Knowing the pupillary distance is important to find the right fit of glasses for your face. PD is mostly mentioned in your prescription slip. If you are not a prescription glasses user and you are looking to buy stylish fake glasses or blue light glasses for yourself, then you can only measure it by yourself. 

Don’t worry, it’s not some rocket science. All you need to know is how to use a ruler correctly and you can accurately measure your PD.

Easy Trick Number 1

1. Stand (at least 30 cm away) in front of a mirror and place a ruler over your overhead
2. Now, close your right eye and place 0 mm on the ruler over the centre of the pupil of the left eye 
3. Next, open both eyes and look straight
4. Now, close your left eye and trace the centre of the pupil of your right eye. The number above your right eye is your pupillary distance
5. Repeat these steps a few more time to get an accurate reading. For an adult, PD is generally between 54-74 mm
6. Those with hyperopia can minus 3 from the result to get the accurate PD

Easy Trick number 2

Ask your friend to take the readings for you. It’s difficult to focus on the small readings on the scale by yourself. Also, when you have a vision defect like hyperopia, then it will be difficult to get an accurate reading. Wearing faulty glasses with the wrong PD can cause you a headache, eye pain, blurry vision. You will also have difficulty in focusing. 

1. Stand still, face straight and look at any object 20 feet away
2. Your friend will mark the centre of the left eye 
3. Without getting into the frame of your view, your friend need to mark the centre of other eye
4. Now measure the distance between both the marks to get accurate PD

Easy Trick number 3

This trick is for a glasses wearer. 

1. Stand 30 cm away from a mirror with your glasses on
2. Look straight
3. Close your right eye and mark the centre of the pupil of the left eye with a non-permanent marker on your glasses
4. Now open your right eye and look straight
5. Close your left eye and look straight
6. Mark the centre of the right eye with a non-permanent marker
7. Now remove your glasses and measure the distance

Easy Trick Number 4

Instead of measuring PD, find your dual PD. For most people, the distance between the centre of one eye to the nose bridge is not the same for both sides. For such asymmetrical faces, a single PD will not be an accurate reading. This will hinder their viewing. For such cases, a dual PD will be accurate.

1. Face a mirror at least 30 cm away and look straight
2. Place a ruler above your forehead and mark the centre of your left eye
3. Now measure the distance between the centre and your nose bridge
4. Repeat this for your right eye

You will get a result like 32 for the right eye and 30 for the left eye. In prescription slips, it is written as 32/30. The first number is OD (Oculus dextrus meaning right eye) and the second number is OS (Oculus Sinister meaning left eye).

If both the numbers are the same, then a single PD would work. If both the numbers are not the same, it will hinder your vision. Hence it is necessary to take dual PD to make your glasses.

Easy Trick Number 5

Finding the centre of the eye or focusing on looking straight while marking is a bit difficult task to do. Also, if you cannot take help from any friend, then try out this trick.

1. Stand still in front of a mirror at least 30 cm away
2. Instead of locating the centre of the eye, place the 0mm mark at the left end of the left eye
3. Now measure to the left end of the right eye
4. To cross-check, place the 0-mark on the right end of the right eye and measure till the right end of the left eye.

A do-it-yourself method is affordable methods but not really reliable. There is room for a lot of errors if you are doing it by yourself. Also, taking the help of others who are not professional is also not a viable option. Your friend may have a vision defect or they did the task sloppily. Anyway, you will suffer from your faulty glasses.

Get an eye test to get an accurate reading. Nowadays, you can avail free eye test while buying glasses. With NHS you can get a free eye test in the UK.

You can even get an eye test at your home or your place of work. You don’t need to take out time to schedule an eye test. Just schedule a time to get an eye test wherever you are comfortable and available.