MakerLab Idea: Eyeglass Frame Generator

MakerWorld
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Just after COVID hit, my glasses broke. I was sick, there were no covid tests yet or vaccines yet, and I wasn’t comfortable trying to visit an optometrist to get new frames (and lenses to fit those new frames).

The lenses were fine - i just needed new frames that could hold them. I tried modelling my own replacement frames, but oh many the proper geometry is far too complex to be modelled by a daft newbie designer, especially given that I couldn’t see properly at the time.

I hunted around and found some interesting tutorials, scripts for blender, OpenSCAD projects, etc. But they all required modelling the lenses in a manner that just wasn’t straight forward enough for me.

I eventually found some “virtual try on” models posted to Cults by someone named Sacha: All the 3D models of Sacha_Zacaropoulos・Cults (cults3d.com)

These models are generally great - some have compliant hinges, others have snap-fit hinges, and the frames include proper bezeling to capture professional lenses as you’d expect from real commercial frames. I printed a pair and found that my lenses kinda sorta fit… but there was a gap on one side of each lens.

I printed a couple other designs and realized that lenses have shapes that are unique to the frames they will be installed in.

Right now I’m wearing 3D printed frames from that same source, meant for a lens shape that’s just a little different than the lenses I still own… and I’d love to refactor the model to fit my lenses better. But oh man, that’s a brittle solution: all that work just to update this one frame for this one set of lenses?

I’d love to see a MakerLab project to assist in capturing lens geometries (the shape and size of the lenses), and a parameterized definition for frames (sizes and styles) so users could print custom frames that fit their own lenses and faces.

I feel like this would be a huge positive for vision-impaired makers everywhere. I’m still a noob in OpenSCAD, but am trying myself to get started on this. It’s a big idea but I’m hoping my engineering background will help bootstrap my process. All the same, perhaps i’m not the right person for this? Or maybe there are others who want to see the same feature and would like to collaborate? Anyone? Bueller? Thanks, I’ll see myself out now.

-bit

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That’s the real problem with glasses. And also the reason why opticians keep trying to sell me new frames, even though the old ones are fine. They then say we have to see if we can still make this shape of lens to fit the frame.

The frame must fit the glass perfectly so that the result is neat.

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The problem with lenses and frames is that the lens shape is cut using the frame geometry acquired with a special tool (tracer).
So you need the frames before shaping the lenses.
This is required to align both lenses on their respective optical center with our unique line of sight and also to be at the exact position given by our inter pupillary distance. If the lenses are not adequately aligned you may suffer blurred vision (with induced headaches) and your vision defects may worsen in the attempt of our brain to adjust to the new (misaligned) glasses.
In addition, if the frame induces some sort of distortion to the lenses, this may cause an additional change in the optical properties of the lenses.
This latter may even happen if your optician mistakenly cut the lens with some relevant geometric differences (it may happen) with the frames causing bending or warping of the lens.
Hope my comment helped.

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It does, I was always wondering how the lense were cut.
Do you know if opticians owns Tracers themselves or if it’s the frame manufacturer that gives the specs for cuting the lens (a CAM file or something ) to the opticians.
Because if opticians own Tracers themselves, we could probably pay for the scan of our custom frame. Convincing them to do it will be the hardest part I guess ^^

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You’re guessing right, and things are much more complicated than you may expect.
In fact there’s no specs nor CAM files to exchange (that’s the reason why they use connected tracer, centering tools and a special edger, not a CNC).
Because of the infinite combinations lenses-frames, today the best way to fit a lens into a frame is to send the cutting path made by the tracer to the edger that actually cut the lens the way the frame is used to accept.
All the data is proprietary of the tracer/edger manufacturer and is in a non-readable format by the optician (at least not like G-CODE that we are used to read).
Opticians may own tracer and the edger to do everything at their shop or just use a lab that shape the lenses and fit them to the frames for him (today the best option to avoid mistakes).
Ophthalmology and Optics markets are a bit complicated …
All lenses before their shaping are round and the center of the round lens coincide with the optical path center. after the shaping this center should go exactly where the eye sight passes through. And of course after the two lenses are mounted their respective centres must be also at the inter-pupillary distance of the client.
To make things more complicated if you own progressive lenses or multi-focal lenses the alignments gets more intriguing.
If you have a lens that’s used for reading and driving it is supposed that the eye sight centres are located in different “heights”. if you use a progressive lens the center of the optical path may pass through an area for the far sight and to another for watching TV and to another one for reading.
Not so easy :slight_smile:

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Oh thanks! I love read detailed informations on stuff/processes I don’t known about.
I guess we need to make an open source tracer an cutter if we want to able to make DIY frames ^^

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yup. but it doesn’t have to be THAT perfect. at least not in order to hold the lenses securely (whether i’m harming my eyes is another question).

right now there is a ~5mm gap between the top of my len and the frame, and the rest of the frame isn’t exactly perfect, although close enough that there are no visible gaps. I suggest that a known-scale outline model of the lens could be used to make a frame that holds lenses “perfectly enough” to be indistinguishable from commercially made frames.

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i understand that this is how it is done in practice today - with lenses being crafted to suit the frames. but that’s an artifact of the business and not a requirement.

the lenses and frames must match. our current system customizes the lenses to make them match the frames because manufacturing frames can be done generically for cost savings, and the lenses will always require customization for each prescription anyway so there isn’t a lot of opportunity to make them cheaper.

however, in our case 3D printers can readily manufacture custom frames. a workflow to customize frames to match existing lenses can save us hundreds of dollars for each replacement frame. a 3D printer can pay for itself quickly if we could just print satisfying frames to match existing lenses without starting the design from scratch each time.

Perhaps a 3D printed jig could be developed (like a fractal vise) for measuring the lens dimensions, and another for finding the distance from temple to lens center (using the face or perhaps the broken old frame?)

@cesare.tanassi i’m wearing satisfying 3D printed frames right now, albeit less than perfect they are quite nice for the ~$0.25 cost in materials and the ~1.5 hours print time.

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I perfectly understand (and agree) your point.
Today’s lenses lifespan is way longer than the frames. And finding a way to easily reproduce a broken frame or even revive with a new design using 3D printing should be easy.
Especially if you have the original prescription, inter pupillary distance is there.
Unfortunately finding the center and the orientation of the lenses is much harder.
You should have at least a lens meter to catch the optical center and the orientations.
I’ve been in the ophthalmology business for decades and always wondering a solution for this problem, but I’m still hunting…

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We’ve passed on this great advice to our MakerLab Team, thank you so much this awesome and practical idea!

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I want to add a detail regarding how the lenses, after being shaped, are fitted into the frame.
Usually the (plastic) frame is warm up to be elastic enough to let the lens slip in and fit perfectly.
So if we want to make 3D printed frames probably we may leverage on the material properties (or use multiple materials) to make our frames somewhat adaptable to the lens.
For example the frame around the lens could be a sort of mechanism that lock the lens and snap to keep it in place …
The final solution should come out in a few attempts.

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I’d love for you to try printing one of the virtualtryon.fr frames (linked in my original post). These generally work as I think you’ve described here.

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I’ll check it! But I also have something in mind to try to give a solution when you brake your frames.
I’ll be back on this.

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