We would talk a lot about how if she looked too pretty or too sexy, people wouldn't listen to her. How important it was for people to see her as an intelligent, smart woman.So maybe she wears glasses to tamp down her looks to appear more serious. I dunno, and this is a trifling thing.
But, I've looked closely at her glasses and think that either they are just clear glass, or her vision correction is so minimal that she doesn't really need to wear them all the time. How do you tell?
Look at the picture of Palin. The stronger the correction, the more that looking through them will cause a vision deflection. If you look through a person's glasses while the person is wearing them, you will notice the the side of the face appears indented in the glasses, if nearsighted. Farsighted, of course, will magnify the face. Anyway, when looking through Palin's glasses you see no deflection. The line of the side of her face is even and unbroken. Thus, weak or no correction.
That's it. No big deal. I draw no conclusions from this. I just think that if she is wearing glasses needlessly, constantly, it's interesting.