Why do you think Matt wears goggles?

I think they're one of his ways of dealing with stuff, similar to an addiction... they shield his eyes and provide a barrier between him and the real world, so to speak.
Also, he might think they look cool. But I think they're mainly a protection.

So if his gameboy screen broke he won't hurt his eyes.I have no idea what I'm talking about

To protect his eyes when he smokes +-+?

There're just his style

because he is fuckin gangster

I think its just his style :). Or to just hide hi9s identity

duh. to make him look cool.

1. To resemble a video game character
2. To make him look original and cool
Or, maybe, something else

maybe he just knows they make him look so frikin' sexy!

I think he wears goggles to shield himself from the real world and the cruel things it does. He likes to pretend he is in his own orange-tinted world. A world worthy enough to be a video game. He also thinks it makes him looks cool and badass. (Which it does) He believes in that sappy crap about when you look into someone's eyes you can see into the soul, so he hides eyes so no one can see into him. -Cake

because his eyes were hurt by Mello←_←

So he will not over-strain his eyes from playing video games and hacking, in order to be able to perform better, as well because the smoke irritates his eyes (possibly).