Aspheric lenses include any object that is not spherical, however, we use the term here specifically to talk about a subset of aspheric lenses, i.e., rotationally symmetric optical elements that have a radius of curvature that changes radially with respect to the center of the lens.

Aspheric lens：
covers any object that is not spherical, but we use the term here specifically to talk about a subset of aspheric lenses, i.e., rotationally symmetric optical elements that have a radius of curvature that changes radially with respect to the center of the lens.

The aspheric approach can improve image quality and reduce the number of elements required while reducing the cost of optical design. From digital cameras and CD players to high-end microscope objectives and fluorescence microscopes, aspheric lenses are rapidly evolving in all aspects of the optics, imaging, and photonics industries because they offer many unique and significant advantages over traditional spherical optical elements.