Lens width, bridge with, and temple length are usually printed from left to right on the frame arm. Sometimes a fourth number, lens height, is included.

There is also a fifth measurement, frame width, which is never printed on the stem. You can use a millimeter ruler to measure the frames yourself. All measurements are in millimeters.

Frame Width

This is the full width of the frame from both sides, including any hinges that stick out.

Lens Width

This is the horizontal width of each lens at its widest point.

Lens Height

Lens height is the tallest distance. Progressive lenses require a lens height of at least 30mm.

The Bridge

Measured at the top of the bridge, from the edge of one lens to the other. Children need smaller bridges to fit their developing faces.

Temple (Arm) Length

Measure from the front to the back and down. Many kids' glasses have straight temples that can be adjusted to fit your child.