Contact lens and a method for manufacturing contact lens
AssigneeBoston Eye Technology, Inc.
InventorChristopher A. Ducharme
Life of this patent
Estimating the term…
Abstract
A contact lens having a smooth surface is made through use of a computer implementing a spline approximation of corneal topology. Piecewise polynomials approximating the corneal topology have equal first and second derivatives where they join. A curve representing the central optical portion of the lens and the piecewise polynomial adjacent to the central optical portion curve have an equal first derivative where they join. A contact lens is cut corresponding to the smooth surface defined by the piecewise polynomials.
Claims12
A method of manufacturing a contact lens to fit a corneal topology comprising the steps of,
- providing data representing said corneal topology,
- generating from said data a plurality of piecewise polynomials approximating said corneal topology,
- a plurality of adjacent pairs of said piecewise polynomials having equal first and second derivatives where said piecewise polynomials join, and
- a first derivative of said piecewise polynomial adjacent to a central optical portion being equal to the first derivative of a curve approximating said central portion, where said piecewise polynomials join, and
- cutting a contact lens surface corresponding to said plurality of piecewise polynomials.
A method of manufacturing a contact lens to fit a corneal topology comprising the steps of,
- providing data representing said corneal topology,
- determining from said data a spline approximating said corneal topology,
- said spline being clamped to a curve approximating a central portion of the corneal topology, and
- cutting a contact lens having a peripheral posterior portion corresponding to said spline.
A contact lens approximating a corneal topology comprising
- a posterior surface constructed and arranged in the form of a plurality of piecewise polynomials joined end to end,
- a plurality of adjacent pairs of said piecewise polynomials having equal first and second derivatives where said piecewise polynomials join, and
- a first derivative of said piecewise polynomial adjacent to a central optical portion being equal to the first derivative of a curve approximating said central portion, where said piecewise polynomial and said optical portion join.
A system to manufacture contact lens comprising,
- a digital data processing system connected to an input device to receive data relating to a corneal topology,
- said processing system comprising
- means to define a lens surface corresponding to a plurality of piecewise polynomials approximating said corneal topology,
- a plurality of adjacent pairs of said piecewise polynomials having equal first and second derivatives where said piecewise polynomials join, and
- a first derivative of said piecewise polynomial adjacent to a central optical portion being equal to the first derivative of a curve approximating said central portion, where said piecewise polynomials join, and
- a lathe connected to said digital data processing system, for cutting a lens corresponding to said defined lens surface.
Dependencies are inferred from the claim text.