If you already have a pair of glasses, you can compare the measurements to your current frame. Just look inside your temple to find your frame measurements. The overall frame size is a combination of lens and bridge's width measurements.

 

	Lens Width	Bridge Width	Temple Length
Small	42-48mm	16-17mm	130-135mm
Medium	49-52mm	18-19mm	136-140mm
Large	53-58mm	20-22mm	141-150mm