Simulating a nonspherical surface profile

A method to approximate a profile of a nonspherical optical surface that has manufacturing defects is described. To approximate measured deviations between the real nonspherical surface profile and designed one are used. Approximation results are new values of coefficients in a formula that specifies nonspherical surface profile. Approximation is carried out to analyze the effect of manufacturing defects on image quality of an optical system that includes the modified nonspherical surface.