About Frame Sizing
Choosing the Correct Frame Size
In order to select the correct frame size you must either measure your existing frames or read the numbers off the frame (if visible). All frame measurements are in millimeters so you need a ruler with millimeter (metric) lines. For an existing frame measure from the OUTSIDE edge of each lens as shown in the image below.
If you have an existing pair of glasses, check the "Frame Numbers" which are usually found on the temples (arms) of the glasses.
Frame Width = Lens Width (Right Eye) + Bridge + Lens Width (Left Eye).