Hi Mtheo,
I am an optician and I can tell you that they legally are required to give you information that was found in your eye test. As part of the eye test they will record the PD - which is pupillary distance - eg distance between your pupils. If you have a high prescription this measurement is very important. It will not damage your eyes if you get the PD wrong - but it may result in eye strain and headaches.
What is your prescription and I will be able to help you further?
Thanks
Simon