My optician didn't give me BC or DIA. What do I do?

If your prescription is missing BC or DIA, three things can be true:

1. The lens you were fitted with comes in only one BC/DIA. Many popular brands (1-Day Acuvue Moist, Biotrue ONEday, Dailies Total1) have a single available size — there is nothing to choose. The optician may have skipped writing it down.
2. You were given a glasses prescription by mistake. Glasses prescriptions never carry BC/DIA. Call the practice and ask specifically for a contact-lens prescription.
3. The values were measured but not recorded. Practices keep them on file — a phone call usually retrieves them in minutes.

What we strongly advise against: ordering "the most common BC" by default. A lens that doesn't match the cornea can cause discomfort, corneal staining, and over time, neovascularisation (new blood vessels growing into the cornea). Always confirm.