Eyeglass vs. Contact Lens Prescriptions: Which One Do I Use?Updated 2 hours ago
We need your eyeglass prescription. We cannot make lenses from a contact lens prescription. They are two separate prescriptions, written for two different things, and they are not interchangeable.
If you are not sure which one you are holding, this article will help you tell.
How Do I Tell the Two Apart?
An eyeglass prescription usually has:
A heading that says eyeglass, spectacle or glasses.
Columns for SPH, CYL and AXIS, plus an ADD value if it is for progressives.
A pupillary distance (PD), or a blank space where one would go.
No brand name anywhere on the page.
A contact lens prescription usually has:
A heading that says contact lens.
A base curve (BC) and a diameter (DIA) for each eye. These two values are the clearest giveaway. Neither one appears on an eyeglass prescription.
A lens brand or product name, since contact lenses are prescribed by specific product.
Usually no PD.
Why Can't You Just Convert It?
Contact lenses sit directly on the surface of your eye. Eyeglass lenses sit about 12 millimeters in front of it. That difference in distance changes how much power reaches your eye, so the same vision often requires different numbers in the two prescriptions. The effect is small at lower powers and grows as the prescription gets stronger.
A contact lens prescription also leaves out things we need, including your astigmatism written in eyeglass terms and your PD.
Converting between them is a clinical judgment, not a calculation we can make on your behalf. Only your eye doctor can write your eyeglass prescription.
What If Both Are Printed on the Same Page?
This is common. Many offices print your glasses and your contacts on one sheet, often with two separate sections.
Send the whole page as it is. You do not need to separate the sections, cover anything up, or ask your eye doctor for a glasses-only copy. We will use the eyeglass section, including the PD, and ignore the contact lens section.
I Have Multiple Prescriptions. Which One Do I Use?
Use your most recent, unexpired eyeglass prescription.
A few common situations:
An old pair and a new pair. Use the newer one. An outdated prescription may no longer match your vision, and it may also have expired.
Glasses and contacts. Use the glasses prescription.
A reading prescription and a distance prescription. Send both, and let us know what you want the sunglasses for. If you have been prescribed progressives, the ADD value will appear on a single prescription rather than arriving as two separate ones.
Different prescriptions from different doctors. Use the most recent one. If the values differ significantly and you are not sure which is current, check with your eye doctor before ordering.
When in doubt, send us what you have. Our Rx Eyewear Experts can tell you which prescription we are able to use.