How to Measure Your PD

How to Measure Your PD

How to Measure Your PD (Pupillary Distance)

Your Pupillary Distance (PD) is the distance in millimetres between the centres of your pupils. It tells us exactly where the optical centre of each lens should sit, so you get the clearest, most comfortable vision from your new glasses.

Why PD Matters

If your lenses aren’t aligned to your pupils, you may experience eye strain, headaches, blurred vision or a “pulling” sensation — especially with higher prescriptions and varifocal lenses. An accurate PD ensures the optical centre of each lens lines up perfectly with your line of sight.

Tip: Your optician usually records your PD on your prescription. Check there first — if it’s listed, you can simply enter that number at checkout and skip the measuring steps below.

Types of PD

Single (Binocular) PD

One number for the total distance between both pupils, e.g. 63 mm. The most common format and suitable for most single vision orders.

Dual (Monocular) PD

Two numbers — the distance from the centre of your nose to each pupil, e.g. 31.5 / 31.5. Often used for varifocals and stronger prescriptions for greater precision.

Measure Your PD at Home — Step by Step

You’ll need a millimetre ruler and a mirror (or a friend to help, which is more accurate).

  1. Stand about 20 cm (8 inches) away from a mirror, or sit facing a friend.
  2. Hold a millimetre ruler flat against your brow, just above your eyes.
  3. Look straight ahead at a fixed point. Close your right eye.
  4. Align the ruler’s 0 mm mark with the centre of your left pupil.
  5. Keeping the ruler still, close your left eye and open your right eye.
  6. Read the millimetre mark that lines up with the centre of your right pupil — that number is your PD.
  7. Repeat 3–4 times and take the average for accuracy. Most adults fall between 54 mm and 74 mm.

Measuring with a Friend (Most Accurate)

  1. Sit down so your eyes are level with your helper’s eyes.
  2. Look straight ahead at a distant object behind them (keep your eyes still).
  3. Your helper holds the ruler against your brow and measures from the centre of one pupil to the centre of the other.
  4. Record the measurement in millimetres and repeat to confirm.

Typical PD Ranges

Group Average PD range
Adult women 54 – 68 mm
Adult men 58 – 74 mm
Children 43 – 58 mm

These are guidelines only — always use your own measured value rather than an average.

Not confident measuring it yourself? No problem. Place your order without the PD and email it to info@ardoreyewear.co.uk, or ask us to verify your PD during checkout. Our qualified opticians check every order before it’s dispatched.

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