Does Pupillary Distance Have to Be Exact?

Pupillary distance – also known as interpupillary distance – is a measure of the distance between a subject’s pupils.

Finding Pupillary Distance

This measurement is factored into the creation of corrective lenses to help locate the optical center of the lenses. Millimeters are the measurement unit used as the industry standard.

Pupillary distance can be measured by machine – a “corneal reflex pupillometer” – or with a millimeter ruler by any optometrist or optical assistant. It can also be measured by you at home with a small ruler, if you’re careful. The pupillary distance measurement does not have to be 100% precise to be useful, as it can tolerate a fairly small error range. If you do measure your own pupillary distance, it is recommended that you try several attempts to be sure you get a fairly accurate measurement.

Measurement ranges

To give you an idea of the kind of measurement readings you should get, here are the typical ranges for various groups:

  • Average pupillary distance for an adult is between 54-68mm, with acceptable measurement deviations generally falling in between 48mm and 73mm.
  • The range for children is approximately 41-55mm.
  • The large majority (95 percentile) of adult males in the USA have a pupillary distance of 70mm while a small minority (5 percentile) measure 55mm.
  • The range for adult females in the USA is between 65mm and 53mm.
  • For Europeans the figures equate to roughly 1mm smaller than the above measurements.

How to Measure Pupillary Distance Yourself

If you recently had an eye exam and were given a written prescription, or have an older prescription on file, the prescription may already indicate your pupillary distance. If it does not, you’ll need to obtain that measurement. To do it yourself, follow these steps:

  1. Obtain a millimeter ruler and place it against your eyes, resting on the bridge of your nose.
  2. Line up the 0mm starting point with the outer side of either your left or right pupil.
  3. Look straight ahead and have someone else note the reading, or look directly into a mirror and note the reading yourself. (If using an assistant be sure they are at the same height as you when they record the measurement.)
  4. Once lined up correctly as stated in step 2, the millimeter mark that falls in the center of your opposite pupil is your pupillary distance.
  5. Repeat the process a few times to be sure you get the same result.
  1. Leah says:

    I ordered glasses with a pd of 65. I was told today it was actually 62. Will I need to reorder new glasses.

  2. Kevin Hooten says:

    If I misread my pd of 69 and ordered my glasses as 65 will they be safe to wear ?

    • Melissa Richard says:

      It is very slightly out of tolerance. You may not experience an issue. It’s hard to say. Depends how sensitive your eyes are.

  3. William says:

    I cant seem to get a consistent measurement of my PD, even via opticians. My first bifocals were 64 (32/32). 18 months later, a different optical chain measured 64 (29.5/33.5). Six months later, at the same first store, they measured 63(29/34) and repeated it with 62 (29.5/32.5)? My own home tests, done multiple times with an EyeQue Pd check app were 64 (31/33). I think my “imperfect” nose/bridge may be an issue, at least when it comes to placing the pd machine or my glasses on my face, because it is hard to keep my glasses from slipping a bit, which alters the measurements, but I want the best vision possible. Any ideas? Ps- all the videos are very informative. Thanks.

    • Melissa Richard says:

      All your PD measurements you are being given are within tolerance of each other. You should be ok sticking with the 64

  4. Caitlyn says:

    I need prescription safety glasses but I am having a hard time finding any that fit a 56 PD. Can I order my script but with a PD that is slightly higher?

    • Melissa Richard says:

      While there is a tolerance with PD, it’s not recommended to order with any different number. If you take a look at our website, rx-safety.com we have a wide variety of frames to choose from. Any flat model, can accommodate your PD of 56.


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