Lens element adapted for an astigmatic wearer

Abstract

Lens element, for example a spectacle lens or a contact lens, adapted for an astigmatic wearer, said lens element providing a first optical function having a maximum power along a first principal meridian and a minimum power along a second principal meridian based on the prescription of the wearer, the lens element further comprising a plurality of optical elements, for example at least twenty optical elements, each optical element of the plurality of optical elements providing at least a second optical function different from the first optical function having a defocus property; wherein the second optical function has a different value of a parameter related to the defocus property along the first principal meridian and along the second principal meridian.

Description

[0001] Lens element adapted for an astigmatic wearer

[0002] TECHNICAL FIELD

[0003] The disclosure relates to a lens element, for example a spectacle lens or a contact lens, adapted for an astigmatic wearer, said lens element providing a first optical function having a maximum power along a first principal meridian and a minimum power along a second principal meridian based on the prescription of the wearer, the lens element further comprising a plurality of optical elements.

[0004] BACKGROUND OF THE DISCLOSURE

[0005] Astigmatism of an eye is characterized by the fact that the eye does not focus light evenly onto the retina due to an irregular curvature of the cornea or lens curvature. This results in distorted or blurred vision at all distances. Astigmatism is usually corrected using a cylindrical lens, which compensates for the irregular curvature.

[0006] It has been observed that some individuals, when corrected using conventional single vision optical lenses, may experience inaccurate focusing when they observe objects situated at varying distances. In the case of astigmatic individuals, this focusing inaccuracy could be due to uneven refractive power across different meridians of the eye. This phenomenon may result in a portion of the image being formed either in front of or behind the retina, even within the central visual area.

[0007] Over time, it may be observed that the severity of the astigmatic defect tends to increase for many of these individuals.

[0008] Today, it is estimated that around 40% of the world population is astigmatic. Astigmatism poses several issues even when corrected with spectacle lenses, such as distortion, adaptation to cylinder power etc. Astigmatism also limits and / or complicates adoption of certain contact lenses.

[0009] Therefore, it appears that there is a need for a lens element, for example a spectacle lens or a contact lens, that would decrease the astigmatism of the eye in particular for myopic or hyperopic eyes.

[0010] SUMMARY OF THE DISCLOSURE To this end, the present disclosure proposes, a lens element, for example a spectacle lens or a contact lens, adapted for an astigmatic wearer, said lens element providing a first optical function having a maximum power along a first principal meridian and a minimum power along a second principal meridian based on the prescription of the wearer, the lens element further comprising a plurality of optical elements, for example at least twenty optical elements, each optical element of the plurality of optical elements providing at least a second optical function different from the first optical function having a defocus property; wherein the second optical function has a different value of a parameter related to the defocus property along the first principal meridian and along the second principal meridian.

[0011] Advantageously, having the second optical function have a different value of a parameter related to the defocus property along the first principal meridian and along the second principal meridian reduces the astigmatism of the wearer or even changes its axis by influencing eye growth differentially in each meridian, so that the more myopic or the less hyperopic meridian grows less and the less myopic or more hyperopic meridian grows more and finally reducing astigmatism of the wearer.

[0012] According to further embodiments which can be considered alone or in combination:

[0013] - the second optical function has a maximum value of the parameter related to the defocus property along the first principal meridian and a minimum value of the parameter related to the defocus property along the second principal meridian; and / or

[0014] - the second optical function has a binary variation of the value of the parameter related to the defocus property from first principal meridian to the second principal meridian; and / or

[0015] - the second optical function has a monotonous variation of the value of the parameter related to the defocus property from first principal meridian to the second principal meridian; and / or

[0016] - the variation of the value of the parameter related to the defocus property follows as function: a*cos(2*(alpha - alpha0)+7t)+b, where the maximum control is (a+b) and the minimum control is (b-a), alpha the angle and alphaO the prescription axis in negative cylinder notation; and / or

[0017] - the lens element has a center area comprising the reference point, for example the optical center, of the lens element free of optical elements and providing the first optical function; and / or

[0018] - the optical elements are positioned in a network, such as for instance a grid, a honeycomb, or concentric rings; and / or at least 50%, for example at least 80%, for example at least 99%, of the optical elements are lenslets, for example have a spherical, aspherical optical function or “bifocal” lenslets; and / or

[0019] - the parameter related to the defocus property is selected among the average mean spherical power of each lenslet, the asphericity of each lenslet, cylinder in each lenslet; and / or

[0020] - the optical elements have a difference of optical power with the prescription of the wearer greater than or equal to 1 diopter, for example greater than or equal to 2 diopters, for example greater than or equal to 5 diopters, for example greater than or equal to 8 diopters; and / or at least 50%, for example at least 80%, for example at least 99%, of the optical elements are diffusive lenslets or Pi-Fresnel lenslets; and / or

[0021] - the parameter related to the defocus property is the integral value of the MFT, for example determined between 0 and 5 cyl / deg in the prescription plane in standard wearing conditions; and / or for every circular zone having a radius greater than or equal to 1 mm, for example greater than or equal to 2 mm, and smaller than or equal to 5 mm, for example smaller than or equal to 4 mm, comprising a geometrical center located at a distance of a reference point greater or equal to said radius + 4mm, for example +5 mm, for example +6 mm, the ratio between the sum of areas of the parts of optical elements located inside said circular zone and the area of said circular zone is greater than or equal to 20%, for example greater than or equal to 30% and smaller than or equal to 80%, for example smaller than or equal to 70%, for example smaller than or equal to 60%; and / or the reference point is one of: o the optical centre as defined in ISO 13666:2019(E), section 3.2.15, or o the design reference point as defined in ISO 13666:2019(E), section 3.2.16, or o the distance design reference point as defined in ISO 13666:2019(E), section

[0022] 3.2.17, or o the near design reference point as defined in ISO 13666:2019(E), section

[0023] 3.2.18, or o the reference point as defined in ISO 13666:2019(E), section 3.2.19, or o the distance reference point or major reference point as defined in ISO 13666:2019(E), section 3.2.20, or o the near reference point as defined in ISO 13666:2019(E), section 3.2.21, or o the primary reference point as defined in ISO 13666:2019(E), section 3.2.22, or o the secondary reference point as defined in ISO 13666:2019(E), section 3.2.23; or o a framing reference point that faces the pupil of the user gazing straight ahead in standard wearing conditions; and / or at least 50%, for example at least 80%, for example at least 99%, of the optical elements are contiguous optical elements; and / or each optical element has a contour shape being inscribable in a circle having a diameter greater than or equal to 0.1 mm, for example greater than 0.5 mm and smaller than or equal to 3.0 mm, for example smaller than or equal to 2.5 mm; and / or

[0024] - the lens element has a center area, for example having a diameter greater than or equal to 5 mm and smaller than or equal to 8.5 mm, comprising the reference point of the lens element, being free of optical elements and providing the power based on a prescription for said eye of the person; and / or

[0025] - the optical elements are positioned along a plurality of concentric rings; and / or each concentric ring consists of a plurality of contiguous optical elements; and / or at least 50%, for example at least 80%, for example all of the optical elements are refractive tori; and / or

[0026] - the concentric rings of optical elements have an inner diameter comprised between 9.0 mm and 65.0 mm, the inner diameter corresponding to the smallest circle that is tangent to at least one optical element of said circle; and / or

[0027] - the optical elements correspond to a series of torus concentric rings; and / or

[0028] - the optical elements are positioned in a network, such as for instance a grid, a honeycomb, or concentric rings; and / or at least 50%, for example at least 80%, for example at least 99%, of the optical elements are refractive lenslets, for example having a spherical, aspherical optical function or “bifocal” lenslets; and / or at least 50%, for example at least 80%, for example at least 99%, of the optical elements are non-contiguous optical elements.; and / or

[0029] - the refraction area comprises a plurality of respectively independent islandshaped areas; and / or

[0030] - the refraction area is formed as the area other than the optical elements and each refraction island shape area is within one optical element; and / or

[0031] - the refraction area is formed as the area other than the areas formed of the plurality of optical elements; and / or

[0032] - the optical elements may provide simultaneously a plurality of optical functions; and / or at least 50%, for example at least 80%, for example at least 99%, for example all, of the optical elements are multifocal lenslets; and / or at least part, for example at least 90%, for example all, of the front and / or the back surface of the lens element is covered with a coating; and / or at least 50%, for example at least 80%, for example at least 99%, for example all, of the optical elements are located on the front surface of the lens element; and / or at least 50%, for example at least 80%, for example at least 99%, for example all, of the optical elements are located on the back surface of the lens element; and / or at least 50%, for example at least 80%, for example at least 99%, for example all, of the optical elements are located between the front and the back surfaces of the lens element; and / or

[0033] - the lens element further comprises at least four optical elements organized in at least two groups of contiguous optical elements; and / or each group of contiguous optical element is organized in at least two concentric rings having the same center, the concentric ring of each group of contiguous optical element being defined by an inner diameter corresponding to the smallest circle that is tangent to at least one optical element of said group and an outer diameter corresponding to the largest circle that is tangent to at least one optical elements of said group; and / or at least part, for example at least half, for example at least 80%, for example all, of the concentric rings of optical elements are centered on the reference point, for example the optical center, of the surface of the lens element on which said optical elements are disposed; and / or

[0034] - the distance between two successive concentric rings of optical elements is greater than or equal to 0.5 mm, the distance between two successive concentric rings being defined by the difference between the outer diameter of a first concentric ring and the inner diameter of a second concentric ring, the second concentric ring being closer to the periphery of the lens element; and / or

[0035] - the optical element further comprises optical elements positioned radially between two concentric rings; and / or

[0036] - the structured mesh is a squared mesh or a hexagonal mesh or a triangle mesh or an octagonal mesh; and / or

[0037] - the mesh structure is a random mesh, for example a Voronoimesh; and / or at least 50%, for example at least 80%, for example at least 99%, for example all, of the optical elements have a constant optical power and a discontinuous first derivative between two contiguous optical elements; and / or at least 50%, for example at least 80%, for example at least 99%, for example all, of the optical elements have a varying optical power and a continuous first derivative between two contiguous optical elements; and / or at least 50%, for example at least 80%, for example at least 99%, for example all, of the optical element have an optical function of focusing an image on a position other than the retina in standard wearing conditions; and / or at least 50%, for example at least 80%, for example at least 99%, for example all, optical elements have a non-spherical focused optical function in standard wearing conditions, for example for peripheral vision; and / or at least 50%, for example at least 80%, for example at least 99%, for example all, of the optical elements have a cylindrical power; and / or

[0038] - the optical elements are configured so that along at least one, for example along at least 6 equally distributed, for example all, section(s) of the lens element, for example a section passing by the reference point, for example the optical center, of the lens element, the average mean sphere of optical elements increases from a point of said section towards the peripheral part of said section; and / or - the optical elements are configured so that along at least one, for example along at least 6 equally distributed, each section passing through the centers of 6 optical elements arranged in regular ways around the reference point of the lens element; and / or

[0039] - the optical elements are configured so that along at least one, for example along at least 8 equally distributed, for example along all, section(s) of the lens the cylinder of optical elements increases from a point of said section towards the peripheral part of said section; and / or

[0040] - the optical elements are configured so that along the at least one, for example along at least 6 equally distributed, for example along all, section(s) of the lens the average mean sphere and / or the cylinder of optical elements increases from the center of said section towards the peripheral part of said section; and / or

[0041] - the refraction area comprises a reference point, for example the optical center, and the optical elements are configured so that along at least one, for example along at least 8 equally distributed, for example all, section(s) passing through the reference point, for example the optical center, of the lens the average mean sphere and / or the cylinder of the optical elements increases from the reference point, for example the optical center, towards the peripheral part of the lens; and / or

[0042] - the refraction area comprises a far vision reference point, a near vision reference, and a meridian joining the far and near vision reference points, the optical elements are configured so that in standard wearing conditions along at least one, for example at least 8 equally distributed, for example all horizontal section of the lens the average mean sphere and / or the cylinder of the optical elements increases from the intersection of said horizontal section with the meridian towards the peripheral part of the lens; and / or

[0043] - the average mean sphere and / or the cylinder increase functions along the sections are different depending on the position of said section along the meridian; and / or

[0044] - the average mean sphere and / or the cylinder increase functions along the sections are unsymmetrical; and / or

[0045] - the optical elements are configured so that in standard wearing conditions the at least one section is a horizontal section; and / or

[0046] - the average mean sphere and / or the cylinder of optical elements increases from a first point of said section towards the peripheral part of said section and decreases from a second point of said section towards the peripheral part of said section, the second point being closer to the peripheral part of said section than the first point; and / or

[0047] - the average mean sphere and / or the cylinder increase function along the at least one section is a Gaussian function; and / or

[0048] - the average mean sphere and / or the cylinder increase function along the at least one section is a Quadratic function; and / or

[0049] - the optical elements are configured so that the mean focus of the light rays passing through each optical element is at a same distance to the retina.

[0050] BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Non-limiting embodiments of the disclosure will now be described with reference to the accompanying drawing wherein: o Figure 1 illustrates a front view of a lens element according to first embodiment of the disclosure; o Figures 2A and 2B illustrate a profile view a lens element according to different embodiments of the disclosure; o Figure 3 illustrates a front view of a lens element according to a second embodiment of the disclosure; o Figures 4A and 4B illustrates a front view of a lens element according to a third embodiment of the disclosure; and o Figure 5 illustrates the variation of the average mean sphere of the optical elements along a ring of optical elements of figure 1.

[0052] Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve the understanding of the embodiments of the present disclosure.

[0053] DETAILED DESCRIPTION OF EMBODIMENTS OF THE DISCLOSURE

[0054] The disclosure relates to a lens element intended to be worn by a wearer.

[0055] In the reminder of the description, terms like « up », « bottom », « horizontal », « vertical », « above », « below », « front », « rear » or other words indicating relative position may be used. These terms are to be understood in the wearing conditions of the lens element.

[0056] In the context of the present disclosure, the term "optical lens" can refer to an uncut optical lens or a spectacle optical lens edged to fit a specific spectacle frame or an ophthalmic lens and an optical device adapted to be positioned on the ophthalmic lens. The “optical lens” in the context of the present disclosure may have a coating such as a hardcoat and / or a stack of anti -reflective coatings.

[0057] The present disclosure relates to a lens element adapted for an astigmatic wearer. The lens element according to the disclosure may be an optical lens such as a spectacle lens or a contact lens.

[0058] Astigmatism is a non-spherical refractive error and can exist along with myopia or hyperopia. Astigmatism is usually corrected with a sphero-cylindrical lens in which the optical power is different in different meridians, as illustrated on figure 1.

[0059] Most commonly, astigmatism is caused by a non-spherical cornea of the eye and requires a sphero-cylindrical correction in which the power varies by lens meridian. For sphero-cylinderical lens element, the lens center should be properly located before the eye and its rotational position before the eye is important.

[0060] Sphero-cylindrical lens elements are specified by their spherical power, their cylindrical power, i.e. the meridional power variation, and the rotational position or axis of the lens element.

[0061] The lens element according to the disclosure, provides a first optical function having a maximum power along a first principal meridian and a minimum power along a second principal meridian based on the prescription of the wearer. Typically, the first and second principal meridians are 90 degrees apart.

[0062] In the sense of the present disclosure, when the lens element is a lens element, for example an optical lens, such as an ophthalmic spectacle lens, adapted for a myopic wearer, the first principal meridian is the most myopic meridian.

[0063] In the sense of the present disclosure, when the lens element is a lens element, for example an optical lens, such as an ophthalmic spectacle lens, adapted for a hyperopic wearer, the first principal meridian is the least hyperopic meridian.

[0064] The idea of the disclosure is to apply different myopia or hyperopia control to different angular portions of the retina by means of the lens element.

[0065] For example, a stronger myopia control slows the eye elongation in this particular region while a retinal region with weaker myopia control in turn elongates faster than the region with stronger myopia control. This regionally differential elongation of the eyeball affects other ocular structures, such as the cornea to modify the astigmatism of the wearer.

[0066] As represented in figures 1 to 4, a lens element 10 according to the disclosure may comprise a refraction area 12 and a plurality of optical elements 14.

[0067] Typically, the refraction area 12 provides the first optical function adapted for the astigmatic prescription of the wearer.

[0068] The lens element 10 may comprise at least twenty, for example at least forty, optical elements 14, each optical element of the plurality of optical elements providing at least a second optical function different from the first optical function having a defocus property.

[0069] The second optical function has a different value of a parameter related to the defocus property along the first principal meridian and along the second principal meridian.

[0070] In the sense of the disclosure, a “defocus property” relates to a property of “not focusing light on the retina of the wearer in standard wearing conditions”.

[0071] According to an embodiment, the lens element is configured so that the defocus property reaches its maximum value along the first principal meridian and its minimum value along the second principal meridian. The defocus modulation therefore directly corresponds to the wearer’s astigmatic axes. Such configuration produces a directional distribution of optical power that provides a stronger defocus stimulus in the meridian where the refractive power is the most negative or least positive, thereby increasing the inhibitory optical signal on ocular elongation in this meridian while maintaining visual clarity in the perpendicular direction.

[0072] The described lens element thus provides a simultaneous control of both myopia and astigmatism by means of a single optical structure. The same defocus modulation that slows axial elongation also compensates for the differential refractive powers between meridians, so that the retinal image receives a balanced stimulus across orientations. This dual action allows both a limitation of myopic progression and a stabilization or reduction of astigmatic error without the need for distinct optical zones or alternating designs.

[0073] In the context of the present invention, the expression “simultaneous control” designates the concurrent management, by a single optical element, of two distinct but related optical phenomena. The lens element of the invention provides at the same time a myopia control function and an astigmatism control function. The myopia control is achieved through a peripheral or meridional contrast management that delivers a stimulus capable of limiting or preventing ocular elongation, while the astigmatism control is obtained through a directional modulation of this same defocus according to the principal meridians of the wearer. In this manner, the lens does not perform these effects successively or in separate optical zones, but rather produces both effects simultaneously over the entire useful optical surface. By arranging the contrast management modulation such that its value is maximum along one principal meridian and minimum along the orthogonal meridian, the lens element creates a single optical field that both generates a defocus signal sufficient to modulate axial growth and provides an anisotropic correction aligned with the astigmatic axes of the wearer. Accordingly, the lens ensures, in one integrated optical design, the simultaneous inhibition of myopic progression and the dynamic reduction or stabilization of astigmatism.

[0074] In the context of the present invention, the expression “locally isotropic” retinal signaling, refers to a situation in which the optical stimulus received by the retina becomes substantially uniform within a limited region of the retina, even though the eye of the wearer presents an overall anisotropic refractive error due to astigmatism. In an astigmatic eye, light rays oriented along different meridians do not focus at the same retinal depth, which leads to direction-dependent image blur. By providing a defocus modulation that varies with the meridian, the lens element of the invention compensates this directional imbalance. The astigmatism correction is for example maximum along one principal meridian and minimum along the other, so that the optical power delivered to the retina is balanced between orientations. Consequently, within small retinal areas such as the macular or near-peripheral zones, the optical signals received by the photoreceptors are more symmetrical with respect to direction. Although the global optical field remains anisotropic, the invention allows the retinal stimulation to be locally uniform in all directions, thereby improving the perceived image quality and contributing to a stable optical environment favorable to the reduction of astigmatism.

[0075] By orienting the defocus modulation along the principal meridians, the invention creates a coherent optical signal that is interpreted by the eye as a spatially oriented cue. The retinal feedback produced by this configuration influences ocular growth asymmetrically in a manner that compensates the wearer’s astigmatism while simultaneously reducing myopic elongation. The optical function is therefore physiologically tuned to the individual’s refractive anatomy, rather than uniformly applied across all meridians. In contrast with known myopia control lenses that distribute the defocus signal isotropically over all directions, the present lens introduces a meridian-specific gradient of optical power. This controlled anisotropy allows to direct the inhibitory stimulus precisely where ocular elongation is most active, while preserving optical quality in less refractive meridians. Such configuration achieves a more efficient and physiologically selective control of eye growth than isotropic defocus systems.

[0076] The optical configuration of the lens thus provides an intrinsic synergy between correction and control functions. The first optical function ensures refractive correction along each meridian, while the second optical function produces a meridionally modulated defocus that acts as a feedback stimulus. The superposition of these two functions results in a single optical field capable of maintaining clear vision and simultaneously driving controlled ocular adaptation.

[0077] The optical elements 14 typically have a transparent optical function of not focusing an image on the retina of the eye of the wearer when the optical lens is worn in standard wearing conditions.

[0078] In other words, when the wearer wears the lens element, for example in standard wearing conditions, rays of light passing through the plurality of optical elements will not focus on the retina of the eye of the wearer. For example, the optical elements may focus in front and / or behind the retina of the eye of the wearer.

[0079] Advantageously, not focusing an image on the retina of the wearer allows creating a control signal that suppresses, reduces, or at least slows down the progression of abnormal refractions, such as myopia or hyperopia, of the eye of the person wearing the lens element.

[0080] In the sense of the disclosure, an optical element is considered to have a transparent optical function when said optical element absorbs less than 50%, for example less than 20%, for example less than 5% of the light over the visible spectrum, i.e. 380 nm to 750 nm.

[0081] According to an embodiment, the second optical function has a maximum value of the parameter related to the defocus property along the first principal meridian and a minimum value of the parameter related to the defocus property along the second principal meridian. Advantageously, the inventors have observed that such configuration increases the effect of the lens element on the control and / or reduction of astigmatism of the wearer. The variation of the value of the parameter related to the defocus property from first principal meridian to the second principal meridian of the second optical function may be a binary variation.

[0082] Advantageously, such variation is easy to implement and control.

[0083] According to an embodiment of the disclosure, the second optical function has a monotonous variation of the value of the parameter related to the defocus property from the first principal meridian to the second principal meridian.

[0084] The inventors have observed an increase of the effect of the lens element on the control and / or reduction of astigmatism of the wearer when the second optical function has such monotonous variation of the value of the parameter related to the defocus property.

[0085] According to an embodiment of the disclosure, the variation of the value of the parameter related to the defocus property follows as function: a*cos(2*(alpha - alpha0)+7t)+b, where a and b are positive non-zero constants, alpha the angle and alphaO the prescription axis in negative cylinder notation.

[0086] The optical elements 14 of the optical lens according to the disclosure may have different shape and / or optical function or a combination of such shape and optical function.

[0087] For example, the optical elements may be spherical lenslets, i.e. having a spherical optical function. An example of myopia control solution with spherical lenslets is disclosed in US20170131567.

[0088] For example, the optical elements may be non-spherical lenslets, i.e. having an optical function with at least two focal points. For example, a non-spherical lenslets may have a continuous power evolution over its surface.

[0089] For example, the optical elements may be “bifocal” lenslets comprising a central part within an annular part. The annular part providing an additional optical power and the center part providing an optical power based on the prescription of the wearer. The refraction area comprises a plurality of respectively independent islandshaped areas. Typically, the refraction area is formed as the area other than the optical elements and each refraction island shape area is within one optical element. For example, the optical elements have an annular shape around a refraction area. An example of such configuration is described in WO2021198362. According to an embodiment of the disclosure, the optical element may be placed on structure network, for example a squared or hexagonal network or a random network. Typically lens element may comprise a plurality of contiguous lenslets arranged on such structured network having an island shape refraction area within the structured network. Such structured network may be obtained by stamping on a single vision lens. An example of such configuration is described in WO2019166657.

[0090] For example, the optical elements are Pi-Fresnel lenslets. For example, a face of the lens element is fully covered with a plurality of contiguous Fresnel type optical elements. The optical element be a Fresnel type optical element whose phase function y(r) has TI phase jumps at the nominal wavelength Xo. One may give these structures the name “Pi-Fresnel lenses” for clarity’s sake, as opposition to unifocal Fresnel lenses whose phase jumps are multiple values of 2K. Examples of such configurations are disclosed in WO2019206569 and WO2021001524.

[0091] For example, the optical elements may be a set of torus concentric rings. An example of such configuration is disclosed in WO2019166657.

[0092] As represented in figure 2A, the optical lens comprises at least a first surface and a second surface opposed to the second surface. For example, the first surface may comprise an object side surface Fl formed as a convex curved surface toward an object side and the second surface may comprise an eye side surface F2 formed as a concave surface having a different curvature than the curvature of the object side surface. The lens element LI, L2 may be made of organic material, thermoset or thermoplastic material, for example polycarbonate, or made of mineral material such as glass. The lens element LI, L2 may also be made of two layers of abovementioned materials having a different refractive index. Whatever the lens is made of one or more materials, the disposition of the optical element may be similar to the figure 1, figure 3 or figure 4 type.

[0093] With reference to figure 2B, an optical element 10 may include a thermoplastic layer 32 and a thermoset layer 34. Optical elements 14 may be formed within / on a first surface 36 of the thermoplastic layer 32. As in figure 2B, the first surface 36 of the thermoplastic layer 32 may be processed such that the optical elements 14 thereon appear to be debossed within the first surface 36 of the thermoplastic layer 32. As can be appreciated, the optical elements 14 on the first surface 36 of the thermoplastic layer 32 may be hemispherical (spherical or not) and of a concave shape or protruding towards the object side of the lens element.

[0094] Advantageously, the front and / or back surfaces of the lens element are smooth. In the sense of present disclosure, the term “smooth” refers to a state of surface of a lens element in which the unevenness of said surface is smaller than or equal to 0.5 pm, for example smaller than or equal to 0.4 pm. The term “unevenness of a surface” refers to the difference between a maximum value and a minimum value of the deviation distance from the most approximate sphere. The term “most approximate sphere” is a spherical shape calculated from a measured value (height distribution) of the surface using the least squares method.

[0095] From the viewpoint of the average surface power, the term “smooth” may be defined as follows. The term “smooth” refers to the state of a surface whose rate of change in the average surface power (unit: D) at a given position of the surface in a given direction is smaller than or equal to 0.5 D / mm, for example smaller than or equal to 0.4 D / mm.

[0096] The term “smooth” may also be defined as a state in which the difference between the minimum value and the maximum value of the average surface power is smaller than the difference (the power added by the filled segments) between the minimum value and the maximum value of the transmission power.

[0097] In an embodiment, the thermoset layer 34 may be, generally, made of a crosslinked material (e.g., thermosetting materials). In particular, the thermoset layer 34 may be one obtained by polymerization of allyl derivatives such as the allyl carbonates of linear or branched aliphatic or aromatic polyols. This may further include diethylene glycol bis(allyl carbonate), isopropylene bis phenol-A bis(allyl carbonate), poly(meth)acrylates and copolymers based substrates, polythio(meth)acrylates, thermosetting polyurethanes, polythiourethanes, polyepoxides, polyepisulfides, as well as copolymers thereof and blends thereof. In an embodiment, the thermoset layer 34 may be an Orma® (Essilor) substrate and the like, such as one obtained by (co)polymerizing bis allyl carbonate of diethylene glycol, marketed by PPG Industries as CR-39®. The thickness of layer 32 and layer 34 may be similar (between 500pm and 1mm thick) or very different (e.g . one of the two layers having a thickness smaller than 400pm and the other one having a thickness greater than 1mm.

[0098] As illustrated in figures 1 to 4, the lens element LI, L2 comprises a refraction area 12.

[0099] The refraction area 12 has a refractive power Px based on the prescription of the eye of the wearer, for example of the person for which the optical lens is adapted. The prescription is for example adapted for correcting an abnormal refraction of the eye of the wearer of the optical lens, in particular for an astigmatic wearer.

[0100] The term “prescription” is to be understood to mean a set of optical characteristics of optical power, of astigmatism, of prismatic deviation, determined by an ophthalmologist or optometrist in order to correct the vision defects of the eye, for example by means of a lens positioned in front of his eye. For example, the prescription for a myopic eye comprises the values of optical power and of astigmatism with an axis for the distance vision.

[0101] The refraction area is preferably formed as the area other than the areas formed of the plurality of optical elements. In other words, the refraction area is the complementary area to the areas formed of the plurality of optical elements.

[0102] According to an embodiment of the disclosure, the refraction area may comprise a plurality of respectively independent island-shaped areas. For example, each refraction island-shape area is within one optical element.

[0103] Such an arrangement of refraction area is disclosed in WO2021198362.

[0104] As illustrated in figures 1, 3 and 4, the refraction area 12 may comprise at least the central zone of the optical lens 10.

[0105] The central zone may have a characteristic dimension greater than 4 mm, for example greater than or equal to 8 mm and smaller than 22 mm, for example smaller than 20 mm, for example smaller than or equal to 12 mm. For example, the central zone is a circular zone centered on the reference point, for example the optical center, of the lens element and has a diameter greater than 4 mm, for example greater than or equal to 8 mm and smaller than 22 mm, for example smaller than 20 mm, for example smaller than or equal to 12 mm.

[0106] The central zone may be centered on a reference point of the optical lens 10. The reference point on which the central zone may be centered is either one of a geometrical center and / or an optical center and / or a near vision reference point and / or a far vision reference point of the optical lens.

[0107] The optical center (ISO 13666:2019, section 3.2.15) of a single vision lens may be located within the central clear zone, i.e. free of optical elements. Progressive ophthalmic lenses may comprise more than one, in particular two central clear zones, i.e. a near portion comprising a near vision reference point (ISO 13666:2019, section 3.15.3) and a far vision portion comprising a far vision reference point (ISO 13666:2019, section 3.15.1). Preferably, the central zone is centered on, or at least comprises a framing reference point that faces the pupil of the wearer gazing straight ahead in standard wearing conditions.

[0108] The wearing conditions are to be understood as the position of the optical lens with relation to the eye of a wearer, for example defined by a pantoscopic angle, a Cornea to lens distance, a Pupil-cornea distance, a center of rotation of the eye (CRE) to pupil distance, a CRE to lens distance and a wrap angle.

[0109] The Cornea to lens distance is the distance along the visual axis of the eye in the primary position (usually taken to be the horizontal) between the cornea and the back surface of the lens; for example equal to 12mm.

[0110] The Pupil-cornea distance is the distance along the visual axis of the eye between its pupil and cornea; usually equal to 2mm.

[0111] The CRE to pupil distance is the distance along the visual axis of the eye between its center of rotation (CRE) and cornea; for example equal to 11.5mm.

[0112] The CRE to lens distance is the distance along the visual axis of the eye in the primary position (usually taken to be the horizontal) between the CRE of the eye and the back surface of the lens, for example equal to 25.5mm.

[0113] The pantoscopic angle is the angle in the vertical plane, at the intersection between the back surface of the lens and the visual axis of the eye in the primary position (usually taken to be the horizontal), between the normal to the back surface of the lens and the visual axis of the eye in the primary position; for example equal to -8°, preferably equal to 0°.

[0114] The wrap angle is the angle in the horizontal plane, at the intersection between the back surface of the lens and the visual axis of the eye in the primary position (usually taken to be the horizontal), between the normal to the back surface of the lens and the visual axis of the eye in the primary position for example equal to 0°.

[0115] An example of standard wearing condition may be defined by a pantoscopic angle of -8°, a Cornea to lens distance of 12 mm, a Pupil-cornea distance of 2 mm, a CRE to pupil distance of 11.5 mm, a CRE to lens distance of 25.5 mm and a wrap angle of 0°.

[0116] Another example of standard wearing condition more adapted for younger wearers may be defined by a pantoscopic angle of 0°, a Cornea to lens distance of 12 mm, a Pupil-cornea distance of 2 mm, a CRE to pupil distance of 11.5 mm, a CRE to lens distance of 25.5 mm and a wrap angle of 0°. The central zone may comprise the optical center of the optical lens and have a characteristic dimension greater than 4mm - corresponding to + / - 8° peripheral angle on the retina side, and smaller than 22mm corresponding to + / - 44° peripheral angle on the retina side, for example smaller than 20 mm corresponding to + / - 40° peripheral angle on the retina side. The characteristic dimension may be a diameter or the major or minor axes of an ellipse shaped central zone.

[0117] The refraction area 12 may comprise a continuous variation of refractive power. For example, the refractive area may have a progressive addition design. The optical design of the refraction area may comprise a fitting cross where the optical power is negative, and a first zone extending in the temporal side of the refractive area when the lens element is being worn by a wearer. In the first zone, the optical power increases when moving towards the temporal side, and over the nasal side of the lens, the optical power of the ophthalmic lens is substantially the same as at the fitting cross. Such optical design is disclosed in greater details in W02016 / 107919.

[0118] Alternatively, the refractive power in the refraction area 12 may comprise at least one discontinuity.

[0119] At least 50%, for example at least 80%, for example all, of a surface of the optical element LI, L2 may covered by at least one layer of coating element. The at least one layer of coating element may comprise features selected from the group consisting of anti-scratch, anti -refl ection, anti-smudge, anti-dust, UV30 filtration, blue light-filtration, anti-abrasion features.

[0120] The layer of coating element may be provided using any known techniques. For example, the layer of coating may be provided using a dipping process where the optical lens simultaneously receives a layer of coating on each surface.

[0121] The optical elements may be of the form of lenslets providing an additional optical power relative to the refractive power based on the prescription of said eye of the person.

[0122] At least 50%, for example at least 80%, for example at least 99%, of the optical elements are lenslets. The lenslets may have a spherical or aspherical or spherocylindrical or sphero-toric or diffusive or diffractive optical function, for example the lenslets are multifocal lenslets, such as bifocal or trifocal lenslets. Examples of such configuration of optical elements are disclosed in WO2019166659 which content is included by reference in this application. According to such embodiment, the parameter related to the defocus property of the optical element is selected among the average mean spherical power of each lenslet, the asphericity of each lenslet, cylinder, torus of each lenslet.

[0123] According to the disclosure, the mean sphere is defined as

[0124] The average mean sphere of an optical element corresponds to an average of the mean sphere of points on the optical element, for example on 80% of the points of the optical element.

[0125] The optical elements may have a difference in absolute value of optical power with the prescription of the wearer greater than or equal to 1 diopter, for example greater than or equal to 2 diopters, for example greater than or equal to 5 diopters, for example greater than or equal to 8 diopters.

[0126] In the sense of the disclosure, the absolute value of an optical power is the nonnegative value of said optical power without regard to its sign.

[0127] In the sense of the disclosure, an additional optical power relative to the optical power at the reference point is to be understood as the optical power beyond the optical power at the reference point or at the vicinity of the reference point, for example the average optical power over a zone of 2 mm diameter, for example 1 mm diameter, for example 0.5 mm diameter, centered on the reference point.

[0128] The optical power may be determined using a two-dimension representation of the local optical power obtained, for example using a commercially available lens mapper such as the NIMO™ solutions proposed by the company Lambda-X.

[0129] As illustrated on figure 1, according to an embodiment of the disclosure, the optical elements are positioned along a plurality of concentric rings. Each ring may consist of contiguous optical elements. Advantageously, such configuration provides an excellent trade-off between the myopia control function of the optical elements and the visual acuity provided by the lens element.

[0130] In other words, the optical elements may be organized in groups of contiguous optical elements. Each group of contiguous optical elements may be organized in concentric rings, for example at least 5 concentric rings, for example 11 concentric rings, having the same center. The concentric ring of each group of contiguous optical elements being defined by an inner diameter corresponding to the smallest circle that is tangent to at least one optical element of said group and an outer diameter corresponding to the largest circle that is tangent to at least one optical element of said group.

[0131] Typically, the outer diameter of concentric rings of optical elements is comprised between 9.0 mm and 65.0 mm. According to an embodiment of the disclosure, the distance between two successive concentric rings of optical elements is greater than or equal to 0.5 mm, for example greater than 1 mm, the distance between two successive concentric rings being defined by the difference between the outer diameter of a first concentric ring and the inner diameter of a second concentric ring, the second concentric ring being closer to the periphery of the lens element.

[0132] As illustrated on figure 3, according to an embodiment of the disclosure, the optical elements are positioned according to a structured mesh, in the illustration of figure 3 such mesh is a hexagonal mesh, which allows a good trade-off between the myopia control function of the optical elements and the visual acuity provided by the lens element. Alternatively, the mesh would also be a squared mesh.

[0133] As illustrated on figure 3, at least 50%, for example at least 80%, for example at least 99%, of the optical elements are non-contiguous optical elements. In the sense of the invention, two optical elements are considered non-contiguous if there is no path between reference points, for example the centers, of the two optical elements that does not pass an area having the refractive power.

[0134] As illustrated on figures 4a and 4b, according to an embodiment of the disclosure, the optical elements have an annular shape limited by an inner diameter and outer diameter.

[0135] According to such embodiment, the optical elements correspond to part of pure cylindrical concentric rings. In this example, the optical elements have constant power but a variable cylindrical axis.

[0136] For example, the optical elements correspond to a set of torus concentric rings.

[0137] Each optical element has also a geometrical center. All the optical elements are positioned such that their geometrical center is at the same location, for example on the optical center of the lens element. The width of the annular shapes and the distances separating 2 neighboring annular shapes impacts the trade-off between the myopia control function of the optical elements and the visual acuity provided by the lens element.

[0138] As illustrated on figure 2, a lens element 10 according to the disclosure comprises an object side surface Fl, for example formed as a convex curved surface toward an object side, and an eye side surface F2 for example formed as a concave surface having a different curvature than the curvature of the object side surface Fl.

[0139] At least part, for example all, of the optical elements may be located on the front surface of the lens element.

[0140] At least part, for example all, of the optical elements may be located on the back surface of the lens element.

[0141] At least part, for example all, of the optical elements may be located between the front and back surfaces of the lens element. For example, the lens element may comprise zones of different refractive indexes forming the optical elements as illustrated on figure 2B. Examples of such configuration are provided in WO2023104982A1.

[0142] At least one of the optical elements may have an optical function of focusing an image on a position other than the retina.

[0143] Preferably, at least 50%, for example at least 80%, for example at least 99%, for example all, of the optical elements comprised in the lens element may have an optical function of focusing an image on a position other than the retina.

[0144] All of the optical elements may be configured so that the mean focus of the light rays passing through each optical element is at a same distance to the retina of the wearer along a meridian, for example along the first principal meridian and / or along the second principal meridian

[0145] The optical function, in particular the dioptric function, of each optical element may be optimized so as to provide a focus image, for example in peripheral vision, at a constant distance of the retina of the eye of the wearer. Such optimization requires adapting the dioptric function of each of the optical element depending on their position on the lens element.

[0146] The optical elements may be configured so that at least along one section, for example along a meridian, for example along the first principal meridian and / or along the second principal meridian, of the lens the average addition optical power of the optical elements varies monotonically from a point of said section at a distance smaller than 4.5 mm from the point of reference of the lens towards the periphery of said section at least to a point at 25mm from the point of reference of the lens element.

[0147] At least part of the optical elements, for example at least 50%, for example at least 80%, for example at least 99%, for example all of the optical elements are mutifocal lenslets. Advantageously, such multifocal lenslet may have a first optical power corresponding to the prescription and a second optical power different from the first optical power so as to focus light other than on the retina of the wearer.

[0148] According to an alternative of the disclosure, at least 50%, for example at least 80%, for example at least 99%, for example all of the optical elements are diffractive lenslets, for example contiguous diffractive lenslets.

[0149] In the context of the present disclosure, two optical elements are to be considered contiguous if there is a path linking the two optical elements all along which one may measure in standard wearing conditions at least one optical power different from the optical power based on the prescription of the wearer, for example for correcting an abnormal refraction of the eye of the wearer.

[0150] According to an embodiment of the disclosure, at least 50%, for example at least 80%, for example at least 99% for example all of the optical elements, has discontinuities, such as a discontinuous surface, for example Fresnel surfaces and / or having a refractive index profile with discontinuities.

[0151] Examples of Pi -Fresnel lenslets are disclosed in WO2019206569.

[0152] According to an embodiment of the disclosure, at least 50%, for example at least 80%, for example at least 99% for example all of the optical elements are diffusive lenslets or scattering elements as disclosed in WO2022074243.

[0153] According to an embodiment, the parameter related to the defocus property is the integral value of the modulation transfer function of the optical element.

[0154] The modulation transfer function may be determined over a range of 5 cycle per degree or less. For example the lower limit of the range is greater than or equal to 0 cycle per degree, for example greater than or equal to 0.5 cycle per degree, for example greater than or equal to 1 cycle per degree, for example greater than or equal to 1.5 cycle per degree and smaller than or equal to 5 cycle per degree, for example smaller than or equal to 3.5 cycle per degree, for example smaller than or equal to 2.5 cycle per degree in the prescription plane in standard wearing conditions.

[0155] The modulation transfer function may be determined by: determining a 2D representation over a pupil aperture of 4mm centered at 10 mm from the reference point, of optical path differences of a light beam arriving normal to the lens element, (measuring the 3D surface over the lens element when the optical elements “protrude” as represented on figure 2A or using an interferometric measure type (Zygo®) when optical elements are between the front and back surface of the lens element as represented on figure 2B), determining the 2D point spread function, for example the optical center of the lens element by a Fourier transform operation, determining the 2D modulation transfer function over said pupil by a Fourier transform operation.

[0156] - Determining a ID modulation transfer function from the 2D modulation transfer function by averaging the 2D modulation transfer function

[0157] The 2D modulation transfer function provides the contrast for each (fx, fy) (where fx & fy are respectively the spatial frequency along x (resp. y) axis), the corresponding spatial frequency is f=sqrt(fx2+fy2).

[0158] One can note : MTF(fx,fy)

[0159] From this, in order to determine the mean radial modulation transfer function, for each spatial frequency f, we choose an interval [f-df, f+df] . This corresponds to an annular area of the 2D-MTF. where N(f) is the number of couples (fx,fy) in 2D-MTF verifying the condition 72+ fy2e f - df, f + df]

[0160] The modulation transfer function has been widely used to quantify the optical quality of a lens element. The modulation transfer function can be determined by any method known to one skilled in the art. According to some embodiments, to calculate modulation transfer function, the complex amplitude in the pupil plane is evaluated, then using fast Fourier transform the point spread function is calculated and finally the modulation transfer function, for example for foveal vision, is calculated (G. Voelz. Computational Fourier optics: a MATLAB tutorial. SPIE Press Bellingham, WA, 2011).

[0161] The values determined in the present disclosure are modulation transfer function computed using one center wavelength ( = 550 nm).

[0162] Typically, the modulation transfer function, can be computed for a pupil aperture of 4mm, a given gaze direction at various spatial frequencies.

[0163] Typically, the modulation transfer function is calculated in a plan at a distance from the reference point of the optical element corresponding to the inverse of the refractive power based on the prescription of the wearer. Figure 1 represents an example of a lens element according to the disclosure adapted for an astigmatic wearer having a prescription of -2.00(-2.00)0, i.e., the power is -2.00D at 0 degrees and -4.00 at 90 degrees.

[0164] The wearer complains about space distortion due to his astigmatism. He is prescribed with a myopia control lens which is based on an alternating ring structure where the lenslet power in each ring follows a variation as illustrated on figure 5, reaching a maximum (+6D) at the most myopic meridian (-4.00 at 90 degrees) and a minimum (+4D) at the least myopic meridian (-2.00 at 0 degrees).

[0165] The prescription may be different for the right and left eye of the wearer.

[0166] According to the disclosure, the astigmatism of the wearer may be checked over time, for example each 6 months or 12 months, and the optical element may be adapted to the evolution of the astigmatism of the wearer. For example, if the astigmatism reduces below a given threshold, such as 0.5 diopters, the wearer may switch to a regular optical lens.

[0167] The use of a lens element according to the disclosure could also be a change in axis rather than a decrease of value of astigmatism: oblique astigmatisms are more difficult to adapt to and distort space perception more. Therefore, a possible outcome could be to have the axis being close to 0 / 90 degrees or to minimize the difference between the right and left eye. The inventors have observed that to change the axis it is advantageous to have the second optical function a few degrees, for example 3° to 15°, off the first principal meridian and second principal meridian.

[0168] The disclosure has been described above with the aid of embodiments without limitation of the general inventive concept. Many further modifications and variations swill be apparent to those skilled in the art upon making reference to the foregoing illustrative embodiments, which are given by way of example only and which are not intended to limit the scope of the disclosure, that being determined solely by the appended claims.

[0169] In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that different features are recited in mutually different dependent claims does not indicate that a combination of these features cannot be advantageously used. Any reference signs in the claims should not be construed as limiting the scope of the disclosure.

Claims

-25-CLAIMS1. Lens element, for example a spectacle lens or a contact lens, adapted for an astigmatic wearer, said lens element providing a first optical function having a maximum power along a first principal meridian and a minimum power along a second principal meridian based on the prescription of the wearer, the lens element further comprising a plurality of optical elements, for example at least twenty optical elements, each optical element of the plurality of optical elements providing at least a second optical function different from the first optical function having a defocus property; wherein the second optical function has a different value of a parameter related to the defocus property along the first principal meridian and along the second principal meridian.

2. The lens element according to claim 1, wherein the second optical function has a maximum value of the parameter related to the defocus property along the first principal meridian and a minimum value of the parameter related to the defocus property along the second principal meridian.

3. The lens element according to claim 1 or 2, wherein the second optical function has a binary variation of the value of the parameter related to the defocus property from first principal meridian to the second principal meridian.

4. The lens element according to claim 1 or 2, wherein the second optical function has a monotonous variation of the value of the parameter related to the defocus property from first principal meridian to the second principal meridian.

5. The lens element according to the preceding claim, wherein the variation of the value of the parameter related to the defocus property follows as function: a*cos(2*(alpha - alpha0)+7t)+b, where a and b are positive non-zero constants, alpha the angle and alphaO the prescription axis in negative cylinder notation.

6. The lens element according to the preceding claims, wherein the lens element has a center area comprising the reference point, for example the optical center, of the lens element free of optical elements and providing the first optical function.

7. The lens element according to any of the preceding claims, wherein the optical elements are positioned in a network, such as for instance a grid, a honeycomb, or concentric rings.

8. The lens element according to any of the preceding claims, wherein at least 50%, for example at least 80%, for example at least 99%, of the optical elements are lenslets, for example have a spherical or aspherical or sphero-cylindrical or sphero-toric or diffusive or diffractive optical function, for example the lenslets are multifocal lenslets, such as bifocal or trifocal lenslets.

9. The lens element according to the preceding claim, wherein the parameter related to the defocus property is selected among the average mean spherical power of each lenslet, the asphericity of each lenslet, cylinder in each lenslet.

10. The lens element according to the preceding claim, wherein the optical elements have a difference of optical power with the prescription of the wearer greater than or equal to 1 diopter, for example greater than or equal to 2 diopters, for example greater than or equal to 5 diopters, for example greater than or equal to 8 diopters.

11. The lens element according to any of the preceding claims, wherein at least 50%, for example at least 80%, for example at least 99%, of the optical elements are diffusive lenslets or diffractive lenslets, for example Pi-Fresnel.

12. The lens element according to the preceding claim, wherein the parameter related to the defocus property is the integral value of a modulation transfer function.

13. The lens element according to any of the preceding claims, wherein the lens element is an ophthalmic lens adapted for a myopic wearer and the first principal meridian is the most myopic meridian.

14. The lens element according to any of claims 1 to 12, wherein the lens element is an ophthalmic lens adapted for a hyperopic wearer and the first principal meridian is the most hyperopic meridian.

15. The lens element according to any of the preceding claims, wherein for every circular zone having a radius greater than or equal to 1 mm, for example greater than or equal to 2 mm, and smaller than or equal to 5 mm, for example smaller than or equal to 4 mm, comprising a geometrical center located at a distance of a reference point greater or equal to said radius + 4mm, for example +5 mm, for example +6 mm, the ratio between the sum of areas of the parts of optical elements located inside said circular zone and the area of said circular zone is greater than or equal to 20%, for example greater than or equal to 30% and smaller than or equal to 80%, for example smaller than or equal to 70%, for example smaller than or equal to 60%.

Images