This is a general guide depending on the frame and brand you choose. For example a medium size frame in millimetres will be shown as: 48-18-138.
Eyewear Frame Size guide
Lens Width
EXTRA SMALL BELOW 42
SMALL 42-48
MEDIUM 49-50
LARGE 53-58
EXTRA LARGE ABOVE 58
Bridge Width
BELOW 16
16-17
18-19
20-23
ABOVE 23
Frame Width
BELOW 130
130-135
136-140
141-150
ABOVE 150
Lens Categories
0-3N or P Refers to Category Level of UV protection while N is Non polarised and P for Polarised options. Shown as 2N