I wear trifocal progressive lenses. I can't get anything in focus at any distance without them. So if I am shooting a low shot, I am looking through the top of the glasses (far distance correction), if I am looking straight ahead through the viewfinder, I am looking through the middle-distance (computer work) part of my lenses, and if it is high on a tripod and I an craning to look through the viewfinder, I am probably looking through the lower part of my glasses, which is the reading lens.
It SUCKS! I can't keep the diopter adjustment on the camera right to work with any single lens distance, so my viewfinder often appears blurred. When I am taking my time, I'll get my angle set and then fiddle with the diopter adjustment so I can verify focus in the viewfinder, but most of the time, it's some wierd situation like on my knees, angled up through a fence or something where I don't have the position long enough to get "comfortable".
Oh, and my glasses get all smudged from the rubber on the camera, and scratched from the camera body.