What we call a “rainbow” is the spectrum of light energy from the sun that we can see. At each end of this visible light are other forms of invisible energy— from radio waves to x-rays. Some of this energy is in the form of ultraviolet waves, or UV. UV is not normally visible, but you might have seen its purplish glow from a special “black light” bulb that makes things glow in the dark.
While we can’t see ultraviolet radiation, it can see—and harm—us if we are not careful. Even on an overcast day, UV light from the sun can cause sunburn of our skin and the cornea of our eyes, which is called “photokeratitis.” Over a long time, it can increase your chance of cataracts (a clouding of the lens of the eye) and damage to your retina that might lead to total blindness.
Team Type 1's Kori Seehafer wearing Nike sunglasses.
Sunscreen protects your skin from overexposure to UV rays. Proper lenses can safely block UV radiation and protect your eyes.
Be Glare Aware!
Glare, or extreme brightness, can be distracting and even dangerous. The direct rays of the sun are the most powerful source of glare and UV radiation, but glare can also be reflected off roads, buildings, water, and snow. Special “polarized” lenses reduce or eliminate glare and reflections. They work by selectively absorbing the reflected glare while transmitting useful light from the scene.
Source: eyedidntknowthat.com
See much more