Do they prescribe glasses the same day?

Yes. The dr writes your prescription at the end of the exam.

If you need glasses you will get a perscription for glasses at teh end of the exam. You will NOT get teh actual glasses. Once you have the perscription you then have to choose frames and where you will buy the glasses from. So think what your budget may be for this. Look at the optometrists frames but also see what costs are elsewhere.

There are advantages to not buying online as frames need adjusting which you get free if not online, also they will sort out any possible problems with lenses and advise.

As others said, you will get the prescription the same day, usually you select frames, lens options etc and it takes like about a week the get the glasses.

If you need glasses on your face that same day, it gets more complicated, there are some places that do that, you would need to check the ads in the yellow pages under opticians, glasses, etc and see which places have "one-day service", "same-day service', "emergency service" etc. Even then, I would call first and check, in case you happen to have some really weird prescription, they might not always have the lens blanks on hand.

Yes.