How to read your prescription
An eyeglass prescription lists sphere, cylinder and axis for each eye, sometimes with ADD, prism and PD. Copy every value exactly as written, including plus and minus signs, and you have everything the lens step needs.
The fields, one by one
| Field | Meaning |
|---|---|
| OD / right | Your right eye. OS or left is your left eye; OU means both. |
| SPH | Sphere: the main power in dioptres. Minus corrects short sight, plus corrects long sight. |
| CYL | Cylinder: correction for astigmatism. Blank or DS means none. |
| AXIS | The direction of the cylinder, from 1 to 180 degrees. Only used with a cylinder. |
| ADD | Extra power for reading, used for progressive and reading lenses. |
| Prism / base | A correction for eye alignment. It needs individual review. |
| PD | Pupillary distance in millimetres; it may be given separately. |
Reading the numbers
Powers move in steps of 0.25. A sphere of -2.00 means moderate short sight; +1.50 means mild long sight. The larger the number, the stronger the lens. Cylinder and axis always go together: a cylinder of -0.75 at axis 180 is a different correction from the same cylinder at axis 90.
Entering it without mistakes
- Use a current eyeglass prescription, not a contact lens prescription.
- Match OD to the right-eye fields and OS to the left.
- Keep every plus and minus sign and every decimal place.
- Enter the axis exactly, without rounding.
- Check each value against the paper once more before you continue.
If you would rather not type it
You can upload a clear photo or PDF of your prescription instead, or choose to send it later. Either way, we review every prescription before your lenses are made and contact you if anything is unclear.
Contact lens prescriptions are different
Contact lens prescriptions include base curve and diameter and use different powers, because the lens sits on your eye. They cannot be used to make glasses.
When to contact us
Prism values need individual help, so contact us before ordering. If a value on your paperwork is hard to read, only your prescriber can confirm it.
An example, line by line
Suppose your right eye reads SPH -2.00, CYL -0.50, AXIS 90 and your left eye reads SPH -1.50, CYL -0.75, AXIS 80, with a PD of 63. That means both eyes are short-sighted, the right a little more than the left, and both have a small amount of astigmatism at slightly different angles. You would enter each value exactly as shown, with a single PD of 63.
Plus and minus
A minus sphere means short sight: distant things are blurred. A plus sphere means long sight, which often shows first as difficulty reading. The sign changes the lens completely, so a missing minus sign is one of the most important things to check before you continue. If a value has no sign at all, check the original or ask your prescriber; do not assume it is plus.
Related guides
Measure your PD
If your PD is missing.
Progressive lenses
Where the ADD is used.
Shop eyeglasses
Find a frame for your prescription.
Prescription questions
What does DS or SPH only mean?
DS stands for dioptre sphere. It means no astigmatism correction, so leave cylinder and axis empty.
Why do my eyes have different numbers?
That is normal. Each eye is measured separately and the lenses are made to match.
How old can my prescription be?
Use a current prescription. Many prescribers recommend an eye test every one to two years.
Can I order if I only have a photo of my prescription?
Yes. Upload the photo in the lens step, or send it later, and we review it before production.
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