How to Measure Your PD
Your Pupillary Distance, or PD, is the distance in millimeters between the centers of your pupils.
PD helps us position your lenses correctly in front of your eyes when preparing your glasses.
If possible, ask your optometrist, ophthalmologist, or other eye-care professional to measure your PD during your eye exam. This is generally the most reliable way to obtain the measurement.
What You'll Need
- A millimeter ruler
- A mirror
- Good lighting
You can measure your PD by yourself in front of a mirror, or ask someone to help you.
How to Measure Your PD by Yourself
Step 1: Stand in Front of a Mirror
Stand approximately 20 cm (about 8 inches) away from a mirror and look straight ahead.
Keep your head level and try not to move while taking the measurement.
Step 2: Position the Ruler
Hold the millimeter ruler horizontally against your forehead or just above your eyes.
Align the 0 mm mark with the center of one pupil.
Step 3: Read the Measurement
Without moving the ruler, look at the millimeter mark that lines up with the center of your other pupil.
That number is your single PD.
If the center of your second pupil lines up with 63 mm, your PD is 63 mm.
Step 4: Measure Again
Repeat the measurement two or three times to make sure you get a consistent result.
If your measurements are different each time, ask someone to help you or have your PD measured by an eye-care professional.
Measuring Your PD With Someone's Help
You can also ask another person to measure your PD.
Look straight ahead at a distant object while the other person holds a millimeter ruler across your eyes.
They should measure from the center of one pupil to the center of the other pupil.
Keep your eyes looking straight ahead while the measurement is being taken. Avoid looking directly at the person measuring you, as this may affect the result.
Single PD and Dual PD
Your prescription may show your PD in one of two ways:
Single PD
A single number, such as 63 mm, represents the total distance between the centers of both pupils.
Dual PD
Two numbers, such as 31.5 / 31.5 mm, represent the distance from the center of your nose to each pupil.
If your prescription already includes a PD measurement, please enter it exactly as provided whenever possible.
What If My Prescription Doesn't Include PD?
PD is not always included on an eyeglass prescription.
If it is missing, you can ask your eye-care professional to measure it for you, or use the steps above to measure it yourself.
For more complex lens prescriptions, we recommend using a PD measurement provided by an eye-care professional whenever possible.
Before You Submit Your PD
Please check your measurement carefully before submitting your lens order.
If you're unsure about your PD or receive significantly different results when measuring several times, contact an eye-care professional for assistance before placing your prescription lens order.
Need Help?
If you have questions about entering your PD or other prescription information when ordering from Rimcoo, please contact us.
Email: service@rimcoo.com