I cannot navigate without vision correction of some sort thanks to a high astigmatism. I wear my contact lenses during the day and early evening when "cosplay counts", including any private shoots and gatherings, and switch over to my glasses for late evening for dinner or unwinding at the lobby bars when most people are moving into social hour and are much less concerned about accuracy.
I have never gotten negative comments from people - but if I did, I would just shrug, I am way too old to care what some young'n says. In fact, like others said, a lot of people get weirdly excited to see a character that does not wear glasses wearing them and they ask for pics. Maybe there is some weird fetish for "academic" versions of characters that I am not aware of? At one convention where I was at my Artist Alley table, I opted to wear my Jack Frost costume for comfort and was wearing my glasses so I could continue making jewelry etc. sans eyestrain. "Academic" Jack was a huge hit though I was doing it for practicality. I got a lot of pics and people asked me to leave my glasses on. It was like being in the twilight zone since protocol is to remove them for pics. The frames are nothing special, just wire gunmetal grey rectangles. So weird.
Years ago when I was taking classes, I had to hand in an assignment while at a con. I was in costume and just ran back to my room for the laptop and switched to glasses. As I sat in the lobby using the wifi, so many people stopped and took pics as I worked. People were somehow excited to see [insert character name] using a Macbook and wearing glasses. Whatever floats their boats, I say.
If you are paranoid about your current pair of glasses clashing with your costume, check out Zenni Optical. They have frames starting from $6.95 and can accommodate a variety of prescriptions. I definitely recommend them and the anti-reflective coating is worth every penny ($4.95) so if someone does get a picture of you with your glasses on, you do not get the crazy glare. Pic related
, this is a selfie I took with a phone and flash. You can hardly see the lenses at some angles