If you have had an eye test:
If you have already had an eye test, then it may be that you already have a prescription that lists your sphere (SF or SPH), pupillary distance (PD) and possibly the presence of astigmatism (C or CYL) and an axis (A, As, AXI, AXS or AXIS). You will need this prescription to order glasses. If you want to order reading or varifocal glasses then you will also need the reading addition (ADD).
If you do not know your prescription, it can be measured by an optician or optometrist by means of an eye test. Do not forget to take a copy of your prescription home with you after your test.
Your prescription document should be no older than 2 years. Additionally for customers who are under 16 the prescription needs to be signed by a GOC registered optometrist.