Optics focusing capacity of an optical system. Fundamentally, optical power is inversely proportional to focal length.
Elemental power is the optical power of a paraxially reversible system.
Although the concept of optical power as originally invented by Gauss was paraxial in nature, in can be extended to geometric optics. Such a formulation is called raytrace power . And as originally defined, power was a global property, every interface having but one value. Corneal and anterior segment topography extends power to every surface point and displays local values in the form of power maps , of which their are several kinds.