On the back of spectacle frames, what do the figures such as 46x22 represent?

The figures on the back of spectacle frames, such as 46x22, denote the size of the lenses and the bridge of the frame. Specifically, the first number (46) represents the width of each lens in millimeters, while the second number (22) indicates the bridge size, which is the distance between the two lenses over the nose. Knowing these measurements is crucial for ensuring a proper fit and alignment of the spectacles on the wearer's face. The right lens and bridge sizing can greatly influence the wearer’s comfort and visual clarity, making it an essential aspect in eyewear fitting. Other figures, such as temple length or frame width, are typically represented elsewhere on the frame or are noted separately, hence the figures 46x22 specifically pertain to lens and bridge dimensions.