PD Measurement Guide
HOW TO MEASURE THE PUPILLARY DISTANCE?
The pupillary or interpupillary distance is the distance in millimeters between the pupils of both eyes at a certain viewing distance (looking closely or away) Example: PD Near: 58, PD Far: 60 (mm). Sometimes it is marked with two values, one for each eye (example: PD Near: 29/30), this distance is very important when ordering your lenses. Having the pupillary distance will allow your lenses to be centered on your frame by matching the optical center of the lens with the visual axis of your eyes.
The pupillary distance is usually found in the glasses prescription, but not always. If you do not know your pupillary distance and / or it is not included in your prescription, you have several options to measure it:
- You can ask the professional that give you the prescription.
- Measure any of the following four options to determine your Pupillary Distance (PD), measurement is done in mm. (Example: Option 4 shows a measurement of 60 mm)
- You can use the conventional method to measure pupillary distance and take a photo. You just need a digital camera or your cell phone (camera included), and a millimeter ruler and someone to take the picture of you.
To measure PD per photo: You need a digital camera or your cell phone (camera included), with good resolution and a millimeter ruler. It will be easier if you ask someone to help you. This photo should be exclusively a photo of your eyes, as you see in the figure.
- You must put the ruler with the “cm” side either under your eyes, or resting it on your eyebrows.
- You should be sitting and looking straight ahead at a fixed point, located 6 ft or more (2 meters or more) and without looking at the camera. You can see a point on the wall, a detail of a picture, etc., etc.
- The person who takes the photo should be at least 1.5 ft (50 cm) away, using the camera zoom so that only your eyes pop out. The camera (not the person) should be in front of your eyes without covering your fixation point.
- You must hold the straight rule horizontally and under your eyes or supporting it above your eyebrows.
- It is advisable to use the flash so that the reflection appears in the center of your pupils.
- Once the photo is taken you can send it by email (firstname.lastname@example.org), It is very important that you follow the instructions so that the measurement is correct.