Goggles are a form of protective eye wear that skiers/snowboarders use to keep wind and snow out of their eyes. Goggles also supplement their vision by filtering out unwanted light. This helps them see better in bright light conditions (where reflection from the snow can make vision sometimes difficult) and they can add contrast to the snow to make gradations and conditions more apparent (especially during flat light conditions).
The main disadvantage to wearing goggles is that they have the ability to fog up. However, there is a host of technologies available to counter this problem, including thermal lenses, vents and even fans.
When choosing a goggle, the main features to consider are field of vision, lens color, antifogging technology and comfort.Full Article