I know I'm responding to this late, but just wanted to add some thoughts. My daughter (who is 21 months) got glasses at 14 months, which honestly, I think made things easier because she was young enough that she didn't fight us all that much.
Others have already said this, but please know that this is not a mommy failure at all! I do remember being so upset when my Zoe got her glasses, being worried about other people's reactions as well as the worry of how we'd get her to wear them, but it has worked out. If it helps, there was recently a study that found that kids think that other kids with glasses are smarter and more honest, but don't think that it changes their appearance otherwise.
I know that whenever I get a new prescription, things look really strange through the new glasses. I have to imagine that for a kid who has never worn glasses, it's probably even more disconcerting, but he'll have to get used to seeing through them before it feels normal. Maybe you could use a timer to have "glasses time", and set it for increasing amount of time each day and make sure that you're doing fun activities during that time to keep him distracted from the glasses.
I also second the suggestion of making sure that the fit isn't bothering him, because poorly fitting glasses are really, really painful. You might also look for books about kids who wear glasses and really talk that up (I have a list on my blog: http://toddlerglasses.wordpress.com/books-for-kids/). My good friend has a son who got glasses at 3 1/2. Even though he had never read any Harry Potter, he knew enough about the character to be really excited that he would get glasses like him.
Good luck!