Method for deciding a bevel curve, method for determining the locus of a bevel, method for processing a lens and apparatus for processing a lens

A method for determining a locus of a bevel in a lenticular lens comprising the steps of:

• calculating a value of a bevel curve based on a value of the curve of a concave face of the lenticular lens;
• determining a location of a reference position of the bevel on a peripheral edge of the lenticular lens in a first portion having a minimum thickness, wherein this first portion having the minimum thickness is on a side of the lens that is closest to a wearer's nose, wherein the location of the reference position is based on a thickness of the first portion having the minimum thickness;
• calculating a correction value of a curve based on a ratio of the thickness of the first portion having the minimum thickness to the thickness of a second portion having a maximum thickness of the lenticular lens in a vertical direction;
• and,
• determining the locus of the bevel, having a value of a corrected curve, by adding the correction value of a curve to the value of the bevel curve that passes through the reference position of the bevel.