Porsche Design P8340 O-3

Porsche Design P8340 eyeglasses.
The numbers engraved on the inside of the temple arm, "53 17 138", are the standard measurements for the frame, typically listed as:
53: Lens Width in millimeters.
17: Bridge Width (the distance between the lenses over the nose) in millimeters.
138: Temple Length (the length of the arm from the hinge to the tip) in millimeters.
The full model details from the image are:
Model Number: P8340
Color Code: COL.04 (This appears to be a blue or blue/gunmetal color combination, though specific color codes can vary slightly by retailer).
Size: 53-17-138 (Lens width-Bridge width-Temple length)
Brand: Porsche Design