Can you tell me when you go for an appointment to see an optometrist, do they prescribe glasses for you the same day?

Yes: Optometrists are very keen to sell eyeglasses and contacts and will encourage you to purchase them after the examination. The prescription is at the same time and you will usually be conducted into the optical shop for the glasses. Ophthalmologists are more disease oriented and will prescribe only if you actually need the glasses so you get a more comprehensive and professional exam there.