How to Measure Pupillary Distance - Vision Express Philippines

How to Measure Pupillary Distance


Pupillary Distance (PD) is the distance between your eyes. In particular, it is the space between the center of your left pupil and the center of your right pupil.


Why is it important to get your pupillary distance measured?

Every pair of prescription lenses has an “optical center,” which is determined by the pupillary distance. The center of the lenses must align with the center of the pupils. The optical center allows the wearer’s eyes to focus properly when wearing a pair of glasses.

The PD measurement ensures that your spectacles are working at its full capacity. This is especially important for people who need varifocals or those who have high-strength prescriptions.

 How to Measure Your Own Pupillary Distance

While many eye clinics can do this for you, measuring your pupillary distance is also possible. Here are the tools you need:

Millimeter Ruler

Here’s how you do it:

Step 1: Place the mirror on a wall. It should be hanging straight and not at an angle. If you’re using a vanity mirror, make sure it is positioned
Step 2: Stand exactly 8 inches away from the mirror.
Step 3: Stand straight and hold the millimeter ruler straight on top of your eyebrows.
Step 4: Close your right eye and align the millimeter ruler’s starting point (zero) to the center of your left pupil. Make sure you do it by looking straight into the mirror.
Step 5: While keeping the millimeter ruler’s position, open your right eye and determine the millimeter line that lands in the center of your right pupil.

Tip: Do this at least 3 to 4 times to get an accurate PD measurement.


Getting a Friend to Measure Your Pupillary Distance

If you feel you can’t do it alone, you can always call in a friend! Here are some tips when measuring pupillary distance with the help of a friend. While you don’t need a mirror for this one, make sure your friend has a steady hand.

Here’s how you do it:

Step 1: Stand next to each other at an arm’s length.
Step 2: Face each other.
Step 3: Ask the friend to hold the mirror to your eyebrows.
Step 4: Ask the friend to place the millimeter ruler’s starting point (zero) to the center of your left pupil.
Step 5: Ask the friend to read the millimeter line that lands right in the center of your right pupil.

Here are some tips:

  • – You don’t need to close one of your eyes.
  • – Don’t look at your friend while he or she is getting your PD measurements.
  • – To avoid obstructing your field of vision, ask the friend to sit down or crouch in front of you while measuring.
  • – Keep your eyes straight as much as you can. To do this, try to look at something about 10 or 20 feet away.
  • – Whether you measure by yourself or with the help of a friend, repeat the process at least 3 to 4 times to check for accuracy.
  • – PD measurements are taken in millimeters. However, if you measured it in inches, you can divide it by 25.4 to get the measurement in millimeters.
  • – If you don’t have a millimeter ruler, you can search for a printable millimeter ruler online and print it at home.
  • – After printing, simply fold the printout along the dotted line and use it as a makeshift millimeter ruler.
  • – The majority of adults’ PDs are between 55 and 65 millimeters.
  • – The majority of children’s PDs are between 42 and 54 millimeters.
  • – Keep your PD measurements handy so you don’t need to measure them again when you need to buy a new pair of glasses.
  • – You can save yourself and your friend a lot of time by visiting eyeglasses clinics in the Philippines so they can get your PD professionally measured.


Keep Your PD Measurement Handy

Measuring your pupillary distance can help you in shopping for prescription glasses online. Knowing this measurement will ensure that your glasses fit and perform well.

An inaccurate PD measurement is called “out of tolerance” in the optical world. A wrong PD measurement will keep your eyes from properly focusing, which can be very uncomfortable for people who depend on their glasses every day.

Not only it is convenient, but measuring your pupillary distance with a millimeter ruler at the comfort of your home before buying prescription glasses or a pair of contact lenses is also economical. Try it out!

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