What is the difference between MX goggles and mountain bike goggles? After my last ride I have decided that I need to get some goggles, and there seem to be some MX and some mountain bike specific ones, but they seem to be the same. The only difference being that MX goggles are cheaper.

Does anybody know what the difference is between MX and mountain bike goggles? (I ride in wet muddy conditions if that's important.)

Thanks.
Mountain bike specific goggles have less foam padding around the top and are generally lighter. Also the lenses seem to be more flexible but that might just be my imagination.

Cheers