/How to Measure Your PD
How to Measure Your PD
How to Measure Your PD

What is the Pupil Distance (PD)

Pupillary distance (PD) or interpupillary distance (IPD) is the distance (the industry standard is to be measured in millimeters) between the centers of the pupils in each eye. This method is used in planning to produce prescription eyeglasses. This measurement is different from person to person and also depends on whether they look at objects nearby or far away.

Why it is necessary to measure the Pupil Distance (PD)

How important it is to your vision, and why do you need it to buy glasses?

A growing range of the prescription lens has an "optical center" which is defined by the gap between the pupils. Pupillary distance is used to assess whether you are aiming through the lens of your glasses which will be as precise as possible.

A pupillary distance measurement is necessary for properly fitting your eyeglass lenses. There is no reason to walk around with inaccurate glasses when it is so easy to get this number. Be sure to take your number, and the rest of your prescription, the next time you shop online for trendy eyeglasses.

How then do we measure the Pupillary Distance (PD)

There are two methods one can measure the pupillary distance. a) Measuring it by yourself and b) Making a friend help you measure.

METHOD ONE (Measuring it by yourself)

step1.Position yourself approximately 8 inches (20cm) away from a mirror or yourself arm’s length from your friend.


step2.Close your left eye and align the ruler’s zero to the center of your right pupil.


step3. Try not to move your head or the ruler. Close your right eye and note the reading directly over your left pupil. That will be your PD.


step4.you also need to measure the distance from two pupils to the center of nose respectively to make sure that if you have two PDs(OD & OS).


METHOD TWO (Making someone help you measure).


Look straight ahead with both eyes open facing your friend. Let the person hold the ruler up to your right so the zero end lines up with your pupil.


Measure the distance from your right to your left pupil. The number that lines up with your left pupil is your PD.


Write the result down. To be certain of the result, let your friend measure a few more times to make sure your measurement is accurate.


Let your friend repeat the process on your left eye by measuring the distance from your left pupil to your right. Use the number that lines up with your right pupil. That's your PD. Write the result down. Repeat the process again to make sure the measurement is right.


Once you've got your PD measurement, input the numbers in your cart and you're good to go.