I'm wondering if it is theoretically possible to construct a lens that overlays directly on top of a watch (or phone) that warps the image in the same way that reading glasses (much farther away) would so that people with presbyopia could clearly see high resolution (or small) screens without reading glasses.
As I was researching this, I found: Screen distort for corrective lens, which has a comment that seems to be related, but the technology it references isn't really a lens, and doesn't appear to be available.
I'm guessing that an additional benefit from such a system would be that people without presbyopia or people looking at the watch from a different angle would see a highly distorted image, making it also act as a sort of privacy filter.
Would the lens need to be so large that it would be impractical? Would a fresnel lens work?