The more he wears them, the easier it will be. If they really help him see, then he will want to wear them. I don't think you need to make a big deal out of it. If he's wearing them at home, he will get used to being able to see better and probably want to wear them elsewhere. If he's getting teased about them, show him how normal they are-point out all the people that you see wearing glasses, on the street in books and magazines, on TV, in the movies, etc.
Here's a few more cool "people" with glasses.
Clark Kent (superman's alter ego)
Milo from the movie "Atlantis"
Dexter (Dexter's Labratory)