To ensure your frames fit perfectly, first you should determine which size frames are best for you. The best place to start is with the eyeglasses measurements on a pair that you already get.

First, search for the three little numbers on the inside of the temple of your glasses. Some may also refer to this section as the "arm" of your glasses. Just like this: 47□19-140 C1. These three numbers are the frame's measurements.

From left to right, these eyeglass measurements appear in the following order:
1.Lens width
2.Bridge width
3.Temple length
Sometimes a fourth number will be noted on the arms, which is your lens height. C means color. Keep in mind that all of these measurements are in millimeters.

Lens Width

This is the horizontal width of each lens at its widest point. It typically ranges from 40mm to 60mm.

Bridge Width

This is the distance between your two lenses. In short, the bridge width is the space where your frames fit against your nose. The size of this piece ranges from 14mm to 24mm.

Temple (Arm) Length

This is the length of the temple from each screw to its temple tip, including the bend that sits on your ear. The temple is typically 120mm to 150mm long.

Lens Height

This is the vertical height of your eyeglass lenses at the widest point of the lens within the frame. The lens height is important when measuring bifocals or progressive lenses.