Contact lens prescriptions can look confusing at first. They often include abbreviations such as BC, DIA, SPH, CYL, AXIS and ADD, as well as a specific brand or lens name.
This guide explains what the common contact lens prescription fields mean, so you can enter your details more confidently when ordering online.
Contact lens prescriptions are different from glasses prescriptions
Your glasses prescription and contact lens prescription are not the same thing. Contact lenses sit directly on the eye, so the prescription needs to include lens-specific details such as brand, base curve and diameter. The power may also differ from your glasses prescription.
When ordering online, use your contact lens prescription or the details from your current contact lens box.
Sphere or power
Sphere, sometimes written as SPH or PWR, is the main prescription power. A minus number corrects short-sightedness, while a plus number corrects long-sightedness.
Make sure you enter the correct sign. -2.00 and +2.00 are very different prescriptions.
Base curve or BC
BC stands for base curve. It relates to the curvature of the contact lens. Different lenses come in different base curve options, and your optometrist chooses the lens that fits your eye appropriately.
Diameter or DIA
DIA stands for diameter. It is the overall width of the contact lens. This is another lens-specific measurement and should match your prescribed lens.
Cylinder and axis
CYL and AXIS appear on toric contact lens prescriptions for astigmatism. Cylinder is the amount of astigmatism correction, and axis is the direction of that correction.
If your lens is a toric lens, both values need to be entered correctly. A wrong axis can make vision unclear or unstable.
Add power
ADD appears on multifocal contact lens prescriptions. It helps with near vision for people with presbyopia. Some multifocal lenses also include extra details such as low, medium or high add, or dominant and non-dominant eye designations.
Brand and lens name
The brand and lens name are just as important as the numbers. Contact lenses vary by material, fit, thickness, moisture profile, replacement schedule and design. If your prescription says a specific lens, order that exact product unless your optometrist has advised otherwise.
Ordering online with your prescription
When ordering from Contact Lens Depot, choose the correct product first, then enter the right and left eye details carefully. If you have ordered before, our easy reorder page can help you repeat your previous order.
We also provide receipts for eligible health fund claims and offer The Replenish Plan for customers who want to stay stocked automatically.
Frequently asked questions
Can I use my glasses prescription to buy contact lenses?
No. You should use a contact lens prescription because contact lenses require lens-specific fitting details.
What does BC mean?
BC stands for base curve. It relates to the curvature of the lens.
What does DIA mean?
DIA stands for diameter. It is the overall width of the contact lens.
What do CYL and AXIS mean?
CYL and AXIS are used for astigmatism correction in toric contact lenses.
What does ADD mean?
ADD is used in multifocal contact lenses to support near vision.
Contact Lens Depot is an optometrist-owned Australian contact lens retailer, helping customers order the exact contact lenses listed on their prescription.