High energy visible (HEV) light is high frequency light that falls in the blue/violet band of the visible spectrum, which means it can be detected by the human eye. Specifically, it’s the light with wavelengths between 400 and 500 nm (see the full electromagnetic spectrum, which shows the range of all types of electromagnetic radiation, on the bottom right-hand side of this page).

You are exposed to HEV light both outdoors and indoors. Not only do sun rays transmit HEV light, but it emanates from indoor lights and digital screens wherever you go. The computer monitors you work on all day at the office, tablets that you read for hours at home, as well as cell phones and flat-screen televisions all emit HEV light. The damaging effects of HEV light, including premature aging and possibly “age spots,” are cumulative over the course of a lifetime.