How to Measure Your Pupillary Distance (PD) for Online Glasses

When ordering glasses online, knowing your pupillary distance (PD) is crucial. PD is the distance between the centers of your pupils and ensures that the lenses are correctly aligned with your eyes for optimal vision. Here’s a simple guide to measuring your PD at home. 

Your Optometrist or Opticians will measure the PD when you are having your new prescription made up into your glasses. First, they would gather their tools: a special millimeter ruler, a fine tip marker and a mirror.  They would sit or stand about 12- inches from you. They would ask you to look straight ahead and hold the ruler against your brow. 

They would then ask you to close your right eye and align the zero mark of the ruler with the center of your left pupil. Then, without moving the ruler, close your left eye and open your right eye. Note the measurement to the center of your right pupil. This number is your PD. For most adults, PD ranges between 54-74 mm. 

You could do this by placing a mirror in front of you at the same distance and following the same steps as mentioned above. 

If you have someone to help, the process can be even easier. Have them stand in front of you and measure the distance between your pupils directly. Ensure you both are looking straight ahead and at the same level. 

Some online applications offer digital tools to measure PD. These tools typically involve uploading a photo of yourself holding a card with a known measurement (like a credit card) next to your forehead. The software calculates your PD based on the reference size.

Ensuring an accurate PD measurement is critical. Incorrect PD can lead to eye strain, headaches, and even distorted vision because the optical centers of the lenses won’t align correctly with your pupils. 

By taking a few minutes to measure your PD accurately, you can ensure your online glasses will be comfortable and provide the best possible vision correction. 

Disclaimer.  

The best results are achieved by having an accurately measured PD, by a qualified person. We accept no liability for PD measurements that are inputted into our platform. If possible, you can attend our store for these measurements at a cost (£25 – other, additional charges such as measurements for bifocals and varifocals or consultation advice. These are by appointment only and payment is made on booking).