I found a site that sells Ultralight reading glasses:

http://www.i4ulenses.com/

The only issue was trying to figure out the strength I would need. They list Mild, Medium, Strong, Stronger and Strongest.

I found out about these lenses about 6 months ago from Glen Van Peski's gear list on Gossamergear.com. I tried them out reading in bed. I fell asleep, the lenses fell off and I didn't find them for weeks (they somehow got between the mattress and box spring).

The listing on the i4u website also includes the diopter numbers. If you already have a closeup lens prescription, use the closest to that, or maybe one step up for better magnification. My prescription is for 2.75 and I found that a 3.0 works fine for map reading. Check with your provider at your next eye exam. If you're not going to use them much (and you probably won't--I found them quite uncomfortable for reading for long periods), you can get an approximate number at the drugstore reading glasses display from their "self test" feature. Better, visit said display with a USGS contour map, try different strength glasses and see which diopter lets you read the map best.

Edited by hikinggranny on 09/27/2011 13:04:02 MDT.

If you have a prescription from you doctor, you can get light weight custom prescription glasses from Zenni Optical for dirt cheap:

I have these and they are very light:

http://www.zennioptical.com/#/?limit=80&q=420611

They also have similar frames in titanium which are probably even lighter:

http://www.zennioptical.com/#/?q=3728

The only difficulty is figuring out your pupilary distance (PD) which is often not included in your prescription. I can weigh my glasses if anyone is interested. In terms of backpacking you would probably need to keep them in a case. The case they came with is pretty light weight.

For those who don't care for the pince-nez style, these are good, and pretty light - 13g or .45 oz:
http://www.fishermaneyewear.com/polarizedeyewear/Magnifiers/Slim+Vision+Magnifiers+Tortoise.html

Amazon sells them.

I like them because the all-plastic construction seems to survive well in my pack. I bring a pair for reading, and a more powerful pair for tiny map details.

Fresnel lens.

I also have a pair of these: http://www.gofastandlight.com/Folding-Reading-Glasses-with-Protective-Case/productinfo/O%2DFOLD/

Very compact, 0.9 oz. with case.

Unfortunately the shipping cost almost three times more than the glasses!

I note on the site that they now come in a soft case instead of hard. Since they are rather delicate, I'm not sure that's a good idea.

Yeah, very light, BUT ... they only work at home.
If you are out walking and have got a bit sweaty, and want to read a map, forget it. They fall straight off your nose.
Well, that's what happened to me, anyhow. Sweaty nose!

Cheers

I use the Eschenbach Clip Read Magnifying Reading Glasses 2-5-G. Only weigh 3.3 grams, 8.5 grams with case. The company has quite a few other options that you may want to look at: http://www.eschenbach.com/products-reading-glasses-miniaturereaders.htm

Edited by butuki on 09/28/2011 06:11:49 MDT.

The easiest and cheapest way to find what diopter power you need in over the counter readers is go to your local drug store and take what you will be reading and try the readers on till your satisfied with the vision.
If you have prescription for glasses and have been diagnosed by your optometrist for Presbyopia. You need to take in consideration what your distance prescription is also so call your optometrist office and find out what is the power you would need for over the counter reader.

Over the counter readers have one flaw they are mass produced made with out consideration to the optical center of the lens when being cut. With optical centers in different places will induce prism effect your not use to and the OTC readers could cause headaches after prolonged use. Also stay away from drill mounted glasses they are fragile and break very often.

If your just reading maps the suggestion of small flexible plastic magnifying Fresnel lens is the best solution because it unbreakable is flat so it packs easily and is the lightest solution for a vision aid to read maps.

I have 15 year experience as Lead optometric tech in optometrist office.
Terry

I use maui Jim Ho‘okipa Readers Sunglasses. Polarized with bifocal readers on the bottom. Total weight is 2 oz.

Can be a little difficult to read in the dark, but I usually sleep at night.

Posted this on another reading glasses thread so I thought I would throw it out here. I have used these stuck onto the bottom of my sunglasses for years as stealth magnification. Sticking these on a pair of sunglasses is one less thing to carry and the weight is negligible. I use contacts for distance but my up close has been slowly doing the "age dance". Since these are sold in pairs you can even use two different magnification adjustments to compensate if you need to. I have found these sold at the local CVX store but I usually hunt the net for the best price when I need to (and haven't for for a while). Durability is excellent and I have never had a lens fall off unless purposely soaked in water to remove them. Brief exposure to water hasn't been a problem.

http://optx2020.com/hydrotac.aspx

Edit

I shopped around for months for some ultra-light reading glasses for backpacking, and tried out a lot of different ones. I finally found some Zoom Slimvision glasses ($9.99) at the local drug store (many stores including Walmart apparently stock these). They are all plastic, including the hinges, pretty bombproof in that I drop them many times a day and step or sit on them many times a month, and I've never broken a pair yet. I quit using other reading glasses during the day because these are so simple, light, and cheap. They are even comfortable to read with while laying on my side because they are flat where they go past your ear. For easy access, I duck tape the cloth case they come with to my backpack straps when hiking or backpacking.

>>>
Yeah, very light, BUT ... they only work at home.
If you are out walking and have got a bit sweaty, and want to read a map, forget it. They fall straight off your nose.
Well, that's what happened to me, anyhow. Sweaty nose!
>>>

I think you should break them apart and use the pincher piece as a handle to your new monocle. Not only does that save weight, but it will make you seem really sophisticated.