A computer-implemented method for providing a finished single vision ophthalmic lens

Abstract

A computer-implemented method for providing, from a target lens having at least one complex surface, a finished single vision ophthalmic lens intended for a wearer, the finished lens having a rotationally symmetric front surface, the method comprising: (a) providing wearer data or theoretical data; (b) defining, on the target lens, a target optical or geometric feature along a predetermined path based on the wearer data or the theoretical data; (c) determining the finished lens by: (c1) selecting an initial lens complying with the prescription data and having a rotationally symmetric front surface and a predetermined curvature at a prescription reference point; (c2) defining a current lens from the initial lens; (c3) modifying the front surface definition of the current lens to reach the target optical or geometric feature until an end criterion is met; (d) providing the finished lens from the current lens.

Description

Technical Field

[0001] This disclosure relates to a computer-implemented method for providing finished single-vision ophthalmic lenses.

[0002] This disclosure also relates to a computer-implemented method for determining a series of finished ophthalmic lenses.

[0003] This disclosure further relates to an associated finished single-vision ophthalmic lens and an associated computer program product. Background Technology

[0004] Regarding the number of lenses produced, single-vision lenses (i.e., lenses designed to provide a single refractive power) represent the majority of ophthalmic lenses on the market.

[0005] Such a large quantity of lenses can only be achieved through industrial means that can provide a large number of lens production lines (i.e., mass production of finished lens inventory).

[0006] Currently, the optical performance of these single-vision finished stock lenses ranges from poor to moderate. Due to casting or injection technology and mass production lines, these lenses cannot be personalized like prescription or surface-treated lines.

[0007] On the other hand, personalized processes for prescription or surface treatment series are much more expensive. Moreover, such processes cannot meet the large-volume lens demand of the market.

[0008] Currently, the best performance has been achieved for mass-produced stock lenses for aspherical lenses (i.e., lenses with rotationally symmetric surfaces on the front or back side of the lens, where the spherical power varies from the center to the periphery of the lens).

[0009] In existing technologies, optical performance is often optimized based on the assessment of aberrations. This can result in optical devices or lens geometries with good performance, but it is impossible to achieve the performance of personalized lenses produced using surface treatment techniques.

[0010] For example, in the article titled "Ophthalmic lens design with the optimization of the aspherical coefficients" published in the April 2000 issue of Optical Engineering, Volume 39, Issue 4, pp. 978-988, Wen-Shing Sun et al. described an optimization of aspherical surfaces that avoids inflection points on the surface.

[0011] The document indicates that the optical quality or geometry obtained for aspherical lenses is quite good. However, the described prior art methods do not take into account objects at any distance and do not provide any hints on how high-performance lenses can be provided by using mass production processes.

[0012] Therefore, there is an unmet need for aspherical pre-made single-vision ophthalmic lenses with controllable optical performance to achieve optimal optical design through a simple mass production process. Summary of the Invention

[0013] The purpose of this disclosure is to overcome at least some of the limitations of the prior art and to meet the aforementioned needs.

[0014] Therefore, this disclosure provides a computer-implemented method for providing a finished single-vision ophthalmic lens intended for use by a wearer based on a target lens having at least one complex surface, the finished lens having a rotationally symmetric front surface, wherein the method includes:

[0015] (a) Provide wearer data that includes prescription data relating to the wearer’s eyes or theoretical data from computer simulations that include prescription data relating to virtual eyes;

[0016] (b) Define target optical or geometric features on the target lens along a predetermined path based on the wearer data or theoretical data;

[0017] (c) The finished single-vision ophthalmic lens is determined by the following methods:

[0018] (c1) Select an initial lens that conforms to the prescription data and has a rotationally symmetric anterior surface and a predetermined curvature at the prescription reference point;

[0019] (c2) Define the current lens according to the initial lens definition;

[0020] (c3) Modify the current lens front surface definition to achieve the target optical or geometric features until the end criteria are met;

[0021] (d) Provide the finished single-vision ophthalmic lens in accordance with the current lens.

[0022] The steps above provide a lens that can be easily implemented in mass production because the lens has a rotationally symmetric surface, making it simple and inexpensive to manufacture.

[0023] This makes it possible to produce lenses with targeted optical or geometric features that will provide performance comparable to Rx, i.e., prescription lenses, obtained in the laboratory through surface treatment techniques, but without the cost of such surface treatment techniques.

[0024] Therefore, the proposed method provides a large number of high-performance, low-cost lenses that meet market demands.

[0025] Furthermore, by taking into account the aforementioned data and characteristics, the proposed method can achieve lenses with optimized optical performance in both the distance and near vision directions. In particular, the proposed method can take into account objects at specific distances defined by the eye's line of sight from top to bottom and the lens positioned in front of the wearer's eyes.

[0026] Furthermore, the proposed method provides a single-vision lens comprising a rotationally symmetric front surface without any cylinders and a rear surface providing cylinders (if present).

[0027] For the same purpose, this disclosure also presents a method for determining a series of finished ophthalmic lenses having a rotationally symmetric anterior surface, wherein the method includes:

[0028] (i) Set the value range of prescription data for the finished ophthalmic lenses in this series;

[0029] (ii) Divide the range into a predetermined number of subdomains of the prescription data values;

[0030] (iii) For each of these subdomains, a sub-series of finished ophthalmic lenses for that series shall be provided in the following manner:

[0031] (iii1) Define a base value for the surface curvature at the optical center of the front surface of the finished ophthalmic lens of the sub-series, based on optical and / or geometric requirements.

[0032] (iii2) Select prescription data representing this subdomain;

[0033] (iii3) This subsequence shall be provided in the following manner:

[0034] (iii3.1) Based on prescription data representing the subdomain, a target optical or geometric feature is defined on the target lens along a predetermined path, the target lens having at least one complex surface;

[0035] (iii3.2) Select an initial lens that conforms to the prescription data representing the subdomain and has a rotationally symmetric anterior surface and a predetermined surface curvature at the prescription reference point;

[0036] (iii3.3) Define the current lens according to the initial lens definition;

[0037] (iii3.4) Modify the current front surface definition of the lens to achieve the target optical or geometric features until the end criteria are met;

[0038] (iii3.5) Provide finished ophthalmic lenses of this sub-series in accordance with the current lens;

[0039] (iii3.6) The finished ophthalmic lens sub-series is provided as follows: all finished ophthalmic lenses have the same front surface consisting of the modified front surface that meets the end criterion and different spherical tortuous posterior surfaces that correspond to all prescription data of the sub-domain respectively;

[0040] (iii4) Check whether all prescription data for this sub-series meet the predetermined performance standards for this subdomain;

[0041] (iii5) If not all prescription data for this subdomain meets the predetermined performance criterion, return to the segmentation step (ii) and modify these subdomains;

[0042] (iv) Determine the series according to the subseries provided for all subdomains.

[0043] For the same purpose, this disclosure also provides an finished single-vision ophthalmic lens intended for use by a wearer, wherein the lens has rotationally symmetric anterior and posterior surfaces according to a target lens having at least one complex surface, and the finished single-vision ophthalmic lens is provided in the following manner:

[0044] (a) Provide wearer data that includes prescription data relating to the wearer’s eyes or theoretical data from computer simulations that include prescription data relating to virtual eyes;

[0045] (b) Define target optical or geometric features on the target lens along a predetermined path based on the wearer data or theoretical data;

[0046] (c) The finished single-vision ophthalmic lens is determined by the following methods:

[0047] (c1) Select an initial lens that conforms to the prescription data and has a rotationally symmetric anterior surface and a predetermined curvature at the prescription reference point;

[0048] (c2) Define the current lens according to the initial lens definition;

[0049] (c3) Modify the current lens front surface definition to achieve the target optical or geometric features until the end criteria are met;

[0050] This finished single-vision ophthalmic lens is the current lens that meets the end criteria.

[0051] For the same purpose, this disclosure further provides a computer program product including instructions that, when executed by a processor, cause the processor to provide a finished single-vision ophthalmic lens intended for use with a wearer based on a target lens having at least one complex surface, the finished lens having a rotationally symmetric anterior surface:

[0052] (a) Provide wearer data that includes prescription data relating to the wearer’s eyes or theoretical data from computer simulations that include prescription data relating to virtual eyes;

[0053] (b) Define target optical or geometric features on the target lens along a predetermined path based on the wearer data or theoretical data;

[0054] (c) The finished single-vision ophthalmic lens is determined by the following methods:

[0055] (c1) Select an initial lens that conforms to the prescription data and has a rotationally symmetric anterior surface and a predetermined curvature at the prescription reference point;

[0056] (c2) Define the current lens according to the initial lens definition;

[0057] (c3) Modify the current lens front surface definition to achieve the target optical or geometric features until the end criteria are met;

[0058] (d) Provide the finished single-vision ophthalmic lens in accordance with the current lens.

[0059] Based on the specific possible features of any of the methods, lenses, computer program products, or mobile terminals described above, either in combination or individually:

[0060] - The predetermined path can be an optical path and can extend vertically from -60° to 60°, preferably from -45° to 45°, more preferably from -30° to 30°;

[0061] - Step (c) of determining the finished single-vision ophthalmic lens may further include checking whether the current lens meets the predetermined performance standards;

[0062] - The predetermined performance criterion may be related to the root mean square deviation of at least one of the optical features along the predetermined path;

[0063] - The root mean square deviation can be less than 0.12 diopters, preferably less than 0.06 diopters, and more preferably less than 0.03 diopters;

[0064] - The step (c3) of modifying the front surface definition of the current lens may include modifying the curvature of the current lens along the axis of rotational symmetry of the front surface of the current lens;

[0065] - The target optical characteristics may include a predetermined distribution of average power and astigmatism in the target lens;

[0066] - The target geometric features may include a predetermined distribution of the average curvature of the front surface of the target lens, or the minimum curvature and axial orientation of the front surface of the target lens, or the maximum curvature and axial orientation of the front surface of the target lens, or simultaneously include a predetermined distribution of the average curvature of the front surface of the target lens, the minimum curvature and maximum curvature and axial orientation of the front surface of the target lens;

[0067] - In a first specific embodiment, the step (c3) of modifying the front surface definition of the current lens may include:

[0068] A representative optical path is defined in the front surface of the current lens, which represents the eye's gaze orientation when the wearer looks up or down to switch between distance and near vision.

[0069] The optical characteristics of the current lens are evaluated along this representative optical path;

[0070] The front surface of the current lens is determined, and the combination of the front surface and the spherical toric rear surface of the current lens provides values ​​of optical features along the optical path that are closest to the values ​​of target optical features along the representative optical path;

[0071] Define the modified front surface of the current lens according to the determined front surface;

[0072] - The representative optical path may include a predetermined number of path segments covering an area for distance and / or near vision purposes;

[0073] - This representative optical path may include two path segments covering an area for distance vision extending from -10° to 0° and an area for near vision extending from 16° to 28°;

[0074] - In a second specific embodiment, the step (c3) of modifying the front surface definition of the current lens may include:

[0075] Define a representative surface path on the front surface of the current lens, which represents the eye's gaze orientation when the wearer looks up or down to switch between distance and near vision;

[0076] The curvature of the front surface of the current lens is evaluated along this representative surface path;

[0077] The front surface of the current lens is determined, which provides values ​​of geometric features along the surface path that are closest to the values ​​of the target geometric features along the representative surface path;

[0078] Define the modified front surface of the current lens according to the determined front surface.

[0079] Since the methods for determining the finished ophthalmic lens series, finished single-vision ophthalmic lenses, and computer program products described above have the same advantages as the methods for providing finished single-vision ophthalmic lenses, these advantages will not be repeated here. Attached Figure Description

[0080] To gain a more complete understanding of the descriptions and advantages provided herein, please now refer to the following brief description in conjunction with the accompanying drawings and detailed description, wherein the same reference numerals denote the same parts.

[0081] Figure 1 This is a flowchart illustrating the steps of a method for providing a finished single-vision ophthalmic lens according to this disclosure in a particular embodiment.

[0082] Figure 2 This is a flowchart illustrating details of the steps involved in modifying the front surface definition of a lens in a method for providing a finished single-vision ophthalmic lens according to this disclosure in a first specific embodiment.

[0083] Figure 3 They are shown separately in Figure 2 The embodiments are non-limiting examples of a pair of optical diagrams of the target lens's power error and unwanted astigmatism.

[0084] Figure 4 It shows in Figure 2 The embodiments are non-limiting examples of the average spherical and cylindrical images of the front or rear surface of the target lens.

[0085] Figure 5 They are shown separately in Figure 2 The embodiments are non-limiting examples of a pair of optical maps of the optimized lens power error and unwanted astigmatism obtained when the end criteria are met.

[0086] Figure 6 This is a flowchart illustrating details of the steps involved in modifying the front surface definition of a lens, included in a method for providing a finished single-vision ophthalmic lens as disclosed in this disclosure in a second specific embodiment.

[0087] Figure 7 They are shown separately in Figure 6 The embodiments are non-limiting examples of surface maps of mean spherical mirror, cylindrical mirror, and mean curvature used in the step of evaluating the end criteria.

[0088] Figure 8 This is a flowchart illustrating the steps of a method for determining a series of finished ophthalmic lenses according to this disclosure in a particular embodiment.

[0089] Figure 9 It is shown in Figure 8The embodiments provide flowcharts detailing the steps involved in producing a series of finished ophthalmic lenses.

[0090] Figure 10 It is shown in Figure 8 and Figure 9 The embodiments provide flowcharts with more details on the steps of producing a sub-series of finished ophthalmic lenses. Detailed Implementation

[0091] In the following description, the accompanying drawings are not necessarily drawn to scale, and some features may be shown in a generalized or schematic form for clarity and brevity or for informational purposes. Furthermore, although various embodiments of manufacture and use are discussed in detail below, it should be understood that many inventive concepts that can be practiced in a variety of contexts are provided herein. The embodiments discussed herein are merely representative and do not limit the scope of this disclosure. It will also be apparent to those skilled in the art that all technical features defined in relation to the process can be transposed individually or in combination to the apparatus, and conversely, all technical features associated with the apparatus can be transposed individually or in combination to the process, and that technical features of different embodiments can be exchanged or combined with features of other embodiments.

[0092] The terms “comprise” (and any of its grammatical variations, such as “comprises” and “comprising”), “have” (and any of its grammatical variations, such as “has” and “having”), “contain” (and any of its grammatical variations, such as “contains” and “containing”), and “include” (and any of its grammatical variations, such as “includes” and “including”) are open-ended connecting verbs. They are used to indicate the presence of a feature, integer, step, or component or group thereof, but do not exclude the presence or inclusion of one or more other features, integers, steps, or components or groups thereof. Therefore, a method or a step in a method that “comprises,” “has,” “contains,” or “includes” one or more steps or elements possesses, but is not limited to, only those steps or elements.

[0093] In addition, in this disclosure, terms such as “above,” “below,” “horizontal,” “vertical,” “above,” “below,” “front,” “back,” or any other words indicating relative position should be understood to be very clearly defined under the most common wearing conditions of ophthalmic lenses (the wearer is standing or sitting).

[0094] Figure 1The flowchart illustrates the steps of a specific embodiment of a method for providing finished single-vision ophthalmic lenses according to this disclosure.

[0095] The finished single-vision ophthalmic lenses considered in this disclosure are intended for human vision and can provide optical functions to the user (i.e., the wearer of the lens).

[0096] For example, the finished single-vision ophthalmic lens can be a corrective lens conforming to a given prescription, i.e., a spherical and / or cylindrical lens for users with refractive errors, used to treat myopia, hyperopia, and astigmatism. The finished single-vision ophthalmic lens can also be a single-vision lens with a given prescription for near vision correction in presbyopia. The expression "prescription reference point" used in this disclosure refers to the optical center of the lens.

[0097] As mentioned above, single-vision lenses are designed to provide a single refractive power. In the case of astigmatism, single-vision lenses have two axes and a minimum and maximum power.

[0098] The purpose of this disclosure is to provide a method for providing a mass-production compatible version of an existing single-vision ophthalmic lens product with a rotationally symmetric anterior surface.

[0099] The finished single-vision ophthalmic lens will be provided based on a target ophthalmic lens having at least one complex surface, that is, a surface that cannot be described by a simple mathematical function, such as a surface without centrosymmetry or axial symmetry. By way of non-limiting example, the surface of the target lens is neither spherical, nor aspherical by revolution, nor toric, nor non-toric.

[0100] This ensures specific and distinct management of aberrations in the distance and near vision regions of the lens. That is, the correction of aberrations will differ for each point in these regions. Therefore, the complex surface of the target lens will have a specific shape without any particular symmetry.

[0101] like Figure 1 As shown, the first step (a) of the method for providing finished single-vision ophthalmic lenses is the step of providing wearer data or theoretical data.

[0102] Wearer data includes prescription data related to the eyes of the wearer under consideration. Wearer data may also include wearing conditions such as tilt angle, wrap angle, and vertex data. If wearing condition data is unavailable, default values ​​can be used.

[0103] Theoretical data includes prescription data related to virtual eyes. Theoretical data can be the result of computer simulations.

[0104] Wearer data may be combined with theoretical data and provided together in step (a).

[0105] By way of non-limiting examples, prescription data may include optical quantities, such as wearer diopter and astigmatism.

[0106] To evaluate this optical quantity, a conventional ray-path method, also known as ray tracing, can be used. In this case, the performance of the target lens can be evaluated using the object distance and the lens's positioning in front of the wearer's eye. By way of non-limiting example, the conventional ray-path method for evaluating power and astigmatism can be the same as or similar to the method described in document WO-A-2019 185848.

[0107] Table 1 below provides non-limiting examples of object proximity values, defined as the reciprocal of the distance along the ray path from the object to the front surface of the lens, expressed in meters, varying with the direction of eye gaze (expressed in degrees). Object proximity provides the starting point of the ray path.

[0108] <![CDATA[Proximity (m -1 )]]> 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Direction (°) -30 -28 -26 -24 -22 -20 -18 -16 -14 -12 -10

[0109] <![CDATA[Proximity (m -1 )]]> 0.0 0.0 0.0 0.0 0.0 0.1 0.3 0.7 1.2 1.7 2.0 Direction (°) -8 -6 -4 -2 0 2 4 6 8 10 12

[0110] <![CDATA[Proximity (m -1 )]]> 2.2 2.4 2.5 2.5 2.6 2.6 2.7 2.7 2.8 Direction (°) 14 16 18 20 22 24 26 28 30

[0111] Table 1

[0112] Figure 3 Non-limiting examples of optical graphs are shown for wearer’s focal error (graph on the left side of the figure) and unwanted resulting astigmatism (graph on the right side of the figure), respectively, where the prescription data is as follows: -5.00(0.00)0°.

[0113] In these two charts, the horizontal axis represents the horizontal direction of vision, named β, in degrees, and is negative for the left or temporal side of the lens for the right eye. The vertical axis represents the vertical direction of vision, named α, in degrees, and is negative for the top of the lens.

[0114] The nearly vertical dashed line in the center of the lens is the optical path, and the cross represents the position of the pupil in the primary direction of gaze. The step size of the equidistant lines is 0.125 diopters.

[0115] In Table 1 above, object distance is defined relative to the vertical line of sight. Therefore, for each given line of sight in the vertical direction, the distance to the fixed object seen by the wearer is provided.

[0116] By way of non-limiting example, the target lens can be evaluated using the following positioning rules: a tilt angle of 8°, a wrap angle of 0°, and an eye-to-lens distance of 12mm.

[0117] exist Figure 3 In the example, the center of the wearer's pupil is located 4 mm above the optical center of the lens.

[0118] like Figure 1 As shown, in step (b) following step (a), target optical or geometric features are defined on the target lens along a predetermined path based on wearer data or theoretical data or both.

[0119] By way of non-limiting example, the target lens may be the same as or similar to the lens described in document WO-A-2019 185848. In this example, the complex surface of the target lens according to this disclosure is a surface without any axis of rotation, and the optical characteristics of this surface are the same as or close to the optical characteristics of the lens described in document WO-A-2019 185848.

[0120] In one embodiment, the predetermined path can be an optical path and can extend vertically from -60° to 60°, preferably from -45° to 45°, more preferably from -30° to 30°.

[0121] In another embodiment, instead of considering a one-dimensional path along the optical path, the target optical features can be defined by considering a two-dimensional region, which is vertically and horizontally defined by viewing direction dimensions from the top to the bottom of the lens and from the left to the right of the lens. This can be achieved using... Figure 3 The reference frame is shown in the optical diagram.

[0122] The two-dimensional region in this reference frame can be defined by a circle with a radius of 30° centered on a point directly in front of the wearer's eye: α = 0°, β = 0°. The radius value can be selected within a range of 18° to 70°, preferably from 24° to 50°, and more preferably from 30° to 40°. The corresponding disk can be sampled using a grid with each point evenly spaced, for example, in steps of 1° in the α and β directions. Then, the optical characteristics at these points are evaluated using all the grid points within the disk.

[0123] In an embodiment, the target optical features may include a predetermined distribution of average power and astigmatism in the target lens.

[0124] In an embodiment, the target geometric features may include a predetermined distribution of the average curvature of the front surface of the target lens, or the minimum curvature and axial orientation of the front surface of the target lens, or the maximum curvature and axial orientation of the front surface of the target lens, or simultaneously include a predetermined distribution of the average curvature of the front surface of the target lens, the minimum and maximum curvature and axial orientation of the front surface of the target lens.

[0125] The following step (c) includes determining the finished single-vision ophthalmic lens by performing the following steps (c1), (c2) and (c3).

[0126] In step (c1), an initial lens is selected, which has a rotationally symmetric front surface and a predetermined surface curvature at the prescription reference point and conforms to the above prescription data.

[0127] By way of non-limiting example, the optical center of the lens can be selected as the prescription reference point.

[0128] Next, in step (c2), the lens optimization process begins by defining the current lens. At the start of the optimization process, the current lens is the initial lens selected in step (c1).

[0129] Then, in step (c3), the optimization process includes minimizing the difference between the optical or geometric features of the current lens and the optical or geometric features of the target lens (i.e., the target optical or geometric features defined in step (b)) through iteration.

[0130] This minimization is achieved by modifying the definition of the front surface of the current lens in each iteration to achieve the target optical or geometric features.

[0131] In an embodiment, the definition of the front surface of the current lens can be modified by performing steps including modifying the curvature of the current lens along the axis of rotational symmetry of the front surface.

[0132] As a variant, the front surface of the current lens can remain rotationally symmetric when the curvature of the front surface is modified along the axis of rotational symmetry.

[0133] Figure 2 Steps 20, 22, 24, and 26 of a first specific embodiment of step (c3) are shown, wherein the target optical features have been defined in step (b).

[0134] In step 20, a representative optical path is defined within the current lens. This optical path represents the eye's visual orientation when the wearer looks up or down to switch between near and far vision. In other words, the optical path represents how the wearer views the image through the lens when looking from a distance to a near object.

[0135] Optical paths can be established by drawing a vertical straight line from the top to the bottom of the lens.

[0136] By way of non-limiting example, a representative optical path may include a predetermined number of path segments covering an area for distance viewing purposes, for near viewing purposes, or for both distance and near viewing purposes.

[0137] For example, a representative optical path may include two path segments covering an area for distance vision extending from -10° to 0° and an area for near vision extending from 16° to 28°.

[0138] In another non-limiting example, the optical path may include three path segments, which are set according to the selected optical points. That is, the optical path may depend on the positioning of the far and near points.

[0139] In this example, the first path segment is a vertical line segment from the top of the lens to the far point of vision of the lens, the second path segment is a line segment connecting the far point of vision and the near point of vision, and the third path segment is a vertical line segment from the near point of vision to the bottom of the lens.

[0140] The distance point of vision is centered on the geometric center of the lens. The geometric center of the lens also corresponds to the optical center of the lens. The near point of vision is positioned in both the horizontal and vertical directions.

[0141] For the horizontal direction, the near point is calculated based on the convergence of the eyes when the wearer is looking at a near object. This calculation includes a set of parameters such as lens prescription, lens base curve, lens position, wearer's interpupillary distance, object distance, eye direction of gaze (eye convergence), and the refractive index of the lens material. Average values ​​can be used for each parameter.

[0142] For the vertical direction, the position of the near focus is determined based on the use of objects at a certain distance. In the described non-limiting example and as shown in Table 1 above, it can be set so that the wearer lowers his / her line of sight by approximately 20° when using an object at a distance of 0.4m (therefore, the reciprocal of the distance is 2.5). This orientation is suitable for the average situation in most everyday use cases for near tasks. Therefore, this sets the near focus orientation.

[0143] The definition of the shape of the optical path can also depend on the usage and / or the complexity of the lens being considered.

[0144] Next, in step 22, the optical characteristics of the current lens are evaluated along the representative optical path defined in step 20.

[0145] like Figure 3 As shown in the optical diagram, for each viewing direction from top to bottom, i.e. between -30° and 30°, the target lens provides the values ​​shown in Tables 2 and 3 below.

[0146] Each table contains data for the gaze direction (expressed in degrees) and the mean diopter (Table 2) or the resulting astigmatism (expressed as Asr) (Table 3) (both expressed in diopters D). These values ​​will be used as target quantities in the optimization process described in this disclosure.

[0147] α direction (°) 38 36 34 32 30 28 26 24 22 Focal length (D) -4.79 -4.84 -4.87 -4.90 -4.93 -4.95 -4.96 -4.98 -4.99

[0148] α direction (°) 20 18 16 14 12 10 8 6 4 Focal length (D) -5.00 -5.01 -5.01 -5.01 -5.01 -5.00 -5.00 -4.99 -4.98

[0149] α direction (°) 2 0 -2 -4 -6 -8 -10 -12 -14 Focal length (D) -4.98 -4.98 -4.97 -4.97 -4.97 -4.97 -4.96 -4.96 -4.95

[0150] α direction (°) -16 -18 -20 -22 -24 -26 -28 Focal length (D) -4.95 -4.94 -4.93 -4.91 -4.90 -4.87 -4.85

[0151] Table 2

[0152] α direction (°) 38 36 34 32 30 28 26 24 22 Asr(D) 0.02 0.01 0.02 0.02 0.03 0.03 0.03 0.03 0.03

[0153] α direction (°) 20 18 16 14 12 10 8 6 4 Asr(D) 0.03 0.02 0.02 0.01 0.01 0.00 0.00 0.00 0.00

[0154] α direction (°) 2 0 -2 -4 -6 -8 -10 -12 -14 Asr(D) 0.01 0.02 0.03 0.04 0.06 0.07 0.09 0.11 0.13

[0155] α direction (°) -16 -18 -20 -22 -24 -26 -28 Asr(D) 0.14 -0.16 -0.17 -0.19 -0.20 -0.21 -0.21

[0156] Table 3

[0157] Then, step 24 involves determining a front surface for the current lens, which, in combination with the spherical toric rear surface, provides values ​​for optical features along the optical path. These values ​​are optimized so that they are closest to the values ​​of the target optical features along the representative optical path defined in step 20. By way of a non-limiting example, the front surface may be rotationally symmetric.

[0158] The above references can be used Figure 1 The same ray path method described in Table 1 is used to evaluate these values ​​of the optical characteristics along the defined optical path.

[0159] By way of a non-restrictive example, the front surface element Z(x,y) to be optimized is a rotationally symmetric front surface defined by the following equation, where the coefficients K1, K2, ..., K are... Q It is the result of the optimization process:

[0160]

[0161] in

[0162] Where x is the horizontal line of sight (e.g., in mm), y is the vertical line of sight (e.g., in mm), and R is the radius at the center of the front surface.

[0163] Finally, in step 26, the modified front surface of the current lens is defined according to the front surface determined in step 24.

[0164] Figure 5 A non-limiting example of the optimized lens obtained is shown. Figure 5 The definitions of the horizontal and vertical axes of the optical diagram shown, as well as the definitions of the dashed lines and crosses, are the same as those described above. Figure 3 same.

[0165] Tables 4 and 5 below provide the values ​​obtained after evaluating the power and resulting astigmatism along the optical path for the optimized lens.

[0166] α direction (°) 38 36 34 32 30 28 26 24 22 Focal length (D) -4.75 -4.79 -4.83 -4.86 -4.89 -4.91 -4.93 -4.94 -4.95

[0167] α direction (°) 20 18 16 14 12 10 8 6 4 Focal length (D) -4.96 -4.97 -4.97 -4.98 -4.98 -4.97 -4.97 -4.97 -4.96

[0168] α direction (°) 2 0 -2 -4 -6 -8 -10 -12 -14 Focal length (D) -4.96 -4.96 -4.95 -4.95 -4.95 -4.95 -4.95 -4.95 -4.94

[0169] α direction (°) -16 -18 -20 -22 -24 -26 -28 Focal length (D) -4.94 -4.93 -4.93 -4.92 -4.91 -4.89 -4.87

[0170] Table 4

[0171] α direction (°) 38 36 34 32 30 28 26 24 22 Asr(D) 0.05 0.02 0.01 0.01 0.02 0.03 0.03 0.03 0.03

[0172] α direction (°) 20 18 16 14 12 10 8 6 4 Asr(D) 0.03 0.03 0.02 0.02 0.01 0.00 0.00 0.00 0.00

[0173] α direction (°) 2 0 -2 -4 -6 -8 -10 -12 -14 Asr(D) 0.00 0.00 0.01 0.02 0.03 0.05 0.06 0.08 0.10

[0174] α direction (°) -16 -18 -20 -22 -24 -26 -28 Asr(D) 0.12 -0.14 -0.16 -0.18 -0.21 -0.23 -0.24

[0175] Table 5

[0176] By way of non-limiting example, the complex surface of the target lens can be its rear surface.

[0177] Figure 4 Non-limiting examples of the average spherical and cylindrical images of the front or rear surface of the target lens are shown. The average spherical image is shown in the left portion of the figure, and the cylindrical image is shown in the right portion of the figure.

[0178] exist Figure 4 In the two graphs, the horizontal axis X represents the horizontal line of sight, in mm. The vertical axis Y represents the vertical line of sight, in mm. The step size of the equidistant lines is 0.125 diopters. In the non-limiting example shown in the attached figures, the radius of the anterior spherical lens is 312.38 mm, the refractive index of the lens material is 1.601, and the thickness at the optical center of the lens is 1.4 mm.

[0179] Figure 6 Steps 30, 32, 34, and 36 of a second specific embodiment of step (c3) are shown, wherein the target geometric features have been defined in step (b).

[0180] In step 30, a representative surface path is defined on the front surface of the current lens. Similar to the optical path defined in step 20 in the first embodiment above, the surface path represents the eye's gaze orientation when the wearer of the lens looks up or down to switch between near and far vision.

[0181] Each gaze direction from the top to the bottom of the lens can be converted into a point on the front surface using conventional ray tracing methods. Therefore, the optical path of the first embodiment described earlier can be converted into a surface path in the second embodiment. The surface path can be as long as the optical path, or shorter, or can be divided into several sub-paths.

[0182] The surface path provides a set of surface values ​​representing the front surface of the lens.

[0183] Next, in step 32, the curvature of the front surface of the current lens is evaluated along the representative surface path defined in step 30. This curvature can be the average curvature of the front surface of the current lens, or the minimum curvature and axis orientation of the front surface of the current lens, or the maximum curvature and axis orientation of the front surface of the current lens.

[0184] Each set of surface values ​​representing the front surface includes data at (x,y) positions on the front surface and curvature values ​​evaluated at those points on the front surface.

[0185] Figure 7 A non-limiting example of three surface plots (X,Y) representing different surface (i.e. geometric) features that can be evaluated on the front complex surface of the target lens is shown below.

[0186] The graph on the left side of the attached figure shows the average spherical mirror, where the step size of the equidistant lines is 0.125D.

[0187] The graph in the middle of the attached figure shows a cylindrical lens, where the step size of the equidistant lines is also 0.125D.

[0188] The graph on the right side of the attached figure shows the average curvature, where the step size of the equidistant lines is 0.25m. -1 .

[0189] Basically, the line in the middle of each chart represents the location on the front surface where surface (i.e., geometric) features can be obtained for evaluation.

[0190] By way of non-limiting example, Tables 6 and 7 below are obtained from the average curvature plot of the target lens in this second embodiment. Tables 6 and 7 show the following example: where the surface path is not a vertical straight line, and therefore, there is no indication of the value of the X-axis.

[0191] Table 6 corresponds to distance vision, and Table 7 corresponds to near vision.

[0192] Y-axis (mm) -11 -9.9 -8.9 -7.9 -6.9 -5.9 -4.9 <![CDATA[Mean curvature (m -1 )]]> 2.85 2.80 2.76 2.73 2.69 2.66 2.63

[0193] Y-axis (mm) -3.9 -2.9 -1.9 -0.9 <![CDATA[Mean curvature (m -1 )]]> 2.61 2.59 2.57 2.56

[0194] Table 6

[0195] Y-axis (mm) 12 13 14 15 16 17 18 19 20 <![CDATA[Mean curvature (m -1 )]]> 2.93 2.99 3.04 3.09 3.15 3.20 3.26 3.31 3.36

[0196]

[0197] Y-axis (mm) 30 31 32 33 34 35 36 <![CDATA[Mean curvature (m -1 )]]> 3.75 3.75 3.75 3.75 3.74 3.74 3.73

[0198] Table 7

[0199] Similar to the first embodiment, these tables corresponding to the target lens are used in the optimization step, which is... Figure 6 Step 34 is shown in the figure.

[0200] As a variant, for any data in the target lens table, an alternative table obtained from the type of table in Table 7 can be used by skipping the horizontal position and setting that position to x = 0 mm. In this variant, the position where the optimized value is applied in the optimized lens is extracted from a straight line from the top to the bottom of the lens.

[0201] like Figure 6 As shown, step 34 following step 32 includes determining a front surface for the current lens, which provides values ​​of geometric features along a surface path that are closest to the values ​​of target geometric features along a representative surface path defined in step 30.

[0202] In the non-limiting example shown in the attached figures, the radius of the rear spherical lens is 92.01 mm, the refractive index of the lens material is 1.601, and the thickness at the optical center of the lens is 1.4 mm.

[0203] Finally, in step 36, the modified front surface of the current lens is defined according to the front surface determined in step 34.

[0204] In both the first and second embodiments, as Figure 1 As shown, step (c3) ends when the termination criterion is met.

[0205] In one embodiment, the termination criterion can be a predetermined number of iterations.

[0206] With the unrestricted example, the number of iterations can be set to 10 or 20.

[0207] In another embodiment, the termination criterion can be defined as the value of the difference between the optical or geometric features of the current lens and the target optical or geometric features (i.e., the deviation of the current lens from the optical or geometric features of the target lens). By way of a non-limiting example, this deviation can be the root mean square deviation.

[0208] By way of a non-restrictive example, the termination criterion can be defined as the value of the merit function representing these deviations, and the optimization process includes minimizing this value such that step (c3) terminates when the value of the merit function is below a given amount.

[0209] Therefore, for a set of points on the lens or in the direction of the line of sight identified by variable i, the merit function can take the following form:

[0210] ∑p i ·∑w ij ·(L ij -T ij ) 2

[0211] in:

[0212] p i It is the weight of point i.

[0213] L ij It is the value of the j-th type of optical or geometric feature at point i.

[0214] T ij It is the target value of the j-th type of optical or geometric feature at point i.

[0215] w ij It is the weight of the j-th type of optical or geometric feature at point i.

[0216] By way of a non-limiting example, 120 points can be defined along an optical or surface path.

[0217] In another non-limiting example, 15 points, preferably 30 points, and more preferably 40 points can be defined along an optical or surface path.

[0218] In another non-limiting example, in the "optical method" (referring to the first embodiment), a predetermined number of points can be defined on the lens within a disk of radius 30° in steps of 2°. Similarly, in the "surface method" (referring to the second embodiment), a predetermined number of points can be defined on the surface within a disk of radius 15mm in steps of 1mm.

[0219] In the above Figure 2 In the first embodiment shown, by way of non-limiting example, the value j can be set to 2, and the optical characteristics can be the wearer's power and unwanted astigmatism (also referred to herein as astigmatic aberration), as previously referenced. Figure 3 As described above. For example, in this case, L i1 It is the wearer's diopter value measured at point i, and L i2 It is the astigmatic aberration value measured at point i.

[0220] In the above Figure 6 In the second embodiment shown, by way of non-limiting example, the value j can be set to 1, and the geometric feature can be the mean curvature, as previously referenced. Figure 7As described above. For example, in this case, L i1 It is the average focal length value measured at point i.

[0221] exist Figure 6 In a second embodiment, in another non-limiting example, the value j can be set to 3, and the geometric features can be the minimum curvature value, the maximum curvature value, and the axis orientation, all measured at point i. In this case, L i1 L is the minimum curvature value measured at point i. i2 It is the maximum curvature value measured at point i, and L i3 The axial orientation is measured at point i.

[0222] weighted parameter p i This allows for the application of higher or lower weights to different areas of the lens.

[0223] For example, if a predetermined number of points are defined in a disk with a radius of 30° in an optical path with a step size of 2°, or if a predetermined number of points are defined in a disk with a radius of 15 mm in a surface path with a step size of 1 mm, then a higher weight is advantageously applied to the predetermined optical or surface path, and a decreasing weight is applied when moving away from the path.

[0224] By way of non-limiting example, the given quantity to be achieved by the value of the merit function can be expressed in diopters and can take values ​​of 0.12, preferably 0.06, more preferably 0.03.

[0225] The two embodiments described above can be combined, meaning that both the termination criterion of a predetermined number of iterations and the value of the merit function below a given amount can be used together.

[0226] Optionally, in addition to the termination criterion, step (c) may further include a step of checking whether the current lens meets the predetermined performance standard. The termination criterion is the root mean square deviation relative to the predetermined target, while the performance standard may be the RMS deviation relative to Rx.

[0227] When performing the step of checking whether the current lens meets the predetermined performance standard, the predetermined performance standard may be related to the root mean square deviation of at least one of the optical features of the lens along the predetermined path compared with the corresponding one of the target optical features defined in step (b).

[0228] By way of non-limiting example, the root mean square deviation can be less than 0.12 diopters, preferably less than 0.06 diopters, and more preferably less than 0.03 diopters.

[0229] Step (d) following step (c3) provides a finished single-vision ophthalmic lens based on the current lens obtained after the end criteria have been met.

[0230] Figure 8 , Figure 9 and Figure 10 The flowchart illustrates the steps of a method for determining a series of finished ophthalmic lenses having a rotationally symmetric anterior surface, according to this disclosure.

[0231] Figure 8 Steps (i), (ii), (iii), and (iv) of the method are shown. Figure 9 The steps (iii1) to (iii4) of step (iii) are shown in detail, as well as the return to... Figure 8 Step (ii) is a possible iterative process step (iii5). Figure 10 It shows Figure 9 Details of step (iii3). Step (iii3) includes the steps of the detailed method described above for providing a finished single-vision ophthalmic lens.

[0232] The method for determining a series of finished ophthalmic lenses according to this disclosure is designed to cover a wide range of possible prescription values.

[0233] like Figure 8 As shown, in the first step (i) of the method, a given range of values ​​for prescription data is set for the finished ophthalmic lenses of the lens series to be provided. This value is hereby denoted as Rx.

[0234] Prescription data may include spherical and cylindrical values, expressed in diopters.

[0235] By way of a non-limiting example, prescription data could be spherical power values ​​in the range of [-6, +3] including the interval boundaries and cylindrical power values ​​in the range of [0, -2] including the interval boundaries, where spherical power and cylindrical power actually represent power and astigmatism.

[0236] In step (ii) below, the range is divided into a predetermined number of Rx subdomains, which are then denoted as Rxn, n = 1, ..., N, where n is an integer.

[0237] By way of a non-limiting example, within the range of the above exemplary spherical and cylindrical lens values, if N = 7, then in step (ii) seven subdomains Rx1, Rx2, ..., Rx7 are defined.

[0238] Then, in step (iii), for each subdomain Rxn, n = 1, ..., N, a subseries of finished ophthalmic lens series is provided.

[0239] The final step (iv) then involves determining the finished ophthalmic lens series by collecting the ophthalmic lens sub-series previously provided for each subdomain Rxn when performing step (iii).

[0240] Now for reference Figure 9 and Figure 10 Describe step (iii) in more detail.

[0241] like Figure 9 As shown, in step (iii1), the so-called base value is defined.

[0242] In an embodiment, the baseline value may be a spherical value, expressed in diopters, representing the surface curvature at the optical center of the anterior surface (hereinafter referred to as FS0) of a finished ophthalmic lens corresponding to the lens sub-series of the considered subdomain Rxn. The baseline value is calculated based on a fixed refractive index of, for example, 1.53, of the lens material.

[0243] For a given front surface curvature and a given refractive index, in a first approximation, the lens power will depend on the curvature of the rear surface.

[0244] In the above non-limiting examples of prescription data for spherical lenses [-6, +3] and cylindrical lenses [0, -2], the base values ​​can be set as follows: (4.69, 4.28, 3.87, 3.42, 286, 2.25, 1.54). The base values ​​are expressed based on the lens refractive index.

[0245] In any case, FS0 covers a given subdomain Rxn, such as Rx1 in the unrestricted example above with seven subdomains.

[0246] As mentioned above, the baseline value is defined based on optical and / or geometric requirements. These requirements differ from the target optical or geometric characteristics mentioned in step (b) of the detailed method described above for providing finished single-vision ophthalmic lenses.

[0247] In step (iii2) below, select prescription data that is available in the considered subdomain Rxn and represents the entire subdomain Rxn, such as the average value of prescription data in subdomain Rxn. This selected prescription data is then denoted as Rxnp, where p is an integer between 1 and p.

[0248] In the above non-limiting example, the subdomain Rx1 may therefore include prescription data Rx11, ..., Rx1p, ..., Rx1P, and the value selected in step (iii2) may be the average of the values ​​of Rx11, ..., Rx1p, ..., Rx1P.

[0249] Next, in step (iii3), by executing Figure 10The steps (iii3.1) to (iii3.6) shown and described in detail below provide a lens sub-series.

[0250] Finally, in step (iii4), it is checked whether the front surface FS0 has good performance for all prescription data of the considered subdomain Rxn, that is, it is checked whether the subsequence meets the predetermined performance criteria for all prescription data Rxnp, p=1, ..., P of the considered subdomain Rxn.

[0251] Step (iii4) is optional. In other words, the proposed method does not necessarily use performance criteria.

[0252] exist Figure 9 In one embodiment, a performance criterion is used, namely, step (iii4), which may be related to the evaluation of lens aberrations.

[0253] Performance criteria can be based on a comparison between the performance of the obtained lens and the prescription, which is calculated along a predetermined path in the lens, without regard to the target optical or geometric features.

[0254] The performance involved can be optical performance, such as the power and astigmatism of the entire lens, including its front and rear surfaces. Smaller power errors and / or less unwanted astigmatism mean better performance.

[0255] In a particular embodiment, the performance criterion may be related to the root mean square deviation of at least one of these optical features along the predetermined path described above. By way of non-limiting example, the root mean square deviation is evaluated relative to Rx.

[0256] exist Figure 9 In the embodiment, if in step (iii4), the performance criteria are met for all prescription data Rxnp, p = 1, ..., P, that is, for the entire considered subdomain Rxn, then step (iii) ends for the considered subdomain Rxn.

[0257] Then execute step (iii) for another subdomain, until step (iii) has been executed for all subdomains.

[0258] On the other hand, if in step (iii4), for any of the prescription data Rnp, p = 1, ..., P, FS0 does not meet the performance criteria, then step (iii5) is executed, which includes modifying the subdomain by returning to the segmentation step (ii) to resegment Rx into a new range Rxn', where n' is an integer included between 1 and N', and N' may be different from N.

[0259] The steps (iii3) for providing lens sub-series for the considered subdomain Rxn of prescription data values ​​include now referencing Figure 10 The steps (iii3.1) to (iii3.6) are described in detail.

[0260] like Figure 10 As shown, in step (iii3.1), based on the prescription data Rxnp representing the considered subdomain Rxn, target optical or geometric features are defined on the target lens along a predetermined path. The target lens has at least one complex surface.

[0261] Then, in step (iii3.2), an initial lens is selected, which has a rotationally symmetric front surface and a predetermined surface curvature at the prescription reference point and conforms to the prescription value of Rxnp, representing the subdomain Rxn. The initial lens is selected based on step (iii2).

[0262] By way of non-limiting example, the optical center of the lens can be selected as the prescription reference point.

[0263] Next, in step (iii3.3), the lens optimization process begins by defining the current lens. At the start of the optimization process, the current lens is the initial lens selected in step (iii3.2).

[0264] Then, in step (iii3.4), the optimization process includes minimizing the difference between the optical or geometric features of the current lens and the optical or geometric features of the target lens (i.e., the target optical or geometric features defined in step (iii3.1)) through iteration.

[0265] This minimization is achieved by modifying the definition of the front surface of the current lens in each iteration to achieve the target optical or geometric features.

[0266] By way of a non-limiting example, the front surface of the current lens can remain rotationally symmetric when its definition is modified.

[0267] Step (iii3.4) ends when the termination criterion is met.

[0268] In one embodiment, the termination criterion can be a predetermined number of iterations.

[0269] With the unrestricted example, the number of iterations can be set to 10 or 20.

[0270] In another embodiment, the termination criterion can be defined as the value of the difference between the optical or geometric features of the lens and the target optical or geometric features (i.e., the deviation of the current lens from the optical or geometric features of the target lens).

[0271] By way of a non-restrictive example, the termination criterion can be defined as the value of the merit function representing these deviations, and the optimization process includes minimizing this value such that step (iii3.4) terminates when the value of the merit function is below a given amount.

[0272] Therefore, for a set of points on the lens or in the direction of the line of sight identified by variable i, the merit function can take the following form:

[0273] ∑p i ·∑w ij ·(L ij -T ij ) 2

[0274] in:

[0275] p i It is the weight of point i.

[0276] Li j It is the value of the j-th type of optical or geometric feature at point i.

[0277] T ij It is the target value of the j-th type of optical or geometric feature at point i.

[0278] w ij It is the weight of the j-th type of optical or geometric feature at point i.

[0279] By way of non-limiting example, the given quantity to be achieved by the value of the merit function can be expressed in diopters and can take values ​​of 0.12, preferably 0.06, more preferably 0.03.

[0280] The two embodiments described above can be combined, meaning that both the termination criterion of a predetermined number of iterations and the value of the merit function below a given amount can be used together.

[0281] Step (iii3.5) following step (iii3.4) is one of the finished ophthalmic lenses in the current lens sub-series obtained after the end criteria have been met.

[0282] Finally, in step (iii3.6), a finished ophthalmic lens subseries is provided as follows: all lenses in the subseries have the same anterior surface, which is formed by the optimized modified anterior surface that meets the end criteria provided in step (iii3.5), and each lens in the subseries has a spherical toric posterior surface that is different from the spherical toric posterior surface of the other lenses in the subseries and corresponds accordingly to one of the prescription data of the considered subdomain Rxn.

[0283] The finished single-vision ophthalmic lens according to this disclosure is a current lens that meets the above-described end criteria, and this current lens is obtained by the above-described method for providing a finished single-vision ophthalmic lens according to any of the described embodiments.

[0284] The computer program product according to this disclosure includes instructions that, when executed by a processor, cause the processor to perform the steps of the method described above for providing a finished single-vision ophthalmic lens according to any of the described embodiments.

[0285] Although representative methods and apparatuses have been described in detail herein, those skilled in the art will recognize that various substitutions and modifications may be made without departing from the scope described and defined by the appended claims.

Claims

1. A computer-implemented method for providing a finished single vision ophthalmic lens intended for a wearer from a target lens having at least one complex surface, the at least one complex surface being a surface that is not centrosymmetric or axially symmetric, the finished lens having a rotationally symmetric front surface, wherein the method comprises: (a) providing wearer data comprising prescription data related to the eye of the wearer or theoretical data from a computer simulation comprising prescription data related to a virtual eye; (b) defining, on the target lens, a target optical or geometric feature along a predetermined path representative of the eye gaze orientation when the wearer of the target lens browses in the lens to switch between distance vision and near vision, based on the wearer data or the theoretical data; (c) determining the finished single vision ophthalmic lens by: (c1) selecting an initial lens that complies with the prescription data and has a rotationally symmetric front surface and a predetermined curvature at a prescription reference point; (c2) defining a current lens from the initial lens; (c3) modifying the front surface definition of the current lens to reach the target optical or geometric feature along the predetermined path until an end criterion is met; (d) providing the finished single vision ophthalmic lens from the current lens.

2. The method of claim 1, wherein, The predetermined path is an optical path and extends vertically from -60° to 60°.

3. The method of claim 1, wherein, The determining the finished single vision ophthalmic lens further comprises checking whether the current lens meets a predetermined performance criterion.

4. The method of claim 3, wherein, The predetermined performance criterion relates to a root mean square deviation of at least one of the optical features along the predetermined path.

5. The method of claim 4, wherein, The root mean square deviation is lower than 0.12 diopter.

6. The method of any one of claims 1 to 5, wherein, The modifying the front surface definition of the current lens comprises modifying the curvature of the current lens along an axis of rotational symmetry of the front surface of the current lens.

7. The method of any one of claims 1 to 5, wherein, The target optical feature comprises a predetermined distribution of mean power and of astigmatism in the target lens.

8. The method of any one of claims 1 to 5, wherein, The target geometric feature comprises a predetermined distribution of mean curvature of the front surface of the target lens, or a minimum curvature and an orientation of the axis of the front surface of the target lens, or a maximum curvature and an orientation of the axis of the front surface of the target lens, or simultaneously a predetermined distribution of mean curvature of the front surface of the target lens, a minimum and a maximum curvature and an orientation of the axis of the front surface of the target lens.

9. The method of any one of claims 1 to 5, wherein, The modifying the front surface definition of the current lens comprises: defining a representative optical path in the front surface of the current lens, the representative optical path being representative of the eye gaze orientation when the wearer looks up or down to switch between distance vision and near vision; evaluating the optical features of the current lens along the representative optical path; determining the front surface of the current lens that, in combination with the spherical toric back surface of the current lens, provides values of the optical features along the optical path that are closest to the values of the target optical features along the representative optical path; defining a modified front surface of the current lens from the determined front surface.

2. The method of claim 1, wherein the target lens is a progressive addition lens.

3. The method of claim 1, wherein the target lens is a single vision lens.

4. The method of claim 1, wherein the target lens is a contact lens.

5. The method of claim 1, wherein the target lens is a spectacle lens.

6. The method of claim 1, wherein the target lens is a multifocal lens.

7. The method of claim 1, wherein the target lens is a photochromic lens.

8. The method of claim 1, wherein the target lens is a photochromic multifocal lens.

9. The method of claim 1, wherein the target lens is a photochromic progressive addition lens.

10. The method of claim 1, wherein the target lens is a photochromic single vision lens.

11. The method of claim 1, wherein the target lens is a photochromic contact lens.

12. The method of claim 1, wherein the target lens is a photochromic spectacle lens.

13. The method of claim 1, wherein the target lens is a photochromic lens having a photochromic coating.

14. The method of claim 1, wherein the target lens is a photochromic lens having a photochromic coating and is a multifocal lens.

15. The method of claim 1, wherein the target lens is a photochromic lens having a photochromic coating and is a progressive addition lens.

16. The method of claim 1, wherein the target lens is a photochromic lens having a photochromic coating and is a single vision lens.

17. The method of claim 1, wherein the target lens is a photochromic lens having a photochromic coating and is a contact lens.

18. The method of claim 1, wherein the target lens is a photochromic lens having a photochromic coating and is a spectacle lens.

19. The method of claim 1, wherein the target lens is a photochromic lens having a photochromic coating and is a photochromic multifocal lens.

20. The method of claim 1, wherein the target lens is a photochromic lens having a photochromic coating and is a photochromic progressive addition lens.

21. The method of claim 1, wherein the target lens is a photochromic lens having a photochromic coating and is a photochromic single vision lens.

22. The method of claim 1, wherein the target lens is a photochromic lens having a photochromic coating and is a photochromic contact lens.

23. The method of claim 1, wherein the target lens is a photochromic lens having a photochromic coating and is a photochromic spectacle lens.

24. The method of claim 1, wherein the target lens is a photochromic lens having a photochromic coating and is a photochromic lens having a photochromic coating.

25. The method of claim 1, wherein the target lens is a photochromic lens having a photochromic coating and is a multifocal lens having a photochromic coating.

26. The method of claim 1, wherein the target lens is a photochromic lens having a photochromic coating and is a progressive addition lens having a photochromic coating.

27. The method of claim 1, wherein the target lens is a photochromic lens having a photochromic coating and is a single vision lens having a photochromic coating.

28. The method of claim 1, wherein the target lens is a photochromic lens having a photochromic coating and is a contact lens having a photochromic coating.

29. The method of claim 1, wherein the target lens is a photochromic lens having a photochromic coating and is a spectacle lens having a photochromic coating.

30. The method of claim 1, wherein the target lens is a photochromic lens having a photochromic coating and is a multifocal lens having a photochromic coating and is a progressive addition lens having a photochromic coating.

31. The method of claim 1, wherein the target lens is a photochromic lens having a photochromic coating and is a single vision lens having a photochromic coating and is a contact lens having a photochromic coating.

32. The method of claim 1, wherein the target lens is a photochromic lens having a photochromic coating and is a spectacle lens having a photochromic coating and is a multifocal lens having a photochromic coating and is a progressive addition lens having a photochromic coating.

33. The method of claim 1, wherein the target lens is a photochromic lens having a photochromic coating and is a single vision lens having a photochromic coating and is a contact lens having a photochromic coating and is a spectacle lens having a photochromic coating.

34. The method of claim 1, wherein the target lens is a photochromic lens having a photochromic coating and is a multifocal lens having a photochromic coating and is a progressive addition lens having a photochromic coating and is a single vision lens having a photochromic coating and is a contact lens having a photochromic coating and is a spectacle lens having a photochromic coating.

10. The method of claim 9, wherein, The representative optical path comprises a predetermined number of path segments covering the area for distance use and / or near use.

11. The method of claim 9, wherein, The representative optical path comprises two path segments covering an area for distance use extending from -10° to 0° and an area for near use extending from 16° to 28°.

12. The method of any one of claims 1 to 5, wherein, The modifying the front surface definition of the current lens comprises: defining a representative surface path on the front surface of the current lens, the representative surface path being representative of the eye gaze orientation when the wearer looks up or down to switch between distance and near; evaluating the curvature of the front surface of the current lens along the representative surface path; determining the front surface of the current lens providing values of geometrical features along a surface path, the values being closest to the values of the target geometrical features along the representative surface path; defining a modified front surface of the current lens in accordance with the determined front surface.

13. The method of claim 2, wherein, The predetermined path is an optical path and extends vertically from -45° to 45°.

14. The method of claim 13, wherein, The predetermined path is an optical path and extends vertically from -30° to 30°.

15. The method of claim 5, wherein, The root mean square deviation is lower than 0.06 diopters.

16. The method of claim 15, wherein, The root mean square deviation is lower than 0.03 diopters.

17. A computer-implemented method for determining a family of finished ophthalmic lenses having rotationally symmetric front surfaces, wherein the method comprises: (i) setting a range of values of prescription data for the finished ophthalmic lenses of the family; (ii) splitting the range into a predetermined number of sub-domains of values of prescription data; (iii) for each of the sub-domains, providing a sub-family of finished ophthalmic lenses of the family by: (iii1) defining a base value of surface curvature at the optical center of the front surface of the finished ophthalmic lenses of the sub-family according to optical and / or geometrical requirements; (iii2) selecting a representative of the prescription data of the sub-domain; (iii3) providing the sub-family by: (iii3.1) defining a target optical or geometrical feature on a target lens along a predetermined path, the target lens having at least one complex surface, which is a surface that is not centrosymmetric or axially symmetric, the predetermined path being representative of the eye gaze orientation when a wearer of the target lens browses in the lens to switch between distance and near, based on the representative of the prescription data of the sub-domain; (iii3.2) selecting an initial lens that complies with the representative of the prescription data of the sub-domain and has a rotationally symmetric front surface and a predetermined surface curvature at a prescription reference point; (iii3.3) defining a current lens in accordance with the initial lens; (iii3.4) modifying the front surface definition of the current lens to reach the target optical or geometrical feature along the predetermined path until a stop criterion is met; (iii3.5) providing the finished ophthalmic lenses of the sub-family in accordance with the current lens. (iii3.6) providing a sub-series of said finished ophthalmic lenses as follows: all finished ophthalmic lenses have the same front surface consisting of said modified front surface satisfying said end criterion and different spherocylindrical back surfaces respectively corresponding to all prescription data of said sub-domain; (iii4) checking whether said sub-series satisfies a predetermined performance criterion for all prescription data of said sub-domain; (iii5) if said predetermined performance criterion is not satisfied for all prescription data of said sub-domain, going back to the segmentation step (ii) and modifying said sub-domain; (iv) determining said series from said sub-series provided for all said sub-domains.

18. A computer program product comprising instructions which, when executed by a processor, cause the processor to determine a finished single vision ophthalmic lens intended for a wearer from a target lens having at least one complex surface, said at least one complex surface being a surface which is not centrosymmetric or axially symmetric, said finished lens having a rotationally symmetric front surface, by: (a) providing wearer data comprising prescription data related to the eye of the wearer or theoretical data from a computer simulation comprising prescription data related to a virtual eye; (b) defining a target optical or geometrical feature on said target lens along a predetermined path, based on said wearer data or said theoretical data, the predetermined path representing the eye gaze orientation when the wearer of the target lens browses in the lens to switch between far vision and near vision; (c) determining said finished single vision ophthalmic lens by: (cl) selecting an initial lens complying with said prescription data and having a rotationally symmetric front surface and a predetermined curvature at a prescription reference point; (c2) defining a current lens from said initial lens; (c3) modifying the front surface definition of said current lens to reach said target optical or geometrical feature along said predetermined path until an end criterion is satisfied; (d) providing said finished single vision ophthalmic lens from said current lens. ​ ​ ​ ​ ​ ​ ​

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