Frame sizes are usually in the format “50 - 20 – 140”. In this example this means that the lens diameter is 50mm the bridge distance is 20mm and the arm length is 140mm.

You can use this as a guideline by comparing them to your own glasses

HOWEVER, this is NOT the BEST way to obtain a good fitting frame. At spex4less I have added two further measurements that are FAR easier to understand and ensure a much better result.

Each of the frames on the website includes the total frame width in millimeters and total frame depth in millimeters. Compare these to your own frames for a good fitting frame.

Article by Mark Bowden.
For more information visit: Spex4less.com