out of the blue

Funny what you come across while researching science fiction. This is from a 1957 article by Isaac Asimov:

This has happened over and over again. Betty Grable (or Marilyn Monroe or Jane Russell) is a librarian or a schoolteacher (the two feminine occupations that, by Hollywood convention, guarantee spinsterhood and unhappiness) and naturally she wears big, tortoise-shell glasses (the most intellectual type) to indicate the fact.

Now to any functional male in the audience, the sight of Betty Grable, or similar female, in glasses evokes a reaction in no way different from the sight of her without classes. Yet to the distorted view of the actor playing the hero of the film, Betty-Grable-in-glasses is plain. At some point in the picture, a kindly female friend of Betty Grable, who knows the facts of life, removes Betty's glasses. It turns out, suddenly, that she can see perfectly well without them, and our hero falls violently in love with the now beautiful Betty and there is a perfectly glorious finale.

Is there a person alive so obtuse as not to see that (a) the presence of glasses in no way ruined Betty's looks and that our hero must be perfectly aware of that, and (b) that if Betty were wearing glasses for any sensible reason, removing them would cause her to kiss the wrong male since she probably would be unable to tell one face from another without them?

No, the glasses are not literally glasses. They are merely a symbol, a symbol of intelligence. The audience is taught two things: (a) Evidence of extensive education is a social hindrance and causes unhappiness; (b) Formal education is unnecessary, can be minimized at will, and the resulting limited intellectual development leads to happiness.

The interesting question is whether I would think glasses are hot without that stereotype.