A pupillary distance is the distance between the centers of your pupils. The optical center of the lenses will be matched to the wearer’s PD if you have a strong prescription or are ordering varifocal lenses.
It is generally accepted that PDs range between 55mm and 72mm, although some people may have PDs that are smaller or larger than that. A survey conducted by the US Army in 1988 found that men’s PD was 64mm and women’s was 62mm. Due to this reason, our default PD for everyone is 63mm.
If your prescription isn’t very strong, you will be able to use the average PD without any problems, but if your prescription is strong, it is very important that it be measured accurately, otherwise you may experience headaches, eye strain or fatigue, and your glasses may not work as effectively.
You have a different PD when you are looking at objects at a distance or at close range. The human species is designed to be a hunter-gatherer and to be able to see clearly over long distances by design. In order for our eyes to be most comfortable and relaxed, they must be looking directly ahead with both eyes parallel to each other. When we look at close objects, our eyes converge, resulting in a PD of approximately 3mm narrower than when we look at distant objects.
What is the best way to determine whether an accurate PD is required?
Typically, you will require an accurate PD if your sphere (SPH) value for either eye exceeds 5.00 or your cylinder (CYL) value exceeds 2.50. Varifocals will require an accurate PD regardless of your prescription value. In addition to the above reasons, our opticians will contact you to discuss the order if the PD is not accurate.
Could you please tell me how I can obtain my Professional Development?
You will have had your PD measured by your optician during the eye examination, however they do not always provide this information when they provide you with your prescription information. You may be able to obtain your pupillary distance from some opticians, though the majority of them will refuse or charge you for this service.
If they will not provide you with your PD measurement, you cannot measure it yourself in the mirror or let someone else do it for you if they are not trained to do so. Do not worry, providing this information is quite straightforward. Check out Glasses Online for more information on how to order your PD.
