Progressive ophthalmic lens

Abstract

A progressive ophthalmic lens includes at least one multifocal surface, in which at each point of its surface, an astigmatism value and a gradient of astigmatism value can be measured, the lens including: a far-vision zone with a reference point (FV), a near-vision zone with a reference point (NV), an intermediate vision zone with a progression path that connects the far vision zone and the near vision zone, a foveal projection, and a para-foveal projection, and said lens defining a lens addition. When the lens addition is different than 2.00 D, the astigmatism value is k*Add*0.41 D, where Add indicates the lens addition and k is 0.5 and, if the progression path is shorter than 15 mm, the maximum astigmatism value of the foveal projection is (−0.03*d) D/mm+0.86 D, and when the lens progression path is larger than 15 mm, the maximum astigmatism value of the foveal projection is (−0.02*d) D/mm+0.71 D.

Claims

1. A progressive ophthalmic lens comprising at least one multifocal surface, in which each point of its surface is associated with an astigmatism value and a gradient of astigmatism value, the progressive ophthalmic lens including: a far-vision zone with a first reference point, a near-vision zone with a second reference point (NV), an intermediate vision zone with a progression path that connects the far vision zone and the near vision zone, a foveal projection, and a para-foveal projection, and said lens defining a lens addition, wherein in an area covered by the foveal projection along the progression path, a maximum astigmatism value is less than 0.41 diopters and: when the lens addition is different than 2.00 D, the astigmatism value is
k*Add*0.41 D, where Add indicates the lens addition and k is 0.5 and, when the progression path is shorter than 15 mm, the maximum astigmatism value of the foveal projection is (−0.03*d) D/mm+0.86 D, and when the lens progression path is larger than 15 mm, the maximum astigmatism value of the foveal projection is (−0.02*d) D/mm+0.71 D, and wherein in an area covered by the para-foveal projection along the progression path, the maximum gradient of astigmatism value is less than 0.29 D/mm, and when the lens addition is different than 2.00 D, the gradient of astigmatism value is
k*Add*0.29 D/mm and when the progression path is shorter than 15 mm, the maximum gradient of astigmatism value of the para-foveal projection is (−0.08*d) D/mm.sup.2+1.49 D/mm, whereas when the progression path is larger than 15 mm, the maximum gradient of astigmatism value of the para-foveal projection is (−0.01*d) D/mm.sup.2+0.44 D/mm.

2. A progressive ophthalmic lens according to claim 1, wherein in a lens area contained in a 45° mid-peripheral projection, an absolute value of a difference of the maximum values of gradient of astigmatism in each side of the progression path is lower than 0.06 D/mm, and when the lens addition is different than 2.00 D, the absolute value of the difference of the maximum value of gradient of astigmatism in each side of the progression path is
k*Add*0.06 D/mm, and when the progression path is different than 15 mm, the maximum absolute value of the difference of the maximum value of gradient of astigmatism in each side of the progression path is lower than (−0.01*d) D/mm.sup.2+0.21 D/mm.

3. A progressive ophthalmic lens according to claim 1, wherein in a lens area contained in a 45° mid-peripheral projection, the maximum value of the gradient of astigmatism is lower than 0.34 D/mm, and when the lens addition is different than 2.00 D, the gradient of astigmatism value is
k*Add*0.34 D/mm and when the progression path is shorter than 15 mm, the maximum gradient of astigmatism value in the same area is (−0.07*d) D/mm.sup.2+1.39 D/mm, whereas when the progression path is larger than 15 mm, the maximum gradient of astigmatism in the same area is (−0.02*d) D/mm.sup.2+0.64 D/mm.

4. A progressive ophthalmic lens according to claim 1, wherein in a lens area contained in a 45° mid-peripheral projection, the maximum value of the astigmatism is lower than 1.60 D, and when the lens addition is different than 2.00 D, the maximum value of astigmatism in the same area is
k*Add*1.60 D, and when the progression path is shorter than 15 mm, the maximum value of astigmatism in the same area is (−0.05*d) D/mm+2.35 D, and when the lens progression path is larger than 15 mm, the maximum value of astigmatism in the same area is (−0.03*d) D/mm+2.05 D.

5. A progressive ophthalmic lens comprising at least one multifocal surface, in which each point of its surface is associated with an astigmatism value and a gradient of astigmatism, the progressive ophthalmic lens including: a far-vision zone with a first reference point, a near-vision zone having a second reference point, an intermediate vision zone with a progression path that connects the far vision zone and the near vision zone, a foveal projection, and a para-foveal projection, and said lens defining a lens addition, wherein in a lens area covered by the foveal projection along the lens progression path, a maximum astigmatism value is less than 0.41 diopters, when the lens addition is different than 2.00 D, the astigmatism value is
k*Add*0.41 D, where Add indicates the lens addition and k is 0.5 and, when the progression path is shorter than 15 mm, the maximum astigmatism value of the foveal projection is (−0.03*d) D/mm+0.86 D, and when the progression path is larger than 15 mm, the maximum astigmatism value of the foveal projection is (−0.02*d) D/mm+0.71 D, and wherein, in an area of the multifocal surface covered by the para-foveal projection along the progression path, the maximum astigmatism value is less than 0.53 D, and when the lens addition is different than 2.00 D, the astigmatism value is
k*Add*0.53 D, and when the progression path is shorter than 15 mm, the maximum astigmatism value of the para-foveal projection is (−0.07*d) D/mm+1.58 D, and when the progression path is larger than 15 mm, the maximum astigmatism value of the para-foveal projection is (−0.02*d) D/mm+0.83 D.

6. A progressive ophthalmic lens according to claim 5, wherein in a lens area contained in a region determined by a 45° mid-peripheral projection, an absolute value of a difference of the maximum values of gradient of astigmatism in each side of the progression path is lower than 0.06 D/mm, and when the lens addition is different than 2.00 D, the absolute value of the difference of the maximum value of gradient of astigmatism in each side of the progression path is
k*Add*0.06 D/mm, and when the progression path is different than 15 mm, the maximum absolute value of the difference of the maximum value of gradient of astigmatism in each side of the progression path is lower than (−0.01*d) D/mm.sup.2+0.21 D/mm.

7. A progressive ophthalmic lens according to claim 6, wherein in the lens area contained in a region determined by the 45° mid-peripheral projection, the maximum value of the gradient of astigmatism is lower than 0.34 D/mm, and when the lens addition is different than 2.00 D, the gradient of astigmatism value is
k*Add*0.34 D/mm and when the progression path is shorter than 15 mm, the maximum gradient of astigmatism value in a region determined by the intersection of the lens with a cone having a solid angle of 45° aperture with its apex in an eye principal plane and center at a lens fitting cross, is (−0.07*d) D/mm.sup.2+1.39 D/mm, whereas when the progression path is larger than 15 mm, the maximum gradient of astigmatism is (−0.02*d) D/mm.sup.2+0.64 D/mm.

8. A progressive ophthalmic lens according to claim 7, wherein in the lens area contained in a region determined by the 45° mid-peripheral projection, the maximum value of the astigmatism is lower than 1.60 D, and when the lens addition is different than 2.00 D, the maximum value of astigmatism is
k*Add*1.60 D, and when the progression path is shorter than 15 mm, the maximum value of astigmatism is (−0.05*d) D/mm+2.35 D, and when the lens progression path is larger than 15 mm, the maximum value of astigmatism is (−0.03*d) D/mm+2.05 D.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) For a better understanding the above explanation and for the sole purpose of providing an example, some non-limiting drawings are included that schematically depict a practical embodiment.

(2) FIG. 1 is an overview of an eye structure;

(3) FIG. 2 shows the fovea, para-fovea and macular dimensions;

(4) FIG. 3a shows a projection of the different vision sensitive structures, with foveal, para-foveal and peripheral vision of an average human eye;

(5) FIG. 3b shows the angular range and specialized stimuli perception of eye structures: foveal, para-foveal, near-peripheral and mid-peripheral;

(6) FIG. 4 shows the foveal and parafoveal regions as projected in the viewing field in reading activities;

(7) FIG. 5 shows a projection at the lens surface of the foveal, para-foveal and 45° mid-peripheral regions;

(8) FIG. 6a shows foveal and para-foveal projected areas along the lens progression path from 4 mm above the fitting cross to the near vision point (foveal projection is represented by the inner dotted line and para-foveal projection is represented by the external dotted line);

(9) FIG. 6b shows a projection in the lens surface of the 45° mid-peripheral zone with center in the lens fitting cross represented by a dotted line;

(10) FIG. 7 shows a progression path of a progressive lens showing the fitting cross (cross), the near vision zone (circle) and the line that connects showing the power variation path;

(11) FIG. 8a shows a map of astigmatism and FIG. 8b a map of optical power of the lens according to example 1;

(12) FIG. 9a shows a map of astigmatism and FIG. 9b a map of optical power of the lens according to example 2; and

(13) FIG. 10a shows a map of astigmatism and FIG. 10b shows a map of optical power of the lens according to example 3.

DESCRIPTION OF PREFERRED EMBODIMENTS

(14) We have realized that it is possible to optimize the optical properties of certain key lens areas, according to specific metrics that we will describe, which quantify optical properties in the areas of the lens related to the parts of the retina where images are formed. Surprisingly, progressive lenses optimized according to these metrics provide maximum visual acuity and do not compromise the overall lens performance. More importantly, we can improve the optical quality of the progressive lenses obtained according to this method and enhance the degree of satisfaction of progressive lenses users.

(15) The progressive lens according to the present invention overcomes the drawbacks of common progressive lenses, providing the following characteristics simultaneously:

(16) I. optimum foveal vision characterized by very low values of astigmatism and gradient of astigmatism, in the area of the lens that corresponds to the foveal projection on the lens surface along the progression path.

(17) II. optimum quality in dynamic vision activities related to para-foveal vision, particularly when reading, thanks to the minimization of the values of astigmatism and gradient of astigmatism in the area of the lens that corresponds to the para-foveal projection on the lens surface along the progression path.

(18) III. enhanced peripheral vision comfort thanks to a reduction of the maximum of astigmatism and of gradient of astigmatism in a cone of 45° aperture projected in the lens and focusing in the peripheral retina

(19) IV. balanced optical symmetry in peripheral vision, characterized by a minimum difference in the maximum of gradient of astigmatism in the peripheral areas of the lens within nasal and temporal sides of the progression path in a cone of 45° aperture angle projected onto the lens surface corresponding to the mid-peripheral retina field of view.

(20) According to the eye retinal physiology, three concentric circumferences that correspond to fovea, para-fovea and macula regions are identified. The area outside the macula is responsible for peripheral vision and is composed of near (18° to 30°), mid (30° to 60°) and far peripheral (>60°) as shown in FIGS. 3a and 3b.

(21) When the emmetropic eye is oriented towards an object its image is perfectly formed in the fovea, whereas for a non-emmetropic eye, a corrective lens is required to focus the image on the fovea. In this last case we can identify the areas of the lens that are responsible for the projection of the image onto the fovea. For progressive lenses, these areas are the ones in the far-vision zone, near vision zone and zones in the nearby of the progression path, so we can evaluate the optical parameters in these areas and particularly the projection of the fovea all along the progression path. The same is valid for para-fovea and the peripheral retina areas.

(22) Boundaries of each retinal area are traced along the view path on the lens surface. For fovea for instance, this projection is the intersection with the internal lens surface of the cone of the foveal aperture (5° aperture angle approx.), with its apex lying in the eye principal plane as defined in paraxial optics, and its center in the line of sight. By considering standard data for eye radius (25 mm) and vertex distance (12 mm)—known as the distance from cornea to the back surface of the progressive lens—the projection on the lens of the fovea, para-fovea and mid periphery (up to 45°) is obtained.

(23) This projection is in the form of three concentric circumferences of diameter of e.g. 1.75 mm, 2.72 mm and 38.67 mm for the projection of the fovea, para-fovea and mid periphery, respectively (FIG. 5).

(24) If the as-worn lens position is accurately known for a given spectacles in its wear position for a specific user (lens pantoscopic angle, vertex distance and lens curvature) the calculations will provide some differences in radii that can be considered instead of the standard radii provided above, but there will be no significant differences in the sizes projected cones of the fovea, para-fovea and mid periphery.

(25) The invention optimizes simultaneously the optical quality of the progressive lens in areas which require most visual acuity, particularly in the fovea, where maximum visual acuity is achieved, and para-fovea which has an important role in reading activities. We call this high vision acuity metric or “Acuity metric”, whereas a second group of metrics related to peripheral vision quality, for which motion perception has a key role, is called “Peripheral metric”.

(26) Metrics developed are defined in order to evaluate the relevant optical properties of progressive lenses (astigmatism and gradient of astigmatism). The metrics relate, according to certain physiologic data, the performance of optical functions in the lens region where these parameters are studied. Each metric is associated with a threshold value which describe the performance of the lenses.

(27) For multipurpose progressive lenses, the corridor length is the vertical distance from the fitting cross to the near vision point and are typically from 12 to 20 mm or from 10 mm to 22 mm. Both metrics should be calculated for a whole progressive lens range, this is, considering all progression corridor lengths (typically from 10 to 22 mm) and all different power additions (from 0.75 D up to 3.75 Diopters). For simplicity, we will provide data for a “reference” progressive lens of addition 2.0 D and standard corridor length (the near vision point situated 15 mm above the fitting cross), and later we provide indication of how to proceed to determine the limited values for power addition values and corridor lengths different from the standard ones. For multipurpose progressive lens the optical power 4 mm above the fitting cross is defined to be the point where the prescription value of the far vision can be measured, and the addition is defined as difference of optical power between that point and the one at the near vision point.

(28) However, since occupational lenses do not cover the full range of vision distances, this addition definition could not be true. Consequently, when the Acuity or Peripheral metrics described above need to be applied to occupational lenses, a new corridor length and addition value will be defined. For these lenses, we will not consider the far vision power point at 4 mm above the fitting cross. Instead, we will identify a point where the minimum optical power is reached along the progression path and, in particular, from the fitting cross towards the upper part of the frame, and the corridor length will be calculated as the distance from 4 mm below that point down to the near vision point. In addition, the considered addition for an occupational progressive will be calculated as the difference between the power at that far vision point and the power on the near vision point.

(29) Table 1 shows the maximum preferable values of the Acuity metrics. Values are specified for a “reference” progressive lens.

(30) TABLE-US-00001 TABLE 1 maximum preferable values of “Acuity” metrics (for a standard progressive lens of addition 2.0 D and near vision point situated 15 mm above the fitting cross) Maximum value Acuity Metric: Part of Maximum value of gradient the retina that is of astigmatism of astigmatism projected along the for “Acuity” for “Acuity” progression path metric (D) metric (D/mm) Fovea 0.41 0.27 Para-fovea 0.53 0.29

(31) The invention also provides a second metric identified as Peripheral metric that relate to peripheral vision quality. Table 2 shows the maximum preferable values of the Peripheral metric for a “reference” progressive lens.

(32) Definitions Relevant to the Peripheral Metrics: The 45° mid-peripheral projection is the intersection with the lens internal surface of a 45° aperture cone, the cone apex lying on the eye principal plane—as defined in paraxial optics—and the cone base centered at the lens fitting cross. The dimensions of this area depend on the back-vertex distance, but typically is 1100 mm.sup.2. (FIG. 6b, dotted line). The maximum value of astigmatism according to the peripheral metric is the absolute maximum of astigmatism in the lens area determined by the 45° mid-peripheral projection. The maximum value of gradient of astigmatism according to the peripheral metric is the absolute maximum value of gradient of astigmatism in the lens area determined by the 45° mid-peripheral projection. The Difference of nasal and temporal maxima of gradient of astigmatism is the difference of absolute maximum values detected in each side of the progression path (nasal and temporal). It is also evaluated in the 45° mid-peripheral projection.

(33) TABLE-US-00002 TABLE 2 maximum preferable values of the “Peripheral metrics” for a “standard” progressive lens of addition 2.0 D and the near vision point situated 15 mm above the fitting cross Peripheral Metric Maximum value Difference of maxima of Maximum value of peripheral gradient of astigmatism of peripheral gradient of between nasal and temporal astigmatism astigmatism side of the lens (D) (D/mm) (D/mm) 1.600 0.34 0.06

(34) Determining the Values of the Metrics for Addition Value Different than 2.0 Diopters:

(35) The maximum preferable values of the metrics “Acuity” and “Peripheral” for a progressive lens of addition different from 2.0 D are calculated proportionally (if the progression path has the same value, otherwise see next chapter). For example, the maximum preferable values of the metrics “Acuity” for a progressive lens of addition 1.00 D are half of values of Table 1 and the maximum preferable values of the metrics “Acuity” for a progressive lens of addition 3.0 D are 1.5 times values of Table 1. In a similar way, values for the metrics “Peripheral”, can be calculated for addition different than 2.0 D using values of Table 2 in the same way.

(36) Determining the Values of the Metrics for Different Length of the Corridor Length:

(37) Due to different requirements of the final user or due to larger/shorter corridor length the spectacle frame dimensions may require; progressive lenses have different corridor lengths.

(38) This distance is normally in the range from 12 mm to 18 mm, or from 10 mm to 22 mm.

(39) We consider d=distance of the progression path defined as the distance from fitting cross (FC) to near vision point (NV) and express this distance in millimeters. If this distance is different from 15 mm, then we shall modify the metrics according to the following rules:

(40) Correction for Addition Different than 2.0 D in Acuity Metric and in Peripherical Metric—the New Metric Value is
k*Add*m
being Add the lens addition, k a constant being 0.5 and m being the metric value for addition=2.0 D.

(41) Correction for Corridor Different than 15 mm in Acuity Metric:

(42) The maximum of astigmatism must be modified according to the length of the corridor (noted as “d”) in the following way:

(43) a) for foveal projection: for distances smaller than 15 mm: (−0.03*d) D/mm+0.86 D for distances larger than 15 mm: (−0.02*d) D/mm+0.71 D

(44) We remark that −0.03*15+0.86=−0.02*15+0.71=0.41 (i.e. both lines joins in the point d=15, maximum of astigmatism=0.41 D).

(45) b) for para-foveal projection: for distances smaller than 15 mm: (−0.07*d) D/mm+1.58 D for distances larger than 15 mm: (−0.02*d) D/mm+0.83 D

(46) We remark that −0.07*15+1.58=−0.02*15+0.83=0.53 D (i.e. both lines joins in the point d=15, maximum of astigmatism=0.53 D).

(47) Maximum of gradient of astigmatism must be modified according to the length of the corridor (noted as “d”):

(48) a) for foveal projection: for distances smaller than 15 mm: (−0.04*d) D/mm.sup.2+0.87 D/mm for distances larger than 15 mm: (−0.01*d) D/mm.sup.2+0.42 D/mm

(49) We remark that −0.04*15+0.87=−0.01*15+0.42=0.27 D/mm (i.e. both lines joins in the point d=15, maximum of the gradient of astigmatism=0.27 D/mm).

(50) b) for para-foveal projection: for distances smaller than 15 mm: (−0.08*d) D/mm.sup.2+1.49 D/mm for distances larger than 15 mm: (−0.01*d) D/mm.sup.2+0.44 D/mm

(51) We remark that −0.08*15+1.49=−0.01*15+0.44=0.29 D/mm (i.e. both lines join in the point d=15, maximum of gradient of astigmatism=0.29 D/mm).

(52) Correction for Corridor Different than 15 mm in Peripheral Metric:

(53) The maximum of astigmatism in the region comprised by the 45° mid-peripheral projection must be modified according to the length of the corridor “d”: for distances smaller than 15 mm: (−0.05*d) D/mm+2.35 D, for distances larger than 15 mm, (−0.03*d) D/mm+2.05 D

(54) We remark that −0.05*15+2.35=−0.03*15+2.05=1.6 D (i.e. both lines join in the point d=15, maximum astigmatism value is =1.6 D).

(55) Maximum of gradient of astigmatism in the region comprised by the solid angle of 45° centered at the fitting point must be modified according to the length of the corridor “d”: for distances smaller than 15 mm: (−0.07*d) D/mm.sup.2+1.39 D/mm, for distances larger than 15 mm: (−0.02*d) D/mm.sup.2+0.64 D/mm

(56) We remark that −0.07*15+1.39=−0.02*15+0.64=0.34 D/mm (i.e. both lines joins in the point d=15, maximum gradient of astigmatism value is =0.34 D).

(57) Maximum of the difference of the maximum of gradient of astigmatism between nasal and temporal side of the lens, in the region comprised by the solid angle of 45° centered at the fitting point must be modified according to the length of the corridor “d”: for distances other than 15 mm: (−0.01*d) D/mm.sup.2+0.21 D/mm,

(58) Correction for Addition Different than 2.0 D and Corridor Different than 15 mm in Acuity Metric and in Peripherical Metric is a Combination of Two Previous Modifications (for Addition and for Corridor).

(59) Metrics related to the fovea, para-fovea and peripheral retina can be applied also independently or in any combination, with the final aim to obtain an optimized vision for activities that require the highest acuity (foveal vision), dynamic or reading activities (para-foveal), and motion perception (peripheral vision).

EXAMPLES OF LENSES

Example 1

(60) An optical lens element according to the present invention was designed having 2.00 D addition power in the lower or near viewing zone and standard corridor length (the near vision point situated 15 mm below the fitting cross). The contour plots of surface astigmatism and mean surface power respectively for the optical lens are given in FIGS. 8a and 8b. The design provides a relatively wide upper or distance viewing zone with the 0.5 D astigmatic contour rising towards the periphery. The lens design exhibits very low values of astigmatism along the lens progression path (0.4016 D for foveal projection and 0.5285 D for para-foveal projection). In addition, the maximum values of gradient of astigmatism along the progression path for foveal projection (0.269 D) and para-foveal projection (0.275 D) are obtained. We can see also that the maximum value of astigmatism and gradient of astigmatism for peripheral metric are below maximum values of table 2.

(61) TABLE-US-00003 TABLE 3 maximum values of the metrics “type A” for the progressive lens of example 1. Maximum value Acuity metric: Part of Maximum value of gradient the retina that is of astigmatism of astigmatism projected in the for metric for metric progression path “Acuity” (D) “Acuity” (D/mm) Fovea 0.4016 0.269 Para-fovea 0.5285 0.275

(62) TABLE-US-00004 TABLE 4 maximum values of the metrics “type B” for the progressive lens of example 1. Maximum values of optical properties according to the Peripheral Metric Maximum value Difference of maxima of Maximum value of gradient of gradient of astigmatism of astigmatism for astigmatism for between nasal and temporal Peripheral metric Peripheral metric side of the lens (D) (D/mm) (D/mm) 1.557 0.310 0.035

Example 2

(63) An optical lens element according to the present invention was designed having addition 2 D and a short corridor length (the near vision point situated 12 mm below the fitting cross. Since this distance is not 15 mm, values of proposed maximum of astigmatism and maximum of gradient of astigmatism in the tables are recalculated to the current corridor length. For instance, foveal projection for the lens in this case, which has a corridor length of 12 mm leads to a maximum of astigmatism value of 0.5 D:
(−0.03*12)+0.86 D=0.50 D,
which is always greater than the measured maximum of the lens according to the invention.

(64) TABLE-US-00005 TABLE 5 maximum values of the “Acuity” metrics for the progressive lens of example 2. Maximum value Acuity metric: Part of Maximum value of gradient the retina that is of astigmatism of astigmatism projected in the for metric for metric progression path “Acuity” (D) “Acuity” (D/mm) Fovea 0.431 (<0.50) 0.317 Para-fovea 0.6132 0.412

(65) TABLE-US-00006 TABLE 6 maximum values of the “Peripheral” metrics for the progressive lens of example 2. Maximum values of optical properties according to the Peripheral Metric Maximum value Difference of maxima of Maximum value of gradient of gradient of astigmatism of astigmatism for astigmatism for between nasal and temporal Peripheral metric Peripheral metric side of the lens (D) (D/mm) (D/mm) 1.683 0.412 0.065

(66) FIG. 9 shows the map of astigmatism and power of this lens. We remark that this lens has the distance between de fitting cross and the near vision point very small, i.e., has one of the shortest corridors in the market.

Example 3

(67) An optical lens element according to the present invention was designed having of addition 2 D with large corridor length, (the near vision point situated 18 mm below the fitting cross). FIGS. 10a and 10b shows the map of astigmatism and power of this lens.

(68) Since this distance is not 15 mm, values of proposed maximum of astigmatism and maximum of gradient of astigmatism in the tables are recalculated to the current corridor length. For instance, foveal projection for the lens in this case, which has a corridor length of 18 mm leads to a maximum of astigmatism value of 0.35 D instead of 0.41 D:
(−0.02*18)+0.71 D=0.35 D,
which is always greater than the measured maximum of the lens according to the invention as reported in table 7. The same is valid for the rest of magnitudes and metrics.

(69) TABLE-US-00007 TABLE 7 maximum values of the “Acuity metrics” for the progressive lens of example 3. Maximum value Acuity metric: Part of Maximum value of gradient the retina that is of astigmatism of astigmatism projected in the for metric for metric progression path “Acuity” (D) “Acuity” (D/mm) Fovea 0.347 (<0.35) 0.219 Para-fovea 0.459 0.239

(70) TABLE-US-00008 TABLE 8 maximum values of the “Peripheral metrics” for the progressive lens of example 3. Maximum values of optical properties according to the Peripheral Metric Maximum value Difference of maxima of Maximum value of gradient of gradient of astigmatism of astigmatism for astigmatism for between nasal and temporal Peripheral metric Peripheral metric side of the lens (D) (D/mm) (D/mm) 1.416 0.240 0.002

(71) FIG. 10 shows the map of astigmatism and power of this lens. We remark that this lens has one of the largest corridors in the market. Despite larger corridor length are technically possible, those lenses would not be suited for most spectacle frames, since the lens will be cut and edged according to the frame boxing dimensions and eye relative position which may eliminate the near vision zone of the progressive lens.

(72) Even though reference has been made to a specific embodiment of the invention, it is obvious for a person skilled in the art that the lens and the method described herein are susceptible to numerous variations and modifications, and that all of the details mentioned can be substituted for other technically equivalent ones without departing from the scope of protection defined by the attached claims.