Just like you use rain boots to protect yourself from bacteria from floods, you use sunglasses to protect your eyes from the sun.
Exposing too much on the sun may damaged our skin as well as our eyes. So if you are conscious on keeping your eyes healthy then better to wear glacier sunglasses. It will surely protect the eyes from damaged by the sun.
Compared with the skin, we usually sun block or sun screen to protect our skin from sun damaged. But with regards to eyes, we can only protect them by simply using UV protecting sunglasses. Too much exposure to sun may cause serious eyes problems. JUst make sure when you purchase the sunglasses it say they protect against UV rays.