All eyewear and sunglasses include a standard three-number size code located inside the left temple. The code is indicated in millimeters (mm) and should be read from left to right.
The first number is called the "eye" and refers to the width of one lens.
The second number is called the "bridge" and refers to the width of the area between the two lenses that goes on top of the nose.
The third number is called the "temple" and refers to the length of the stems attached to the sides of the eyeglass frames.
How to get the total width: Multiply the first number (eye) by 2 then add the second number (bridge).
Lens Width: This refers to the distance across one lens. Bridge: This is the area between the two lenses that goes on top of the nose. Temples: These are the stems connected via hinges to the sides of the eyeglass frame. The temples extend behind the ears to hold the eyeglass frame in place