US: M to Europe Size 49-18-140

US: M: Corresponds to a lens width baseline of 52 $\text{mm}$ (2.05 $\text{in}$), bridge width of 19 $\text{mm}$, temple arm length of 145 $\text{mm}$, and fit classification Standard / Regular Frame.

Europe Size 49-18-140: Corresponds to a lens width baseline of 49 $\text{mm}$ (1.93 $\text{in}$), bridge width of 18 $\text{mm}$, temple arm length of 140 $\text{mm}$, and fit classification Standard / Medium Frame.