Pupillary Distance
How To Measure Your Pupillary Distance
What is Pupillary Distance?
Pupillary distance (PD) is the distance between the centers of
your pupils measured in millimeters. The average adult’s PD
is between 54 – 74mm; children’s are between 43 – 58mm.
Why Is It Important?
The PD is used by the lens maker to align the “Optical Center”
of each lens with your pupil. An inaccurate PD may cause
headaches and eye strains.
Measuring Your Own Pupillary Distance
Before we get started, make sure you
have the following handy:
Now, follow these steps to measure your own PD:
Step 1. Stand 8 inches away from the mirror.
Step 2. With your face straight, hold the ruler against your
eyebrow.
Step 3. Close your right eye and align the ruler’s zero to the
center of your left pupil.
Step 4. While looking straight, close your left eye and open
your right eye.
Step 5. Read the millimeter line that lines up with the center
of your right pupil. This number is your PD.
Make sure you repeat this atleast 3 or 4 times to
make sure that your PD is accurate. You can read
the average PD of adults and children at the
beginning of the article.
Having a Friend Measure Your Pupillary Distance
If a friend is measuring your PD;
Keep both eyes open and have your friend put the zero of the millimeter ruler over the center of one pupil. Then measure the distance to the center of the other pupil.
Keep both eyes open and have your friend put the zero of the millimeter ruler over the center of one pupil. Then measure the distance to the center of the other pupil.
Make sure to keep your eyes still and don’t look at the person
measuring. You can look above his/her head at something
10 – 20ft away.
