Do they make eye glasses with a bi-focal lens that isn't visible?

Yes. That is correct. But some people can’t never get used to them. I tried them one time and they gave me headaches. Most optical places will give you a refund if you can’t get used to them but it takes a while for the whole process of getting them done and trying them and then return them and get them done again.

yes ive heard about it in an add

That’s exactly right, Janice. I wear them, too.

When I temped at an optical lab 20 years ago there were a lot of people who couldn’t get used to progressives so we remade them as conventional bifocals. Lens makers have improved progressives a great deal since I made glasses. Today there are few non-adapts in correctly fitted modern progressive lenses. If you are still interested in progressives you might give them another try.

This is basically correct but there are many different types of progressives. There are a few progressives that are mostly distance and close focus with a very small intermediate section; these are more like no-line bifocals than the smoother gradient lenses.