The measurement used to determine the distance between the optical centers of spectacle lenses is what?

The measurement used to determine the distance between the optical centers of spectacle lenses is known as pupillary distance (PD). This measurement is crucial for ensuring that the lenses are correctly positioned in front of the wearer’s eyes. If the optical centers of the lenses align with the wearer’s pupils, it helps to achieve optimal vision correction and comfort.

Pupillary distance is typically measured in millimeters and can vary between individuals. It can be measured for distance vision and near vision, depending on the prescription requirements. Accurate PD measurements are essential for correctly fitting glasses, as they play a significant role in how effectively the lenses compensate for any refractive errors.

The other measurements, such as axial length, vertex distance, and refractive error, serve different purposes in the field of optometry and ocular health, but they do not specifically refer to the distance between the optical centers of spectacle lenses. This makes pupillary distance the most directly relevant choice in the context of this question.