The purpose of this blog is to provide a brief resume of
the types of spectacle lenses available to the patient
for better vision (visual needs).
Here we can discuss and share all about ophthalmic lenses, theories, individual findings, inventions, optical standards, tolerance, errors, complex optics and more..
Friday, July 22, 2011
How Do You Get Your PD?
What is Pupillary Distance?
Pupillary Distance (PD) is the distance in millimeters between the center of your eyes’ pupils. The typical PD range is between 54 and 74 mm. (Exceptions are there)
Your PD is needed for ordering glasses because it is used to custom-fit your glasses’ lenses to focus directly over your pupils, allowing you to see your personal best.
Measuring Your PD Yourself
If you can’t get to the eye doctor and still need your PD, follow these steps to measure your PD yourself.
Have ready: a straight ruler, a pencil, and a mirror
Facing the mirror, place the mirror on the bridge of your nose, bringing the start of the ruler directly below the center of one eye’s pupil.
Looking straight into the mirror, hold the ruler (keeping it steady and parallel to the floor!) and mark the location on the ruler of the other eye’s pupil.
Measure the distance in millimeters between the two marks. This is your PD.
Repeat this process a couple of times to ensure you have an accurate measurement.
If you have a willing assistant, you can simplify the process even further by having your friend measure your PD using a ruler. (Your job will be to stand still.)
Whether measuring with someone or alone, be sure to hold the ruler steady and parallel to the floor!