What does the notation A + DBL equal when measuring lenses?

The notation A + DBL refers to specific measurements often used in the context of optical lenses, particularly when fitting glasses. Here, ‘A’ typically represents the horizontal width of the lens, while ‘DBL’ stands for distance between lenses, an important measurement in the overall fitting of eyewear.

When you add A (the width of the lens) to DBL (the distance between the lenses), the result often corresponds to DBC, which is indicative of the overall width that includes both the lens widths and the distance between them. This is significant for ensuring that the lenses are aligned properly in relation to the wearer's eyes, providing both aesthetic and functional benefits.

This relationship is crucial for opticians when taking measurements for custom eyewear, as miscalculations can lead to poor fit and discomfort for the wearer, as well as affect the optical performance of the lenses. Understanding these measurements is essential for effective lens fitting.