

It took centuries to get to disposable contact lenses while trying to figure out the physics, both in optics and in manufacturing any sort of spectacles, at the same time.
Will the survivors of the apocalypse be able to pick up where we left off or will they essentially start from scratch? That depends on the apocalypse and on the survivors. Do documents and knowledge survive, perhaps in a stash or in digital form? Do the survivors include an optician or a material engineer? Chances look good if that’s the case. If no, life will get a lot harder for many people.
Just out of interest: what’s on FB messenger that makes all the things you are willing to do to circumvent the grubby data tentacles worth it? I’m just asking because I came to the conclusion not to use FB a while ago and I haven’t looked back.