The question of how to measure eyeglasses probably didn't occur to people prior to being able to order eyeglasses over the Internet. They went to the eye doctor's office and picked out a pair of frames after the doctor examined their eyes. Today, with a prescription from the eye doctor in hand, picking out new frames can be done online, eliminating the fitting process. You will get your eyes tested, After the tests are performed, the doctor will write a prescription for your eyeglass lenses, and take measurements, like the distance between your pupils. This measurement, abbreviated as PD, is essential to ensuring the optical centers of your lenses will sit directly in front of your pupils. This number is measured in millimeters, and the average distance is about 63 mm. This measurement is extremely important for strong prescriptions. If PD is incorrectly measured, eyestrain and headaches may occur, and vision will not be optimal.When ordering glasses online, check your old glasses for the numbers you will find either behind the bridge (nose-piece) or on the inside of the arm. The numbers will look like this: 50/17 135 and may be separated by a box shape. These numbers represent the frame size you will need to order. If this is your first pair of glasses, visit an eyeglass store and ask to be fitted, copy the number down, or simply order from the store.
Actually, your frame size is usually stamped somewhere on the frame, usually inside one of the temples. Other places you may look are along the nose pad, across the bridge, or sometimes on the ear piece. Keep in mind that the eyeglasses size and your sunglasses size are slightly different, depending on the frame style. There always be three number on the temple. A Two-digit number ranging from 40 to 62 is your eye size. Another Two-digit number ranging from 14 to 24 is your bridge size. A Three-digit number ranging from 120 to 150 is your temple size. Hope this helpful.
To find a frame of your size, you must first know the measurements of the frame that you require. In order to do that, please refer to the figure below and measure it accordingly. If you wear glasses and have a pair handy already, first check the inner side of the temples (arms) of those glasses. Usually, there are some numbers listed on them (see figure below). For Example, it says: Brand Model 52/18 135 or 52 18-135, it refers to the following measurements. a) 52-Lens Width b) 18-Nose Bridge c) 135-Temple size