Patent Description:
As described in <NPL>; <NPL>; <NPL>; and <NPL>, in more detail, epidemiologic surveys from different parts of the world have documented an increased prevalence of myopia. Myopia not only makes distance vision blurry but also, by way of pathologic changes in the retina and choroid associated with extensive elongation of the eye, increases risks for developing macular degeneration, retinal detachment, and glaucoma in the latter half of life; see e.g. <NPL>; <NPL>. Hence, it is desirable to improve preventive treatment for myopia in childhood when myopia progression and axial elongation are most rapid.

Based on experimental results which demonstrate that a hyperopic retinal defocus elongates the axial length of an eye, leading to the progression of myopia, while an image clearly focused on the retina or in front of it would work as a stop signal for the elongation, it has been proposed to use progressive spectacle lenses which are capable of reducing both a lag of accommodation and a hyperopic defocus on the peripheral retina in order to generate a retarding effect on myopia progression, see e.g. <NPL>; and <NPL>.

<CIT> discloses a multi-focal spectacle lens having two progressive zones which are spatially separated from each other and which provide smooth transition of dioptric power, from one to the next of three different viewing-distance regions. The progressive surface is calculated in accordance with the technique of spline analysis and is twice continuously differentiable. In a particular embodiment, the progressive lens has a central viewing zone for distance vision, a lower viewing zone having an addition power of +<NUM> D for near vision, and an upper viewing zone having the addition power of +<NUM> D for intermediate vision.

<CIT> discloses a progressive ophthalmic lens element including a lens surface having an upper viewing zone having a surface to achieve a refracting power corresponding to distance vision, a lower viewing zone having a greater surface power than the upper viewing zone to achieve a refracting power corresponding to near vision, and an intermediate zone extending across the lens element having a surface power varying from that of the upper viewing zone to that of the lower viewing zone and including a corridor of relatively low surface astigmatism, the progressive ophthalmic lens element including progressive design elements selected to reduce myopia progression.

<CIT> discloses an ophthalmic lens element for correcting myopia in a wearer's eye. The lens element includes a central viewing zone and a peripheral zone. The central viewing zone provides a first optical correction for substantially correcting myopia associated with the foveal region of the wearer's eye. The peripheral zone surrounds the central viewing zone and provides a second optical correction for substantially correcting myopia or hyperopia associated with a peripheral region of the retina of the wearer's eye. A system and method for dispensing or designing an ophthalmic lens element for correcting myopia in a wearer's eye is also disclosed.

<CIT> discloses an ophthalmic lens element which includes a front surface and a rear surface, at least one of which includes a horizontal meridian and a vertical meridian. A central viewing zone of the lens element includes a foveal vision zone providing a first power for providing clear foveal vision for a wearer. A peripheral region of positive power relative to the first power is also included. The peripheral region includes dual progressive zones located bilaterally of the vertical meridian and extending radially outwardly from the central viewing zone. The lens element provides a distribution of surface astigmatism which provides, on the horizontal meridian, a relatively low surface astigmatism in the central viewing zone and the progressive zones.

<CIT> discloses a progressive ophthalmic lens having an upper viewing zone, a lower viewing zone, a corridor, and a peripheral region disposed on each side of the lower viewing zone. The upper viewing zone includes a distance reference point (DRP) and a fitting cross (FC) and provides a first refracting power for distance vision. The lower viewing zone, which is for near vision, provides an addition power relative to the first refracting power. The corridor connects the upper and lower zones and provides a refracting power varying from that of the upper viewing zone to that of the lower viewing zone. Each peripheral region includes a zone of positive power relative to the addition power which provides therein a positive refracting power relative to the refracting power of the lower viewing zone. The zones of relative positive power are disposed immediately adjacent to the lower viewing zone such that the lower viewing zone interposes the zones of relative positive power.

<CIT> discloses an ophthalmic lens element which includes a central viewing zone of low surface astigmatism and a peripheral region. The central viewing zone includes an upper viewing zone for providing a first power suitable for a wearer's distance vision tasks. The peripheral region has a positive power relative to the first power and surrounds the central viewing zone. The peripheral region provides an optical correction for retarding or arresting myopia for a wearer and includes one or more regions of relatively higher surface astigmatism, a lower or near viewing zone of low surface astigmatism, and a corridor of low surface astigmatism having a surface power varying from that of the upper viewing zone to that of the lower viewing zone. The lower viewing zone is for a wearer's near vision tasks.

In <NPL>, the effect of newly designed progressive spectacle lenses, which reduce both lag of accommodation and hyperopic defocus on the peripheral retina, on the progression of early-onset myopia, are evaluated. The progressive spectacle lenses have relative plus power in a peripheral zone of the lens compared with the central viewing zone, wherein power and surface astigmatism are distributed in a fashion to provide clear distance vision in the central viewing zone and clear near vision in a lower part of the peripheral zone. In addition, the peripheral zone provides a positive mean addition power in an upper portion of the lens intended as a stop signal for myopia progression. The region of the peripheral zone providing low astigmatism includes a near viewing zone connected to the central viewing zone via a nearly umbilic corridor. Further, the progressive spectacle lenses have a very short power progression corridor adapted for use with children or juveniles with full nominal addition being reached <NUM> below the fitting point. However, a positive aspherizing of the distance zone of the progressive spectacle lens with an astigmatic surface extension did not lead to a higher efficacy in controlling progression of myopia compared to a conventional progressive spectacle lens without such a positive aspherization.

<CIT> discloses an ophthalmic lens element which includes an upper distance viewing zone and a lower near viewing zone. The upper distance viewing zone includes a central region with a first refractive power for clear distance vision and peripheral regions that are relatively positive in power compared to the first refractive power. The lower near viewing zone has a central region that is relatively positive in power compared to the first refractive power to account for accommodative lag. The powers of the peripheral regions of the lower near viewing zone are one of: i) equal to the power of the central region of the lower near viewing zone, ii) relatively positive in comparison to the power of the central region of the lower near viewing zone.

Further background to the present invention is disclosed in <CIT>, <CIT>, and <CIT>.

Despite the advantages as implied by the above-mentioned progressive spectacle lenses, there is still room for further for improvements with respect to an increased preventive treatment for myopia in childhood, in particular under contemporary circumstances which are distinguished by an intensified use of computer devices.

In particular with respect to the disclosure of any one of <CIT>, <CIT> and Hasebe S. , see above, it is therefore an objective of the present invention to provide a progressive spectacle lens, a method for producing a progressive spectacle lens, and a computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the steps of the method for producing the progressive spectacle lens, which at least partially overcome the above-mentioned problems of the state of the art.

It is a particular objective of the present invention to correct a relatively hyperopic peripheral shift of the eyes of the wearer of the progressive spectacle lens during distance vision tasks when looking straight ahead, and, concurrently, to reduce an accommodative lag during both near vision tasks, such as reading, and viewing objects at intermediate viewing distances, such as a screen of a computer monitor.

This problem is solved by a progressive spectacle lens, a series of progressive spectacle lenses, and a method for producing a progressive spectacle lens with the features of the independent claims. Preferred embodiments, which can be implemented in an isolated fashion or in any arbitrary combination, are listed in the dependent claims and throughout the specification.

In a first aspect, the present invention relates to a progressive spectacle lens according to claim <NUM>.

Based on standard ISO <NUM>:<NUM>, Ophthalmic optics - Spectacle lenses - Vocabulary, also referred to herein as the "standard", Section <NUM>. <NUM>, the term "spectacle lens" relates to an optical lens which is used for determining and/or correcting the at least one ocular aberration of an eye of a wearer, wherein the spectacle lens is carried in front of the eye of the wearer. Instead of the term "wearer", a different term, such as "subject", "person", "test person" or "user", may also be applicable. Further, the Standard, Section <NUM>. <NUM>, defines the term "progressive spectacle lens" as a particular kind of spectacle lens having a progressive surface that comprises at least two reference points for focal power, generally designed to provide correction for presbyopia and clear vision from distance to near. In particular, the progressive spectacle lens has a primary reference point also denoted as "DRP" and a secondary reference point also denoted as "near reference point" or "NRP".

Further, the term "ocular aberration" refers to a difference between a surface of an ideal optical wavefront and a surface of an actual optical wavefront which is determined for the eye of the wearer. Herein, the term "optical wavefront" relates to a surface that is perpendicular to a ray along which light propagates. In particular, the ocular aberration within a typical human population, usually, comprises at least one second-order sphero-cylindrical focus error, also denoted as "refractive error". For describing a spherocylindrical lens which is designed for correcting a sphero-cylindrical focus error, various approaches are possible. As defined in the standard, Section <NUM>. <NUM>, the term "spherocylindrical lens" refers to a spectacle lens having one spherical surface and one cylindrical surface. Further, the spherocylindrical lens is defined, according to Section <NUM>. <NUM>, as a spectacle lens which combines a paraxial, parallel beam of light in two individual, mutually perpendicular focal lines, whereby the spectacle lens has a refracting power only in two meridians. As generally used, the term "refracting power" refers to a measure of a degree to which a spectacle lens converges or diverges incident light. Further, the term "vertex power" is, according to Section <NUM>. <NUM>, defined as a reciprocal value of the width of the paraxial section. As further defined in Section <NUM>. <NUM> and <NUM>. <NUM>, the term "meridian" relates to one of two perpendicular planes of the spectacle lens having an astigmatic effect being parallel to the two focal lines. Further, the terms "astigmatic effect" or "astigmatic power" correspond to an "astigmatic difference" which is defined in Section <NUM>. <NUM> as a difference between the value of the vertex power in the horizontal meridian and the value of the refracting power in the vertical meridian. As further generally used, the term "surface astigmatism" refers to a measure of a degree to which a curvature of the spectacle lens varies among intersecting planes that are normal to the surface of the spectacle lens at a point on the surface of the spectacle lens. Further, the "cylindrical power" refers, according to Section <NUM>. <NUM>, to an algebraic difference between the refractive values of the meridians, wherein the refractive value of a particular meridian being used as a reference is subtracted from the refractive value of the other meridian, while the "cylinder axis" indicates according to Section <NUM>. <NUM> the direction of the principal meridian of a spectacle lens whose vertex power is used as reference. As further defined in Section <NUM>. <NUM>, the term "surface power" refers to local ability of a finished surface to change the vergence of a bundle of rays incident at the surface, wherein the surface power is determined from at least one radius of a surface and the refractive index of the optical material as used for the progressive spectacle lens.

The progressive spectacle lens has a lens body comprising a front surface and a back surface, wherein the back surface is facing the eye of the wearer while the front surface is firstly hit by an incident light beam impinging on the progressive spectacle lens. In general, two types of progressive lenses exist, i.e. a first type having a progressive surface on the front surface of the optical lens and a prescription surface selected from a spherical surface or a toric surface on the back surface, and a second type having a spherical front surface, while the back surface combines the progressive surface and the prescription surface. The first type is usually cast as a semi-finished progressive surface, whereinafter the prescription surface is applied to the back surface. The second type is usually cast as a spherical puck having a spherical front surface, whereinafter the back surface is treated with a free form generator and polisher in order to obtain a complex surface combining the progressive surface and the toric surface.

The progressive spectacle lens may be formulated from any suitable material, in particular from a polymeric material. Herein, the polymeric material may be of any suitable type, especially of a thermoplastic or thermoset material. Specifically, a material of a diallyl glycol carbonate type, e.g. CR-<NUM> (PPG Industries) may be used. Herein, the polymeric article may be formed from crosslinkable polymeric casting compositions. Further, at least one of the front surface and the back surface may comprise at least one addition used in casting compositions such as inhibitors, dyes including thermochromic and photochromic dyes, polarizing agents, UV stabilizers, or materials capable of modifying refractive index. Further, the progressive spectacle lens may comprise additional coatings to at least one of the front surface or back surface, in particular electrochromic coatings. The front surface may, further, comprise at least one of an anti-reflective (AR) coating or an abrasion resistant coating. For further details, reference can be made to <CIT>.

According to the present invention, the progressive surface has a central viewing zone. As generally used, the term "viewing zone" refers to a portion of the progressive surface which is designated for providing refracting power for a particularly selected kind of vision. As generally used, both terms "central viewing zone" and "distance viewing zone" refer to a portion of the progressive surface which is located around the center of the progressive surface and which is designated for providing refracting power for distance vision, specifically for providing foveal vision for on-axis viewing of the wearer of the progressive spectacle lens. The refracting power as provided by the central viewing zone may, typically, be a prescribed power that corresponds with an optical correction for the distance vision requirements of the wearer. For a purpose of correcting myopia, the central viewing zone exhibits a negative power in order to bring an image to the retina of the wearer of the progressive spectacle lens from an uncorrected position in front of the retina. In particular, the central viewing zone may cover an area of the progressive surface which corresponds with typical eye rotations of the wearer.

Further according to the present invention, the progressive surface comprises four different stable addition power regions which are located in peripheral portions of the progressive surface of the progressive spectacle lens around the central viewing zone in a manner that they surround the central viewing zone. As generally used, the term "peripheral" refers to a portion of the progressive surface outside the central viewing region. According to the present invention, the peripheral portions provide, throughout the peripheral portions, addition power relative to the first refracting power of the central viewing zone. As generally used, the term "addition power" refers to a portion of refracting power which is provided in addition to the refracting power as provided by the central viewing zone.

The lower viewing zone is located along a lower portion of a vertical meridian of the progressive surface and provides a second refracting power corresponding to near vision. Therefore, the lower viewing zone may also be denoted as a "near viewing zone". Herein, the second refracting power provides a first addition power of +<NUM> D to +<NUM> D, preferably of +<NUM> D to +<NUM> D, relative to the first refracting power of the central viewing zone, thus providing a greater surface power than the central viewing zone. As generally used herein, the term "greater" indicated that the surface power of the respective viewing zone exceeds the surface power of the central viewing zone. In particular, the lower viewing zone may reduce the need for the wearer to tilt the head during near vision tasks, such as reading, and thus may make the lens more comfortable to wear. Further, the lower viewing zone may reduce accommodative demand imposed on the eye of the wearer for the near vision tasks, such as reading. In particular, the lower viewing zone may assist juvenile wearers in reducing their accommodative demand during near viewing tasks, which has been shown to have a non-negligible effect on the retardation of the progression of myopia.

Both peripheral vision zones are extending bilaterally from the vertical meridian of the progressive surface. As indicated by the term "bilaterally", both peripheral vision zones are located along a horizontal meridian of the progressive surface in a symmetrical manner along the horizontal meridian of the progressive surface with respect to a center of the progressive surface, specifically a first peripheral vision zone in a nasal direction and a second peripheral vision zone in a temporal direction of the progressive surface. Both peripheral vision zones are designed for providing a third refracting power at a prescribed field angle which is devised to correct a peripheral hyperopic shift of a static eye looking straight ahead. Herein, the third refracting power provides a second addition power of +<NUM> D to +<NUM> D, preferably of +<NUM> D to +<NUM> D, relative to the first refracting power of the central viewing zone. As a result, the first addition power may exceed the second addition power by +<NUM> D or less, in particular the first addition power may equal the second addition power.

In particular accordance with the present invention, the upper viewing zone is located along an upper portion of the vertical meridian of the progressive surface, thereby pointing to a top of the progressive surface. Herein, the upper viewing zone is designated for providing a fourth refracting power corresponding to intermediate vision. As a result, the upper viewing zone may improve viewing of objects at intermediate viewing distances, such as a screen of a computer monitor. Herein, the fourth refracting power provides a third addition power of +<NUM> D to +<NUM> D, preferably of +<NUM> D to +<NUM> D, relative to the first refracting power of the central viewing zone. As a result, both the first addition power and the second addition power may exceed the third addition power.

Further, the progressive surface comprises a set of progressing power regions. As used herein, the term "progressing power region" refers to a region having a positive gradient of surface power which is located on the progressive surface and which is formed as a "corridor" by connecting the central viewing zone and each of the lower viewing zone, the two peripheral vision zones, and the upper viewing zone. As generally used, the term "corridor" refers to a portion of the progressive surface which is designated for connecting at least two individual viewing zones which are located on different parts of the progressive surface. According to the present invention, each progressing power region has increasing addition power with increasing distance from the center of the progressive surface, wherein the addition power increases until the respective addition power of the corresponding progressing power region is fully reached. As described below in more detail, each corridor forming a progressing power region on a portion of the progressive surface, simultaneously, exhibits a low surface astigmatism, wherein the term "low surface astigmatism" refers a low degree of astigmatic power at the respective portion of the progressive surface that amounts to less than +<NUM>. In contrast hereto, a higher surface astigmatism may exhibit an astigmatic power of up to +<NUM> D.

A conventional progressive lens for presbyopes may comprise an intermediate viewing zone which is located in a progression zone between the distance viewing zone and the near viewing zone. The distance from the fitting cross (FC) in the central viewing zone to the near reference point (NRP) in the lower viewing zone is quite short in the progressive surface as comprised by the progressive spectacle lens according to the present invention. As a result, too little space remains to fit an intermediate viewing zone between the fitting cross and the near reference point. Consequently, the intermediate viewing zone is now comprised by the upper viewing zone which is located in an area above the distance viewing zone, whereby the distance from the fitting cross to the upper viewing zone is shorter than the distance from the fitting cross to the near viewing zone. Herein the viewing of a monitor could, further, be improved by adjusting a height of the monitor, in particular slightly upwards, and/or by exerting a slight tilt of the head down when viewing the monitor in front of the wearer.

More particular, both the first addition power and the second addition power may be fully reached at a first distance from the center of the progressive surface, wherein the first distance may be of <NUM> to <NUM>, preferably of <NUM> to <NUM>, in particular of <NUM> ± <NUM>. Similarly, the third addition power of the upper viewing zone may be fully reached at a second distance from the center of the progressive surface, wherein the first distance may, preferably, exceed the second distance, wherein the second distance may be of <NUM> to <NUM>, preferably of <NUM> to <NUM>, in particular of <NUM> ± <NUM>. However, further values may also be feasible.

Further, the progressive surface may comprise a set of blending regions. As generally used, the term "blending region" refers to an area of the progressive surface which has a non-prescribed surface mean power that only provides minimal visual utility. As used herein, the term "blending region" may, in particular, refer to a region which is located between two adjacent progressing power regions.

Further, the progressive spectacle lens comprises a particular distribution of surface astigmatism over the progressive surface. Herein, the low surface astigmatism having an astigmatic power of less than +<NUM> D is present in the central viewing zone, subject to the limitations imposed by the international standards on the power at the DRP, and is extending from the central viewing zone to each of the lower viewing zone, the two peripheral vision zones, and the upper viewing zone through each of the progressing power regions that connect the central viewing zone and the corresponding lower viewing zone, the two peripheral vision zones, and the upper viewing zone, respectively. In contrast hereto, a higher surface astigmatism, such as having an astigmatic power of up to +<NUM> D, may be present in the blending regions which are located between two adjacent progressing power regions.

In a further aspect, the present invention relates to a series of progressive spectacle lenses, wherein a subsequent progressive spectacle lens in the series has a range of addition powers wherein at least one of those addition powers is higher than the corresponding addition power of a preceding progressive spectacle lens in the series, while the other addition powers are equal or higher than the corresponding addition powers of the preceding spectacle lens in the series. In particular, the addition power of the lower viewing zone for near vision may vary, such as in a conventional progressive lens series, with increments of +<NUM> D, whereas the other addition powers in the series may be maintained at the same level or incremented by +<NUM> D, especially depending on peripheral refraction needs and intermediate vision needs, respectively. As a particular advantage of the increments of the progressive spectacle lenses in a series, the preceding progressive spectacle lens in the series may, in particular, be used at an earlier stage of a myopia control treatment, while the subsequent progressive spectacle lens in the series may, in particular, be used at a later stage of the myopia control treatment, specifically, in order to introduce a boost to the plus power which may be advantageous to maintain the efficacy of the myopia control treatment during a later stage of the treatment.

In a further aspect, the present invention relates to a method for producing a progressive spectacle lens as disclosed elsewhere herein. The method according to the present invention comprises the following steps a) and b), which may, preferably, be performed in the given order commencing with step a) and continuing with step b), wherein, depending on the selected production method, both steps may also at least partially be performed in a simultaneous manner. In addition, further steps, whether disclosed herein or not, may, additionally, be performed.

The steps of the present method for producing a progressive spectacle lens are as follows:.

According to step (a), the respective values for the corresponding refracting powers are determined, in particular, by using the knowledge of the person skilled in the art. Based on the first value, the second value, the third value and the fourth value of the optical correction, the progressive spectacle lens is, subsequently, produced according to step (b) by processing at least one lens blank as well-known to the person skilled in the art.

In general, the method according to the present invention can be performed in a fashion in which a lens blank may be provided and, subsequently, be grinded, such as by using a grinding device, in order to produce a desired progressive spectacle lens by using the first value, the second value, the third value and the fourth value of the optical correction as used for compensating the at least one ocular aberration in the eyes of the wearer.

However, in a preferred embodiment, the method according to the present invention may be a computer-implemented method. As generally used, the term "computer-implemented method" refers to a method which involves a programmable apparatus, specifically a computer, a computer network, or a readable medium carrying a computer program, whereby at least one method step is performed by using at least one computer program. For this purpose, the computer program code can be provided on a data storage medium or a separate device such as an optical storage medium, e.g., on a compact disc, directly on a computer or a data processing unit, in particular a mobile communication device, specifically a smartphone or a tablet, or via a network, such as an in-house network or the internet. The present method can, thus, be performed on a programmable unit which is configured for this purpose, such as by providing a particular computer program.

For further details concerning the method for producing the progressive spectacle lens and the related computer program, reference may be made to the progressive spectacle lens as disclosed elsewhere herein.

The progressive spectacle lens, the method for producing the progressive spectacle lens and the related computer program exhibit various advantages with respect to the prior art. In particular, the progressive spectacle lens may, in particular, be used for inhibiting a myopigenic stimulus during both distance vison and near vision. This use of the progressive spectacle lens according to the present invention is in particular contrast to the progressive spectacle lens as described by Hasebe S. , see above, in which attempting to positively aspherize the distance zone of the progressive spectacle lens with an astigmatic surface extension did not show a higher efficacy in controlling progression of myopia compared to a conventional progressive spectacle lens without such a positive aspherization.

In contrast to the lens design concepts as claimed in <CIT>, the spectacle lens according to the present invention does not comprise lower peripheral zones having mean power equal to or higher than the near zone power. Rather, the present spectacle lens has considerably lower mean powers in those areas than the power of the near zone. Further, the spectacle lenses of <CIT> exhibit the region from the distance point to the near point as a single channel of low astigmatism having progressing power, wherein discontinuous inserts in the peripheral areas or a blending of those areas of high plus power through blending zones with high astigmatism are proposed. In contrast hereto, the present spectacle lens has <NUM> channels of low astigmatism transitioning smoothly from one power to another until they reach areas of stable power. Further, <CIT> does not disclose the upper viewing zone for intermediate vision.

Even in view of the further documents <CIT>, <CIT> or <CIT>, the skilled person would not regard it as a normal design procedure to implement low surface astigmatism profiles in order to connect different viewing zones of D1. All mentioned documents implement the low surface astigmatism profiles along one axis, a vertical axis or a horizontal axis. In contrast hereto, our invention simultaneously implements these channels along two axes, which are almost perpendicular to each other. Only this implementation allows solving the problem in ophthalmic lens design of providing plus power with low astigmatism in <NUM> different directions to cater for different requirements of both foveal and peripheral vision in young progressing myopic wearers.

As used herein, the terms "have", "comprise" or "include" or any arbitrary grammatical variations thereof are used in a non-exclusive way. Thus, these terms may refer to both a situation in which, besides the feature introduced by these terms, no further features are present in the entity described in this context and to a situation in which one or more further features are present.

As further used herein, the terms "preferably", "more preferably", "particularly", "more particularly", or similar terms are used in conjunction with optional features, without restricting alternative possibilities. Similarly, features introduced by "in an embodiment of the invention" or similar expressions are intended to be optional features, without any restriction regarding alternative embodiments of the invention, without any restrictions regarding the scope of the invention.

Further optional features and embodiments of the present invention are disclosed in more detail in the subsequent description of preferred embodiments, preferably in conjunction with the dependent claims. Therein, the respective optional features of the dependent claims may be implemented in an isolated fashion as well as in any combination within the scope of the claims. It is emphasized here that the scope of the invention is not restricted by the preferred embodiments.

The invention will now be described with reference to the drawings wherein:.

<FIG> illustrates a contour plot <NUM> of a surface mean power <NUM> for a preferred exemplary embodiment of a progressive spectacle lens <NUM> according to the present invention. As described above and below in more detail, the progressive spectacle lens <NUM> as presented herein can, preferably, be used for myopia control, especially with children. The progressive spectacle lens <NUM> has a lens body which may be transparent, or at least partly transparent, to an incident light beam in order to be able to correct at least one ocular aberration of the eye of a wearer. The lens body of the progressive spectacle lens <NUM> has a front surface and a back surface, wherein the back surface is facing the eye of the wearer while the front surface is firstly hit by the incident light beam impinging on the progressive spectacle lens <NUM>. Herein, either the front surface or the back surface, preferably the back surface, of the progressive spectacle lens <NUM> may combine a progressive surface <NUM> as described below in more detail and a prescription surface, which may include a toric component to correct the wearer's astigmatism of the eye, while the other surface (not depicted here) may be a spherical surface designated for providing distant viewing in a specific distance. As further illustrated in <FIG>, the progressive surface <NUM> may, typically, assume a circular or a slightly oval form, having a center <NUM> in which a vertical meridian <NUM> and a horizontal meridian <NUM> intersect each other. Herein, a fitting cross (FC) may be located at the center <NUM>. Each contour plot <NUM> as displayed in <FIG> shows a distribution of a respective variables over a diameter of <NUM>, which corresponds to a size of a typical children's frame or juvenile's frame in an approximate fashion.

As schematically depicted in <FIG>, the progressive surface <NUM> has a central viewing zone <NUM>, which is located around the center <NUM> of the progressive spectacle lens <NUM>. The central viewing zone <NUM> is designated for providing a first refracting power, in particular over an area that corresponds with typical eye rotations of the wearer, wherein the first refracting power may, preferably, be adjusted to be suitable for distance vision tasks of the wearer. Further, the progressive surface <NUM> has peripheral portions <NUM> which surround the central viewing zone <NUM> and which are adjusted to provide, throughout the peripheral portions <NUM>, an addition power relative to the first refracting power as provided by the central viewing zone <NUM>.

Firstly, a lower viewing zone <NUM> is located along a lower portion <NUM> of the vertical meridian <NUM> within the peripheral portions <NUM> of the progressive surface <NUM>. The lower viewing zone <NUM> is designated for providing a first addition power which is suitable for near vision tasks of the wearer, such as reading or looking at a keyboard of a computer. In the exemplary embodiment of the progressive surface <NUM>, as shown in <FIG>, the first addition power provided by the first stable addition power region <NUM> assumes value of about +<NUM> D relative to the first refracting power as provided by the central viewing zone <NUM>.

Further, two peripheral vision zones <NUM>, <NUM> extend bilaterally from the horizontal meridian <NUM> within the peripheral portions <NUM> of the progressive surface <NUM>, one in a temporal direction and the other in a nasal direction of the progressive surface <NUM>, respectively. Herein, both peripheral vision zones <NUM>, <NUM> are designated for providing a second addition power at a prescribed field angle which is devised to correct a peripheral hyperopic shift of a static eye looking straight ahead. In the exemplary embodiment of the progressive surface <NUM> as shown in <FIG>, the addition power of both peripheral vision zones <NUM>, <NUM> assumes a value of about +<NUM> D which is similar to that of the first stable addition power region <NUM>.

According to the present invention, an upper viewing zone <NUM> is located along an upper portion <NUM> of the vertical meridian <NUM> within the peripheral portions <NUM> of the progressive surface <NUM>, thus pointing to a top <NUM> of the progressive surface <NUM>. Herein, the upper viewing zone <NUM> is designated for providing a third addition power which is devised to reduce the accommodative lag during intermediate vision. As a result, the upper viewing zone <NUM> may improve viewing of objects at intermediate viewing distances, such as a screen of a computer monitor. In the exemplary embodiment of the progressive surface <NUM> as shown in <FIG>, the third addition power of the upper viewing zone <NUM> assumes a value of about +<NUM> D relative to the first refracting power as provided by the central viewing zone <NUM>. This value is considerably smaller compared to both the first addition power of about <NUM> D provided by the lower viewing zone <NUM> and the second addition power of also about <NUM> D provided by the peripheral vision zones <NUM>, <NUM>.

As further schematically depicted in <FIG>, a progression of the surface mean power <NUM> from the center <NUM> of the progressive surface <NUM> to the first addition power of about +<NUM> D in the lower viewing zone <NUM> and to the second addition power of also about +<NUM> D in the peripheral vision zones <NUM>, <NUM> is fully reached at a first distance of <NUM> ± <NUM> from the center <NUM> of the progressive surface <NUM>, whereas the third addition power of about +<NUM> D in the upper viewing zone <NUM> is, in this exemplary embodiment, already fully reached at a second distance of about <NUM> ± <NUM> from the center <NUM> of the progressive surface <NUM>.

As a result of this exemplary arrangement, a progression length of a first progressing power region <NUM> connecting the central viewing zone <NUM> to the lower viewing zone <NUM>, of a second progressing power region <NUM> connecting the central viewing zone <NUM> to the peripheral vision zone <NUM>, and of a third progressing power region <NUM> connecting the central viewing zone <NUM> to the further peripheral vision zone <NUM> considerably exceeds the progression length of a fourth progressing power region <NUM> connecting the central viewing zone <NUM> to the upper viewing zone <NUM>. In particular, the progression lengths of the first progressing power region <NUM> and of the fourth progressing power region <NUM> as arranged in this fashion may be beneficial to increase compliance with a use of the lower viewing zone <NUM> for near vision and the upper viewing zone <NUM> for intermediate vision.

<FIG> illustrates the contour plot <NUM> of surface astigmatism <NUM> for the same exemplary embodiment of the progressive surface <NUM> of the progressive spectacle lens <NUM> as depicted in <FIG>. Herein, it is schematically depicted that each progressing power region <NUM>, <NUM>, <NUM>, <NUM> as defined above has a low surface astigmatism, in which an astigmatic power of the low surface astigmatism may be less than +<NUM> D, preferably close to zero.

As further depicted in <FIG>, the peripheral portions <NUM> of the progressive surface <NUM> may, in addition, comprise blending regions <NUM>, <NUM>, <NUM>, <NUM> of high surface astigmatism, wherein each blending region <NUM>, <NUM>, <NUM>, <NUM> may be located between two of the adjacent progressing power regions <NUM>, <NUM>, <NUM>, <NUM>. In the exemplary embodiment of the progressive surface <NUM> as shown in <FIG>, the astigmatic power of each blending region <NUM>, <NUM>, <NUM>, <NUM> is between +<NUM> D to +<NUM> D. In this exemplary embodiment, the astigmatic power of those blending regions <NUM>, <NUM> which adjoin the lower viewing zone <NUM> may, especially, exhibit a higher astigmatic power of about +<NUM> D to +<NUM> D compared to the astigmatic power of about +<NUM> D to +<NUM> D of the other blending regions <NUM>, <NUM> which adjoin the upper viewing zone <NUM>.

<FIG> illustrates the contour plot <NUM> of an optical mean power <NUM> as distributed over the progressive surface <NUM> of the preferred exemplary embodiment of the progressive spectacle lens <NUM> as schematically depicted in <FIG>. Herein, values of the optical mean power <NUM> have been obtained by ray tracing. For this purpose, an analysis of the optical mean power <NUM> as distributed over the progressive surface <NUM> has been performed by a simulation of a process of measuring the progressive spectacle lens <NUM> using an ophthalmic instrument, in particular a lensmeter or a lensometer, especially a vertometer or a focimeter, specifically a Humphrey Lens Analyzer, on the progressive surface <NUM>. For this purpose, the progressive spectacle lens <NUM> is positioned with a measurement point on an optical axis of the ophthalmic instrument, wherein the progressive surface <NUM> is placed flush against a measurement aperture. Parallel light on a side of the progressive spectacle lens <NUM> opposite to the measurement aperture is refracted through the progressive spectacle lens <NUM>, whereby a resulting vergence of a ray passing directly through the measurement aperture is determined for obtaining the respective value of the optical mean power <NUM>. Hereby, a configuration has been used in which the ray is parallel to the optical axis of the ophthalmic instrument.

<FIG> illustrates the contour plot <NUM> of an optical astigmatism <NUM> as distributed over the progressive surface <NUM> of the preferred exemplary embodiment of the progressive spectacle lens <NUM> as schematically depicted in <FIG>. Herein, values of the optical mean astigmatism <NUM> have been obtained by ray tracing in a similar fashion as in <FIG> with respect to the optical mean power <NUM>.

<FIG> illustrates the contour plot <NUM> of the surface mean power <NUM> for a further preferred exemplary embodiment of the progressive surface <NUM> of the progressive spectacle lens <NUM> according to the present invention while <FIG> illustrates the contour plot <NUM> of the surface astigmatism <NUM> for the same further exemplary embodiment of the progressive surface <NUM> of the progressive spectacle lens <NUM> as depicted in <FIG>.

<FIG> illustrates the contour plot <NUM> of the optical mean power <NUM> and <FIG> the contour plot <NUM> of the optical astigmatism <NUM> both as distributed over the progressive surface <NUM> of the preferred exemplary embodiment of the progressive spectacle lens <NUM> as schematically depicted in <FIG>. For further details with respect to determining the optical mean power <NUM> and the optical astigmatism <NUM>, reference can be made to the description of <FIG> above.

In the further preferred exemplary embodiment of <FIG>, the progressive surface <NUM> has higher addition powers compared to the preferred exemplary embodiment of the progressive surface <NUM> as depicted in <FIG>. In this exemplary embodiment of <FIG>, the first addition power in the lower viewing zone <NUM> along the vertical axis <NUM> assumes a value of about +<NUM> D, while the second addition power in the peripheral vision zones <NUM>, <NUM> along the horizontal axis <NUM> assumes a value of about +<NUM> D, and while the third addition power in the upper viewing zone <NUM> assumes a value of about +<NUM> D, each in addition to the first refracting power as provided by the central viewing zone <NUM> of the progressive surface <NUM>.

Consequently, the progressive surface <NUM>, as depicted in <FIG> and <FIG>, could be considered as another progressive spectacle lens in a series of progressive spectacle lenses <NUM> with respect to the progressive spectacle lens <NUM> as depicted in <FIG> and <FIG>.

As a result of this particularly preferred arrangement, the progressive spectacle lens <NUM> as depicted in <FIG> and <FIG> may, in particular, be used at an earlier stage of a myopia control treatment, whereas the progressive spectacle lens <NUM> as schematically depicted in <FIG> and <FIG> may, in particular, be used at a later stage of the myopia control treatment, specifically, in order to introduced a boost to the plus power which may, be advantageous to maintain the efficacy of the myopia control treatment during the later stage of the myopia control treatment.

<FIG> illustrates a preferred embodiment of the method <NUM> for producing the progressive spectacle lens <NUM> according to the present invention.

In a determining step <NUM> according to step a),.

In a producing step <NUM> according to step b), the progressive spectacle lens <NUM> as described elsewhere herein is produced by processing at least one lens blank by using the first value <NUM>, the second value <NUM>, the third value <NUM> and the fourth value <NUM> of the optical correction. As a result, the progressive spectacle lens <NUM>, as produced according to the producing step <NUM>, has the progressive surface <NUM> which is capable of performing the desired optical correction for the eye of the wearer of the progressive spectacle lens <NUM>. Preferably, a set of glasses is produced which are capable of performing the desired optical correction for both eyes of the wearer in a simultaneous fashion. In particular, the progressive spectacle lens <NUM> is capable of correcting a relatively hyperopic peripheral shift of the eyes of the wearer during distance vision tasks when looking straight ahead, and, concurrently, to reduce an accommodative lag during both near vision tasks, such as reading, and viewing objects at intermediate viewing distances, such as a screen of a computer monitor.

Claim 1:
A progressive spectacle lens (<NUM>), having a front surface and a back surface, wherein the front surface or the back surface is a progressive surface (<NUM>), comprising:
a central viewing zone (<NUM>) having a surface power providing a first refracting power for distance vision;
a lower viewing zone (<NUM>) having a greater surface power than the central viewing zone (<NUM>) providing a second refracting power corresponding to near vision, wherein the lower viewing zone (<NUM>) is connected to the central viewing zone (<NUM>) by a first progressing power region (<NUM>) having a surface power varying from the surface power of the central viewing zone (<NUM>) to the greater surface power of the lower viewing zone (<NUM>) and having a corridor of low surface astigmatism; and
two peripheral vision zones (<NUM>, <NUM>) extending bilaterally from a vertical meridian (<NUM>) of the progressive surface (<NUM>), each having a greater surface power than the central viewing zone (<NUM>) providing a third refracting power at a prescribed field angle for correcting a peripheral hyperopic shift of a static eye looking straight ahead, wherein each peripheral vision zone (<NUM>, <NUM>) is connected to the central viewing zone (<NUM>) by a second progressing power region (<NUM>, <NUM>) having a surface power varying from the surface power of the central viewing zone (<NUM>) to the greater surface power of each peripheral vision zone (<NUM>, <NUM>) and having a corridor of low surface astigmatism;
characterized by an upper viewing zone (<NUM>) having a greater surface power than the central viewing zone (<NUM>) providing a fourth refracting power corresponding to intermediate vision, wherein the upper viewing zone (<NUM>) is connected to the central viewing zone (<NUM>) by a third progressing power region (<NUM>) having a surface power varying from the surface power of the central viewing zone (<NUM>) to the surface power of the upper viewing zone (<NUM>) and having a corridor of low surface astigmatism, wherein each viewing zone (<NUM>, <NUM>, <NUM>, <NUM>) consists of a stable power region, wherein each low surface astigmatism amounts to less than +<NUM> D.