A method of designing an aspheric ophthalmic lens with both refractive and
diffractive powers that is capable of reducing chromatic aberration and
at least one monochromatic aberration of an eye comprises combining
aspherical refractive and diffractive surfaces, selecting an appropriate
eye model, establishing a design lens having at least one aspheric
surface with a capacity to reduce monochromatic aberration in said eye
model, establishing a diffractive lens element that corrects for
chromatic aberration of the model eye; and adjusting the lens surface
design in order to obtain a suitably high polychromatic image quality in
a form that is weighted to comply with a spectral merit function.