Help & Advice

How to Read
Your Prescription

Your glasses prescription contains measurements that tell us how to manufacture lenses that correct your vision. Below is a guide to help you understand the most common terms you may see on your prescription.

SPHSphereLens strength
CYLCylinderAstigmatism correction
AXISAxisCorrection orientation
PDPupillary DistancePupil alignment

Sphere (SPH)

Sphere indicates the strength of the lens needed to correct your vision. It is measured in diopters (D).

Minus (−) Value

You are short-sighted (myopic) and need help seeing distant objects clearly.

+
Plus (+) Value

You are long-sighted (hyperopic) and need help focusing on nearby objects.

Example
SPH −2.00

Cylinder (CYL)

Cylinder is used when correcting astigmatism, which occurs when the eye is not perfectly round. If your prescription includes a cylinder value, it means your lenses must correct this irregular curvature of the eye.

Example
CYL −1.25

If the CYL box on your prescription is blank, it means no astigmatism correction is required.

Axis

Axis works together with the cylinder value to correct astigmatism. It is measured in degrees from 1 to 180 and indicates the orientation of the correction needed.

90°180°

Axis ranges from 1° to 180° — shown here at 90°

Example
AXIS 90

Pupillary Distance (PD)

Pupillary Distance is the distance between the centres of your pupils, measured in millimetres. This measurement ensures your lenses are correctly aligned with your eyes for clear and comfortable vision.

If your PD is not listed on your prescription, you may measure it yourself or ask your optician for this information.

Example Prescription

Below is an example of what a typical prescription might look like. This tells us the exact lens strength required for each eye.

EyeSPHCYLAxis
Right (OD)−2.00−1.0090
Left (OS)−1.75−0.7585

SPH

Lens power for each eye

CYL

Astigmatism correction

AXIS

Direction of astigmatism

Important

Your prescription should normally be no more than 24 months old. Regular eye examinations are important for maintaining healthy vision and ensuring your prescription remains accurate.

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