Ok. I can finally give some real input into this thread. I finally got my a900's today (yay
) and I can say that wearing glasses with my 'phones doesn't really bother me that much. I notice that they shift my glasses about a little bit, but it isn't uncomfortable by any means, nor does it distort my vision. I've worn them for a little over an hour while wearing my glasses, and the only thing I notice really is that my ears are getting a little warm... but no discomfort due to my glasses, and I'm not wearing those ultra thin metal frames either. I'm wearing my thick plastic frames with temples that are approx. 5 mm in width (compared to my wire frame's 1 mm in width temples).
I just switched over to my wire frames to see if I feel any difference. Yes I do. The wire frames are even less noticeable (I figured it would be). So, even with my thicker plastic frames, I am not bothered by my glasses. Of course, if I take off my glasses, it feels more comfortable, but I don't notice any difference in sound, and definitely not a significant difference in comfort.
Maybe you should go get your glasses adjusted like I suggested before and see if it helps. If it doesn't help, at least your glasses will be straight! Also, if comfort is your only problem, then maybe consider tweaking the headband so it doesn't clamp down as much. I've heard that the senns clamp like a mofo.
Hope you figure it out. Me, I'm gonna get acquainted with my new friend...
Cheers!