A Guide to Prescription Eyewear
Your PD is the measurement of the center of one pupil to the measurement of the other. It’s important because it tells us where you look through the lens of your glasses. We measure this during your eye exam, but you can do it yourself too. Here’s how:
Step 1: Get ready to measure
Stand in front a mirror (ideally about 8 inches away). Hold your ruler up parallel to your brow bone. Use millimeters as your unit of measurement.
Step 2: Look directly at your left eye
Close your right eye and move the start of your ruler (0mm) right above the center of your left pupil.
Step 3: Look directly at your right eye
Close your left eye and find the number that is directly above the center of your right pupil. This is your single pupillary distance measurement. Divide this number by two, and that’s what you input in the prescription box.