What is the term for the distance between the optical centers of a pair of glasses?

The term "pupillary distance" refers specifically to the measurement between the optical centers of a pair of glasses. This distance is crucial for ensuring that the lenses are properly aligned with the wearer’s pupils, which helps to optimize vision and comfort while wearing the glasses. Accurate pupillary distance is essential for prescription glasses as it allows for proper refractive correction and alignment of the optical axis.

Other terms provided do not accurately describe this specific measurement. Vertex distance refers to the distance from the back surface of the lens to the cornea, which is more relevant in discussing how prescription lenses affect vision at different distances. Lens distance and visual distance are terms that generally do not have standard definitions in the context of eyewear measurements and are not recognized in optical practice like pupillary distance is.