To find the perfect fit for your aviator sunglasses, stand in front of a mirror while looking directly at it. Then hold a ruler horizontally in front of your face. Now measure the distance between your right and left temples.
Note: To find your current sunglass frame size without the chart:
On your current pair of sunglasses, look on the inside of either temple. The eye/lens size is usually first, then the bridge size, then temple size. Use the eye/lens size to determine the best frame size.
52 - 18 140MM
The eye size is important for identifying how a pair of sunglasses will look. The eye size is measured from the bridge. The bridge width is the distance between the lenses in millimeters. And the third number is the length of the temple in millimeters.