Measure my PD
What is my pupil distance?
The pupillary distance, PD or Interpupillary distance is the horizontal distance between pupils. It is an easy measurement to take and DIY’ers can measure it themselves. It is measured in millimeters (mm).
But here is the problem. People have more than one PD. You have a distant and near PD. Further – to be sure your glasses coincide with your visual axis you need a HORIZONTAL and VERTICAL measurement. You need the OPTICAL CENTER (OC) measurement.
Try and watch yourself or someone else’s pupils when transitioning from looking at an object far away to looking at something up close. Three things occur:
- your eyes focus on the near object (accommodate)
- your pupils actually get smaller (miosis) to increase depth of focus.
- your eyes turn in toward the object (converge).
What this means is that the pupil distance is not just one measurement, it should consist of more than one measurement to reflect the fact that we do not look at only one distance.
I’m a DIYer, I like remodeling my own bathroom, changing my own oil and I want to buy my glasses online. Where do I get my PD?
Online retailers have one main purpose – sell you glasses. They cannot legitimately attempt to do this without getting a PD measurement (at a minimum).
Often if your prescription is not complicated & does not have a prism correction, patients can google “how do I measure my PD”. Just follow instructions and provide the measurement yourself to an online retailer. That may be enough to get a pair of glasses. But what if you get headaches and blurry vision? Is your online retailer able to troubleshoot what is wrong with your prescription? Maybe yes, maybe no.
Do eye doctors have to give me my PD?
Nearly every state with the exception of New Mexico and a few others recognize a pupil distance measurement is obsolete. The PD is not a required part of a prescription for eyeglasses or contact lenses in Washington.
What is the best measurement for my eyes?
At Tacoma Eye we’ll refine your prescription with our digital refraction process (we’re still the only office on North Tacoma with this technology).
With the push of a button, we can even show you the difference in vision between not wearing glasses, your old prescription and the new prescription! YOU decide if you see better and if you need new glasses. After the prescription process, our staff will help you select some quality frames that meet your budget. Then we measure the horizontal and vertical distances, the optical center (OC).
In the end, combining the Digital refraction, the OC and a digitally surfaced EYEZEN or PROGRESSIVE lens you’ll get the best value over the long run.”