Did Rex Harrison have a glass eye?

An eye glass for one eye is called a spectacle. Not spectacles, that would be another name for glasses as a pair.

They Correct people's vision

No, eye glasses improve you vision not impair it.

Yes! if you don't have the right eye prescription in your glasses. No. According to the National Institutes of Health (see link below), the use of glasses or contact lenses does not affect the normal...

A monocle!