You need to see to the sides of you, as well as in front of you, while you are riding. The goggle's frame should be flexible. A Frame has air vents on the frame and lens of the goggle. Foggy lenses are always a pain. So, your goggles should have some anti-fog features.
Air vents are one way to prevent fogging.
Air vents can be located on the lens or on the goggle s frame. Also, double pane lenses help prevent fogging. Some goggles even have a small fan to help move air inside the goggle. The color of your goggle s lens is also important. Dark tints should be used on days when the sun is bright, and light tints should be used when it is darker out.