fixed missing bridge connector. 38 of you probably should redownload the eyepiece. 

Requires:

2x M4x20-25mm Screws

28x M2x (6 + glass thickness) mm Screws

Plastic, Plexiglass, or your favorite thin transparent material (that you can shape, cut, or form)

A thin strip of elastic, found on reusable cloth masks or at a craft store.

Instructions:

Print the parts however you like (I tried to make it support-less), mirroring the eyepiece to get both sides. I printed mine in PETG (because safety-something). 

Test all fittings, try not to tighten too much, as I left out the M2 nuts because it was hard to design. 

Cut/shape transparent material to fit inside “cage” of screws. I should've saved a blueprint of the shape to make a template for cutting, but you can just use the front plate holes and a fine tip pen to get a good idea. 

Secure the glass between the front plate and eyepiece using M2 screws (I added some washers because I had them), and add the bridge with the M4 screws. 

I did a little sewing to secure the elastic band, but I think you could get away with a solid knot.  

Tips:

If you are thinking to use this for a practical reason such as university labs, filament weld the gap between the plate and eyepiece to prevent leaking. The way I did it was by using a bad soldering tip to melt a line of filament between the plates. Combined with a tight fit to the glass, it is surprisingly watertight. Also look at this prusa article: https://blog.prusa3d.com/watertight-3d-printing-part-2_53638/?_gl=1*1v3e1wg*_ga*MTAzMzg4ODg1NC4xNjc3MDEyNzYz*_ga_3HK7B7RT5V*MTcwNTU4MjY2MC42NDMuMC4xNzA1NTgyNjYwLjAuMC4w 

Cosplayers and whatnot can use a thin sheet of plastic (like from a water or soda bottle) and just screw it in place. Also fun to add a layer of transparent colored plastic over the glass to get a nice tint. However with plastic, you may get some… durability issues.

Issues:

The number of M2 screws is definitely overkill, but better safe than sorry. If I can find a usable Fusion360 file, I will remedy this. The goggles are also fairly wide (140mm? I'm not sure). Good for cosplay (I think?), but bad for actually using them. Another to-do I guess. I wonder if you can use these for airsoft… not sure I want to test that actually. 

These were designed as a cheap and available university lab goggles that fit over my glasses and into my oversize jacket pockets. Turns out, it looks like a steampunk prop. Someone asked where I bought it, and now here I am.