I bought these cycling glasses (along with a few others) on ebay a while back for around $3 each. I expected to get what I payed for and was just hoping that they would be good enough to use for a few months. Well, we are going on month 3 and here is what I think so far.
They have kept my eyes protected from things like flies and dust.
They have prevented water loss when descending or riding in the wind.
They look good.
Those are the three things I wanted to get out of them and I have.
I don't know how these glasses will hold up if a rock for example were to shoot in the direction of my eyes. Perhaps the lens will shatter? For this reason I would probable invest in a more expensive/quality pair IF I was doing a lot of racing.
When you ride in a bunch it is not uncommon for rocks to come flying up from others cyclist tires.
I only do 2-3 races a year and have nothing planned right now, so for me these glasses are still more than good enough.