than other visible light, it is not as easily focused. When you’re looking at computer screens and other digital devices that emit significant amounts of blue light, this unfocused visual “noise” reduces contrast and can lead to eye strain, blurred vision, headaches, and trouble sleeping.
