A Simple Guide to Reading Your Glasses Prescription (UK)
Clarity starts with understanding your numbers
Ordering new glasses should be simple — but if your prescription looks like a jumble of numbers and abbreviations, it can feel like a code you’re not meant to crack.
At SpecHaus, we believe the more you understand your eyewear, the better your choices will be. Here’s our straightforward guide to reading a UK glasses prescription.
1. SPH (Sphere)
This number shows whether you’re short-sighted (minus sign) or long-sighted (plus sign).
- = Short-sighted (clear close-up, blurry distance)
+ = Long-sighted (clear distance, blurry close-up)
2. CYL (Cylinder)
If you have astigmatism, this number measures the lens power needed to correct it.
It’s often followed by AXIS, which tells us where the astigmatism is positioned in degrees.
3. AXIS
Always linked to CYL, this value (0°–180°) pinpoints the exact angle of astigmatism correction.
4. ADD (Addition)
For multifocal or reading lenses, ADD shows the extra magnifying power needed for close work.
Common in prescriptions for progressive or bifocal lenses.
5. PD (Pupillary Distance)
This is the distance in millimetres between your pupils.
It ensures your lenses are aligned perfectly with your eyes for maximum comfort and clarity.
Why it matters when ordering from SpecHaus
Every pair of glasses we make is glazed in the UK, meaning your prescription is crafted with precision and checked by experienced technicians.
By knowing what your prescription means, you can feel confident that you’re getting lenses tailored exactly to your needs.
Final tip: If you’re unsure about any part of your prescription, send us a photo — our team will review it before your order is processed.
