This project contains a source file that you can print on a 3D printer. The part you make can be used to mount a lens on Google Glass. The Instrucable also helps you choose the correct lens.
Mounting a lens fixed some problems for me with Google Glass. My right eye (the one that sees the Google Glass display) is very nearsighted. As a result, the Google Glass display was too blurry for me to read, as the optics mimic seeing a larger display at a distance of about 8-10 feet. It should also solve the problem for people whose right eye is too farsighted. I do not normally wear glasses because my left eye is not nearsighted.
I've found that when I wear Google Glass, others often want to give it a try. The mount is very easy to remove, so this makes it easy to let others give it a try.
Step 1: Find a lens
Non-prescription glasses are available inexpensively. In most drug stores you can find "reading glasses", which allow nearsighted people to see up close, often for about $10. I needed the opposite kind of glasses, called "distance glasses", and I found some on eBay for about $16.
Such glasses are rated by the amount of diopter change they cause. Don't worry if you aren't familiar with diopters. If it is a positive number, they are reading glasses for farsighted people. If it is a negative number, they are distance glasses for nearsighted people. The bigger the number, the stronger they are, usually in the range 1.0 to 3.0 or -1.0 to -3.0.
My right eye can see an object 2 feet away in perfect focus, but by the time the object is at arm's length, it has started to get blurry. Glasses with a -1.5 diopter rating worked fine for me.
Step 2: Remove the lens from the frame
It is probably easiest to use a hacksaw to cut the frame, and then when there is almost nothing left, clip the remaining piece with a pair of wire cutters. When the frame is cut all the way through, the lens is easy to pull out.
I use the entire lens, but you don't need one that large. If you want to cut the lens down, a Dremel cutting disk works well.
Step 3: Print the part
The attached GlassHolder.stl file contains the 3D model for you to print. If you use Makerware and a Makerbot 3D printer, I've also included the GlassHolder.thing file, but you don't need it. This part is small and printed easily on a Makerbot 2X printer. I used a 0.10 mm layer height, the highest resolution on the printer, which is probably a good approach since the features are small. I printed it using a raft.GlassHolder.stl
Step 4: Try the fit
The part has a curvature that will be different from that of the lens and different from that of the Google Glass frame. This slightly different curvature allows the part to grip tightly. But the curvature should be in the same general direction. If the curve is opposite, turn the part around.
The outer slot is for the Glass frame, and the inner slot is for the lens. Try putting the lens into the part (the top of the lens against the part), and then remove it. Then try fitting the part onto the top of the Glass frame.
Step 5: Put it all together!
Remove the part from the Glass frame. Attach the lens, then attach it to the Glass frame.