US-12619102-B2 - Ophthalmic lens

US12619102B2US 12619102 B2US12619102 B2US 12619102B2US-12619102-B2

Abstract

A method for determining a progression length of an ophthalmic lens, the method including providing an addition value Add, providing a model, the model linking an addition value Add with a progression length, and based on the model and on the provided addition value, determining the progression length.

Inventors

Olivier Roussel
Carlos Rego
Alain GOULET
Mélanie HESLOUIS

Assignees

ESSILOR INTERNATIONAL

Dates

Publication Date: 20260505
Application Date: 20211122
Priority Date: 20201120

Claims (15)

1 . A method implemented by a computer for determining a progression length of an ophthalmic lens intended to be worn in front of an eye of an user, the method comprising: obtaining an addition value Add; obtaining a model, the model linking an addition value Add with a progression length; and based on the model and on the obtained addition value, determining the progression length, the progression length corresponding to a difference between a value on a y-axis of a fitting cross of the ophthalmic lens and a value on the y-axis of a near vision reference point of the ophthalmic lens.
2 . The method according to claim 1 , wherein the progression length is a virtual progression length of a virtual ophthalmic lens.
3 . The method according to claim 2 , wherein the eye is a cyclopean eye, the ophthalmic lens is a virtual ophthalmic lens, the progression length is a virtual progression length.
4 . The method according to claim 1 , wherein the model comprises a first sub model and a second sub model, the first sub model linking an addition value Add with a lowering gaze angle, and the second sub model linking a lowering gaze angle with a progression length, and wherein the determining the progression length comprises: based on the first sub model and on the obtained addition value, determining the lowering gaze angle, and determining the progression length based on the second sub model and the lowering gaze angle.
5 . The method according to claim 1 , wherein the model is based on a prescription of the user.
6 . The method according to claim 1 , wherein the model is based on a statistical database.
7 . The method according to claim 1 , wherein the addition value is obtained from at least one of the following parameters: a prescribed addition of the user, a prescribed mean power of the user for near vision and a prescribed mean power of the user for far vision, age of the user, a prescribed mean power of the user for far vision and the age of the user.
8 . A non-transitory computer-readable storage medium including one or more stored sequences of instructions that are accessible to a processor and which, when executed by the processor, causes the processor to carry out the method according to claim 1 .
9 . A method implemented by a computer for obtaining ophthalmic lens surface data intended to be used for manufacturing an ophthalmic lens, the method comprising: determining a progression length of an ophthalmic lens by obtaining an addition value Add, obtaining a model, the model linking an addition value Add with a progression length, and based on the model and on the obtained addition value, determining the progression length, the progression length corresponding to a difference between a value on a y-axis of a fitting cross of the ophthalmic lens and a value on the y-axis of a near vision reference point of the ophthalmic lens; and obtaining ophthalmic lens surface data by taking into account the determined progression length.
10 . The method according to claim 9 , wherein the ophthalmic lens is defined such that the ophthalmic lens has at least a far vision region having a far vision reference point, a near vision region having the near vision reference point, a main meridian of progression passing through the at least far vision reference point and near vision reference point, a portion on the meridian passing through the far vision region defining a vertical axis, the fitting cross, a prism reference point being an origin of a reference frame with the y-axis, the reference frame making it possible to define for each point on the lens a value on the y-axis relative to the vertical axis, and the progression length corresponding to the difference between the value on the y-axis of the fitting cross and the value on the y-axis of the near vision reference point, and wherein the obtaining ophthalmic lens surface data by taking into account the determined progression length comprises: obtaining surface data S, obtaining modified surface data S′ by modifying the surface data S in order to change at least the value on the y-axis of the near vision reference point such that the distance between the value of the y-axis of the fitting cross and the value on the y-axis of the near vision reference point corresponds to the determined progression length, and a mean sphere and a cylinder at the far vision reference point of the modified surface data S′ and the mean sphere and the cylinder at the near vision reference point of the modified surface data S′ have respectively a maximal difference of 0.05D with the mean sphere and the cylinder at the far vision reference point of the surface data S and the mean sphere and the cylinder at the near vision reference point of the surface data S, and obtaining ophthalmic lens surface data from the modified surface data S′.
11 . The method according to claim 10 , wherein the obtaining surface data S comprises: obtaining an initial surface data Sini associated with a first coordinate system, said initial surface data Sini comprising a plurality of surface points PI, each surface point PI having a mean sphere Sph(PI) and a cylinder Cyl(PI), selecting n modifying surface data S mod 1 . . . S mod i , . . . , S mod n , n, i being integers with n>1 and with 1<i<n said modifying surface data S mod 1 . . . S mod i , . . . , S mod n , S mod i being associated with a second coordinate system, with n being a nonzero integer, positioning the n modifying surface data S mod 1 , . . . S mod i , . . . , S mod n , during which the relative position and/or the relative orientation of the first coordinate system with respect to the second coordinate system is determined and during which the n modifying surface data S mod expressed in the first coordinate system are S′ mod 1, . . . S′ mod i, . . . S′ mod n, and combining the n modifying surface data such that the surface data S is determined by: S = Sini + ∑ i = 1 n ⁢ alpha i · S ′ ⁢ mod i alpha i being a nonzero weighting coefficient.
12 . The method according to claim 11 , wherein the n weighting coefficient alpha; are calculated based on at least one of the following parameters: prescribed mean power, prescribed astigmatism, prescribed addition, addition from age of a user.
13 . The method according to claim 11 , wherein the modifying surface data are selected to enlarge the near vision region and/or the far vision region.
14 . The method according to claim 10 , wherein the obtaining surface data S comprises: obtaining an initial surface data Sini associated with a first coordinate system, said initial surface data Sini comprising a plurality of surface points PI, each surface point PI having a mean sphere Sph(Pl) and a cylinder Cyl(Pl), selecting n modifying surface data S mod 1 . . . S mod i , . . . , S mod n , n, i being integer with n≥1 and with 1≤i<n said modifying surface data S mod 1 , . . . S mod i , . . . S mod n being associated with the first coordinate system, with n being a nonzero integer, and combining the n modifying surface data such as the surface data S is determined by: S = Sini + ∑ i = 1 n ⁢ alpha i · S ⁢ mod i alpha i being a nonzero weighting coefficient.
15 . An ophthalmic lens calculating device, comprising: processing circuitry configured to obtain an addition value Add, obtain a model, the model linking an addition value Add with a progression length, and based on the model and on the obtained addition value, determine the progression length, the progression length corresponding to a difference between a value on a y-axis of a fitting cross of the ophthalmic lens and a value on the y-axis of a near vision reference point of the ophthalmic lens.

Description

FIELD OF THE DISCLOSURE The disclosure relates to a method implemented by computer means for determining a progression length of an ophthalmic lens intended to be worn in front of an eye of an user. The disclosure also relates to a method implemented by computer means for providing ophthalmic lens surface data intended to be used for manufacturing an ophthalmic lens. Additionally, the disclosure relates to an optical element associated. BACKGROUND OF THE DISCLOSURE Wearers with low addition values are often new progressive lenses wearers. These new progressive lens wearers are not used to lower their gaze direction for near vision tasks. Thus, they need easy access to the near vision zone while keeping a comfortable and large vision in the near vision region. Usually, a person needing to wear spectacles and having thus a prescription filled by an ophthalmologist or optometrist goes to the shop of an optician. The optician orders a pair of optical lenses corresponding to the prescription of the wearer. The pair of optical lenses sent to the optician are designed and manufactured according to optical criteria. In the case of progressive lenses, the pair of optical lenses are designed by determining the position and extent of the far vision region and the position and extent of the near vision region. In particular, for these new progressive lenses wearers, the position of the near vision region is important. The choice of a frame places certain constraints on the determination of the location of the near vision zone. Customarily, the choice of the location of the near vision zone is made by the optician on the basis of subjective criteria such as the fitting height, posture of the wearer or feedback given by the latter on his preceding piece of equipment. The choice of the location of the near vision zone may be also obtained by measuring the near vision behavior to perfectly adapt this location to the wearer. This measurement is made by the optician. However this measurement “costs” time to the optician in shop with the wearer but also for the mandatory training to be allowed to realize this measurement. Thus there is a need to provide a progressive lens having easy access to the near vision zone and higher visual comfort that requires less subjective choice and time consuming measurement from the optician. SUMMARY OF THE DISCLOSURE To this end, the disclosure proposes a method implemented by computer means for determining a progression length of an ophthalmic lens intended to be worn in front of an eye of an user, comprising the following steps: providing an addition value Add,providing a model, the model linking an addition value Add with a progression length,based on the model and on the provided addition value, determining the progression length. The ophthalmic lens is a progressive ophthalmic lens, The ophthalmic lens has two surfaces, a front surface and a back surface. At least one surface of the ophthalmic lens comprises at least, a far vision region having a far vision reference point FVP,a near vision region having a near vision reference point NVP,a main meridian of progression passing through the at least far vision reference point FVP and near vision reference point NVP, a portion on the meridian passing through the far vision region defining a vertical axis,a fitting cross FC,a prism reference point being an origin of a reference frame with a y-axis, the reference frame making it possible to define for each point on the lens a value on the y-axis relative to the vertical axis,a progression length LP corresponding to a difference between a value on the y-axis of the fitting cross FC and a value on the y-axis of the near vision reference point NVP, The ophthalmic lens also has a first mean power value P1 at the far vision reference point FVP and a second mean power value P2 at the near vision reference point NVP. The ophthalmic lens comprises an addition value Add corresponding to the difference between the first mean power value P1 and the second mean power value P2. The provided addition value and the progression length LP may be associated to the ophthalmic lens. The eye of the user may be the right eye of the user or the left eye of the user or the virtual right eye of the user or the virtual left eye of the user or the cyclopean eye of the user. In the sense of the invention, “virtual eyes” means a numerical representation of the eyes of the user. It could be for example a point with three coordinates such as the rotation center of eyes. It could be for example a point with three coordinates such as the rotation center of eyes, optionally with a prescription. In the sense of the invention, the cyclopean eye of the user is a virtual eye of the user used as a reference of the binocular visual system, which is positioned by default in the middle of the centers of rotation of both eyes, but which can be positioned elsewhere on the segment connecting the centers of rotation of the both eyes, for