Accurate frame measurements are essential when shopping for glasses online. To find the measurements, check the inside of the temple arm or nose bridge. You will typically find a set of numbers that represent the frame measurements. For example: 59/16 140. The first two numbers (i.e., 59) indicate the eye size, the second two digits (i.e., 16) represent the bridge size, and the last three numbers (i.e., 140) denote the temple size.
If you're unable to read the numbers on the inside of your frame, you can manually measure the frame. When measuring the frame width, start from one temple screw and measure to the other. For temple length, measure from the temple screw to the temple tip.