Your pupillary distance (PD) is the millimeter distance between your pupils.
We need this information so we know where to put the optical center on each lens, so you’ll have the truest vision. If it’s incorrect, it can throw off your vision — making it hard to focus properly and potentially causing headaches or nausea.
The best way to obtain this information is to ask your prescribing eye doctor or optician. If you didn’t obtain it at your appointment, we recommend going to a see an optician at a local eyewear shop. Sometimes they will measure your PD for free, and other times they may charge a small fee.
If you choose to do it yourself, you can find instructions and a downloadable PD ruler here: