How to Measure Your Pupillary Distance (PD)?
To craft a pair of glasses correctly, accurate diopters are not enough—your pupillary distance (PD) is equally essential. This measurement ensures that the optical center of the lenses is aligned perfectly with your pupils, providing clear and comfortable vision.
Where to Find Your PD
In an eye prescription, this measurement is typically abbreviated as P.D. (Pupillary Distance). Eye care professionals generally measure it in two ways:
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Binocular PD: This is the total distance from the center of one pupil to the center of the other. The value is a single two-digit number, such as 64 mm. (For example, in the illustration above, the measured PD is exactly 63 mm).
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Monocular PD: This is the distance from the center of each pupil to the center of the face (the bridge of the nose). In this case, you will see two separate numbers, one for the right eye and one for the left (e.g., 33 mm / 31 mm). This method is used when eyes are not perfectly symmetrical.
How to Measure It Yourself
If your PD is not listed on your prescription, you can measure it at home. All you need is a ruler (with millimeter markings) and a mirror. You can also ask a friend to help for better accuracy.
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Stand in front of a mirror: Ensure you are in a well-lit area.
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Align the ruler: Hold the ruler against your brow. Align the 0 mm mark exactly with the center of your left pupil.
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Measure the distance: Look straight ahead and find the millimeter mark that aligns with the center of your right pupil.
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Read the measurement: The number you see is your binocular PD.
For the most accurate results, it is a good idea to repeat the process two or three times to ensure the number is consistent.
Have questions? Consult with an optician!
