How to read your glasses prescription
A glasses prescription is a short table of numbers written by your doctor. Here is what each abbreviation means, so you know what to send us when you order lenses. This guide explains the terms only; it is not medical advice, so ask your doctor about your own prescription.
The abbreviations
- OD (oculus dexter): the right eye. OS (oculus sinister): the left eye. OU: both eyes.
- SPH (sphere): the main lens power, measured in dioptres (D). A plus or minus sign shows the direction of the power.
- CYL (cylinder): extra power in one direction, written when the prescription includes astigmatism correction.
- AXIS: a number from 1 to 180 degrees that gives the direction of the cylinder. It appears whenever there is a CYL value.
- ADD (addition): extra power for near vision, used in progressive and similar lenses.
- PD (pupillary distance): the distance between your pupils in millimetres. It is used to position the lenses in the frame.
What to send us
Send a clear, complete photo of the whole prescription so every value is readable. If your prescription does not include a PD, tell us and we will explain what we need.
Next step
Ready to order? See our prescription lenses page, or message us on WhatsApp.
Frequently asked questions
What do OD and OS mean on a prescription?
OD is the right eye and OS is the left eye. They come from the Latin words oculus dexter and oculus sinister.
What does SPH mean?
SPH means sphere. It is the main lens power for that eye, measured in dioptres.
What is PD on a glasses prescription?
PD is pupillary distance: the distance between your pupils in millimetres. It helps position the lenses in the frame.
Can you make lenses from my prescription?
Yes, if it was issued by a licensed doctor. Send a clear photo on WhatsApp or bring it to the shop.
Is this guide medical advice?
No. It only explains the terms. Ask your doctor about your own prescription.