Half-rim frames have unique sizing considerations. The partial frame changes weight distribution and fit dynamics.
I use 52-18-140 for half-rim frames, same as my full-rim glasses. The measurements work the same, but the fit feels different due to less frame material.
Half-rim frames are lighter than full-rim. This affects how they sit on my nose. I needed nose pad adjustments to compensate for the lighter weight.
Professional, lightweight glasses with proper sizing. The half-rim design works well when measurements are correct.