Renewed Third Class Medical

Well, I'm legal to fly again (as I noted on twitter). My medical had expired on Saturday, but I had my appointment with the AME this morning and am legal again. Alas, from now on, I must carry my glasses with me for near vision (I wear them all the time, so that isn't really a big deal). I asked the doctor what the difference was between a third class and a second class since I'm considering pursuing my commercial license in the next year or so. He told me it was all about vision. With my glasses, I actually met the standards for a second class. Of course, for the training (and checkride) I don't need the second class, only to "exercise the privileges" of the certificate.