In article ,
"Harold and Susan Vordos" wrote:

I have a few pairs of 3.25 diopters. For close-up work, I'd love to have
some even higher, but I've yet to find them.

At the risk of beating a dead horse, order some from Zenni or another
inexpensive on-line optical store - or patronize your local
higher-priced shop. I don't think they even start charging extra until
more than 6 diopters, which is getting into whacky
short-working-distance land unless you are starting from farsighted.

At $8/pair for the low-end frames and $4.95 shipping per order (no
matter how many pairs you order), they are an excellent way to stock a
range of custom magnifiers. The are made in China, and I suspect that
many glasses that you might think are being made elsewhere are also
being made in China, but that information is not being shared with the
customer when the higher bill is presented.

You can have any other aspects of your base prescription dealt with
(astigmatism correction, differences between eyes, etc.) before adding
whatever diopter number you'd like (keeping the working distance
limitations in mind, and doing the math better than I did a couple of
days ago for what the working distance will be). Ask your eye doctor to
provide the inter-pupillary distance (commonly not written down), which
may be slightly less as you focus in close - you can try out
prescription additions at the optometrist if you bring along a work-like
object to look at up close. At some point the short working distance
becomes a problem, and you'll want to think about dropping either $100
or up to several thousand $ on a pair of telescopic magnifiers -
however, these also limit field of view a lot. A third approach is a
macro video camera and a large display screen.

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