On your existing pair of eyeglasses you may have noticed certain numbers on the arm. These indicate the dimensions of your eyeglasses frame and are commonly visible on eyeglass frames.
The numbers of interest to us in the example above are 49 – 21 – 140
where
49 (mm) is the Lens Diameter
21 (mm) is the Bridge Width
140 (mm) is the Arm Length
Understanding Frame Measurements
Frames generally have five different sizing measurements. In addition to the three mentioned already there are another two.
Frame Width – which is the width of the glasses across the face and is used to indicate whether frames are Narrow, Medium or Wide
