How to Read Your UK Eye Prescription: A Complete Guide

Have you just stepped out of the optician with a slip of paper covered in numbers and symbols? Understanding your eye prescription is the first step toward perfect vision. At CINILY, our optical lab team has spent over a decade helping UK customers translate these numbers into the perfect pair of prescription glasses.

Decoding the Key Terms

Your prescription is usually divided into two sections: Right Eye (OD) and Left Eye (OS). Here is what each column means:

• SPH (Sphere)
  Indicates the strength of the lens. A minus sign (-) means you are short-sighted (myopia), while a plus sign (+) means you are long-sighted (hyperopia).
• CYL (Cylinder) & AXIS
  These numbers relate to Astigmatism. If these boxes are blank, your eyes are perfectly spherical. If there are numbers, you need a specific correction for the shape of your cornea.
• ADD (Addition)
  Commonly found for reading glasses or progressive lenses. It’s the extra magnifying power needed for close-up work.

Our CINILY Specialists ensuring every prescription is crafted to 100% accuracy.

The Missing Link: What is PD?

In the UK, opticians sometimes don't include your Pupillary Distance (PD) on your prescription. This is the distance between your pupils in millimetres.

"Without an accurate PD, the optical centre of your lenses won't align with your eyes, causing strain or blurriness." - CINILY Optical Lab

Don't worry if it's missing. You can follow our Step-by-Step PD Measurement Guide to find your numbers accurately at home.