In the boxing system of lens measurement, what does the "B" represent?

In the boxing system of lens measurement, the "B" specifically refers to the lens depth. This measurement is taken vertically from the highest point of the lens to the lowest point that is enclosed by the boxing system. Understanding this measurement is crucial for ophthalmic dispensing as it helps ensure that the lenses fit properly within the frame and that the optical center aligns with the wearer's visual axis.

The boxing system is a standardized way of describing the dimensions of a lens using a rectangular box that just encompasses the lens shape. The "B" measurement helps technicians and opticians ensure that lenses will fit correctly in the chosen frame and provide the necessary visual correction. Knowing the depth of the lens is also essential for fitting progressive or bifocal lenses, where precise positioning can significantly impact vision quality for the wearer.