ANSI Z80.20-2016 pdf free download
ANSI Z80.20-2016 pdf free download.Contact Lenses – Standard Terminology, Tolerances Measurements and Physicochemical Properties. 3.5 Apical radius of curvature: The radius of curvature of an imaginary spherical surface having a sagittal depth that is approximately equal to the sagittal depth of the actual aspheric surface in a small area surrounding its apex. 3.6 Aspheric lens: Contact lens with either front...