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

A method of manufacturing a spectacle lens comprising:

• providing a spectacle lens element with a front surface and a rear surface;
• providing individual prescription data for the spectacle lens to be manufactured,
• wherein the individual prescription data contain at least one value of a combination of:
• a spherical power and a cylindrical power,
• the spherical power, the cylindrical power, and an axis, or
• the spherical power, the cylindrical power, and a prismatic power,
• wherein the at least one value is in each instance independently a near vision value or a far vision value;
• providing two or more domains containing possible values of prescription data for the spherical power and the cylindrical power, wherein each domain from among the two or more domains has a continuous functional relationship;
• determining whether the at least one value is contained in a specific domain from among the two or more domains until the at least one value has been found in the specific domain;
• and
• calculating a base curve of the front surface from the received individual prescription data based on the continuous functional relationship between the at least one value included in the individual prescription data and the specific domain;
• and
• machining the front surface and the rear surface of the spectacle lens element based on the individual prescription data and the determined base curve value on the front surface,
• wherein all domains except for one domain have a continuous, non-constant functional relationship, and
• wherein the base curve value is determined by a computer.

A computer program comprising:

• a program code stored on a non-transitory computer readable medium,
• the program code being configured to, when the computer program is loaded or executed in a computer:
• receive individual prescription data containing at least one value of a combination of:
• a spherical power and a cylindrical power,
• the spherical power, the cylindrical power, and an axis, or
• the spherical power, the cylindrical power, and a prismatic power,
• wherein the at least one value is in each instance independently a near vision value or a far vision value;
• provide two or more domains containing possible values of prescription data for the spherical power and the cylindrical power, wherein each domain from among the two or more domains has a continuous functional relationship;
• determine whether the at least one value is contained in a specific domain from among the two or more domains until the at least one value has been found in the specific domain;
• and
• calculate a base curve of the front surface from the received individual prescription data based on the continuous functional relationship between the at least one value included in the individual prescription data and the specific domain,
• wherein all domains except for one domain have a continuous, non-constant functional relationship.

A computer-implemented method of determining one base curve value or two base curve values representing a base curve for a front surface of a spectacle lens, the method comprising:

• receiving frame data;
• determining the one base curve value or the two base curve values for the front surface of the spectacle lens from the received frame data by:
• calculating the one base curve value from the received frame data by a fit of a sphere to a curve or to points of the curve, which represents the frame rim data, or
• calculating the two base curve values from the received frame data by a fit of a torus to the curve or to points of the curve, which represents the frame rim data, or
• calculating the one base curve value or the two base curve values from the received frame data by a fit of a freeform surface to the curve, or to points of the curve, which represents the frame rim data.

A method of manufacturing a spectacle lens comprising:

• providing frame data for the spectacle lens to be manufactured;
• providing a spectacle lens element having a front surface and a rear surface;
• determining one base curve value or two base curve values for the front surface of the spectacle lens element based on the frame data by:
• a) calculating the one base curve value from the received frame data by a fit of a sphere to a curve, or to points of the curve, which represents the frame rim data;
• or
• b) calculating the two base curve values from the received frame data by a fit of a torus to the curve, or to points of the curve, which represents the frame rim data;
• or
• c) calculating the one base curve value or the two base curve values from the received frame data by a fit of a freeform surface to the curve, or to points of a curve, which represents the frame rim data,
• wherein the 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 the one base curve or the two base curve values with the one determined base curve value or the two base curve values on the front surface;
• and
• machining the front surface and the rear surface of the spectacle lens element based on the frame data and on the one determined base curve value or the two base curve values on the front surface.

A computer program comprising:

• a program code stored on a non-transitory computer readable medium;
• the program code being configured to, when the computer program is loaded or executed in a computer:
• receive frame data;
• determine the one base curve value or the two base curve values for the front surface of the spectacle lens from the received frame data by:
• calculating the one base curve value from the received frame data by a fit of a sphere to a curve or to points of the curve, which represents the frame rim data, or
• calculating the two base curve values from the received frame data by a fit of a torus to the curve or to points of the curve, which represents the frame rim data, or
• calculating the one base curve value or the two base curve values from the received frame data by a fit of a freeform surface to the curve, or to points of the curve, which represents the frame rim data.