Blue light and Sleep
TV, Mobiles, Ipad, Laptops, Macs, Smart Watches, LED lighting and fluorescent lighting – (basically all LED screens) emit blue light. Blue light can slow or halt the production of melatonin, the hormone that tells our brain that it’s time for sleep. It is also believed that blue light is also harmful to your eyes since the eye natural filter cannot provide sufficient protection.
(Taken from http://www.bluelightexposed.com)