Boxing sizes (e.g. 47-19)
- Eye size (lens width, horizontally.) The most important measurement (here 47)
- Bridge size (the piece that connects the lenses and sits on the bridge of nose.) The shortest distance between the lenses. (here 19)
- Temple size (arms) Length from the lens to the end of the piece that wraps around the ear; from the hinge to the very tip of the arm (135 mm, 140 mm, 145 mm)
- Lens height or "B Measurement." Anything over 25mm is progressive friendly.