I originally purchased a pair of safety glasses similar to those Guard-Dogs mentioned by Dartyppyt and they worked pretty well, however recently I purchased a pair of MCR Safety's Force Flex safety glasses and they have been serving me well to say the least. Like the Guard-Dogs, the Force Flex meets/exceeds ANSI Z 87 + standards in addition to military ballistic level impact standards (MIL-PRF-31013-Clause 3.5.1.1.). They are constructed from some kind of thermo-plastic urethane material which make them super flexible and uses a polycarbonate material to improve the frame's rigidness. Also, they come with the basics: anti-fog coating, anti-scratch coating, and flexible rubber temples to hug your head comfortably. I've even tried to crush these in my hand, but they just fold back out to their original shape. I know these frames are smaller then some of these other safety glasses, but thus far I have enjoyed their comfort and performance and they have held up great while riding.I have also heard guys say to use pledge furniture polish. I was told that it really helps the rain to bead up and roll off your face shield.
P.S. I Don't have a site link, but I will find one.