Should take off my eyeglasses if i know I'm going to get into a fight?!

Should take off my eyeglasses if i know I'm going to get into a fight?

Well, from my professional poit of view, If you know how to defend yourself in a street fight, then leave them on. That is in case you know how to dodge the arriving punches and you can punch back after dodging.Just like a boxer.
If you don't know how to defend yourself but you are kinda a fast runner, then I suggest leave them on and run your a*s off.
But if you are a punching bag type of guys, better take them off, get beaten up and then put them back on....LOL.
Ah...In the last case don't forget to say thank you to the guy beating you.

I personally believe street fighting is the most immature behaviour one can have.
In younger ages, it's kinda inevitable. I also had lots of them. My younger brother was even worse.He used to have one in every single day. I understand that. It's about the age. During the teens, even if you don't look for the trouble, sometimes the trouble comes looking for you.
So you must try to put yourself in the first group that I described. the one who should leave the glasses on cause he's not gonna recieve any punches.
For that, I advice you to pick up a self defence course.
The reason why I suggest self defence and not Kick Boxing, is that you just want to defend yourself and get out of trouble.
Self defence teaches how to avoid recieveing any attacks and how to disarm the attacker mostly by lock up techniques.
These techniques usually pin the attacker to the ground under your control. From this point on, since you have full control over the attacker, you can decide weather you want to really hurt him(i.e by breaking a few fingers or ribs or even breaking a joint such as the wrist or the elbow) or you just wanna scare him by displaying what you are actually capable of. I personally suggest the second style. Just make the guy apologize and then let him go. I assure you he'd run his a*s off and will never make any troubles for you.
Hurting the guy in a serious way such as attacking the eye balls or the balls as the others have suggested can cause you troubles big time. So the best way is to make them scared but not really hurt.
In self defence, you'll learn how to avoid fights in the first place by how to behave in a way that no one find enough courage to confront you. Your self confidence will be increased and so will your physical power. Believe it or not, The better I became in martial arts, the less I had street fights. An now it is 7 years I have not had any fights. Even if a guy comes up to me looking for trouble, I just make him change his mind by my calmness. Street fighters have a lot of experience in fighting. They know who is strong and who is not by the first glance. They can smell your self confidence and power and they avoid confronting you as soons as they see you.
Another reason I don't suggest other martial arts, is that they are designed for FIGHTING. i.e. hittin the opponent to hurt him. They need physical strength.
But self defence, employs useful techniques from all martial arts.Self defence just uses the techniques that don't need Silvester Stalone's body to perform. These techniques can be perfomed by a small girl on the BIG SHOW too. They are desigend in a way that they do not rely on physical strength. So even if you are a small guy, you can perform them on big bad a*ses.
Self Defence has hundreds of techniques, it'll give you at least one technique for any situation. Cause street fight is all about the first 10 - 12 seconds. The first 10 - 12 seconds defines the winner and the loser. So the self defence gives you techniques to use your opponents' strength against himself and pin him to the ground upon his attack. it takes 5 seconds and is efficient. cause you don't need a lot of stamina.
I give you an example on one of the techniques:
imagine a big guy has grabbed your wrist with one hand.
his thumb is on one side of your arm and the other four fingers are on the other side.
The rule is, always twist your arm toward the direction of the thumb and your arm will be released.fighting against the other four fingers is useless but the thumb is the weak point of any one hand grab.
This can be done on 95% of the guys. Only 5% of the guys have a thumb like triple H's thumb.
So as you see, this simple technique doesn't need you to be Mike Tyson to be able escape the grab and it'll save your a*s in 95% of the situations.
So if you are a guy like me(i.e. you are not the one looking for trouble, it's the trouble which is looking for you), Then I suggest you pick up a self defence course.

Good Luck dude. try to keep your a*s off any street fight.