As someone who doesn't wear glasses I'm equally amazed and disappointed at their invention. Yes, a simple pair of lenses and a frame can convey sight, great. But, the invention of glasses has effectively devalued my perfect sight. In medieval times I'd be sent for as the chap who knows things AND can see. I'd be medieval rich, whatever that looks like. Anyhow, being able to see is great, corrective lenses can do this quite well. But, large parts of the world are conspicuously devoid of 1hr prescription lens stores.
Since quite a lot of the assessment of eye sight is just asking people if things look better or not, to some extent people can choose their own prescription. One way this was used for glasses was quite ingenious. I can't find the original, but here's the similar idea <link>. Basically, two clear plastic membranes, separated by water constitute the lens. The magnification is changed by simply adding or removing water to change how much the membranes bulge in the middle. In the version I saw, this was done with a syringe, the wearer would look at things and change the pressure on the syringe until things looked good, then lock off a valve and remove the syringe to have a wearable pair of glasses.
This is great, only there will always be the possibility of leaks be they from damage, or just the way liquid containers behave over long periods. So how to get around this?
Simple, instead of water, we use one of the many UV curable resins currently popular in one type of 3D printing amongst many other applications.
Using the resin, the wearer pushes/pulls the syringes until the best possible prescription is reached, then, goes outside for a wander about in the sun. The UV resin will cure quickly in sunlight and in a few minutes the lenses will be solid plastic. Now, the membranes, syringes and possibly some/all of the frame can be removed leaving sleeker more durable user-made glasses.-- bs0u0155, Mar 08 2021 Water adjustable glasses https://www.economi...6/05/seeing-clearly [bs0u0155, Mar 08 2021] Medieval spectacles https://www.medieva...thirteenth-century/ [pocmloc, Mar 09 2021] Prior art. Omnioculars [2 fries shy of a happy meal, Mar 14 2021] //medieval rich, whatever that looks like//
Overweight, vitamin-deficient and mocked by a stonemason in a satirical gargoyle.-- pertinax, Mar 08 2021 //mocked by a stonemason in a satirical gargoyle.//
I WISH!-- AusCan531, Mar 09 2021 The water ones would work both better and worse in freezing climates.-- AusCan531, Mar 09 2021 Brilliant [+]-- Voice, Mar 09 2021 //The water ones would work both better and worse in freezing climates.//
Not water, temperature setting thermo-hydrate. Or some other marketeering.-- bs0u0155, Mar 09 2021 It is obvious you don't wear glasses, or you would know about this tricky thing called astigmatism.
You probably have it and simply don't know it.-- UnaBubba, Mar 13 2021 ^ I've got Stigmata if that counts.-- AusCan531, Mar 13 2021 Astigmatism means without stigmata, so no, that doesn't count.-- pocmloc, Mar 13 2021 Nailing yourself to a cross wasn't your smartest idea, was it, [AsuCan531]?-- UnaBubba, Mar 13 2021 Although, the gubbins and manipulations, to do it properly, would be next level.-- wjt, Mar 13 2021 I get stigmata on my eyes if I don't get enough sleep.-- sninctown, Mar 13 2021 // It is obvious you don't wear glasses, or you would know about this tricky thing called astigmatism.//
I got tested last year because I was under the impression my eyesight had taken a distinct downturn. Because I work with optics/microscopes most of my working life, I have objective ways to know it was worse. My prescription was -0.25 in one eye... I got some glasses and I concluded they weren't worth it. For the slight improvement in one eye, it's not worth the frames in the way and my eyelashes putting streaks on the lenses.
But yeah, we're not going to be able to correct astigmatism here. I wouldn't know how, to be honest.-- bs0u0155, Mar 14 2021 Would a UV filter layer be added after curing?
Maybe a wash from two tiny dye packs that burst after the correct exposure from the sun.-- wjt, Mar 14 2021 random, halfbakery