Computer implemented method of determining a base curve for a spectacle lens and method of manufacturing a spectacle lens

Abstract

A computer implemented method of determining a base curve value representing a base curve for a front surface of a spectacle lens comprises the steps of receiving individual prescription data and determining the base curve value for the front surface of the spectacle lens based on the prescription data. The base curve value is calculated from the received prescription data based on a functional relationship between one or more values included in the prescription data and the base curve value.

What is claimed is: 
     
         1 . A computer implemented method of determining a base curve value representing a base curve for a front surface of a spectacle lens, the method comprising the steps of:
 receiving individual prescription data; and,   determining the base curve value for the front surface of the spectacle lens from the received individual prescription data;   wherein said determining the base curve value is done by calculating it from the received individual prescription data based on a continuous, non-constant functional relationship between at least one value included in the individual prescription data and the base curve value, wherein the at least one value included in the individual prescription data comprises at least one of:   spherical power and object distance,   spherical power and cylindrical power and optionally object distance,   spherical power and cylindrical power and axis and optionally object distance,   spherical power and prismatic power and optionally object distance, and,   spherical power and cylindrical power and prismatic power and optionally object distance; and,   wherein each value included in the individual prescription data is for at least one of far vision and near vision.   
     
     
         2 . The computer implemented method of  claim 1 , wherein the values representing spherical power and representing cylindrical power which are included in the individual prescription data are divided into at least two domains of values and the continuous, non-constant functional relationship between values included in the individual prescription data and the base curve value depends on the domain that the value representing spherical power and the value representing cylindrical power contained in the prescription data are part of. 
     
     
         3 . The computer implemented method of  claim 1 , wherein said determining the base curve value is done by calculating it from the received individual prescription data based on a continuous, non-constant functional relationship between at least the spherical power and a preset curvature of the rear surface. 
     
     
         4 . The computer implemented method of  claim 1 , wherein the minimum curvature of the rear surface is constant for a domain of prescription data and the base curve results from the dioptric requests of the individual prescription data and optionally the data of the as-worn position and optionally the frame data. 
     
     
         5 . The computer implemented method of  claim 1  further comprising the steps of:
 receiving at least one of as-worn position data and frame data; and, 
 taking into account at least one of the received as-worn position data and the received frame data when calculating the base curve value. 
 
     
     
         6 . A method of manufacturing a spectacle lens comprising the steps of:
 providing individual prescription data and optionally individual as-worn position data for the spectacle lens to be manufactured;   determining a base curve value for the front surface of the spectacle lens element based on the individual prescription data and optionally based on the individual as-worn position data;   providing a spectacle lens element with a front surface and a rear surface; and   machining the spectacle lens element based on the individual prescription data and optionally based on the individual as-worn position data;   wherein said determining the base curve value is done by calculating it from the received individual prescription data based on a continuous, non-constant functional relationship between at least one value included in the individual prescription data and the base curve value, wherein the at least one value included in the individual prescription data comprises at least one of
 spherical power and object distance, 
 spherical power and cylindrical power and optionally object distance, 
 spherical power and cylindrical power and axis and optionally object distance, 
 spherical power and prismatic power and optionally object distance, and 
 spherical power and cylindrical power and prismatic power and optionally object distance, 
   wherein each value included in the individual prescription data is for at least one of far vision and near vision; and,   wherein said providing the spectacle lens element includes determining the front surface and the rear surface of the spectacle lens element so as to obtain the spectacle lens with a base curve with the determined base curve value on the front surface.   
     
     
         7 . The method of  claim 6 , wherein said determining the base curve value is done by using a computer implemented method which calculates the base curve value from the provided individual prescription data based on a continuous, non-constant functional relationship between at least one value included in the individual prescription data and the base curve value. 
     
     
         8 . The method of  claim 8 , wherein at least one of the front surface and the rear surface of the lens element is machined such that the spectacle lens in its as-worn position has a dioptric power according to the individual prescription data. 
     
     
         9 . The method of  claim 6 , wherein said spectacle lens is a progressive addition lens. 
     
     
         10 . The method of  claim 9 , wherein a progressive surface of the progressive addition lens is formed on the front surface of the spectacle lens element. 
     
     
         11 . The method of  claim 6 , wherein the machining of the front surface includes forming a free-form surface and in which frame data are provided and the machining of the spectacle lens element is also based on the frame data. 
     
     
         12 . A computer program comprising:
 a program code stored on a non-transitory computer readable medium;   said program code being configured to, when the computer program is loaded or executed in a computer, receive individual prescription data and determine a base curve value for a front surface of a spectacle lens from the received individual prescription data;
 wherein the determining the base curve value is done by calculating it from the received individual prescription data based on a continuous, a non-constant functional relationship between at least one value included in the individual prescription data and the base curve value, wherein the at least one value included in the individual prescription data comprises at least one of: 
 spherical power and object distance, 
 spherical power and cylindrical power and optionally object distance, 
 spherical power and cylindrical power and axis and optionally object distance, 
 spherical power and prismatic power and optionally object distance, and, 
 spherical power and cylindrical power and prismatic power and optionally object distance; and, 
   wherein each value included in the individual prescription data is for at least one of far vision and near vision.