Originally Posted by
Bahnzo
Because there isn't one. The main reason you wear glasses when riding is eye protection. What protects your eyes? Safety glasses. Sure, you might pay more for style or the name, but if eye protection is why you wear them, then buy glasses made for that reason. Slapping a Nike swoosh on the side doesn't make them better at protection.
On the contrary, there's more to eye protection than physical stuff getting in your eyes, which is the only thing safety glasses prevent. More expensive glasses will provide:
UV protection
polarization
light weight
ventilation to reduce/eliminate fogging
better clarity
scratch resistance
More comfort
better fit (if I wore safety glasses while running, they would be bouncing every step)
tinting
Just to name a few things. There's more to brand name than a company logo. If not, you'd see professional cyclists using safety glasses or 99 cent store glasses.