For those of us who aren’t so fortunate to have 20/20 vision, we have in our employ a pair of tools called prescription glasses. To get these glasses done, we’d have to go to our eye doctors, take an eye exam, and get a recommendation based on this examination for a pair of prescription glasses. If you’ve ever tried a pair of glasses and you complained that you feel some form of eye strain, then you may have heard your doctor go, “Ooh. Seems like your PD’s off”.  At HipOptical , we have clients that do express your feelings to us. 

Also, If you use recommended frames, then the term PD shouldn’t be strange to you. You must have come across it from your optician. If you haven’t and still wondering what all the fuss is about, then wonder no longer; we will explain it to you shortly. In this article, we’ll be delving into this phrase and sharing insight on what PD is and how important it is for you. 

So, without further ado, let’s get right into it!

WHAT IS PD?

Pupillary distance (PD), also referred to as Interpupillary distance (IPD), is basically the measured gap between the pupil center of one’s eyes. This pupillary distance measurement is usually guaged in millimeters (mm). For clarity, the pupil is the round and black dot around the center of the iris of your eye. Consider the picture below for clarity.

CAUTIONS ABOUT PD MEASURES

It’s important to note that the pupillary distance is not constant across every human being on the planet. The pupillary distance pd measurement varies from one individual to another. Also, it depends on the nature of the object an individual is sighting. The object nature can range from small to big. Furthermore, the variation is influenced by the closeness of an object to a person. HipOptical teams often call the attention of patients to this crucial information. It’s vital to take good note of it. 

That being said, the average pupillary distance for a full-grown adult is around 63-64 mm, but pupillary distance measurements can vary widely ranging from 51 mm and 75 mm for women, and 52 mm and 78 mm for men.

MEASURING PD

There are two fundamental methods for measuring Pupillary distance. These are:

Monocular or Dual Pupillary distance

Binocular or Single Pupillary distance

Monocular or Dual PD refers to a pupillary distance measurement between the bridge of a person’s nose and each of his/her eye. This is believed to be the most accurate since a lot of people may find that their nose-to-pupil measurement isn’t equal on both sides. For individuals who find wearing prescription glasses important, the eye doctor most often requires the measurement of one’s monocular PD to ascertain that the lenses are well positioned in the most optimum location. This is done to avoid any form of eye strain.

Binocular or Single PD, on the other hand, refers to a Pupillary distance measured from pupil to pupil between each eye. It is essentially the total distance between your pupils

WHAT MAKE A DIFFERENCE DURING AN EYE CARE PROFESSIONAL MEASURES THE DISTANCE

It’s important to also realize that a monocular PD measurement will most often be two numbers, while a binocular PD measurement would be a single number. Hence, a PD measurement of 35/35 is a monocular PD measurement meaning that the distance of your right and left pupils from the center of the bridge of your nose is 34mm. It is also equivalent to a total PD of 70 mm (representing your binocular PD). 

However, the monocular PD is preferred for accuracy as it tells where exactly to place the lens, taking one pupil in isolation. For instance, if the right eye is 30mm, and the left eye is 32mm, then the most obvious thing to deduce is you’d have to place the center of the right lens closer to the center of the eye than the left lens’ center, and vice versa. This is very important in improving the quality of service provided by the prescription glasses to its wearer. HipOptical eye care professionals don't joke with accuracy. We always enjoy our prescription glasses are configured accurately. 

The actual determination of pupillary distance can be done with a PD Stick, a small ruler graduated in millimeters, or a pupilometer(corneal reflex ). This machine is calibrated to ensure accuracy from the eye care professional. With it, the optician will measure pupillary distance accurately. With the advent and constant improvements in technology, pupillary distance can equally be measured through several applications available on mobile phones.

HOW TO MEASURE YOUR PUPILLARY DISTANCE

Contrary to what most people think, measuring your pupillary distance can by far be one of the easiest things you can engage in. The term may come across as technical at first, but you’ll quickly realize that often times, you don’t need to visit an eye care professional or an optical professional before you know what your pupillary distance is. All you need to do is follow a few basic steps and, in a matter of minutes, you’ll know what your pupillary distance is.

MEASURING YOUR PD BY YOURSELF

STEP 1: Grab a standard magnetic card

The first step to getting your PD measurement is to get a standard magnetic card , usually light-colored cards. Know that using this magnetic card requires your presence in a room that is well lit and has no backlight. 

STEP 2: Place the magnetic card to your forehead 

The next step is to measure the distance entails taking off your glasses from your eyes and subsequently placing the magnetic card to your forehead. Then, take a picture with your phone front camera or laptop webcam. While you’re in Measure Your PD front of the camera ,ensure you’re closer to it and your eyes show clearly on the screen.

STEP 3: Proceed for capturing

To ensure that your pupillary distance measurements are accurate, it’s important you use an intelligent PD calculator. The one at is much more effective to serve your needs. When you visit the link, you will see the ‘measure PD ‘ button. Hit on it and follow the voice prompt to get measurement done. 

GETTING A FRIEND TO MEASURE YOUR PD BEFORE GETTING THE PRESCRIPTION GLASSES

If you decide to get a friend or associate to help you out with your PD measurement then you’ll need to note a few things.

The measurement process is essentially the same as measuring yourself. In this case, however, you won’t be needing a mirror.

You’ll have to keep your eyes very still, and avoid blinking or sudden movements if possible. Sudden movements or consistent blinking can often time get unsteady your friend’s hands or the ruler which may lead to an inconsistent measurement.

Before your friend takes the measurement, ensure to look above his/her head or past them for some 20 or so feet. Try not to look directly at your friend. As a general recommendation, you should stand whilst your friend sits or squats so they are out of your sphere of vision.

Have your friend measure total distance between your pupils and the isolated left and right pupils to nose bridge (as discussed above)

Repeat measurements to get consistent results. If you really want to be thorough, you can get more than one person to help with your PD measurements.

If no one is available to assist you with your PD measurement, you can seek help at http://hipoptical.com/ .It’s more advisable to even consult the help of a professional for this kind of task. 

WHAT IF YOU MANAGE TO GET AN INACCURATE PUPILLARY DISTANCE?

Generally, if your pupillary distance is inaccurate (even slightly off), you may experience some strain in your eyes, which can lead to headaches, fatigue, and blurry vision. It’s important that your pupillary distance accurately matches the centers of your pupils to get the most optimal prescription for your lenses. This cannot be overemphasized.

Now that you know what PD is and how to go about measuring it, you can delve into the act of actually knowing your PD measurement right now, without having to make the arduous visit to the eye doctor. 

Once you’ve got your PD measurement and your prescription, you can begin the phase of checking out our beautiful selection of glasses here at http://hipoptical.com/. Explore now !