METHODS FOR DETERMINING A PROGRESSIVE OPHTHALMIC LENS AND A SET OF SEMI FINISHED LENS BLANKS

摘要

The invention relates to a method for determining a progressive ophthalmic lens, comprising: - determining a first intermediate value of regression (d1) as the strongest regression that can be applied on the front surface of the lens while keeping a mean sphere value in at least a portion of the lower part of the rear surface of the lens less or equal to a first predetermined value (V1); - determining a second intermediate value of regression (d2) as the strongest regression that can be applied on the front surface of the lens while keeping a mean sphere value in at least a portion of the lower part of the front surface of the lens superior or equal to a second predetermined value (V2); - determining a third intermediate value of regression (d3) as the strongest regression that can be applied on the front surface of the lens while keeping an addition on the rear surface of the lens less or equal to a third predetermined value (V3); - determining a value of regression (d) for the front surface as the maximum value among the first, second and third intermediate values of regression.