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

The term for the distance between the optical centers of a pair of glasses is known as pupillary distance. This measurement is crucial for providing accurate lens placement in eyewear. It ensures that the optical centers of the lenses align with the wearer's pupils, which is essential for optimal visual comfort and clarity.

Pupillary distance (PD) directly impacts how well the lenses work in correcting vision, as any misalignment can lead to visual disturbances such as double vision or discomfort. When prescribing lenses, optometrists and opticians will carefully measure this distance to ensure the lenses are manufactured correctly to suit the individual’s vision needs.

Understanding the significance of pupillary distance is important in the field of ophthalmology and optometry, as it plays a vital role in the fitting and effectiveness of corrective eyewear. Other options, such as vertex distance, optical axis distance, and focal length, relate to different concepts in optics or lens design but do not define the distance between the centers of the lenses in glasses.