Regarding your second question, that's basically what computer glasses (and reading glasses) do. They basically make things that are close, visually farther awa

Regarding your second question, that's basically what computer glasses (and reading glasses) do. They basically make things that are close, visually farther away. For people who can't focus up close anymore (elderly), they move the book visually farther away where the eye can still focus. When used as computer glasses, you could see the screen without the glasses, but with the glasses they are shifted farther away visually which helps with eye strain.