normally, I don't recommend comebacks, I like peace, but when I got my glasses I had the same problem.
I usually came up with something like "well at least I can see." *points toward outfit or hair or something their proud of* " you, on the other hand, obviously can't/need some work"
despite such stings though, I was often disappointed at myself for falling to their level adn it never ended good, as I only ended up alienating myself.
be the bigger man in this case. Be mature, adn let them know your mature. Turn it around and make them the fool
"you know, making fun of someone who needs glasses is really immature. do you make fun of deft people because then need to talk with their hands, or a war veteran whose in a wheel chair cause he lost his foot?", " you know, I bet your one of those people who laughs at the fireman getting an award for sacrificing his legs for his job and now needs a chair, cause you know, people who need help from medical devises like me and him are hilarious" , "oh yeah, I can't see, that's freaking HILARIOUS *laugh loudly and rudely*"
let them know that they aren't bothering you (even if they are) adn that you, adn most everyone else, aren't amused. Even if they don't like you, you'll no longer be a fun target, or if they're just trying to joke around, they'll see that they are hurting your feelings and stop.
on that note, I know there may be a few that are trying to be malicious, but some may be going for the ride or see your lack of reaction adn think its a safe topic to joke about. Make it clear you are uncomfortalble with your glasses, and with them jokeing about it, and let them know that you know they think you look better, but you are more comfortable with them than with contacts, or are unable to get/wear them, as some may be trying to mearly get you to stop so that you will "look better" ( had this happen once, I almost broke a friendship because one friend was making fun of my new pair during our slumber party, when I finally confronted her, she told me that "I saw you last night without your glasses and you were really pretty, so I thought if you hated your new pair and decided to get rid of them I could convince you to get contacts")
just remember those few points, be the bigger man, and make yor feelings clear, and both the malicious and non malicious/joking teases should stop, or at least slow.
I rememebr growing up in the age where a lot of the kids were still glasses free becuase computer damage had yet to kick in. I was one of the first and so one of the teased.
I really hope this helps