Eyeglasses come in a variety of sizes. Several sizes will fit one person but it is important to be as accurate as possible to ensure a good fit.
Eyeglasses are measured in three sizes, each reflecting a different part of the frame.
The lens size measures the horizontal width of each lens, ranging from 40mm to 62mm. The lens size reflects only the actual lens size, excluding any parts of the frame.
The bridge size measures the gap (connected by the bridge) between each of the two lenses. The bridge size will vary according to your specific face shape.
The temple length measures the size of the temple from the hinge connecting to the lens to the end of the tip.
Reading your current size
It is recommended to always look on a current pair of eyeglasses to best determine the correct size, however, if this is your first time purchasing eyeglasses, or if your pair is not available, it is a good idea to stop by a local eyeglasses store to get your measurements.
On the inside of the frame temple you will find a series of numbers. These numbers reflect your current frame size as in the sample below (in order of display):
54 - The size of the lens, ranging from 40mm to 62mm.
18 - The size of the bridge, ranging from 14mm to 24mm.
135 - The size of the temple (handle), ranging from 120mm to 150mm.
Note: If there is only one number available on your frame, it is usually the lens size measure.