Sunlight is made up of red, orange, yellow, green, blue, indigo and violet light. When combined, it becomes the white light we see. Each of these has a different energy and wavelength. Rays on the red end have longer wavelengths and less energy. On the other end, blue rays have shorter wavelengths and more energy.
Maybe blue light exposure you receive from screens is small compared to the amount of exposure from the sun. But there is concern over long-term effects of screen exposure because of the close proximity of the screens and the length of time spent looking at them.
According to a recent study funded by the National Eye Institute (NFI), children’s eyes absorb more blue light than adults from digital device screens.