I have a few different pairs of reading glasses at different magnification strengths, depending the level of detail I need to see. 2.5 for really close-up stuff, 1.25 for the 2- to 3-foot range, and a few in-between. My 'distance' vision, i.e. 4ft and beyond, is pretty good though (20/25).
I have had both of those magnification devices for over 25 years, but I still refuse to "N" gauge!
They are great for smaller items - even help in "O" scale!
I know what you mean about sight not being what it used to be when you get older. I have a number of these magnifiers I use. One at the work bench and a couple of them down in the train room.
There are three different magnifications in the head set and then the little loop if needed. I also have a lamp that mounts the same way to my workbench, but not with a magnifier. I may have to look into one of these.