Sunglasses what do you use while riding?

Flip down internal sun visor.

If you MUST wear sunglasses make sure they have ballistic proofed lenses. One spiky bit of gravel is all it takes.
Find polarised ones if you can.
 
I usually wear my army issued eye pro. Seem to do a pretty good job for me.

I wear contacts and cannot wear glasses due to an obscure eye disease, so the glasses are REALLY important to me.

I wear Gatorz. Got a couple pair, Wraptor and Radiators and am going go be getting some clears soon. Absolutely the best riding glasses on the planet in my opionion.
 
I use a transitions face shield with a drop down visor. No more lost sunglasses.transitions face shield cuts down headlight glare at night a big plus, and no need to swap shields at night
 
I wear Ray Bans with antiglare coating, both prescription and sunglasses. The curved lenses are great not the wayfarer, the flat lenses cause a vortex behind lens
 
I have a Sheoi GT Air helmet that has built in flip down tinted section also at times wear Maui Jim MJ Sport polarised sunnys as well.
 
Oakley Gascan. They are impact resistant and exceed the the ANSI regs.
 
Under Armor Cores. The lenses attach magnetically to the frames. I have drk lenses for day and amber for night. Lenses swap in about five seconds