How to measure your pupillary distance (PD)
Which glasses shapessuit oval faces?
So, first thing’s first: what is pupillary distance (PD)? Essentially, it’s the distance between the centres of your pupils (the black bits in the middle of the eyes).
Your PD is an important part of your glasses prescription that makes sure you’re looking through the best spot in your lenses for clear vision. We’ll need this measurement if you’re buying your specs online.
Office
Measuring your own PD
If you’d rather measure your PD yourself, or get a friend to help you out,have a look through our step-by-step guides.
1. Stand about 30cm away from a mirror
2. Looking at yourself, hold a ruler up against your eyebrows
3. Close your right eye, then line up the ruler so that 0mm is in line with the middle your left pupil
4. Look straight ahead again and then open your right eye and close your left
5. Your pupillary distance measurement will be the figure that linesupwiththe centre of your right pupil
Measuring a friend’s pupillary distance
- To measure someone else’s PD, have them look at something around 20 feet away from them with both their eyes open.
- Using a ruler, line up the 0mm mark with the centre of one pupil, then measure to the centre of the other.
- You just need to make sure that you stay out of their line of sight, they keep looking straight ahead with their eyes as still as possible, and that they don’t look at you while you’re measuring.
- Do this a few times to make sure the measurement you get isconsistent. The average pupillarydistance for adults is usually between 54-74mm.
If you have a prescription with us, you can always give your store a call to ask for your
pupillary distance measurement.
What is 'pupillary distance’?
Your pupillary distance (PD) is the distance between the centers of your pupils. Your PD is an important part of your prescription because it shows exactly which part of the lens you look through.
Can l find my PD on my glasses?
There are various mobile apps that can measure your PD using your phone’s camera. You can find EyeBuyDirect’s PD measurement tool by pressing the ‘i’ button in the PD section when entering your prescription.
Does my PD have to be exact?
You usually can’t find your PD number written on your eyeglasses. The numbers on the inside of the temple arms of some frames show the measurements for the frame itself. Your PD number should be written on your eyeglass prescription in the PD section.
Where is my PD on my prescription?
Your PD should be exact. If your lenses aren’t centered correctly, they can cause discomfort and eye strain. A small margin of error might not cause problems, but it’s better to be as accurate as possible.
What happens if my pupillary distance measurement is off?
If your eyeglass lenses aren’t properly centered based on your PD number they can cause dizziness, headaches or blurred vision. Your vision is centered on a small section of the lenses, so a PD number is needed to shape the lenses to perfectly suit your needs.
Does PD change over time?
A person’s pupillary distance will change when they are young as they are still physically growing. Once we reach maturity and stop growing, our pupillary distance will change very little, if at all.