They can be depending on your vision issues. Mine are essentially bifocals where the reading portion isn’t visible. If I focus there’s a tiny fuzzy line where the readers meet the normal lens.
To be honest I wasn’t aware of the sides issue and it seems you might have different problem that requires a third lens.
No, he likely couldn’t do that as Andre Previn, her actual adoptive father, was alive until a few years ago. Allen and Farrow’s relationship was really weird and he and Soon-Yi supposedly never met until she was 18.