My glasses are thick, even with high index plastic, and I have a hard time seeing the 28mm frame lines on the R-D1 without peering around every corner of the viewfinder. But since RF viewfinder frames are just approximations anyway, it's not that bad. Once I can see a corner of the 28mm frame lines, I pretty much know where everything else would fall. If you're used to shooting a camera with glasses, then it shouldn't be that much more of a bother. I always use the 28mm frame lines when shooting indoors at close quarters, like events or parties.
/T