What does “farsighted” mean?

In the simplest sense, “farsighted” should mean able to see far away. Of course, the only reason to use the term is that it precludes being “all sighted,” or able to see far away and up close, so, presumably, someone who is farsighted has difficulty seeing up close.

When we use the term in ophthalmology, we usually mean someone who has a “+ power” glasses prescription, meaning that their eye needs extra converging power to focus light in order to see. The funny thing in this regard is that, especially at young ages, people with “+ power” glasses prescriptions may be able to see far away and up close without glasses, which would make them “all sighted” rather than “farsighted,” right? They do this by adding extra focusing power to their own eye by flexing the natural lens inside the eye.

I think the moral of this story is that young people are confusing.