I suspect a lot of the polymer lenses are cast to a rough shape and then ground/polished a relatively small amount to reach the final dimension.

Subtractive manufacturing is not the same as additive manufacturing.

Formlabs has demoed a 3d printed camera lens, but it's a far cry from the optical quality of eyeglasses. https://formlabs.com/blog/creating-camera-lenses-with-stereo...

Who does the grinding? How many people in third world countries have access to trained and equipped lensmakers?

I’m sad about all your hate. I thought posters to HN were more insightful that this.