Actually a lot of girls have used this to initiate flirting with me and some of my bespectacled friends, and it's a good ice breaker ime.

Some ask if they can try them on. So that's an opening if they're flirting. You can offer to let them. If they wear glasses you can swap. It's a nice cute little ice breaker and it should be easy to keep the conversation going from there. My eyes are really bad so if she laughs at my shitty jokes about it that's a good sign. Laughing at my shitty jokes is always a good sign cuz I know I ain't that funny.

If it wasn't what you thought you should (hopefully) know by the end of the exchange and if they are still into talking further (not everyone who compliments your glasses is looking for your number, spare grandma please). But yeah you'd be surprised how many girls have opened with that line and followed up on it.