If they're like mine, even wearing corrective lenses doesn't help when looking at small thing like details on coins. I ran across these online and don't see a downside to trying them at only $12. http://dailygrabs.com/binocular-magnifier-20x-glasses
I'd prefer a monocle so that I can have one eye on the coin, and the other on something else. It may be good so that you don't stumble your finger on something and get a fingerprint on it. Watchmakers wear a loupe like in this Omega ad below with its celebrity ambassador, George Clooney. To temporarily set it aside, you can lift the monocle and place it on your forehead.
$5.34 for a card of 5 batteries (CR1620's) at Amazon. And the glasses are $5 on Ebay. You get what you pay for.
I got a pair for x-mas. I like them, 20X, Both sides flip up and out the way, so you can use just one side if you want. The lights swivel left and right so it changes the brightness. I even used them to take a photo of a Mintmark.
As an addendum, watchmakers where these for hours at a time - to piece back a movement when repairing, or to put new parts together to build a watch. There's also a noticeable quality difference between, say, Bausch & Lomb loupes and the ones that are priced for only a couple bucks or so on the 'Bay. That said, I think that either will do the job.
I just ordered a pair, those look like just what I've been looking for, for awhile..... but could never find. To anyone else ordering, trying entering SAVE5 in the coupon code area and you should save 5% on the order
I got a plastic head mounted double layer magnifier for like $5 from the Bay. It has the first layer at 2x magnification and then a little thing swivels down over right eye for another 10x. It's plastic so quality leaves much to be desired, but it doesn't matter much when I'm just trying to look at minute details (in my case, picking out excess gilding with a needle when regilding clarinet logos)
I'm gonna get a pair. I think I'll wear them to a restaurant when looking at the menu...that should draw some attention!