Reading Your Rx
Ever looked at your prescription and felt a little lost in the sea of numbers, symbols, and abbreviations? Don’t worry, you’re not alone! At first glance, it can seem a bit intimidating, but we’re here to make it easy! Below, we’ll walk you through how to read your prescription for glasses or contact lenses, and how to accurately enter it when ordering your perfect pair of Zenni glasses (or lenses). Let’s get started!
How to Read Your Prescription
OD/OS: These abbreviations indicate which eye the prescription is for.
OD: Right eye
OS: Left eye
OU: Sometimes used to indicate both eyes.
SPH (Sphere): Indicates how much lens power is needed to correct nearsightedness or farsightedness.
A negative (-) SPH commonly means you are nearsighted (things are blurry far away).
A positive (+) SPH commonly means you are farsighted (things are blurry up close).
CYL (Cylinder) and Axis: These appear on your prescription if you have astigmatism (when your eye's shape causes blurred vision).
CYL: Measures the power needed to correct your astigmatism.
Axis: A number between 0 and 180 that shows the direction of the correction.
ADD or NV Add (Near Vision Addition): This value adds extra lens power for close-up tasks like reading. It’s used when ordering multifocal lenses like bifocals or progressive lenses.
PD (Pupillary Distance): The distance between the centers of your pupils (in millimeters). This ensures that your prescription is properly aligned with your eyes for crystal-clear vision.
Single PD: A single number for both eyes (e.g., 62).
Dual PD: Two numbers for each eye (e.g., 33/31).
Distance/Near PD: Separate values for distance and near vision (e.g., 62/59).
PRISM △**:** Used if you have issues with vision alignment or double vision.
Prism Value: Measures how much correction is needed.
Base Direction: Shows the placement of the correction (e.g., Base Out, Base In, Base Up, or Base Down).
Note: If you have a prism correction on your prescription, it’s important to include this when ordering glasses.
Signs to Look Out For
Plus (+) and Minus (-) Signs: Always double-check these signs to ensure your prescription is entered correctly. These are small details that make a big difference in your prescription!
Extra Terms & Abbreviations
On top of sphere, cylinder, axis, and ADD, your prescription may have extra abbreviations. They can look confusing, but they’re just shortcuts or extra information eye doctors may use. Here are some common ones and how to handle them when ordering glasses:
DS or SPH: When these abbreviations are written as the CYL (cylinder), there is no astigmatism correction for that eye.
DS or SPH in the cylinder box = 0.00 cylinder
PL or Plano: This indicates that there is no sphere power for that eye.
PL or Plano in the sphere box = 0.00 sphere
BAL or Balance: Indicates that this eye has no vision.
Enter the same prescription as the other eye for balanced lenses.
For BAL prescriptions, impact‑resistant lenses are always recommended to help protect the eye with good vision.
You might also see these, but you don’t need them when ordering glasses:
VA (Visual Acuity): Shows how clearly each eye sees, like 20/20 or 20/30. For example, 20/30 means you see at 20 feet what someone with standard vision sees at 30 feet.
BVD (Back Vertex Distance): The distance between the back of the lens and your eye. It tells the dispenser how the lenses were measured. This distance can slightly change how strong lenses feel, especially with higher minus or plus powers.
How to Enter Your Prescription (Rx)
Single Vision Glasses: Single vision lenses have one prescription strength for nearsightedness, farsightedness, OR reading.
Select "Prescription" and then "Single Vision."
Select your PD (Single PD or Dual PD).
Enter the SPH, CYL, and Axis values for both eyes.
If you have a prism correction, click "Add Prism Values" to input the Prism (power) and Base (direction) values.
Double-check that all the values, particularly the signs (+ or -), are correct.
Customize your lenses and proceed to checkout.
Bifocal & Progressive Glasses: Bifocals have two focuses (distance AND near) with a visible line. Progressives have multiple focuses (distance, intermediate, AND near) with no visible line.
Select "Prescription" and then choose “Bifocal” or "Progressive.”
Select your PD (Single PD or Dual PD).
Enter the SPH, CYL, and Axis values for both eyes.
Enter your ADD.
Prism is not available for multifocal lenses. If your prescription includes prism correction, we recommend exploring single vision lenses as a great option.
Double-check that all the values, particularly the signs (+ or -), are correct.
Customize your lenses and proceed to checkout.
By following these steps, you'll be on your way to receiving perfectly tailored glasses that meet your vision needs. Feel free to contact us via chat or phone if you have any questions. Our team is here to help!
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