This is a question that many are concerned about, since it is well known that you cannot order your prescription eyeglasses online, if you don’t know your “PD”. So what is “PD” in eyesight and how can one find it without paying (!) an optometrist doctor to get it.
Think back at the time you entered a local eye store and just for fun, you tried on a pair of Eyeglasses. Remember that sharp strain and discomfort you felt? This is exactly how you would feel if the “PD” – Pupillary distance of your eyes, is not measured correctly and it is mistakenly applied on the prescription of your order.
Pupillary Distance – AKA “PD” – is always measured in millimeters and it is defined as the distance from the center of the one pupil to the center of the other pupil, of one’s eyes.
Of course there is an average which you may consider, regarding the pupillary distance, but this is something we strongly advise that you will only take as a reference and you will not rely your orders upon.
For example, the average pupillary distance for a male adult is about 64 mm, for a female adult is about 61.7 mm and for children about 53 mm. Once again these measurements are given only as a reference and not as a guide.
What you need to know is that there two fundamental ways to measure your “PD”:
Single PD: A single PD (or binocular PD) is the measurement of distance, in millimeters, from the center of one pupil to the center of the other pupil.
Dual PD: Dual PD (or monocular PD) is the measurement of distance, in millimeters, of the center of each pupil, to the center of the bridge of your nose.
From the two measurement methods, Dual PD is thought-out to be the most precise measurement method because the distance between one’s pupils to the center of the bridge of their nose, is unique for each person.
PD is extremely important, especially when trying to acquire glasses with progressive lenses, which it is a requirement to have an exact lens-to-pupil adjustment to confirm the best possible vision at all distances.
How to Measure your PD:
Do you have a millimeter ruler and a mirror at home? Then you are more than capable to measure your PD all by yourself!
Stand away from your mirror about 203 mm (or 8 inches distance) and place the ruler’s zero, exactly to the center of your left eye and horizontal to your eyebrow. Without moving the ruler, and keeping it at a straight line, find the center of your right pupil.
And that’s about it. You have now found the distance between the centers of your pupils which corresponds to the single pupillary distance. Just for you to be safe, we advise that you repeat this process a couple of times, to be as accurate as possible.
Quick Fit Tip 1.: Many find it a bit challenging to do this themselves, so if you have a friend that will assist you in this process, everything will be much easier.
Quick Fit Tip 2.: If you are looking to purchase reading glasses online, then from the Pupillary distance you have acquired yourself, you will need to subtract 3 mm from the measurement.