Eyeglasses come in many various shapes, sizes, colors and styles. The actual prescription is specific to the individual and based on the results of an eye examination. There are two width measurements, and they are the front width of the frames and the width of each lens.
Things You’ll Need:
1 Place the eyeglasses face up on a flat surface such as a table or desk. To do this, close the stems (also know as arms and ear pieces).
2 Measure, using the metric ruler, from one end of the frame, where the left stem connects to the front of the frame, to the other end of the frame, where the right end stem connects to the frame. In other words, the measurement is taken from one hinge to the other hinge. This is the front width of the frame. The measurement should be taken in millimeters.
3 Measure from the left side of one of the lenses, using the metric ruler, to the right side of the same lens. This is the lens width. The measurement should be taken in millimeters.
4 Know that in the eyeglass industry the millimeter is the standard unit of measurement.