This is a question that many are concerned with, since it is well known that you cannot have your prescription eyeglasses ordered 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 have it.
Think back at the time you entered a local eye store and just for the fun of it, you tried on a pair of Eyeglasses. Remember that sharp strain and discomfort you felt? That is exactly how you will 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 on 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 actual orders on it.
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 only as references and not as guides.
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 their nose, is quite unique to 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 your house? 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).
- Hold a ruler against your brow.
- Close your right eye then align the ruler’s 0 mm with the center of your left pupil.
- Look straight then close your left eye and open your right eye.
- The mm line that lines up to the center of your right pupil is your PD.
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.
Optics FiTip 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.
Optics FiTip 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.
Armed with your PD and prescription, you can shop at Opticsfit to find your perfect pair of glasses.