# What is Curvature of eye lens?

I wanted to know what do we mean by "curvature of eye lens", is it the reciprocal of $r$ i.e $c=1/r$ or is it synonymous to radius of curvature of the eye lens. Moreover how does aperture relate to the curvature of eye lens, is curvature of eye lens dependent on the aperture? Moreover a definition of curvature of eye lens stated that: curvature of eye lens is the arc of the eye lens but isn't this similar to the definition of aperture of lens which is the effective diameter of circular outline of the spherical lens.

in this diagram, is the perpendicular distance A, the aperture and the circular outline distance the curvature?