Blue light or high-energy visible light (HEV) refers to wavelengths between 390 and 500 nm. It is emitted from a big number of artificial light sources, such as blue LED, and from direct sunlight.
Considered as the most energetic part of the spectrum, blue light penetrates more deeply into the skin. Although the mechanisms are not fully understood, it appears that HEV is involved in human photoaging. Daily exposure to blue light, especially from artificial sources, is one of the main factor responsible for premature skin aging, along with the sun and pollution. These wavelengths emitted by our screens reduce gradually the ability of the skin cells to regenerate. Some studies have demonstrated that visible light can induce cellular dysfunction and cell death.