Posted on by Kaioptics LLC


When purchasing prescription Asian Fit Eyeglasses online, you’ll need to measure your Pupillary Distance, or PD, and provide that measurement to your online eyewear provider. An accurate PD measurement helps ensure you’ll see perfectly with your new prescription glasses from day one.  

A lot of people who are ordering prescription glasses online from other sites get this step wrong; at Kaioptics, we care enough about your total satisfaction to provide you with this thorough guide to measuring your PD with care and precision.

What Is Pupillary Distance and Why Do I Need It?

Pupillary distance, sometimes called interpupillary distance, is the distance in millimeters between the center of your left pupil and the center of your right pupil.  

When you have an accurate PD on your Asian Fit prescription eyeglasses, you’ll look through the ideal spot on your lenses for maximizing your vision. When your PD measurement is off, it can negatively impact your vision. That’s why we want to help you take an accurate PD measurement.

Steps to Getting an Accurate Pupillary Distance Measurement

If you’ve already seen an optician, then you can ask your optician for your measurement.  If this is not an option for you, take heart. It’s really quite simple to take your PD measurement yourself if you’ll keep a few pointers in mind. We’ll walk you through it now.

You’ll need a ruler (any ruler that can measure in millimeters (mm)), a mirror, and a fairly steady hand.

You’ll also need to know what your iris is; your iris is the colored part of your eye.

Close up of Asian woman's left brown eyes with an arrow pointing to the iris.

Some people measure the center of the left pupil to the center of the right pupil. It’s fine to let your optician do this, as he or she has the proper tool to get an accurate center-of-the-pupil measurement. We don’t advise this method, though, because it is extremely difficult to determine where the exact center of the pupil is on your own.  Online eyewear providers who teach the pupil-to-pupil measurement method are doing a great disservice to their customers


However, it is easy to tell where your iris begins and ends on each eye.  Thus, that’s what we’ll use to take your pupillary distance measurement.


Ready?  Here are the exact steps we recommend for taking an accurate PD measurement for your Asian Fit glasses:


  1. You’ll need a ruler that can measure in millimeters (mm).


      2.  Stand about eight inches or so away from the mirror and look straight ahead, holding your head as still as possible.


      3.  Hold your ruler exactly horizontal below (or above) your eyes.   


      4.  Close your right eye and align the ruler’s zero (0) to the LEFT (outer) edge of your left eye.  Next, open your right eye and close your left eye to measure the total distance in millimeters to the LEFT (inner) edge of your iris on your right eye.


Very Important: You must measure from the outer iris on your left eye to the inner iris on your right eye.  Refer to image below.

Close up of an Asian woman's eyes with a ruler below the eyes to show measurement


You can hold the ruler above your eyes, if that helps you steady your hand.  If you’re still having trouble getting the measurement yourself, ask someone else to hold the ruler for you and take a measurement.


      5.  For accuracy, repeat the process two or three times and use an average of your measurements for your final PD measurement.


How Will I Know If I Measured Correctly?


The average woman’s PD measurement is 62mm, for men it’s 64mm.  If your measurement is between 54 and 72, you’re in the normal range. If it is outside that range, you may want to check again.


You can fill in the numbers in your cart once you've got your PD measurement. Please contact us if you have any questions!