What is your PD Measurement
Pupillary distance is sometimes referred to as pupil distance or just PD. It is the distance between the centre of each pupil and the bridge of your nose, measured in millimetres. Pupil distance is essential for making prescription glasses, because it helps us to position the optical centre of your lenses in the correct place.
Without a correct measurement, the prescription power of your lenses will be off-centre from your eyes.
This will cause your vision to be distorted, reducing optimal clarity, even if your prescription is 100% correct.
When you bought any prescription glasses in the traditional method on the High Street, you will have had your PD measured.
This is usually done by the optical assistant after you have chosen your frames.
If you intend to buy your prescription glasses online, you can ask the optician for your PD measurement when you have an eye test. If they are unwilling to give it to you, it’s easy to measure it yourself. (Click Me).
Can I just guess my PD?
No, don’t guess, pupillary distance must be accurate in order for your prescription glasses to work correctly. Imagine you dont know your shoe size and you make a guess. If you end up with a pair of shoes too small or too big to wear, you would then need to measure your feet properly, then order a new pair. The same principle applies here, if you guess you might not be able to see out of your glasses correctly, and you would then need new prescription glasses, with a different pupillary distance.
What is single and duel PD?
They are non-scientific terms for the following:
Monocular PD- is sometimes referred to as duel PD. This measurement has two numbers, it is the measurement from the centre of the bridge of your nose to the centre of your pupil. It is measured separately for each eye, hence the two numbers found.
Binocular PD- is Sometimes referred to as single PD.
This is the total distance between the centre of both your pupils, measured with one single reading.
Why do we have Monocular and Binocular PD?
We have two ways of measuring, because not all eyes are completely symmetrical, one may be a bit further from the bridge of your nose than the other.
So say your Binocular PD is 60, this will be split equally between your eyes 30/30.
If however, the same person is measured with a mono PD, the overall PD should be the same, but it might be made up differently, say 31/29.
What is the average Pupillary Distance?
The average for a women is 62
For a man, the average is 66.