Patent ID: 9411170
Filing Date: 2016-08-09
CPC Classification: G02C

Claim Text:
1. A process for determining a pair of progressive ophthalmic lenses comprising the steps of; determining a prescribed far vision mean power (P determining a prescribed addition (A) for each lens of the pair; determining a reading direction for a wearer of the lenses; defining a temporal side and a nasal side on each lens of the pair; defining, on each lens being worn and for each gaze direction, a refractive power (P defining a proximate vision gaze direction (α defining, for each lens of the pair, a temporal half-width field of refractive power (T defining, for each lens of the pair, a nasal half-width field of refractive power (N defining, for each lens of the pair, a temporal half-width field of module of resulting astigmatism (T defining, for each lens of the pair, a nasal half-width field of module of resulting astigmatism (N wherein the ratio of the difference over the sum of temporal and nasal half-width fields of refractive power ((T wherein the ratio of the difference over the sum of temporal and nasal half-width fields of refractive power ((T if the reading direction determined for the wearer is left-to-right, then the ratio of the difference over the sum of temporal and nasal half-width fields of refractive power and/or resulting astigmatism is negative for the left eye lens, and positive for the right eye lens; and if the reading direction determined for the wearer is right-to-left, then the ratio of the difference over the sum of temporal and nasal half-width fields of refractive power and/or resulting astigmatism is positive for the left eye lens, and negative for the right eye lens.