Who knows how you got the scratch, you'd be the best judge of when it may of happened, but I'd definetely get some cycling glasses. They don't even have to be cycling specific, but I would say that I do prefer the ones I have that are.
Glasses give you a lot of benefits in things such as shielding your eyes from the sun, from foreign objects and even just letting your eyes stay moist better by blocking some of the wind.
If you are unsure, just pick up some cheap sports glasses. If you like them, keep them or upgrade to some nicer ones.
Oh, and sorry about your luck.