Prescription help

How to read your prescription

A prescription is a small grid of numbers with Latin abbreviations, and almost nobody is told what they mean. Here is what each column is.

This page explains the form, not your eyes. EYVRO is an eyewear retailer and optical workshop. We can tell you what the SPH column is; we cannot tell you what your prescription means for your vision, and we cannot issue one. That comes from an eye test with an optometrist or ophthalmologist.

What each column means

OD and OSRight eye and left eye: From the Latin oculus dexter and oculus sinister. Some prescriptions write R and L instead. If your prescription uses OU, that means both eyes together.
SPH (Sphere)The main power of the lens: Measured in dioptres. A minus value corrects short-sightedness (distance blurry), a plus value corrects long-sightedness. The sign matters as much as the number — copy it exactly.
CYL (Cylinder)Astigmatism correction: Present only if you have astigmatism. If the CYL box is blank, or reads DS, SPH or 0.00, you do not have a cylinder correction and there will be no axis either.
AXISThe orientation of the cylinder: A number from 0 to 180 degrees. It always appears alongside a CYL value — one without the other cannot be made, and if you have a CYL with no axis written down, go back to your optometrist for it.
ADDExtra reading power: Appears on bifocal and progressive prescriptions. It is a plus value added to the distance power for close work. Often written once and applied to both eyes.
PDPupillary distance, in millimetres: The gap between the centres of your pupils. It tells us where to place the optical centre of each lens so you are looking through the right part of it. Usually 54–74 mm for an adult. Sometimes given as two numbers, one per eye, measured from the bridge of the nose.
Prism and BaseA specialist correction: Only on some prescriptions. If yours has prism values, send us a photo of the prescription rather than typing it in — the notation varies and we would rather read it ourselves.

Measuring your PD

If your prescription does not include a PD, you can get close enough with a mirror and a ruler — and we will confirm it with you before cutting anything.

Stand about 20 cm from a mirror, looking straight ahead.
Hold a millimetre ruler flat against your brow.
Close your right eye. Line the ruler's zero up with the centre of your left pupil.
Without moving the ruler, open your right eye and close your left. Read the millimetre mark that now sits at the centre of your right pupil.
That number is your PD. Do it three times and take the middle value — it should land somewhere between 54 and 74.

Easier still: someone else holding the ruler while you look at a fixed point across the room is more accurate than doing it in a mirror.

Giving us your prescription

Four ways, and you can change your mind later:

Upload it — A phone photo of the slip is fine, as long as both eyes' values are readable.
Type it in — Enter the values exactly as printed, sign included.
Send it later — Order now, send it when you have it. We will message you.
Ask us — Send us a photo on WhatsApp and we will tell you what we need.

Common questions

My prescription doesn't have a PD. What do I do?

Leave it blank and order anyway. We will contact you to confirm it before cutting your lenses — either by talking you through measuring it, or from a photo. We would rather ask than guess, because the optical centre being in the wrong place is one of the few errors you genuinely notice.

How old can my prescription be?

Prescriptions change over time. If yours is more than a couple of years old we would suggest a fresh eye test first, but the decision is yours and we will fill what you send us.

Can you work it out from my current glasses?

Sometimes. If you still have a pair you see well with, we can measure the lenses in store to read the power off them. That is not the same as an eye test and it will not catch a change in your vision, but it is better than a guess if your prescription is lost.

Can you test my eyes online?

No, and nobody legitimately can. An eye test requires equipment and a person. We fit lenses to a prescription you already have.

What is the difference between single vision, bifocal and progressive?

Single vision has one power across the whole lens. Bifocal has two, split by a visible line. Progressive transitions smoothly between distance and near power with no line, which costs more and takes some getting used to. Which is right for you depends on your prescription and how you use your eyes — your optometrist's recommendation should be on the prescription.