How to Measure Your PD


A Pupillary Distance (PD) Measurement is the distance from the center of one pupil to the other. PD measurements are measured in millimeters, and it lets us know where to put the optical center on each lens. The average adult’s PD is between 54-68 mm and kids' are between 41-55 mm.


 

Step 1: Download Designer Optics PD Ruler.

Step 2: Stand 8 in. away from a mirror.

Step 3: Close your right eye then align the ruler’s 0 mm with the center of your left pupil.

Step 4: Look straight then close your left eye and open your right eye.

Step 5: The mm line that lines up to the center of your right pupil is your PD measurement.


What's the Difference Between Single, Bifocal, Trifocal, and Progressive Lenses?


 

Single Vision Lenses have one power throughout the entire lens. Therefore, they can be used to correct vision in either distance or near viewing.

Bifocal Lenses have two distinct powers in the lens. The top portion corrects for distance viewing, and the bottom part corrects for near viewing. In addition, there is a visible line separating the two viewing points.

Trifocal Lenses have three distinct powers in the lens. The top portion corrects for distance viewing. The center of the lens is used for intermediate viewing, and the bottom of the lens corrects for near viewing. There are two visible lines separating the different viewing points.

Progressive Lenses have three distinct powers in the lens. The top portion corrects for distance viewing. The center of the lens is used for intermediate viewing, and the bottom of the lens corrects for near viewing. They’re very similar to a trifocal lens. However, there is no visible line separating the different viewing points.


PD Ruler

 

Step 1: Print the page
Without scaling, at 100%
Step 2: Double-check scale
By measuring against the credit card box.
Step 3: Fold the ruler
Along the dotted line.

 

Flowers

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