What is Pupillary Distance (PD)?
Pupillary Distance (PD) or interpupillary distance (IPD) is the distance (the industry standard is to measure in millimeters) between the centers of the pupils in each eye. This measurement is used when preparing to make prescription eyeglasses. This measurement is different from person to person and also depends on whether they are looking at near objects or far away.
Why measuring your Pupillary Distance (PD) is important?
How is this important for your vision and why do you need it to buy glasses?
Every set of the prescription lens has an “optical center,” which is determined by pupillary distance. Pupillary distance is used to determine where you look through the lens of your glasses and should be as accurate as possible.
A pupillary distance measurement is necessary for properly fitting your eyeglass lenses. There is no reason to walk around with inaccurate glasses when it is so easy to get this number. Be sure to take your number, and the rest of your prescription, the next time you shop online for trendy eyeglasses.
How then do we measure the Pupillary Distance (PD)?
There are two methods one can measure the pupillary distance. a) Measuring it by yourself and b) Making a friend help you measure.
METHOD ONE (Measuring it by yourself)
step1.Position yourself approximately 8 inches (20cm) away from a mirror or yourself arm’s length from your friend.
step2.Close your left eye and align the ruler’s zero to the center of your right pupil.
step3. Try not to move your head or the ruler. Close your right eye and note the reading directly over your left pupil. That will be your PD.
step4.you also need to measure the distance from two pupils to the center of nose respectively to make sure that if you have two PDs(OD & OS).
METHOD TWO (Making a friend to help you measure).
Look straight ahead with both eyes open facing your friend. Let your friend hold the ruler up to your right so the zero end lines up with your pupil.
Measure the distance from your right to your left pupil. The number that lines up with your left pupil is your PD.
Write the result down. To be certain of the result, let your friend measure a few more times to make sure your measurement is accurate.
Let your friend repeat the process on your left eye by measuring the distance from your left pupil to your right. Use the number that lines up with your right pupil. That's your PD. Write the result down. Repeat the process again to make sure the measurement is right.
Once you've got your PD measurement, input the numbers in your cart and you're good to go.