Your current lens box
The product name and values are normally printed on the outer box and often on each blister pack.
Lens parameters
Understand your contact lens prescription
Use this guide to match the values on your prescription or lens box with the fields shown when you order.
Always order the exact lens model and values recommended for you by an optician or eye care professional.
Start here
Where can I find the values?
The safest reference is the packaging from lenses you currently wear successfully, together with your current contact lens prescription.
Your contact lens prescription
Use a current prescription that states the contact lens model and parameters for each eye.
Ask your optician
If you no longer have the packaging, ask your optician for the exact lens model and contact lens prescription.
Read the box
Where the values appear on the packaging
Look for the technical abbreviations beside the printed values. The exact layout varies by manufacturer.
Packaging designs differ, but the abbreviations and values are normally printed on the box or individual blister pack.
The six common values
What each parameter means
The abbreviation is what you usually see on the manufacturer's packaging. The accompanying name and explanation can be translated for each market.
SPH/PWR
Power
The optical power of the lens. A minus value corrects short-sightedness and a plus value corrects long-sightedness.
CYL
Cylinder
The amount of correction for astigmatism. It appears on toric and multifocal toric lenses.
AX/AXIS
Axis
The orientation of the cylinder correction, expressed in degrees from 0 to 180.
ADD
Addition
The additional near-vision power used in multifocal lenses. It may be shown as a number or as LOW, MED or HIGH.
BC
Base Curve
The curvature of the back surface of the lens, which is part of how the lens fits the eye.
DIA
Diameter
The overall diameter of the contact lens, measured in millimetres.
Please note
Names and placement may vary between manufacturers and lens models. Always use the exact values from your own packaging or contact lens prescription.
Different names, same value
Manufacturers may use different names
Use the technical notation to identify the matching field when a box, prescription and product page use slightly different wording.
| On the packaging | Parameter |
|---|---|
| SPH / PWR / Power | Power |
| CYL / Cylinder | Cylinder |
| AX / AXIS | Axis |
| ADD / Addition | Addition |
| BC / Base Curve | Base Curve |
| DIA / Diameter | Diameter |
Right and left
Check which values belong to each eye
Prescriptions do not use the same right- and left-eye notation in every country. The labels and examples below are fully editable for each market.
Right eye
These are common examples. Your prescription may use another local abbreviation.
Left eye
Read each row carefully because the model or values can differ between your eyes.
Lens types
Which parameters does each lens type use?
The values you need depend on the type of contact lens prescribed for you.
Spherical
A standard contact lens for correcting short- or long-sightedness.
Toric
A lens that also corrects astigmatism.
Multifocal
A lens with distance and near-vision correction.
Multifocal Toric
A multifocal lens that also corrects astigmatism.
Practical examples
How parameter combinations can look
Different lens types require different combinations of values.
These examples only show the format. Do not copy them—use the exact values prescribed for you.
Spherical
- SPH -3.50
- BC 8.6
- DIA 14.0
Toric
- SPH -3.50
- CYL -1.25
- AX 180
- BC 8.6
- DIA 14.5
Multifocal
- SPH -3.50
- ADD HIGH
- BC 8.6
- DIA 14.2
Multifocal Toric
- SPH -3.50
- CYL -1.25
- AX 180
- ADD HIGH
- BC 8.6
- DIA 14.5
Good to know
Why can't I select BC or DIA when ordering?
BC and DIA are still normally printed on the packaging. Some lens models are only manufactured in one base curve, one diameter, or one fixed combination. When the value is fixed for that product, Netlens may not need to show it as a selectable option.
Important
A contact lens prescription is not the same as a glasses prescription
Contact lenses sit directly on the eye, while glasses sit in front of it. The values can therefore differ, and a contact lens prescription also identifies the lens model and fitting parameters.
Do not convert or copy values from a glasses prescription. Use a current contact lens prescription and the exact lens model fitted for you.
The product matters
Parameters are only part of the match
Two lenses can show the same power, BC and DIA but still be different products. Always order the exact contact lens model prescribed or fitted for you.
Match the complete product name
A family name is not always enough. Daily, monthly, toric and multifocal versions can have different parameters and materials.
Check who makes the lens
The same or similar wording can appear across different brands. Compare the manufacturer as well as the full model name.
Do not guess
Can't find your exact value?
Do not simply select the nearest CYL, AX, ADD or other value. A nearby option is not automatically an appropriate substitute.
First check that you have selected the exact lens model. If the prescribed value is still unavailable, contact your optician or eye care professional before ordering.
The easiest reference
Reorder the lenses you already use
If your current lenses work well and your prescription is still valid, use the product name and values from the current packaging. Check the right and left eye separately before completing the order.
Optician's own brand
Your lens may be sold under another name
Some opticians sell a manufacturer's contact lens under their own brand name. An equivalent-name guide can help identify the original product.
Only use an equivalent when the product match is confirmed. Do not rely on similar parameters alone.
Quick answers
Frequently asked questions
Can I order using only the values on my old box?
The box is a useful reference when it is the exact lens model you currently use and your contact lens prescription is still valid. Check both the product name and every value for each eye.
Can I use my glasses prescription?
No. A glasses prescription is not a contact lens prescription and may contain different values. Ask your optician for your contact lens prescription.
Why is BC or DIA printed on the box but not selectable?
The lens model may only be available in one fixed BC or DIA. Netlens therefore does not need to present that fixed value as a choice.
Can my right and left eye have different values?
Yes. They may also use different lens models. Read and enter the information for each eye separately.
What should I do if my exact value is missing?
Check that you selected the correct lens model. Do not choose the nearest value; ask your optician or eye care professional before ordering.
Ready to reorder?
Use the model and values from your current lenses
Find the exact product, enter the values for each eye and check your choices before adding the lenses to your cart.