Wearing prescription glasses all day long is one thing and understanding prescription terminology is another!
When shopping for glasses online do we essentially know all the scientific abbreviations used on our prescription?
Well, we at Twin Eyewear believe that a little know-how about prescription won’t do any harm. We might just end up educating someone or having an interesting optical conversation.
So here’s what you need to know about the terms popping up on an eyeglass prescription:
SPH (Sphere):
SPH is a representation of a curved lens that corrects vision by converging light that enters the pupil. The power is positive (+) for hypermetropia also known a long sightedness, and is negative (-) i.e. myopia for short sightedness. It is measured in dioptres.
CYL (Cylinder) & Axis:
Cylindrical axis is used to correct astigmatism and the geometry of the lens allows light to reflect at different focal meridians.
The transition of the two perpendicular powers is determined by the axis. A vertical axis is measured at 90 degrees and the horizontal axis at 1-180 degrees.
ADD (Addition):
ADD is the magnifying power denoted by (+) sign to correct presbyopia and instilled at the bottom of multifocal and bifocal lenses to facilitate reading.
PD (Pupillary Distance):
The distance between your left and right eye pupils measured in millimetres is the Pupillary Distance. An adult PD ranges between 55mm- 67mm. PD can be measured by pupil to pupil distance or measurement of pupil from centre of the face.
PRISM:
PRISM rectifies vision alignment concerns and is measured in P.D (prism diopters). It is given in a decimal form and denotes the thickness of the base rotation of prism. It is measured in dioptre strength and direction is classified as Base Up (BU), Base Down (BD), Base In (BI) and Base Out (BO) indicating the amount of binocular vision required.
Now that you know the unconventional terms appearing on a prescription, make sure you read well into it and make an informed decision when shopping for designer glasses online for yourself or for a loved one!
How do I submit my prescription?
Once you’re ready to checkout, you can upload an image of your eyeglasses prescription to your order (snap a photo or scan it in), submit your doctor’s contact information, or select to send your prescription to us later! If you’ve already placed an order, email the image of your prescription to hello@twineyewear.com or whatsapp it to us at +19137359491.
We’ll also need your pupillary distance (PD) for progressives.
Your PD is the distance in millimetres between your pupils, and it helps us centre your prescription correctly in your frames. If your doctor did not include this measurement with your prescription, you have a few options:
Please note: We’re unable to fill expired eyeglasses prescriptions and prescriptions for contact lenses. If your doctor provided an expiration date on your prescription, we will always abide by the doctor’s orders. If your doctor did not provide an expiration date, we’ll adhere to the optical rules of the nation where your prescription was written to determine if we’re able to fill it.
How do I obtain a prescription?
There are a few easy ways to get a prescription:
Can you fill my prescription?
Deciphering prescriptions can be tricky. If you have any questions about whether or not we can fill yours, give us a ring at +919137359491, 10 a.m.–5 p.m. EST daily.
Prescription Eyeglasses
We can fill prescriptions with a sphere (SPH) value between -18.00 and +6.00. High-index lenses are recommended in some instances and required if the sphere (SPH) value on your prescription is stronger than -10.00. You may add these lenses to your order at checkout or we will follow up with you if they’re recommended.
Uh-oh! We cannot fill this prescription because the sphere (SPH) value is stronger than -18.00.
If you have astigmatism in either eye, you will have a cylinder (CYL) value in your prescription. We can fill prescriptions with a cylinder (CYL) value within ±10.00. High-index lenses are recommended in some instances and required if the cylinder (CYL) value on your prescription is ±4.00 or stronger. You may add these lenses to your order at checkout or we will follow up with you if they’re recommended.
Uh-oh! We cannot fill this prescription because the cylinder (CYL) value is stronger than -10.00.
We can fulfil progressive lens prescriptions with ADD powers between +0.75 and +3.50 and a combined sphere (SPH) and cylinder (CYL) value between -18.00 and +6.00. High-index lenses are recommended in some instances and required if the combined sphere (SPH) and cylinder (CYL) value on your prescription is stronger than -10.00. You may add these lenses to your order at checkout or we will follow up with you if they’re recommended.
Uh-oh! We cannot fill this prescription because the ADD power is stronger than +3.50.
Prescription Sunglasses
We can fill sunglasses prescriptions with a combined sphere (SPH) value and cylinder (CYL) between -12.00 and +6.00. We cannot fill prescriptions with a cylinder (CYL) value stronger than ±10.00. High-index lenses are recommended in some instances and required for sunglasses if the combined sphere (SPH) and cylinder (CYL) value on your prescription is -7.00 or stronger. You may add these lenses to your order at checkout or we will follow up with you if they’re recommended.
What range of values are you able to fill for prism lenses?
We can fill prism values up to 6 diopters combined for single-vision, and up to 5 diopters combined for progressives.
If we are unable to fill your prescription, you can still purchase Twin Eyewear frames. Call us at +19137359491, 10 a.m.–5 p.m. EST daily to purchase a pair of frames with demo lenses for 10% off. Just take them to your doctor to have your prescription lenses filled!
