On a bright day when you go outside, you're more than likely to start squinting. It's the body's natural response to limit the amount of light getting into the eyes so that the light can't damage the sensitive light sensors in the back of the eye that your optical nerves use to give your brain the data necessary to make an image.
However, you might also reach for your sunglasses. They're an essential part of many people's lives, and they come in all different shapes and sizes. Their function is to prevent harmful light rays from entering your eyes and causing damage to those sensitive light sensors.
The most destructive kinds of light are ultraviolet (UV) and high frequency, both of which are emitted from the sun. To cancel out UV light, many sunglasses are yellow or amber in tint color. Darker lenses cancel out UV, as well as high frequency light.
By blocking these harmful rays, you'll prevent unwanted damage to your eyes. These harmful rays are capable of damaging the DNA in your eyes, which leads to all kinds of problems over time, even blindness.
It's a great idea to pick a fancy set of sunglasses that you enjoy and wear them on bright days. Your eyes will thank you.