When it comes to making a pair of glasses that are right for you, having your pupillary distance (PD) measured is an important part of the process as it ensures that the lens sits correctly over your eyes.
What is Pupillary Distance (PD)?
Pupillary Distance alias PD is the distance from the centre of the pupil of one eye to the other. PD is necessary for getting eyeglasses, to correct your vision. The measurement plays a vital part in determining correct positioning of your lenses within the frame. Especially, when you are looking for bifocal or multifocal lenses, PD is mandatory.
Understanding Single and Dual PD
Single PD, scientifically known as monocular PD, is the measurement from the centre of each pupil to the nose bridge.
Dual PD, scientifically known as binocular PD, is the total distance measurement between your pupils.
Monocular PD or Binocular PD, what to opt?
Monocular PD is mostly recommended for more accurate PD. Since both our eyes are generally asymmetrical. Not both the eyes will be at an equal distance from the nose of the bridge. For e.g. If the total binocular distance is 58 mm, it is not necessary that it will be equidistant on both sides. From one eye to the nose bridge it might be 31 mm while other it might be 27 mm. This can get the PD wrong. Monocular PD helps to get accurate measurement, especially for crafting progressive lenses.
How to measure PD yourself? What do you need?
You simply require:
Ruler (mm)
Mirror
Steps:
Stand in front of the mirror, around 8 inches away
Keep your head straight and hold a millimetre ruler horizontally on the bridge of your nose
The 0 mm point of the ruler should be in line with the centre of the left pupil (the black dot which you can see inside your eyeball)
Measure across, from the centre of left pupil to the centre of right pupil. Make sure you hold the ruler steadily. The measurement which you get is your pupillary distance
Repeat the above step 3, 4 times constantly, so that you get the accurate measurement. That's it, your PD is ready.
*Things to note:
Usually in case of bifocal or multifocal lenses, two PD will be required. It is better to get PD recommended from your eye doctor / eye care professional
The range of PD for adult is 54 - 74 mm and for kid is 43 - 54 mm
With your PD and prescription, you can order perfect pair of glasses at with us and enjoy enhanced vision.