The size of the glasses frame is composed of three parts: the frame, the bridge of the nose and the temples. The specifications of each part are divided into singular and even two.
The distance between the inner side of the two sides of the mirror ring at the midpoint of the vertical line of the plane where the frame is located. There are generally two methods of measurement: the box method and the baseline method. The singular number is 33-59mm, and the even number is 34-60mm.
The straight distance from the center of the frame hinge to the end of the temple. The odd number is 125-155mm, and the even number is 126-156mm.
Nose bridge size：
13~21mm in odd numbers and 14~22mm in even numbers
Frame outer width:
The distance between the visible areas on the left and right sides of the frame, that is, the distance between the frame and the junction of the two temples. According to the analysis of the ratio of the face size to the frame size, the frame with an outer width of less than 128mm is classified as Small size, 129mm to 138mm are classified as medium size, and those above 139mm are classified as large size.