Frame Width
Measure horizontally across the frame from hinge to hinge.
Lens Height
Measure the lens vertically at its tallest point.
Bridge width
At the top of the bridge, measure horizontally one lens edge to the other.
Temple Arm
Measure from the hinge to the bend, and then the bend to the end of the arm. Add the two measurements together.
Lens Width
Measure the lens horizontally at its widest point.