The most potent harmful blue light is known as high energy visible light (HEV), which induces retinal damage and contributes towards inflammation of the skin. It also contributes to symptoms such as eye strain and headaches. It sits across both the UV and visible light spectrum.

Blue light between 470-500nm is known generally as “good” blue light useful for various treatments (sleep disorders, seasonal depression, etc.). But, if you expose yourself to this light after the sun sets, aka in the evening, it works against you and will keep your body awake - as it will trick your body into thinking it's the daytime.