Answering Your Top Questions About Pupillary Distance (PD)
- BY Dr. Sophia Moh
- IN Eye Care
Pupillary distance (PD) is a term you’ll encounter when ordering eyeglasses online, and it’s an essential measurement for ensuring optimal vision and comfort. To help demystify PD and address some common questions, we’ve put together a brief guide:
1. What is ‘PD’?
PD stands for pupillary distance, which is the distance in millimeters between the centers of your pupils. It’s a crucial measurement used to ensure the proper alignment of lenses in your eyeglasses.
2. How do I measure my PD without a ruler?
Measuring your PD is easy with Zenni’s Digital PD Ruler online tool. All you need is a digital device equipped with a camera and a standard-sized card, such as a credit card. Visit Zenni’s Digital PD Ruler to get started.
3. Can I find my PD on my glasses?
No, your PD is not typically printed on your glasses. Instead, it’s measured separately during an eye exam or when you order new glasses to ensure the lenses are placed correctly for your vision.
4. Does my PD have to be exact?
Yes, an accurate PD measurement is crucial, especially for those with multifocal lenses or higher prescription strengths. Even a minor discrepancy can affect visual comfort and clarity.
5. Where is my PD on my prescription?
PD may or may not be included on your prescription. It’s often measured separately by your eye care provider and can be provided upon request (sometimes with an additional fee). You can also easily measure your PD using Zenni’s Digital PD Ruler online at your convenience.
6. What happens if my pupillary distance measurement is off?
An inaccurate PD can lead to eyestrain, discomfort, and compromised vision. To enjoy the best visual comfort, ensuring an accurate measurement is crucial.
7. Does PD affect frame size?
Absolutely. Eyeglass frames have specific acceptable PD ranges they can accommodate. When browsing for frames on Zenni, use the filter feature to find frames matching your PD, or check the specifications to ensure they fit within your PD requirements.
8. Does PD change over time?
In adults, PD usually remains stable, but it can change during childhood growth or due to certain medical conditions. Therefore, periodic measurements are advisable.
9. Is PD important for single vision glasses?
Yes, PD is crucial for all types of prescription glasses, ensuring lenses are correctly positioned for clear and comfortable vision.
10. What is the difference between ‘single’ and ‘dual’ pupillary distance?
Single PD is a single measurement for both eyes, while dual PD includes separate measurements for each eye. You can use either when ordering glasses on Zenni.
11. How to find pupillary distance?
PD can be measured during an eye exam by your eye care professional, or you can request it from them. Alternatively, use Zenni’s Digital PD Ruler online tool for a quick and convenient measurement.
12. What does PD mean for glasses?
PD ensures that the optical centers of your lenses align precisely with your pupils, ensuring clear vision and comfort.
13. Do you need the PD for sunglasses?
Yes, PD is essential for prescription sunglasses as well, ensuring accurate vision correction.
14. What is the average pupillary distance?
The average adult PD typically falls between 54-68 mm, but individual variations exist. For children, the range is approximately 43-58 mm.
Understanding your PD is key to enjoying the best vision possible with your eyeglasses. Whether you obtain the measurement during an eye exam or use our convenient Digital PD Ruler, getting this measurement right ensures a clear and comfortable visual experience.
About the Author: Dr. Sophia Moh, OD, ABOC
Dr. Sophia Moh, OD is an optometrist located in Bay Area, California. She completed her undergraduate studies at UC San Diego and earned her doctorate at UC Berkeley School of Optometry. She has experience in a variety of eye care settings including primary care optometry, general ophthalmology, community health clinic, and Veterans Affairs. Her mission is to help the world see better by developing high-quality, affordable eyewear for everyone. She is also a certified American Board Optician (ABO) and provides training and lectures on optical education topics.