Light is categorized by wavelengths: the shortest is ultraviolet, followed by visible and infrared. In the visible light spectrum, the shortest wavelength and highest energy light falls between 400-420 nm and this light is considered high-energy visible (HEV) light.

Sun, LEDs and digital screens emit at high energy a type of short wavelength light, called “blue light”. In this part of visible spectrum, because the blue light has such high energy it is described to be harmful due its capacity to pass through the cornea and concentrate directly on the retina inducing physical and chemical reactions.

For this reason, it has been demonstrated that prolonged blue light exposure can cause photokeratitis (sunburn of the eye), and can lead to chronical problems such as pterygium and cataracts, retinal damage to light-sensitive cells and also greater oxidative stress (digital eye strain, fatigue, dry eyes, blurred vision, headaches are most common and obvious symptoms).

Children and younger individuals (up to around 20 years old) are in high-risk category for retinal damage because their eyes are especially transparent and they tend to participate in more outdoor activities.