Ordering contact lenses is easier when you understand the numbers on your prescription. SPH, BC and DIA describe lens power and fitting specifications; CYL and AXIS appear when a lens includes astigmatism correction. These details work together, so checking the power alone is not enough.
This guide explains what to look for before ordering from LensDirectAu. Keep your current contact lens prescription beside you, and ask your optometrist about any missing or unclear information.
Your contact lens prescription at a glance
| Abbreviation | Meaning | What it describes |
|---|---|---|
| SPH / PWR | Sphere / power | Spherical lens strength, in dioptres |
| BC | Base curve | Back-surface curvature, usually in millimetres |
| DIA | Diameter | Lens width, in millimetres |
| CYL | Cylinder | Astigmatism correction, in dioptres |
| AXIS / AX | Axis | Orientation of cylinder correction, in degrees |
SPH: understand the power and its sign
SPH may be labelled PWR or Power. A minus sign indicates correction for short-sightedness; a plus sign indicates correction for long-sightedness. For example, −2.50 and +2.50 are different prescriptions. “Plano” means zero spherical power.
Check each eye separately. Do not choose the same power for both eyes unless your prescription specifies it. If your prescribed lens is Dailies AquaComfort PLUS (90 Pack), match the exact product and each eye’s parameters before ordering.
BC: what base curve tells you
Base curve describes the curvature of the lens’s back surface. It is a fitting specification selected by your optometrist, rather than a number to estimate yourself. Matching BC alone does not establish that a different lens will fit.
DIA: why diameter matters
Diameter is the distance across the contact lens from edge to edge. Your optometrist checks how the complete lens design fits your eye. BC and DIA are part of that assessment; two brands with matching numbers are not automatically interchangeable.
If you are reordering Dailies Total 1 (90 Pack), select the prescribed product rather than a different lens with similar measurements.
CYL and AXIS: reading a toric prescription
CYL identifies the cylinder power used to correct astigmatism. AXIS specifies the orientation of that correction, on a scale running up to 180 degrees. The two values must be read together: a larger axis number does not mean a stronger prescription.
A toric lens includes astigmatism correction. A spherical product from the same brand is not a substitute. LensDirectAu stocks 1-Day Acuvue Moist for Astigmatism/Toric (30 Pack) and Acuvue Oasys for Astigmatism/Toric (6 Pack); order either only if it is the exact lens prescribed for you.
If a product menu does not offer your cylinder or axis, stop and check with your optometrist. Do not round to the nearest available option or omit a value to complete checkout.
Other details to check
OD means right eye and OS means left eye; some prescriptions use R and L. Multifocal lenses may also specify ADD, the additional near-vision power, or a manufacturer-specific category. Products such as 1-Day Acuvue Moist Multifocal (90 Pack) require the relevant multifocal specifications as well as the prescribed product.
Can you use a glasses prescription?
A glasses prescription does not replace a contact lens fitting and prescription. Spectacles sit away from the eye; contact lenses sit on its surface and require additional fitting information. Ask your optometrist for a current contact lens prescription rather than attempting your own conversion.
Your checklist before ordering online
- Confirm you are using a current contact lens prescription.
- Match the exact brand, lens model and replacement schedule.
- Enter the right and left eye specifications separately.
- Check plus and minus signs, decimal points and any CYL, AXIS or ADD fields.
- Ask your optometrist about missing values or unavailable options before placing the order.
Shop your prescribed lenses with confidence
Understanding the abbreviations helps you check an order; it does not replace professional fitting. Once you have confirmed your prescription, use the product links above to find your prescribed lenses at LensDirectAu.
General educational information. Follow your optometrist’s advice and the manufacturer’s directions for your lenses.
Further reading: ACUVUE Australia contact lens prescription FAQs; ACUVUE prescription terminology.
