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

The correct term for the distance between the optical centers of a pair of glasses is Pupillary Distance. This measurement is crucial in ensuring that the lenses are correctly positioned in front of the eyes for optimal vision. When the lenses are aligned with the pupils, it minimizes optical distortion and provides clarity, making the glasses function effectively for the wearer.

Each person's pupillary distance may vary, and it is typically measured in millimeters. This measurement is especially important for those who require corrective lenses, as it directly affects how light enters the lenses and how the image is perceived.

Vertex Distance refers to the distance from the back of the lens to the front of the cornea, which affects how prescriptions are calculated but is not the same as pupillary distance. Eye Relief is a term typically used in the context of telescopes and binoculars, signifying the distance between the lens and the user's eye, which is essential for comfortable viewing. Frame Width pertains to the overall width of the glasses frame and does not relate to the positioning of the lenses concerning the eyes.