Why will my optician not give me my PD Measurement?

Why will my optician not give me my PD Measurement?

Have you ever noticed that when you have an eye test, your PD measurement or Pupillary Distance measurement is NOT given to you as part of your prescription? This may seem odd, but there is a reason. The optician doesn’t want to give you your PD measurement because they want you to buy your glasses from them, at the prices they set. The PD measurement is the distance between the centre of one pupil to the centre of the other pupil, which ensures that the optical centres of the lenses in your glasses are aligned properly to give maximum comfort and effectiveness.

Buying new glasses on the high street can be an expensive business, but did you know that you can save between 60-70% by simply buying your glasses online. In the past few years the internet has changed our buying habits. We automatically shop around for things like Insurance, package holidays or household appliances, so why not for our glasses? The savings can be significant especially if you have a strong or complex prescription.  Online there is actually a greater choice in lens options available than you will find in the high street.

Your optician will of course discourage you from buying glasses online by telling you that you will end up with an inferior quality product and you will also have problems with your vision as your glasses won’t be fitted correctly because no one has taken your PD measurement.

None of this is true, the main reason why buying glasses online is cheaper than buying in-store is because online-stores have much lower overheads than brick and mortar stores, so they are able to pass the savings onto their customers.

To buy your glasses online all you need is a copy of your prescription and your PD measurement. Many people are given the impression that the PD measurement is a very complex process and can only be carried out face to face by a professional. This is simply not true, there are in fact several ways to measure your PD yourself.  

 You have a couple of options:

  1. You can use a clever online tool that enables you to get an accurate Pupillary Distance (PD) measurement within seconds. Simply go to http://www.thinlenses.co.uk/pages/Pupillary-Distance-Online.aspx and follow the simple steps outlined.


  1. You can measure your Pupillary Distance (PD) with the help of a friend. To do this, follow these  simple steps:


      • Put your glasses on.
      • Ask someone to stand in front of you, and look straight into their eyes.
      • Ask them to put a dot on each lens where each of your pupils are, using a non-permanent marker.
      • Take off your glasses and measure the distance between the two dots in mm, to get your Pupillary Distance (PD).
      • Wipe away the marks and repeat the process a couple of times to ensure an accurate reading.


For adults the PD measurement never changes, so once you know it you then have the freedom to purchase your glasses from anywhere that you want for the rest of your life.

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