2019-07-30 I've uploaded a V2 version that eliminates the bottom magnet in favor of a hook design, and trims off some of the structure and tapers it in order to maximize space around the nose area. Eliminating the bottom magnet means this version probably fits the Rift S, unlike the original.
This thing is a prescription lens adapter designed for my Oculus Quest. It uses a base that you snap onto each headset lens and leave there, and magnets to mount the prescription lens adapter to the base. The magnets make removing the lenses quick and easy for when you want to share the headset with others or clean the lenses. I use the quest glasses spacer with this adapter.
Short clip that shows putting the lens onto the base: https://youtu.be/cTAAFVNzPQg
The prescription lenses that fit this adapter are available by ordering eyeglasses from Zenni optical with frame #550021. (https://www.zennioptical.com/p/stainless-steel-round-eyeglass-frames-/5500?skuId=550021)
The glasses should be ordered with 65mm IPD, OR you should set the Quest IPD adjustment to the center if you've ordered your Zenni glasses with your own prescription IPD. Note that if you already have lenses, depending on how far from 65 your IPD is, the optical sweet spot of your prescription lenses might be a bit off of the sweet spot of the headset lenses. You may need to play with the IPD slider to find a spot that works for you.
The magnets used are 5mm x 2mm disc magnets.
I'm actively using the latest version of this design and it's working well for me. If you decide to try these, let me know how they work and if you have any suggestions.
I've only been printing these at .1 mm layer height but .2 would probably work.