Whilst I've never seen any reports of lasting eye damage from wearing mesh, it is arguably still a risk. More concerning is the very really prospect of getting a ricochet from shooting glasses hit your eye, or at best the surrounding area. After the blog post from the chap at Shadow Stalkers I saw a few marshals posting things along the lines of "oh yeah i've seen that happen a couple of times" which is pretty concerning to say the least. It could go into a whole debate about sites enforcing specific eyepro, but more to the point: it isn't as uncommon as you would think.
Personally I'd wear sealed glasses/goggles over mesh which i'd wear over shooting glasses. However if I ended up having real problems with fogging to the point it became dangerous, well then I'd definitely use mesh. Basically what Ian says is a good point, although when I read physics based discussions I feel like this: