You can find your contact lens details in several places, on the prescription from your eye doctor, on the contact lens box and also on the actual contact lens recepticle.

This is all the information that your contact lens provider will need so you can purchase the correct contact lenses

OD = Right Eye
OS = Left Eye
Brand Name (e.g. Acuvue)
BC / Base Curve (a number between 8.0 and 10.0)
DIA / Diameter (a number between 13.0 and 15.0)
Power / Sphere / Rx (a number between -20 and +20)

For astigmatic patients, they will also need:
Cylinder (a number between -4.00 and +4.00)
Axis (a number between 0 and 180)
Cylinder and Axis are usually separated by "X" and read as "times"

A regular prescription would look like this:

OS Brand Name: eg: Frequency 58 OS BC: 8.8 DIA: 14.4 POWER or SPHERE: -2.50 OD Brand Name: eg: Optima FW OD BC: 8.4 DIA: 14.0 POWER or SPHERE: -2.75

A prescription for astigmatism would look like this:

OS Brand Name: eg. Acuvue Toric OS BC: 8.8 DIA: 14.4 POWER or SPHERE: -2.50 OS CYL & AXIS :- 1.25 X 180 OD Brand Name: eg. Focus Toric OD BC: 8.7 DIA: 14.0 POWER or SPHERE: -4.50 OD CYL & AXIS: - 0.75 X 95

This information may appear complicated but in fact it is very straightforward. Just consult your current contact lens packaging for reference. If you have further trouble obaining the correct information, the customer service department of the contact lens supplier will help you as they want to receive the correct contact lenses.

Frequently Asked Contact Lens Prescriptions Questions

What does Axis mean?

An axis (often abbreviated to AX) is one of the values or measurements used to describe toric lenses. Toric lenses are used to correct astigmatism, a condition marked by unevenness of the cornea. The axis is measured in degrees and is the amount of orientation needed in the cylinder of the lens to compensate for the astigmatism patients oval cornea instead of round cornea.

What does cylinder mean?

Cylinder (often abbreviated to CYL) is one of the values or measurements used to measure astigmatism. It is measures in diopters. The measurement describes how severe your astigmatism is. A negative sign is myopic (near-sightedness) astigmatism and a plus sign is hyperopic (far-sightedness) astigmatism.

Where can I find my parameters?

You can find your parameters on the paper copy of your prescription, or on the box containing your lenses. You will find details of the power/strength/sphere (SPH), base curve (BC) and diameter (DIA). If you have astigmatism you will also find an axis (AX or AXIS) and cylinder (CYL). If you use bifocal, multifocal or progressive lenses, you will find the extra strength or "add power". The brand name you were prescribed will also be described.

What does base curve, BC or radius mean?

The base curve or radius (often abbreviated to BC) describes the curvature of the lens. It is measured in millimeters and your contact lenses BC has to complement your own curvature of your cornea. The lower the number the steeper the curve.

What does diameter mean?

The diameter (often abbreviated to DIA) is the size of the lens measured in millimetres from edge to edge. It is important as this determines where the contact lens will sit on your eye. If it is wrong your lenses will be irritating and can cause abrasion.

What does extra strength or add mean?

Add power describes the difference in strength between the focal fields in multifocal and bifocal lenses. This is the difference for close up viewing such as reading compared to your vision for focusing on far away objects. It is always expressed with a plus sign, if the plus sign is absent it is always understool that it is a plus figure.