aspheric intraocular lens u201d filed on mar 31 2009 the contra aspheric toric lens with lsas of the eye model depicted on the fig9 meets the bi sign aspheric lens description as applied to a toric lens and thus is designed to improve image quality at large pupils as compare with a spherical toric lens of similar power the same specification is defined for base surface of a toric multifocal diffractive surface fig1 demonstrate shapes of lsas of the eye in y and x axes coinciding with the principle meridians of a toric surface not only within 3 mm diameter but at 5 mm diameter that is important for scotopic condition of low illuminance and where the surface profile along each principle meridian takes one sign asphericity both lsa shapes take a configurations of a one sign aspheric where each tangential lsa and sagittal lsa includes the lsa regions of the same sign within about 3 mm diameter and outside about 3 mm diameter in order to include aberration compensation at large pupils the same specification is defined for base surface of a toric multifocal diffractive surface fig1 demonstrate shapes of lsas of the eye in y and x axes coinciding with the principle meridians of a toric surface not only within 3 mm diameter but at 5 mm diameter that is important for scotopic condition of low illuminance and where the surface profile along sagittal principle meridian takes one sign asphericity and tangential u2014 bi sign asphericity tangential lsa and sagittal lsa shapes are opposite signs within about 3 mm diameter and the same.