I meant more, when someone has cancer, that's bad and you pity them. Cancer is an Evil that we should Fight. Whereas we don't tend to think this about nearsightedness. It is, like you say, "part of being human." It's just a screwed-up part of being human that we universally reject and patch over without thinking too much about it. Like having worms[1].

The reason I wouldn't compare it to having robot parts, is that I don't want people to associate it with having robot parts. Because some people don't think we need robot parts.

Imagine if glasses didn't exist, and we had just invented them--with everyone already being as nearsighted as they are. There are some people who would insist--in the mode of thinking of glasses as an "enhancement"--that people should just "learn to cope" with their nearsightedness, and "use their willpower" (that is, squint).

It seems pretty clear to me that there is a distinction between "things people deserve to have to make them functional" (like glasses) and "things people could use to make them even better" (like, say, a Google Glass headset.) I want to be clear that ADD/ADHD medication should be thought of as the former, not the latter.

(And I didn't vote you down, if you're curious.)

1: http://www.radiolab.org/2009/sep/07/sculptors-of-monumental-...