Pupillary Distance (PD)

You'll need to know your PD if you want to order new glasses online from Drsowl. Don't worry if your glasses prescription doesn't include your PD, we can show you how to measure it by yourself at home. It’s easy to measure PD online. You can also measure friends’ sizes and have them assist with telling you yours. If you’ve ordered prescription eyewear online with us before, you may have asked yourself, “what’s my PD and how do I measure it?” You can usually find your pupillary distance on your prescription, but if it’s missing, we can help!

What Is Pupillary Distance?

Pupillary distance, or PD, is the measurement in millimeters from the center of one pupil to the center of the other. It's essential to have the right PD on your vision prescription to ensure that you're looking through the best spot in your lenses for optimal clarity and comfort.

No worries if your eye doctor didn't give you the pupillary distance (PD) on your prescription! You can totally measure it yourself at home. It's pretty easy, and there are plenty of guides and tools online to help you do it right. Just follow the instructions, and you'll have your PD ready to roll when you order your glasses online.

How to Measure PD

If you're using our PD ruler on someone else (or they're using it on you), fold it to the side that says "Using a friend." Then, have them sit down and ask them to focus on something 10 to 20 feet ahead to keep their eyes steady during the measurement process.

Next, position the PD ruler against their forehead and make sure the zero mark aligns with the center of their right pupil. The number located above the center of their left pupil represents their PD measurement. During the measurement, it might be helpful to close one of your eyes so that you can read the number more precisely.


How to Measure PD by Yourself?

Measuring your pupillary distance is quite straightforward, even if you're alone. All you need is our PD ruler and a mirror. Once you have these, follow the steps below:

  1. Fold the PD ruler, and then flip it to the side that says "Using a mirror."
  2. Stand approximately 8 inches in front of a mirror. Hold the PD ruler horizontally, positioning it over your eyes, and ensure that the zero mark is directly aligned with your left pupil. If necessary, you can steady the ruler against your forehead for added stability during the measurement.
  3. Now, cover or close your left eye. Look at the reflection of your right eye in the mirror. The number directly above your right pupil on the PD ruler is your pupillary distance. This measurement represents the distance between the centers of your pupils and will help you get accurate glasses that suit your vision needs.
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To get the most accurate pupillary distance, relax and measure it a few times. If you get different numbers, find the average by adding them together and dividing by the total number of measurements. That will be your final pupillary distance measurement to use for ordering your glasses.

The person measuring should follow the same instructions as they would to get your regular PD. However, instead of focusing on an object 10 to 20 feet away, hold a pen between you and the measurer and focus on it. While you do this, the measurer can read and mark down your PD.

To measure your near focus PD for progressive or bifocal lenses, have someone follow the same instructions as for your regular PD measurement. But this time, focus on a pen held between you and the measurer. They can then read and record your near focus PD accurately.

How Do I Find My PD for Glasses?

Your PD is vital for aligning the lenses over your pupils, especially with high-powered lenses. It ensures better vision and comfort.

Your vision prescription may or may not include your pupillary distance. If it's listed, it's typically given as a single number, for example, 64. However, if there's a difference in measurement between the bridge of your nose and the center of each eye, your PD may appear as two numbers, like 32 and 31. This represents your pupillary distance separately for each eye.


What's the Average PD for Women and Men?

The average pupillary distance (PD) for both women and men typically falls between 48 mm and 73 mm. Women tend to have an average PD of around 60 mm, while men's average PD is about 64 mm. However, it's essential to remember that pupillary distance can vary for each individual and may not precisely match the averages. It's crucial to measure and use your specific PD for getting the best-fitted glasses.


Single vs. Dual PD

Single PD measures the distance between the centers of both pupils. Dual PD measures the distance between each pupil and the middle of the nose. The two numbers in dual PD represent the right eye's measurement followed by the left eye's.

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Frequently Asked Questions


What do ‘OD’ and ‘OS’ mean?

‘OD’ and ‘OS’ are abbreviations of the Latin words ‘oculus dexter’ and ‘oculus sinister’, respectively. In the context of an eye prescription, ‘OD’ means ‘right eye’ and ‘OS’ means ‘left eye.

What does Sphere, Cylinder and Axis mean?

In the context of an eye prescription. ‘Sphere’ is basically a measure of how strong your prescription needs to be. The number marked ‘axis’ describes the orientation of astigmatism. It will be a number between 1 and 180. The number under ‘cylinder’ provides the lens power needed to correct the astigmatism.

What does ‘base’ mean on an eye prescription?

Your prescription may have a ‘base’ column, or it may be included in the same column as ‘prism’ this gives further information about the required prism correction, telling us the orientation needed in the lens.

What does ‘add’ mean on an eye prescription?

The number under the ‘add’ column tells us the 2nd lens prescription needed for multifocal lenses.

What is a strong eye prescription?

The higher the number on your prescription, the stronger your prescription is. A number with a minus symbol before it means you are nearsighted, and a number with a plus symbol, or no symbol, means you are farsighted. A number over 5 is generally considered to be on the stronger side.

What is an astigmatism?

If you have an astigmatism, indicated by an “axis” and “cylinder” number on your prescription, it means that the front of your eye is irregularly shaped. This stops light from focusing properly on your retina and makes your vision blurry. It usually occurs along with near or farsightedness.

Is astigmatism hereditary?

Astigmatism is often present at birth, but it can develop, or become more severe, as you get older.

What is a diopter count?

Diopter is the measurement used for the strength of eyeglass lenses. The number under the ‘OD’ and ‘OS’ measurement in your prescription is measured in diopters.