Just to relate this back to cycling: one morning, on my way to work, I was riding along the dark urban trail, when - whack! - I feel like I'm punched in the side of the head and next thing I know I'm lying with the bike in a pile on the pavement. My Oakleys are laying next to me, and I'm otherwise fine, but it turns out I had smacked the branch of a tree that had fallen onto the trail during the night and that was still half-supported by the cyclone fence next to the trail. The branch was right at eye-level, and although my bike had a 1-watt LED headlight, it was pointed too low to see the tree in time. Good thing it was near the start of the trail, so I hadn't accelerated to cruising speed! I was able to ride to the hospital, where the area around my right eye had by then turned purple. But the Oakleys had protected my eye. Kinda scratched up, but it did its job! Went to work after, and had to explain the story over and over. Eventually I just got tired of the details and resorted to, "yeah, but you shoulda seen what I did to the other guy..."

L.