Patent ID: 6145988
Filing Date: 2000-11-14
Classification: B24B,G02C,G05B

Abstract:
A method for designing and manufacturing contact lens with aspherical geometry, said lens having a front surface, an edge and a back surface suitable for matching an eye's cornea surface by interposition of a tear film layer, comprising the steps of:conducting digital topography of said cornea surface and creating a numerical definition of said cornea surface;choosing a surface portion approximating said cornea surface as defined by said numerical definition of said cornea;determining a numerical definition of a tear film layer covering said cornea surface;choosing a lens back surface approximating the summation of said surface portion and said tear film layer as defined by said numerical definitions;designing the front surface shape and edge shape; andcutting the lens by a CNC machine tool, wherein the step of choosing a surface portion approximating said cornea surface as defined by said numerical definition of said cornea further comprises the steps of:defining as approximating surface a function having rotational symmetry with respect to an axis starting from an origin,adding to said approximating surface a function of non-rotational axial symmetry.