Sizing for glasses are typically described with 3 numbers.

They'll look something like this 48 - 21 - 145

These 3 numbers represent, in mili-meters, the 

lens width (48mm)

nose bridge width (21mm)

arm length (145mm)


These are the 'average' size ranges for an adult

48-53mm lens width

17-22mm nose bridge width

135-150mm arm length


Currently the only 'narrow' frame option we carry is the Charlie Mini. All other frames, while different dimension, fall in the typical range and sizes for each frame are located in the product description. If for some reason they don't fit how you imagined then just ship 'em back and we can send you another pair to try.