Julia,
The general term for what you describe is “telescopic loupe”.
Usually the little telescopes are mounted in an eyeglass frame,
sometimes set into holes bored thru the lenses. They have been made
in varying strengths over the years by many makers, one of the better
and most precise in fitting is Keeler Optical of England. They used
to have a US office in Philadelphia.
These devices are rather pricey when made with good optics. For
bench work I think a real microscope is a far better solution. If you
can hang on until I finish the writing and, with Hanumans help, I
think we can get some helpful in everyones hands.
Dr. Mac
Without corrective lens, I am legally blind.
Before my last semester at TIJT Paris TX, I had my vision checked and
new contact lens fitted. I have worn contact lens since the Cuban
Missile Crisis, and I have them corrected for distance.
I purchase across the counter glasses for general use. I wear them
and over them I have my optivisors. I have several of them in
differing magnifications. They hang on a stiff rod by my flexshaft
holder. I change them as needed for the task at hand. They all have a
small round auxiliary lens attached. I use this set up for most jobs.
I have a Russian made copy of the older Ziess telescopic glasses.
They are heavy and a little over robust but useful for when I need
magnification, but at more distance.
For Nicer work, I have a Reichert, American Optical, zoom binocular
microscope. With the right lens set I can go from a low magnification
to much more magnification. This also has a fiber optic ring
illuminator.
Best value for the money, a 50 mm f 1.4 to 2.0 camera lens. I got a
optically clean, lens which was unsuitable for photography. - CHEEP.
Don’t be cheep with your health.
I have found I can use a higher magnification to get a mental image
of what I am doing, then switch to something with less magnification’
but more working room.
Best wishes
Robb.