Bicentric grinding is also known as what?

Bicentric grinding is a specialized technique used in the fabrication of lenses, particularly for bifocal or multifocal eyewear. This grinding method is specifically designed to create a specific type of optical surface that helps in aligning the optical centers of the upper and lower segments of the lenses. The purpose of bicentric grinding is to compensate for vertical imbalance in prescriptions, often seen in lenses with different powers in each segment.

The term "slab-off" refers directly to this grinding technique, as it involves cutting a slight prism into the lower part of the lens, thus providing a smoother transition and reducing visual distortion for the wearer. This technique is especially beneficial for those who have significant differences in the prescription of each eye, as it helps ensure that the optical centers are properly aligned and that the wearer can look through the most appropriate part of the lens for their vision needs.

Other terms listed, such as safety bevel, prism axis, and reading level, pertain to different concepts within optical dispensing and do not describe the bicentric grinding process. Understanding these distinctions helps clarify why "slab-off" is the correct answer regarding bicentric grinding.