Off for viewing the LCD (look over the glasses).
Being extremely near-sighted and presbyopic on top of that, I do the same thing. I glance over the top of my bifocals to see closer than reading distance (effectively adding an uncorrected option to the near and far options of my spectacles).
Something I discovered: There is a style of modern (i.e., narrow) frames called the "Randy Jackson" line that is designed to be worn lower on the nose, similar to reading glasses.
Because of that specific design feature, when used with a bifocal prescription, the near distance area is comparatively larger than with similar modern narrow frames designed to be worn higher on the nose--with those frames, the near distance portion can be a thin sliver impossible to use. The area designed for distance vision is a bit smaller, but large enough (there's just more uncorrected sky in your vision area).
Because they're fairly narrow and worn lower on the nose, it's also very easy to peer over the top of them so that we hyper-nearsighted folk can easily see the LCD of our cameras. Very nice for Live View.
Very cool, too, according to my daughter.