Method for producing a contact lens

Abstract

The present invention relates to a method for producing individually adapted contact lenses, and to contact lenses produced according to said method. The present invention also relates to a corresponding method for producing universally usable contact lenses by way of a moulding method, and to a method for producing a mould used in such a method. According to the invention, a contact lens blank having a rear side and a front side, and topography data which describe an inverse representation of the three-dimensional topography of the eye of the user are provided. The wearing zone arranged on the surface of the rear side of the contact lens is shaped on the basis of the topography data, and an additional three-dimensional surface structure is formed on the wearing zone. In this manner, when the contact lens is worn, the wearing zone lies on the eye of the user in the form of a face defined by the inverse representation of the three-dimensional topography of the eye onto which the three-dimensional surface structure has been superimposed.

Description

Method for producing a contact lens Technical background

[0001] The present invention generally relates to a method for producing individually fitted contact lenses and to contact lenses produced by this method. Furthermore, the present invention relates to a corresponding method for producing universally applicable contact lenses by a molding process or to a method for producing a mold used in such a process.

[0002] According to the invention, both the vision correction to be achieved with the contact lens of an eye suffering from an imaging error and the detailed topography of the cornea of ​​the eye are taken into account and, at the same time, daytime comfort and tolerability are ensured.

[0003] The optical effect of a contact lens is defined, among other things, by the specific eye defect and / or the intended use of the contact lens, such as progressive contact lenses or multifocal lenses, which represent different diopter ranges. Other influencing factors can include the specific topography of the eye lens, the specific topography / physiology of the cornea, and the specific geometry of the eyeball. In this context, the specific geometry of the eyeball can also be influenced with orthokeratology lenses to correct refractive errors. These are rigid, highly oxygen-permeable lenses that specifically reshape the cornea overnight.

[0004] The optical effect of a contact lens can be achieved through the appropriate selection of the front surface geometry, the back surface geometry, or a combination of these two geometries. The correspondingly defined optical zone is usually, but not exclusively, spanned around the geometric center of the lens, although this zone only forms a partial surface of the entire contact lens.

[0005] Further partial surfaces of the contact lens, which are usually arranged at least in sections in a ring around the optically active area, have different functionalities, such as the positioning of the lens on the eye (rotation, basic position, etc.), the provision of orientation or positioning aids (prism / slab off, ballast, alignment edges, etc.), the guarantee of a sufficient wearing zone (hereinafter also referred to as "landing zone") or the "skipping" of particularly sensitive areas of the eye (location of high nerve density (limbal zone), scars, etc.).

[0006] Although the wearing area generally has no optical effect, it is nevertheless extremely relevant for the use of the lens, as it represents the area where the lens rests directly on the eye. Thus, an inappropriately designed wearing area can cause significant impairments, such as a loss of the contact lens's intended position on the eye and a corresponding reduction in the corrective effect; interaction with the eyelid, which can lead to potentially undesired displacement of the lens; irritation of the eye through, for example, "pressure points"; or suppression of the tear film on the surface of the eye, thus impairing the eye's oxygen supply.

[0007] In today's common processes for manufacturing contact lenses, the wearing area is essentially realized by three geometric variants, namely a spherical basic shape, a toric basic shape or a quadrant-symmetrical shape "Quadsim", in which the geometry is usually defined by four meridians at 90° intervals.

[0008] Which shape is ultimately used for the patient / wearer is decided by the respective fitter / optician. Spherical basic shapes are generally used for eyes with high rotational symmetry, while toric or quadrant-symmetric basic shapes are used for eyes with a sufficiently high deviation from rotational symmetry—for example, in the case of astigmatism.

[0009] The measurement of the eye required for lens fitting can be performed using various methods. A common method involves a qualitative measurement of the lens's contact with the eye, for example, using a fluorescence image and a test lens. The fluorescence image shows where the test lens rests, and the fitter assesses the fit and iteratively corrects the lens design. A quantitative measurement of the Three-dimensional eye topography can be used to determine the actual topography / geometry of the user's eye, which can significantly reduce the number of iterations.

[0010] In the case of such quantitative measurements, compensating gates are sometimes suggested by accompanying software.

[0011] In addition to the basic shape of the wear zone, this is essentially defined by its radial start and end, hereinafter also referred to as start / end diameter, as well as by its edge shape, the latter being determined by the usual parameters such as bevel radius, edge lift, non-rotationally symmetric edge, etc.

[0012] The wear zone is therefore determined in today's standard procedures by selecting the basic shape of the wear zone (spherical, toric, etc.), the starting and ending diameters, and the edge shape. It should be noted that the wear zone is generally not a perfect inverse of the actual topography of the eye. Rather, there are at least some "gaps" or distances between the contact lens and the eye, which are bridged by the tear film on the surface of the eye.

[0013] The tear film fulfills two functions. First, it prevents optical aberrations. Since the tear film itself has an optical effect due to its refractive index, optical aberrations caused by the "lifting" of the lens from the cornea can be avoided or compensated for. Second, the tear film enables the fluid film beneath the lens to be exchanged, both to ensure a good supply of oxygen to the ocular surface and to remove any debris / cells that may have formed.

[0014] Overall, it can be said that the better the lens's wearing zone is designed, the better the wearing comfort, the local positioning, the oxygen supply, the removal of debris / cells, etc. Description of the invention

[0015] Accordingly, the object of the present invention is to optimize the wearing zone of a lens as far as possible with regard to the above-mentioned points.

[0016] According to the present invention, the support zone is therefore designed using a different approach. In particular, the present invention aims to optimize the support zone by superimposing different surfaces.

[0017] By using measuring devices to measure the three-dimensional eye geometry, the actual topography of a user's eye can first be measured, at least in those areas that are to serve as the wearing zone. By creating an inverse surface of this, an "ideally adapted" wearing zone can be defined. This inverse can be achieved either by creating a corresponding point cloud or by a mathematical description, for example, by using the methods commonly used for this purpose (B-splines, NURBS, Zernike polynomials, or similar). However, it should be noted that a "perfect inverse" can have negative properties, as the lens can adhere to the eye, resulting in an uncomfortable wearing experience.This can also disrupt the flow of the tear film, resulting in a loss of tear fluid exchange, which adversely affects oxygen supply or the removal of cells / debris. To prevent this, the invention applies a three-dimensional surface structure to the "perfect inverse." This three-dimensional surface structure can be selected from a corresponding library of existing and predefined topographies and mathematically fused with the "perfect inverse," for example, by superposition.

[0018] The three-dimensional surface structure ensures that the lens in the wearing zone is adapted as best as possible to the actual topography of the user's eye, but that the lens does not lie flatly over the entire wearing zone.

[0019] An advantage of the inventive approach is therefore that by using the additional three-dimensional surface structure In conjunction with a perfectly inverted surface, a significantly wider wearing zone can be set, as the negative effects commonly encountered today, such as suction of the lens onto the eye and the associated poor wearing comfort, as well as the reduced exchange of tear fluid and the resulting inadequate oxygen supply to the area of ​​the eye beneath the lens, can be avoided when the wearing zone is completely flat. A wider wearing zone, in turn, enables significantly improved and more stable positioning of the lens on the eye.

[0020] Although the inventive approach can initially be applied in connection with individually fitted contact lenses, it can also be easily transferred to the production of universally applicable contact lenses. In this sense, the mold used in a molding process would be designed accordingly, i.e., an "inverted" three-dimensional surface structure would be applied to the surface provided in the mold, at least in the area of ​​the wear zone of the contact lens to be molded, so that a contact lens molded with the mold would then again exhibit the corresponding desired three-dimensional surface structure in the wear zone.

[0021] Accordingly, according to a first aspect, the present invention relates to a method for forming a wearing zone of a contact lens individually adapted for a user, wherein the wearing zone of the contact lens is the area in which the contact lens rests on an eye of the user when worn. The method first comprises providing a contact lens blank having a rear side which faces an eye of the user when the contact lens is worn, and a front side which faces away from the eye when the contact lens is worn. Furthermore, topography data are provided which substantially reproduce an inverse image of the three-dimensional topography of the user's eye at least in the area covered by the wearing zone of the contact lens when worn.Based on this topography data, the wearing zone arranged on the surface of the back of the contact lens is formed. Furthermore, an additional three-dimensional surface structure is created on the wearing zone. Contact lens designed so that the wearing zone of the contact lens rests on the user's eye in the form of a surface defined by the inverse image of the three-dimensional topography of the eye superimposed with the three-dimensional surface structure.

[0022] The topography data used within the scope of the invention can be determined in a well-known manner by measuring the eye of the contact lens wearer. Naturally, the topography data can capture not only the area covered by the lens's wear zone when the contact lens is worn, but also the remaining area covered by the contact lens, i.e., including the areas of the optically active zones of the contact lens. In this case, the topography data can also be used to define the optical areas to be formed to correct the visual impairment, since the actual shape of the user's eye can also play a relevant role here.

[0023] According to a preferred embodiment of the invention, the forming of the support zone and / or the forming of the three-dimensional surface structure can be carried out by machining along a substantially spiral path. Several individual machining steps can be performed using different tools for rough / fine machining.

[0024] Preferably, before forming the wear zone, the method further comprises providing data of the three-dimensional surface structure and generating a fusion data set by overlaying the topography data with the data of the three-dimensional surface structure. The shaping of the wear zone is then carried out based on the fusion data set. In this way, the shaping of the wear zone arranged on the surface of the back of the contact lens based on the topography data and the shaping of the additional three-dimensional surface structure on the wear zone of the contact lens can be carried out in a single processing step.

[0025] In this embodiment, the generation of the fusion data set may involve a spatial superposition of the topography data with the This can include data on the three-dimensional surface structure. This can be done in a known way by mathematically superimposing and calculating the data sets.

[0026] Even when using a fusion dataset, the forming of the support zone can preferably be carried out by machining that essentially follows a spiral path. Here, too, several individual machining steps can be performed using different tools for rough / fine machining. The proportion of the three-dimensional surface structure data in the fusion dataset can be mapped by varying the movement of the machining tool with respect to the engagement angle and / or engagement depth.

[0027] As an alternative to using a fusion dataset in connection with the formation of the wear zone including the three-dimensional surface structure in a single work step, the shaping of the wear zone arranged on the surface of the back of the contact lens based on the topography data and the shaping of the additional three-dimensional surface structure on the wear zone of the contact lens can also be carried out in two separate work steps. The two shaping steps could be carried out using the same machining process, for example, a machining process. However, it would also be conceivable for the two shaping steps to be carried out using different machining processes. For example, in a first step, the wear zone could be shaped using a machining process based on the topography data.Subsequently, the additional three-dimensional surface structure could be introduced into the support zone in a second step by means of a laser surface treatment.

[0028] According to a further aspect, the present invention also relates to a method for producing a contact lens, in which a contact lens blank is provided with a back side facing an eye of the user when the contact lens is worn, and a front side facing away from the eye when the contact lens is worn. Based on provided optical data representing an imaging aberration of the user's eye to be corrected by the contact lens, an optically active zone is formed on the front of the contact lens and / or an optically active zone on the back of the contact lens. Furthermore, a wearing zone of the contact lens is formed according to one of the methods described above with a corresponding three-dimensional surface structure.

[0029] The formation of the optically active zone on the back of the contact lens and the wearing zone is preferably carried out in one processing step.

[0030] Preferably, both the forming of the optically active zone and the forming of the support zone are carried out by machining following a spiral path.

[0031] The invention further relates to a contact lens which is individually adapted for a user and which has a wearing zone which has been formed by one of the methods described above and has a corresponding three-dimensional surface structure.

[0032] According to a further aspect, the invention also relates to a method for producing a mold for use in the manufacture of a contact lens by means of a molding process. According to the invention, the method comprises shaping a portion of the mold that corresponds to a wearing zone arranged on a surface of the back of the contact lens to be manufactured, facing a user's eye. The wearing zone of the contact lens to be manufactured is the area in which the contact lens rests on the user's eye when worn. The shaping is carried out using a fusion data set that is generated by overlaying topography data, which represent an inverse image of the three-dimensional topography of the user's eye, at least in the area covered by the wearing zone of the contact lens when worn, with data of a three-dimensional surface structure.

[0033] In this way, it can be achieved that the support zone is also suitable for universally applicable and manufactured by a molding process. Contact lenses which have the advantages according to the invention with regard to wearing comfort and tear fluid exchange.

[0034] In all of the inventive methods described above, it must be considered that the shaping of the wear zone should be carried out in a manner that takes manufacturing cost-effectiveness into account. In this sense, especially when considering topography data, it may be necessary to compromise between the labor time / complexity required for processing the contact lens blank and the ultimately achievable wearing comfort, since a completely identical representation of the topography of the user's eye would only be possible, if at all, with significantly increased manufacturing effort.Usually, an approximate adaptation of the wearing zone to the actual three-dimensional topography of the user's eye, sufficient for the present invention, can be achieved by specifying various support points of the topography during the processing of the blank, which are then further processed mathematically and used as the basis for the mechanical processing.

[0035] The three-dimensional surface structure to be applied to the wearing zone according to the invention can preferably have an amplitude, viewed in the direction from the back of the contact lens to the front of the contact lens, in the range of 0.01 - 0.5 mm, preferably in the range of 0.05 - 0.3 mm. In other words, there is a corresponding distance between the "highest point" of the three-dimensional surface structure and the "lowest point of the three-dimensional surface structure." With a typical tear film thickness in the range of 0.005 mm - 0.01 mm, it can thus be achieved that the three-dimensional surface structure ensures a certain storage function and, at the same time, a sufficient exchange of tear fluid. It should be noted that the three-dimensional surface structure does not have to have a constant amplitude across the wearing zone or even merely across regions thereof. This amplitude can vary between a predetermined maximum value and a minimum value.The three-dimensional surface structure can also have an amplitude of 0 in some sections, i.e. be flat.

[0036] In a preferred embodiment, the three-dimensional surface structure can be designed such that the contact surface resting on the wearer's eye in the wearing zone represents a maximum of 70%, preferably a maximum of 50%, particularly preferably a maximum of 30% of the total area of ​​the wearing zone. By appropriately limiting the effective contact surface, the wearing comfort and detachability of the lens from the eye can be increased, while simultaneously ensuring sufficient tear fluid exchange.

[0037] Preferably, the three-dimensional surface structure, viewed in the circumferential direction of the contact lens, can essentially have a periodicity of 2 Pi / n, where n is a natural number. In other words, the three-dimensional surface structure repeats periodically in the circumferential direction, i.e., the same structures are found in the three-dimensional surface structure at intervals of 3607n, viewed in the circumferential direction. The use of a three-dimensional surface structure with a corresponding periodicity is particularly advantageous in a rotary manufacturing process.

[0038] Further preferably, the three-dimensional surface structure can essentially correspond to a random distribution. This means that the structure does not have a clearly recognizable spatial periodicity, but essentially corresponds to random noise, wherein, in particular, the amplitude of the three-dimensional surface structure does not correspond to a regular, predetermined distribution. A corresponding random distribution does not have to be generated for each individually produced support zone; rather, a previously generated and stored random distribution can be used. Furthermore, the term "random distribution" within the scope of the present invention is also intended to encompass "artificially generated" "quasi-random distributions."

[0039] Preferably, the three-dimensional surface structure can correspond to at least a singly continuous, preferably a 3-fold continuous three-dimensional function on the support zone. A multiply continuous function is understood to be a function for which the corresponding derivatives are also a continuous function. In this sense, For example, a 3-fold continuous function is understood to be a function in which the first and second derivatives also form a continuous function. In some preferred embodiments, the three-dimensional surface structure can be doubly or even triply continuously differentiable.

[0040] In a further embodiment, the three-dimensional surface structure can be designed such that, at least in the circumferential direction, it essentially corresponds to at least a singly continuous, preferably a triple continuous, function. Radially, the three-dimensional surface structure should preferably correspond to at least a singly continuous function.

[0041] The aforementioned (multiple) continuity of the three-dimensional surface structure prevents the formation of edges or other discontinuous transitions between the individual structures of the three-dimensional surface structure, which could negatively impact the wearing comfort and tolerability of the contact lens. Such continuity also enables economical production and even machining of the contact lens.

[0042] In principle, the entire shape of the wear zone after molding, based on both the topographical data and the three-dimensional surface structure, should preferably be consistent to ensure the desired wearing comfort. Preferably, the final result should be C2 consistency in the wear zone.

[0043] However, the transition between individual partial surfaces (e.g., viewed radially) may be discontinuous in the original definition / calculation of the surface. However, since discontinuities cannot be handled during machining, the surfaces must be modified in such a machining process that the discontinuity is forced into continuity. In this sense, the desired C2 continuity cannot always be achieved, at least in the transition region between partial surfaces.

[0044] In a further embodiment, the three-dimensional surface structure may comprise at least one annular surface which is The surface is modulated circumferentially by a sine function. By appropriately selecting the sine frequency (periodicity) and amplitude, the respective effective contact area of ​​the support zone can be easily adjusted as required. The three-dimensional surface structure can also have multiple ring surfaces with sinusoidal modulations that differ in terms of periodicity and / or amplitude.

[0045] In various embodiments, the three-dimensional surface structure can also comprise several concentric annular surfaces, each of which is preferably separated from one another by an annular groove. The three-dimensional surface structure can be designed differently on each individual annular surface. If the annular surfaces are separated from one another by corresponding annular grooves, these can preferably have a depth and width whose dimensions are significantly larger than the surface structures present in the annular surfaces. This advantageously enables a further improved tear fluid exchange in the area of ​​the wear zone.

[0046] In one embodiment, the three-dimensional surface structure can correspond to a superposition of a first sine function in a radial direction and a second sine function in a circumferential direction, as seen from a center of the lens. The periodicity and amplitude of the two sine functions can be different.

[0047] Preferably, the three-dimensional surface structure can be selected from a library of predefined surface structures depending on the topography data. This has the advantage that the three-dimensional surface structure does not have to be recalculated / generated for each individual manufacturing process. Individual three-dimensional surface structures that are particularly suitable for specific eye types or eye topographies can also be defined in advance. For example, it would be conceivable to classify the individual basic forms of eye topographies into different groups and then assign each of these groups a specific three-dimensional surface structure or several different three-dimensional surface structures. Embodiments

[0048] The present invention will be explained in more detail below using various embodiments and with reference to the figures. They show: Figure 1 is a schematic cross-sectional view illustrating the basic structure of a contact lens; Figure 2 is a plan view of the back of the contact lens shown in Figure 1 with a schematic representation of various embodiments of the surface structure according to the invention on the wearing zone; Figure 3 is a schematic illustration of the manufacturing process used in a preferred embodiment of the invention by machining along a substantially spiral path; Figures 4a-c show exemplary developments of the spiral line traversed by the machining tool in a manufacturing process shown in Figure 3, with various superimposed structures; Figure 5a is a block diagram of the method according to the invention; Figure 5b is a block diagram of a preferred embodiment of the method according to the invention; and Figure 6 is a schematic representation of a molding process for producing a contact lens using a mold designed according to the invention with a schematic representation of various embodiments of the surface structure according to the invention on the wearing zone of the contact lens produced by the method. Character description

[0049] Figure 1 shows a schematic cross-sectional view of a conventional contact lens 10, which in the present example is essentially rotationally symmetrical about its center 13. The contact lens 10 has a front side 11 and a back side 12. The back side 12 faces the user's eye when the contact lens 10 is worn. At its central point 13, the lens 10 has a central thickness "central lens thickness" clt. A front optically active zone 14 having a diameter df is formed on the front side 11 of the lens 10, while a rear optically active zone 15 having a diameter db is formed on the back side 12 of the lens 10. Both optically active zones 14 and 15 jointly serve to correct imaging errors in the user's eye. In the example shown, the diameter df of the front optically active zone 14 is greater than the diameter db of the rear optically active zone 15.

[0050] Concentrically around the rear optically active zone 15, on the back 12 of the contact lens 10, there is a transition region 16 in a ring shape and around the transition region 16 there is a wearing zone 17 in a ring shape.

[0051] In the wearing zone 17, the contact lens 10 rests on the user's eye when worn. To adapt the contact lens 10 to the geometry of the eye in the periphery of the lens 10, the shape of the lens in this region deviates by the so-called "edge lift" (el) from the central radius defined by the posterior optical zone 15. Furthermore, the lens 10 has an "edge lens thickness" (eit) in its edge region, which can differ from the "central lens thickness" (clt) in the central region.

[0052] Figure 2 shows a schematic rear view of the lens 10 shown in Figure 1 with the rear optical zone 15 as well as the transition region 16 and the support zone 17 adjoining it in a ring shape.

[0053] In the support zone 17, a three-dimensional surface structure was formed according to the invention, wherein in Figure 2, for example, various embodiments of three-dimensional surface structures 17a-17e are shown schematically.

[0054] As already mentioned, the three-dimensional surface structures formed in the wearing zone 17 serve to prevent the lens 10 from resting completely on the user's eye in the area of ​​the wearing zone 17 formed according to the topography data of the user's eye and to enable a sufficient exchange of tear fluid.

[0055] The three-dimensional surface structure 17a shows a completely irregular structure, such as could be created by imaging random noise.

[0056] The three-dimensional surface structure 17b shows a regular structure based on a two-dimensional superposition of sine functions.

[0057] The three-dimensional surface structure 17b also shows a regular structure based on a two-dimensional superposition of sine functions, with the structure being described in detail by the function sin(x 2 +y 2 ) is defined.

[0058] The three-dimensional surface structure 17d shows a structure in which irregular wavy channels have been introduced into the surface of the support zone 17 of the lens 10.

[0059] The three-dimensional surface structure 17e shows a structure in which regular linear channels have been introduced into the surface of the support zone 17 of the lens 10.

[0060] By arranging the channels in the three-dimensional surface structures 17 d and 17 e essentially radially, an exchange of tear fluid between the transition region 16 or the optical zone 15 and the area of ​​the user's eye not covered by the contact lens 10 can be further improved.

[0061] The three-dimensional surface structures 17a-17e shown in Figure 2 are of course to be regarded only as examples and basically any three-dimensional surface structure can be used according to the invention which, on the one hand, corresponds to the selected manufacturing process for the wearing zone 17 or the contact lens 10 and which, on the other hand, achieves the effect desired according to the invention.

[0062] Figure 3 schematically shows an overview of a preferred embodiment of the method according to the invention, in which the back surface 14 of the contact lens 10 is formed by machining using a machining tool. The lens blank is clamped, and the machining tool essentially follows a spiral path 30 during machining. Figure 3 also shows a schematic enlarged view 31 of this spiral path 30.

[0063] It should be noted that the path 30 shown in Figure 3 does not have to extend over the entire rear side 14 of the lens 10. Rather, it is conceivable that, for example, only the support zone 17 is formed by machining. The machining of the rear optical zone 15 and / or the transition region 16 and / or the support zone can also be performed in separate steps, so that no continuous spiral path 30 would result.

[0064] Furthermore, it should be noted that the track width of the track 30, i.e. the radial distance between two consecutive tracks, can be smaller than the effective radius of the processing tool, so that when traveling along the track 30, the same point on the back 14 of the contact lens engages with the processing tool several times.

[0065] In a preferred embodiment of the method according to the invention, as mentioned above, a fusion data set is used which is generated by overlaying the topography data of the user's eye with the data of the desired three-dimensional surface structure, wherein the shaping of the wearing zone according to the invention then takes place on the basis of the fusion data set.

[0066] In the machining process shown schematically in Figure 3, the machining tool can then be guided when traversing the path 30 with regard to its engagement depth or its engagement angle in such a way that the proportion of the data of the three-dimensional surface structure in the fusion data set is determined by a variation of the movement of the machining tool with regard to the pressure angle and / or the depth of engagement thereof.

[0067] Figures 4a-4c show, by way of example, various forms of a possible simple mathematical overlay of the topography data with data of various three-dimensional structures to be achieved.

[0068] Figures 4a-4c each show a development of the spiral path shown in Figure 3 over 720°. For the sake of simplicity, it was assumed in the examples shown that the base path 40a, 40b, 40c of the machining tool resulting from the topography data corresponds to a sine function.

[0069] In Figure 4a, the base path 40a is superimposed by another sine function 41a with a significantly smaller amplitude and shorter period, resulting in the superposition function 42a.

[0070] In Figures 4b and 4c, the base path 40b and 40c are superimposed with a simple triangular function 41b and a simple rectangular function 41c, respectively. The triangular function 41b and the rectangular function 41c also each have a significantly smaller amplitude and shorter period than the base path 40b, c, resulting in the superposition functions 42b and 42c.

[0071] Figures 5a and 5b show flow diagrams of preferred embodiments of the method according to the invention.

[0072] According to the method illustrated in Figure 5a, a contact lens blank having a front side and a back side is first provided in step 610. Topography data describing the topography of the user's eye is then provided in step 620.

[0073] Based on the topography data, the wearing zone of the contact lens is then formed in step 650, before an additional three-dimensional surface structure is formed on the wearing zone in step 650.

[0074] Optionally, optical data can be provided in step 630 which serve to correct the optical ametropia of the user by shaping the optically active zone(s) of the contact lens in step 640.

[0075] It should be noted that, as far as technically possible, the steps carried out in the method according to the invention do not necessarily have to be carried out in the order shown in Figure 5a.

[0076] Thus, in the case of the additional use of optical data, it would be conceivable to execute steps 630 and 640 before the provision of the topography data in step 620. Alternatively, steps 630 and 640 could also be executed after step 650 or after step 660.

[0077] It is also conceivable that the shaping of an optically active zone on the back of the lens carried out in step 640 takes place in a processing step together with the shaping of the support zone according to step 650 and / or the shaping of the additional three-dimensional surface structure.

[0078] The method illustrated in Figure 5b differs from the method illustrated in Figure 5a in that, after providing topography data in step 620, data of the three-dimensional surface structure is provided in step 670, which is then overlaid with the topography data in step 680 to generate a fusion data set. Subsequently, in step 690, the support zone is formed based on the functional data set.

[0079] Here too, optical data can optionally be provided in step 630, which serve to correct the optical ametropia of the user by shaping the optically active zone(s) of the contact lens in step 640.

[0080] Also with regard to the method shown in Figure 5b, it should be noted that, as far as technically possible, the steps carried out in the method according to the invention do not necessarily have to be carried out in the order shown in Figure 5b.

[0081] Thus, in the case of the additional use of optical data, it would be conceivable to execute steps 630 and 640 before the provision of the topography data in step 620. Alternatively, steps 630 and 640 could also be executed after step 670, after step 680, or after step 690.

[0082] Furthermore, the shaping of an optically active zone on the back of the lens carried out in step 640 can take place in a processing step together with the shaping of the wearing zone on the basis of the fusion data set according to step 690.

[0083] Figure 6 shows a schematic representation of a molding method 600-640 for producing a contact lens 63 using a mold designed according to the invention with a schematic representation of various embodiments of the surface structure 17a-17e on the wearing zone 63a of the contact lens 63 produced by the method.

[0084] In step 600, a female mold half 60 is provided, the surface 60a of which serves to form the front side of the contact lens 63. In step 610, the starting material used to produce the lens 63 is then introduced into the female mold half 60 and, in step 620, is distributed within the female mold half 60. In step 630, a male mold half 61 with a surface 61a is introduced into the female mold half 60 and pressed against it, whereby the starting material 65 arranged between the mold halves 60 and 61 is shaped into the contact lens 63. The mold halves 60 and 61 are then separated from one another, and the molded contact lens 63 can be removed (see step 640).

[0085] According to the invention, the edge region 61b of the surface 61a of the male mold half 61 has been formed using a fusion data set which was generated by superimposing topography data, which represent an inverse image of the three-dimensional topography of the user's eye at least in the area covered by the wearing zone 63a of the contact lens 63 when worn, with data of a three-dimensional surface structure.

[0086] In this way, the desired three-dimensional surface structure is formed in the wear zone during the shaping of the wear zone 63a of the contact lens 63 in step 630 of the molding process outlined in Figure 6. Figure 6, as previously shown in Figure 2, shows various examples of three-dimensional surface structures 17a-17e.

Claims

Patent claims 1. A method for forming a wearing zone (17) of a contact lens (10) individually adapted for a user, wherein the wearing zone (17) of the contact lens (10) is the area in which the contact lens (10) rests on an eye of the user when worn, comprising - Providing (610) a contact lens blank having a back side (12) facing an eye of the user when the contact lens (10) is worn, and a front side (11) facing away from the eye when the contact lens (10) is worn, - providing (620) topography data which represent an inverse image of the three-dimensional topography of the user's eye at least in the area covered by the wearing zone (17) of the contact lens (10) when worn, - shaping (650) the support zone (17) arranged on the surface of the back (12) of the contact lens (10) on the basis of the topography data and - forming (660) an additional three-dimensional surface structure (17a - 17e) on the wearing zone (17) of the contact lens (10), so that the wearing zone (17) of the contact lens (10) rests on the eye of the user when worn in the form of a surface defined by the inverse image of the three-dimensional topography of the eye superimposed with the three-dimensional surface structure (17a - 17e).

2. Method according to claim 1, characterized in that the shaping (650) of the support zone (17) and / or the (660) shaping of the three-dimensional surface structure (17a - 17e) is carried out by machining following a substantially spiral path (30).

3. The method according to claim 1, wherein the method further comprises, prior to forming (650) the support zone, - providing (670) data of the three-dimensional surface structure (17a - 17e), and - generating (680) a fusion data set by overlaying the topography data with the data of the three-dimensional surface structure (17a - 17e), wherein the shaping (690) of the support zone is carried out on the basis of the fusion data set.

4. The method according to claim 3, characterized in that the generation (680) of the fusion data set comprises a spatial superposition of the topography data with the data of the three-dimensional surface structure (17a - 17e).

5. Method according to claim 3 or claim 4, characterized in that the shaping (690) of the support zone on the basis of the fusion data set is carried out by a machining operation following a substantially spiral path (30) 6. Method according to claim 5, characterized in that the portion of the data of the three-dimensional surface structure (17a - 17e) in the fusion data set is mapped by a variation of the movement of the machining tool with respect to the engagement angle and / or the engagement depth.

7. A method for producing a contact lens (10), comprising - Providing (610) a contact lens blank having a back side (612) facing an eye of the user when the contact lens (10) is worn, and a front side (11) facing away from the eye when the contact lens (10) is worn, - Providing (630) optical data representing an imaging error of the user's eye to be corrected by the contact lens (10), - forming (640) an optically active zone (15) on the back (12) of the contact lens (10) on the basis of the optical data and - Forming a support zone (17) using a method according to one of claims 1 - 6.

8. Method according to claim 7, characterized in that the shaping (640) of the optically active zone (12) and the shaping of the support zone (17) take place in one processing step of the contact lens blank.

9. Method according to claim 7 or 8, characterized in that the shaping (640) of the optically active zone and the shaping of the support zone (17) are carried out by machining following a spiral path (30).

10. A method for producing a mold (61) for use in the manufacture of a contact lens (63) by means of a molding process (600 - 640), comprising Shaping a section (61b) of the mold (61) which corresponds to a wearing zone (63a) arranged on a surface of the back of the contact lens (63) to be produced, said wearing zone facing a user's eye, wherein the wearing zone (63a) of the contact lens (63) to be produced is the region in which the contact lens (63) rests on the user's eye when worn, wherein the shaping is carried out using a fusion data set which is generated by superimposing topography data which reproduce an inverse image of the three-dimensional topography of the user's eye at least in the region covered by the wearing zone (63a) of the contact lens (63) when worn, with data of a three-dimensional surface structure (17a - 17e).

11. Method according to one of the preceding claims, characterized in that the three-dimensional surface structure (17a - 17e) has an amplitude in the range of 0.01 - 0.5 mm, preferably in the range of 0.05 - 0.3 mm, seen in the direction of the back (12) of the contact lens (10, 63) to the front (11) of the contact lens (10, 63).

12. Method according to one of the preceding claims, characterized in that the three-dimensional surface structure (17a - 17e) is designed such that the contact surface resting on the eye of the user in the wearing zone (17, 63a) is a maximum of 70%, preferably a maximum of 50%, particularly preferably a maximum of 30% of the total surface of the wearing zone (17, 63a).

13. Method according to one of the preceding claims, characterized in that the three-dimensional surface structure (17a - 17e) viewed in the circumferential direction of the contact lens (10, 63) substantially has a periodicity of 2 Pi / n, where n is a natural number.

14. Method according to one of the preceding claims, characterized in that the three-dimensional surface structure (17a - 17e) essentially corresponds to a random distribution (17a).

15. Method according to one of the preceding claims, characterized in that the three-dimensional surface structure (17a - 17e) corresponds to at least a single-continuous, preferably a triple-continuous three-dimensional function on the support zone (17, 63a).

16. Method according to one of the preceding claims, characterized in that the support zone (17, 63a) essentially has a C2 continuity.

17. Method according to one of the preceding claims, characterized in that the three-dimensional surface structure (17a - 17e) comprises at least one annular surface which is modulated in the circumferential direction by a sine function.

18. Method according to one of the preceding claims, characterized in that the three-dimensional surface structure (17a - 17e) comprises a plurality of concentric annular surfaces, which are preferably each separated from one another by an annular groove.

19. Method according to one of the preceding claims, characterized in that the three-dimensional surface structure (17b) corresponds to a superposition of a first sine function in a radial direction and a second sine function in a circumferential direction as seen from a center (13) of the lens (10, 63).

20. Method according to one of the preceding claims, characterized in that the three-dimensional surface structure (17a - 17e) is selected from a library of predefined surface structures (17a - 17e) depending on the topography data.

21. A contact lens (10) individually fitted to a user, characterized in that it was manufactured by a method according to any one of the preceding claims.

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