Many cyclist wear sunglasses not just for the accessory. They use the sunglasses to protect their eyes from the uv or strong light to come into. At the same time, the additional function of sunglasses is to keep out the wind which may let the eyes feel dry and get infection.
Generally speaking, cyclists wear sunglasses just in order to protect eyes from dirt, dust and a laundry list of projectiles. In other words, sunglasses are the best way to ensure that they won't suffer from cataracts, keratitis and other eye ailments caused by UV radiation. You also should know that many studies have shown that the risk of cataracts, a gradual clouding of the lens of the eye that can lead to total blindness. As we know that it is tripled by long-term exposure to the sun's UV rays. So they wear sunglasses that block 100 percent of the sun's UV radiation.
Well, cyclists aren't wearing them to flaunt or to look good for the shutterbugs. They are neither wearing them to endorse brands to make more money. Cyclists wear them to keep their eyes protected from the elements that could hurt and harm. Imagine the speed at which they ride their cycles, and in addition to that the amount of dust, dirt and let's not get started about the harmful UV rays of the sun!