Method for determining an ophthalmic lens

摘要

The invention relates to a method for determining an ophthalmic lens wherein: a first and a second reference axes are determined, the first reference axis is comprised between [γT−20°, γT+20° ] with γT being the mean axis of astigmatism over a first temporal portion, and the second reference axis is comprised between [γN−20°, γN+20° ] with γN being the mean axis of astigmatism over a second nasal portion; a combined reference axis is determined as a linear combination of the first and second reference axes; over the first portion, the sphere value along the combined reference axis is greater than the sphere value along a perpendicular axis to the combined reference axis; and over the second portion, the sphere value along the combined reference axis is greater than the sphere value along a perpendicular axis to the combined reference axis.

主权项

1. A method for manufacturing a progressive ophthalmic lens, the lens comprising a main meridian separating the lens in a nasal area (Area_nasal) and a temporal area (Area_temporal), comprising:
providing data relative to the eyes of a wearer; transmitting the data relative to the wearer; determining a front surface of a lens according to a determining method comprising the steps of:
choosing a target optical function suited to a wearer, the target optical function defining, for each gaze direction when the lens is worn, a refractive power (Pα,β), a module of astigmatism (Astα, β) and an axis of astigmatism (γα,β), each gaze direction corresponding to a lowering angle (α) and to an azimuth angle (β);defining a front surface of the lens and a rear surface of the lens, each surface having in each point a mean sphere value (SPHmean), a cylinder value (CYL) and a cylinder axis (γAX);defining at least one first surface portion (Portion1) of the front surface in the temporal area (Area_temporal) and at least one second surface portion (Portion2) of the front surface in the nasal area (Area_nasal);for the first and second surface portions of the front surface (Portion1, Portion2), determining respectively a first or a second reference axes (Γ1, Γ2), the first reference axis (Γ1) being set to a value comprised between [γT−20°, γT+20° ] with γT being a mean axis of astigmatism of the target optical function for gaze directions intersecting the front surface over the first temporal surface portion (Portion1), and the second reference axis (Γ2) being set to a value comprised between [γN−20°, γN+20° ] with γN being a mean axis of astigmatism of the target optical function for gaze directions intersecting the front surface over the second nasal surface portion (Portion2);determining a combined reference axis (Γ) as a linear combination of the first and second reference axes: Γ=α1*Γ1+α2*Γ2, where α1 and α2 are weights, wherein weights α1 and α2 are between 0 and 1, and α1+α2=1; andmodifying the front surface so that:
over the first surface portion (Portion1), a sphere value (SPH(Γ)) along the combined reference axis is greater than a sphere value (SPH(⊥Γ)) along an axis perpendicular to the combined reference axis (SPH(Γ)>SPH(⊥Γ)); andover the second surface portion (Portion2), a sphere value (SPH(Γ)) along the combined reference axis is greater than a sphere value (SPH(⊥Γ)) along an axis perpendicular to the combined reference axis (SPH(Γ)>SPH(⊥Γ));wherein the first surface portion (Portion1) in the temporal area is delimited by a gaze direction with a lowering angle (α) between 0° and 50° and an azimuth angle (β) between −50° and −10° and such that a resulting astigmatism in the first surface portion (Portion1) is more than 0.50 diopters, andwherein the second surface portion (Portion2) in the nasal area is delimited by a gaze direction with a lowering angle (α) between 0° and 50° and an azimuth angle (β) between 10° and 50° and such that a resulting astigmatism in the second surface portion (Portion2) is more than 0.50 diopters; transmitting data relative to the front surface; carrying out an optical optimization of the lens based on the transmitted data relative to the front surface; transmitting the result of the optical optimization; and manufacturing the progressive ophthalmic lens according to the result of the optical optimization.