How Can I Determine the Fitting Height of My Glasses?

I have no-line bifocals and want to determine the fit height of my
lenses. Aren't there some kind of engraved marks that show where the
lens transitions to the add portion? I've noticed a couple of circles
or o's in my lenses and am wondering if that is the markings.

Please, what does 'fitting height' of glasses mean?

How does it work?

On Aug 21, 2:03 pm, powrwrap <powrw...@aol.com> wrote:
> I have no-line bifocals and want to determine the fit height of my
> lenses. Aren't there some kind of engraved marks that show where the
> lens transitions to the add portion? I've noticed a couple of circles
> or o's in my lenses and am wondering if that is the markings.

those are the markings -but the fitting height will usually be either
2 or 4 mm above the height of the circles (depending on lens type)