How to find pupillary distance?

How to find pupillary distance?

Going for an eye test is expensive. For each visit, you can easily spend £20- £30. And many times, your eyesight does not fluctuate a lot. So, you get your old prescription slip and start ordering your new prescription glasses online. But then you are faced with the hurdle of PD. What is pupillary distance or this PD for short? Do you have to get an eye test to get this number, or can you solve this issue by yourself? You will want to save every penny. After all, glasses are expensive.

What is pupillary distance?

Pupillary distance is the distance between the center of your pupils. Knowing this help in making prescription glasses accurately. Where you look through the lenses to see clearly determines the centre of focus for the lenses. If this number is not accurate, you will have trouble focusing, headaches, or see blurry visions.

Usually, this number is mentioned in your prescription slip. If you don’t have this number for some reason, you can easily find it out in your home. My prescription slip also does not mention PD. When I was ordering my glasses, the optician marked the centre of focus right on the lenses of the chosen frames. My glasses give me accurate vision, but I don’t know the exact numbers. For your next prescription gaming glasses or any glasses, you will need to calculate them yourself or visit your eye doctor again.

How to measure PD?

The first easiest method is to have a helping hand. Ask your friend or any family member to help you find your PD. For this method, you will need a non-permanent marker and your glasses. 

  1. Sit straight and see in the straight direction.
  2. Ask your friend to mark the centre of your pupil on the lenses.
  3. Repeat this for both your eyes.
  4. With a ruler, measure the distance between the two points.

This number is your PD. For adults, this number is 54-74 mm. For kids, PD is between 43-58 mm. If you are getting a similar result, you can confidently input this number on your online order. If not, you are making mistakes somewhere.

If you cannot take help from anyone, no need to feel lonely, you can fly solo too. I mean, you can measure your PD on your own too. It would have been easy with someone’s help, but it doesn’t mean you cannot do it on your own. For this method, get a mirror.

  1. Stand 8 inches away from the mirror.
  2. Place a ruler over your eyes on the brows.
  3. Now, close your right eye and look straight with your left eye.
  4. Mark the centre of your pupil on the ruler.
  5. Close your left eye and look straight with your right eye.
  6. Mark the centre on the ruler.
  7. Measure the distance between the two points.

The final number is your PD. You might get inaccurate results. It’s difficult to concentrate on looking straight while marking with your hand. Repeat this step few more times to get accurate results.

Then there is dual PD…

Some online glasses sellers ask for dual PD rather than PD. No need to bash your head on the wall for this jargon. Dual PD measures the distance between the centre of the pupil of one eye to the nose bridge. 

Dual PD is usually more accurate. You will get two numbers with dual PD, one for the right eye and another for the left eye. Sum them up, you have your PD. For most people, both the numbers of dual PD are the same. For some people, these numbers differ slightly. 

How to measure dual PD?

For this, stand in front of the mirror about 8 inches away and look straight. Close your left eye and mark the centre of your right eye. Now, measure the distance from the nose bridge. Do this for your other eye too. There, you have your dual PD. 

In your prescription slip, dual PD is marked under OD and OS. OD stands for Oculus dexterous, meaning right eye, and OS stands for Oculus sinister, meaning left eye. If you have this number, then you can provide the number for your new glasses.

Finding PD for your near vision

PD for near vision is different for far vision. The centre of focus is different when you are looking at a distance and when you are reading. To calculate your reading PD, you need to subtract 3mm from your PD. For example, if your PD is 64, then your reading PD will be 61.

For finding dual PD for your near vision, subtract 1.5 from both OD and OS. FOr example, if your dual PD is 34/32, then your near dual PD will be 32.5/30.5.

I hope this solution helps you find your perfect glasses. Now, what are you waiting for? Go and order your favourite glasses frames that you have left in the cart.

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