Three mathematical models are presented for the regression and correlation of a cloud of N points in R 3 with Cartesian coordinates xj, yj as abscissas, with his respective ordinate ri as a radius of curvature of the axial or sagittal section, but not corresponding to the Gaussian curvature, with a paraboloid, ellipsoid, and hyperboloid of revolution in canonical form. This model assumes that data are properly centered, that is, the apex of the surfaces of revolution is preset at the origin; therefore, it is applied in human cornea.