Just some additional info:
The RFID tag is also used as an anit-counterfeiting measure. According to Essi-Luxx:
“For greater effectiveness in the battle against counterfeiting and the expansion of parallel markets that divert goods into unauthorized sales channels, Luxottica has developed GLOW (Guaranteed Luxottica Origin Worldwide), an innovative system capable of guaranteeing the traceability of its products. Based on RFID technology, it verifies the authenticity of its products and the legitimacy of its sales channels by means of a sensor (RFID TAG) built into the iconic Ray-Ban and Oakley models. This device contains the essential information required to unequivocally identify every pair of glasses from its production site to the wholesale client where it has been sold. Furthermore, it emits no radio signals, and as such is completely safe for health, and does not record personal data.”