With over 10 years working with our visitors to tailor eyewear solutions for them, our Vision Ambassadors have curated some of the top questions received from our visitors and customers. Today we start with our most frequently asked question: what are the numbers on my glasses or contact lens prescription and how do I read them? Clearly’s Head Optician, Claudia Rojas, provides us with key guidelines that she also provides to our Vision Care Team on how to read your optical prescriptions.
The following are some tips on understanding your eyewear prescriptions. If you’re unsure of anything call our Vision Care team at 1-866-414-2326 who are also happy to contact your Eye Care Provider to check your prescription on your behalf.
What do the numbers on my prescription mean?
Your prescription may include a SPH, CYL, Axis, ADD and Pupillary Distance (PD). If your prescription does not include one of those it simply means that you do not require that corrective power. There is a separate prescription for your right eye, and for your left eye.
Right eye parameters
Left eye parameters
Sphere indicates the amount of lens power prescribed for nearsightedness or farsightedness.
CYL & AXIS
A Cylinder (CYL) and Axis is required to correct Astigmatism. Both parameters will be required together.
This provides magnifying power for reading, progressive and bifocal lenses. You will have the same number for both eyes.
How do I Read My Glasses Prescription?
In addition to the general parameters, a glasses prescription also requires a Pupillary Distance (PD).
Pupillary Distance (PD)
PD is the distance between the centre of one pupil (the central black dot of your eye) to the centre of the other pupil, measured in millimeters.
This is how you would include the numbers on our website for glasses:
How do I Read My Contact Lens Prescription?
In addition to the general parameters, a contact lens prescription will include a Base Curve and a Diameter.
BASE CURVE (BC) & DIAMETER (DIA)
Both the Base Curve (BC) and Diameter (DIA) of a contact lens ensures a proper fit on your cornea and total eye surface to ensure comfort, and encourages eye health including allowing proper oxygen to the eye.
This is how you would find your prescribed contact lens product and enter your prescription:
1) Find your prescribed brand (in this case it is Acuvue 2 but your Eye Care Professional will prescribe the best product for your eye health)
2) Following your prescription, enter the Power, Base Curve and Diameter
If you have any questions about your glasses or contact lens prescription call our Vision Care Team at 1-866-414-2326 for assistance.