How to design toric contact lenses

Abstract

The present invention provides a method for designing a front toric soft contact lens with a substantially circular optical zone. Specifically, the present invention describes a method for designing a front toric soft contact lens that features a substantially circular optical zone with a smooth transition between the optical zone and the peripheral non-optically stabilized carrier zone. The optical zone diameter is designed independently of the cylinder power and shape or curvature of the posterior surface. The present invention describes a method for designing a front toric soft contact lens in which neither the edge profile nor the optical zone diameter is affected by the magnitude of the cylinder power or the orientation of the cylinder axis.

Description

[Technical field]

[0001] The present invention relates to a method for designing a front toric soft contact lens having a circular optical zone. The present invention describes a method for designing a front toric soft contact lens characterized by a circular optical zone with a smooth transition between the circular optical zone and a non-optical peripheral stabilization carrier zone. The diameter of the circular optical zone is designed independent of the cylinder power and shape or curvature of the posterior surface. The present invention describes a method for designing a front toric soft contact lens in which neither the edge profile nor the optical zone diameter is affected by the magnitude of the spherical power, the magnitude of the cylinder power, and / or the orientation of the cylinder axis. [Background technology]

[0002] Astigmatism is a type of refractive error of the eye caused by deviations from the spherical curvature of the eye's cornea and / or lens, causing light rays from an object to focus at focal lines rather than a common focus, resulting in a distorted image on the retina.

[0003] Astigmatism can occur with other refractive errors, such as myopia, hyperopia, or presbyopia, and affects a large portion of the population to some degree. To correct astigmatism, cylindrical optical correction, also known as toric optical correction, is used, allowing individuals who are myopic or hyperopic as well as astigmatic to be fitted with a single soft contact lens that contains both spherical and cylindrical components within the optical zone.

[0004] Toric or cylindrical optical correction involves the use of optical features in which the optical zone of a contact lens has two different target refractive powers along two mutually perpendicular orientations. Essentially, an astigmatism lens has one refractive power, known as the spherical power, to correct the myopic or hyperopic component of the refractive error, and a second refractive power, known as the cylindrical power, to correct the astigmatism component, both of which are incorporated into a single optical region in the optical zone of the contact lens.

[0005] In general, the toric power of a lens can be produced by a continuously varying radius of curvature of the front or back surface of the lens or both between meridian angles. Most prior art toric soft contact lenses are back toric contact lenses, but there are some commercially available front toric soft contact lenses, which are often prescribed primarily for eyes with phakic astigmatism.

[0006] For posterior toric soft contact lenses, the smallest radius of curvature is called the steep meridian of the posterior toric soft contact lens, and the largest radius of curvature is called the flat meridian of the posterior toric soft contact lens. By convention, the orientation of the flat meridian, the meridian with the greatest positive refractive power, is used to identify the axis of the astigmatic orientation of the posterior toric soft contact lens.

[0007] Conversely, in anterior toric soft contact lenses, the toric power of the lens is produced by a continuously varying radius of curvature of the anterior surface, in which case the convention described above is reversed, i.e., the flat meridian is the meridian with the least positive power.

[0008] To achieve the desired toric correction, the orientation of the lens' cylindrical axis must be aligned with the eye's astigmatism axis. Toric optical correction is utilized in eyeglasses, contact lenses, and intraocular lenses as a correction mode. The toric optical correction utilized in eyeglasses and intraocular lenses is held stationary relative to the eye. However, contact lenses without any stabilizing features will naturally rotate on the eye. Therefore, toric contact lenses must include a mechanism to rotate the lens in the correct manner to hold the contact lens relatively stable on the eye when the wearer blinks or looks around while wearing the toric contact lens.

[0009] The mechanical properties of the non-optical peripheral carrier zone of the toric soft contact lens are altered to maintain the on-eye orientation of the toric soft contact lens. For example, the use of truncated prisms, prism ballasts, or intentional thickening of the periphery of the lower region of the toric soft contact lens can contribute to improving the on-eye stability of the toric contact lens. These methods are described in the prior art US patents and patent applications US10747021B2, US6626534B1, US8814350B2, US8646908B2.

[0010] Other stabilization methods include double slab-off designs or peri-ballasted toric soft contact lenses. A common feature of all these designs is a peripherally rotationally symmetrical posterior surface with peripheral thickness variation achieved by a peripherally non-rotationally symmetrical anterior surface. Traditionally, posterior toric soft contact lenses for astigmatism correction have an elliptical shaped optical zone, with the longest axis corresponding to the meridian with the most positive refractive power and the shortest axis corresponding to the meridian with the least positive refractive power. For higher cylinder powers, e.g. cylinder powers greater than -3.00DC, the difference between the steep meridian and the flat meridian, i.e. the ellipticity of the optical zone, becomes large, making it difficult to maintain an ellipticity of the optical zone that can provide adequate pupil coverage or a peripheral thickness profile that can provide good comfort and stability of on-eye orientation.

[0011] There is a need in the art for new design methods that can maintain a circular optical zone of appropriate diameter for any given magnitude of spherical and cylindrical power and any orientation of the cylinder axis. Summary of the Invention

[0012] Certain methods and algorithms of the present invention are directed to the design of front toric soft contact lenses for correcting distance vision that maintain a circular front optical zone of appropriate diameter for any given magnitude of spherical and cylindrical power and any orientation of the cylinder axis.

[0013] Other methods and algorithms of the present invention are directed to the design of anterior multifocal toric soft contact lenses for distance and near vision correction that maintain a circular optical zone of appropriate diameter for any given magnitude of sphere, cylinder, and add power and any orientation of the cylinder axis.

[0014] In the present invention, the term "front toric soft contact lens" means a contact lens that corrects distance vision with astigmatism, ie, myopia or hyperopia.

[0015] The term "front multifocal toric soft contact lens" refers to the front toric soft contact lens of the present invention designed for presbyopia, correcting far and near vision and astigmatism. In the present invention, the method described for designing the front toric soft contact lens is also applicable to designing the front multifocal toric soft contact lens. The design method of the front multifocal toric soft contact lens is considered to be completely within the scope of designing the front toric soft contact lens of the present invention.

[0016] One preferred method of designing the front toric soft contact lens embodiments of the present invention includes: (a) defining a particular magnitude of cylindrical power and a particular orientation of the cylindrical axis for the front toric soft contact lens; (b) defining a particular optical zone diameter for the front toric soft contact lens; (c) defining a posterior surface shape for the front toric soft contact lens across the lens diameter, the posterior surface shape may be defined by a spherical curve, or an aspheric curve, or a number or combination of both combined with or without a mixture; (d) defining a central thickness of the front toric soft contact lens; and (e) calculating the required power profile for each semi-meridian in the optical zone of the front toric soft contact lens based on the specified magnitude of cylindrical power and orientation of the cylindrical axis, the power profile along each semi-meridian in the optical zone of the front toric soft contact lens may be defined with or without spherical aberration, the sign of the spherical aberration in the optical zone may be positive or negative, and the magnitude of the spherical aberration in the optical zone may be determined by the magnitude of the spherical aberration in the optical zone. The thickness of the front toric soft contact lens may be between 0D and 2D; (f) calculating a thickness profile for each semi-meridian of the optical zone of the front toric soft contact lens using the defined semi-meridian power profile, central thickness, and refractive index of the front toric soft contact lens; (g) generating a front optical surface shape within the specified front optical zone diameter by adding the defined thickness profile along each semi-meridian to the posterior surface profile; (h) defining a thickness profile of the peripheral non-optical stabilization zone along the corresponding semi-meridian; (i) defining a blend zone along each semi-meridian to substantially smoothly merge the optical zone of the front surface of the front toric soft contact lens with the peripheral non-optical stabilization zone; (j) defining an edge profile; and (k) using an existing lathe technology platform, such as state-of-the-art computer numerically controlled (CNC) lathe technology, to generate a front surface having the precision required to obtain a good optical quality surface and a smooth transition without the need for polishing.According to the present invention, the plurality of identified semi-meridians of the optical zone of the front toric soft contact lens may be selected to range from about 12 to about 400 semi-meridians. According to the present invention, by calculating the front surface shape based on the thickness profile of the optical zone of the front toric soft contact lens, the posterior surface design of the front toric soft contact lens is not constrained by the requirement to accommodate the major and minor axes within the peripheral non-optical stabilization zone. For example, one distinct advantage of the present invention is that an asphericity value (p value) less than 1 can be used for an aspheric or polycurved posterior surface, i.e., flattening toward the periphery. In some other embodiments, the asphericity may be expressed as Q or k. The method described herein is applicable to both lathe cut and casting modes for manufacturing front toric soft contact lenses.

[0017] The particular methods and algorithms of the present invention are directed to the design of front toric soft contact lenses that offer two distinct advantages over conventional posterior toric soft contact lens design methods: (a) they allow for the maintenance of a circular optical zone of appropriate diameter that can be maintained across all of the spherical, cylindrical, and axial prescriptions of the front toric soft contact lens, and / or (b) they allow for an optimized blend between the optical zone and the non-optical peripheral stabilization zone for each semi-meridian and each individual prescription of the front toric soft contact lens.

[0018] Another preferred method of designing the front toric soft contact lens embodiments of the present invention includes: (a) defining a particular magnitude of cylinder power and a particular orientation of the cylinder axis for the front toric soft contact lens; (b) defining a particular optical zone diameter for the front toric soft contact lens; (c) defining a rotationally symmetric posterior surface shape of the front toric soft contact lens, which may be defined by a single aspheric curve or a multi-curve defined by a set of spheres and / or aspheric surfaces; (d) defining a posterior optical zone diameter that is preferably similar to or larger than the front optical zone diameter of the front toric soft contact lens when the posterior surface is defined as a multi-curve aspheric surface; (e) defining a total lens diameter of the front toric soft contact lens; and (f) selecting a plurality of semi-meridians in the optical zone of the front toric soft contact lens to define the front surface, where a suitable plurality of semi-meridians in the optical zone of the front toric soft contact lens may be between about 12 and 400 semi-meridians. (f) calculating for each semi-meridian within the optical zone of the front toric soft contact lens a required power profile based on a lens prescription with a particular magnitude of spherical power, cylindrical power, and cylindrical axis, and the required magnitude and sign of the spherical aberration to be included within the optical zone; (g) selecting a lens material with known refractive index and expansion characteristics; (h) selecting an appropriate central thickness of the front toric soft contact lens; (i) defining a circular diameter of the front optical zone of the front toric soft contact lens; (j) calculating a radius of curvature or axial thickness profile along each semi-meridian that achieves a desired refractive power within the front optical zone diameter of the front toric soft contact lens based on the refractive index and central thickness of the material, the radius of curvature or axial thickness profile may be defined at discrete data points along the semi-meridian of appropriate density, and in this step (j), for a front toric soft contact lens designed with prism ballast stabilization, it is beneficial to add a matching prism thickness difference to each semi-meridian of the front toric soft contact lens;(k) defining a desired thickness profile for the peripheral non-optical stabilization zone along each semi-meridian of the front toric soft contact lens; (l) defining a blend width between the front optical zone and the peripheral non-optical stabilization zone of the front toric soft contact lens along each semi-meridian of the front toric soft contact lens; (m) applying a suitable blending algorithm to smoothly combine these two zones along each semi-meridian of the front toric soft contact lens; (n) applying the thickness profile along each semi-meridian to the posterior surface of the front toric soft contact lens to obtain front surface data points; (o) applying a suitable edge profile to the front and posterior surface profiles of the front toric soft contact lens, the edge profile being defined independent of the magnitude of the cylindrical power and independent of the orientation of the cylindrical axis; and (p) converting the front and posterior surface data points into a format suitable for manufacturing the respective surfaces of the front toric soft contact lens.

[0019] In some embodiments of the invention, the contact lens is a front surface soft multifocal contact lens, and one or more steps of a preferred exemplary method of the invention also include defining a specific magnitude of the add power of the front surface soft multifocal contact lens and calculating a required power profile based on a lens prescription of specific magnitudes of sphere power, cylinder power, add power, and cylinder axis, and the magnitude and sign of the required spherical aberration to be included in the optical zone.

[0020] In some embodiments, one or more steps of a preferred exemplary method of the present invention may be combined with one or more steps of another preferred exemplary method of the present invention, and the steps resulting from such combination are considered as another preferred exemplary method of the present invention within the scope of the present invention. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a front view of a prior art posterior toric soft contact lens having a non-circular optical zone.

[0022] [Diagram 2] FIG. 1 is a front view of a front toric soft contact lens of the present invention having a substantially circular optical zone surrounded by a blend zone of variable width.

[0023] [Diagram 3] Disclosed herein are cross-sectional views of the posterior surface of an anterior toric soft contact lens embodiment of the present invention defined using two exemplary steps: (a) a single curve aspheric surface, and a posterior surface defined using a lens diameter or radius.

[0024] [Figure 4] FIG. 2 is another cross-sectional view of the posterior surface of an anterior toric soft contact lens embodiment of the present invention disclosed herein, defined using three exemplary steps: (a) a set of multi-curve aspheric surfaces, (b) a posterior optical zone radius, and (c) a posterior surface defined using a lens diameter or radius.

[0025] [Diagram 5] FIG. 2 is a front view of the optic zone diameters of a front toric soft contact lens embodiment of the present invention, illustrating the steps of selecting multiple semi-meridians for the front optical zone radius of a front toric soft contact lens as disclosed herein.

[0026] [Figure 6] FIG. 2 is a cross-sectional view of the optical zone radius of a front toric soft contact lens embodiment of the present invention, illustrating the steps of defining the optical power profile for a number of selected semi-meridians with respect to the optical zone radius of a front toric soft contact lens disclosed herein.

[0027] [Figure 7]FIG. 1 is a cross-sectional view of a radius of a front toric soft contact lens embodiment of the present invention, illustrating the steps of defining a blend zone width and selecting a blend curve to provide a substantially no interface or smooth contour between a plurality of selected semi-meridians and a plurality of selected peripheral non-optical stabilization zone thickness profiles for the front optical zone radius of a front toric soft contact lens disclosed herein.

[0028] [Figure 8] FIG. 2 is a cross-sectional view of a radius of a front surface toric soft contact lens embodiment of the present invention, illustrating the steps of generating a front surface sag profile for a plurality of selected semi-meridians for the front surface radius of a front surface toric soft contact lens disclosed herein.

[0029] [Figure 9] 1 depicts front surface sag profile data for three selected semi-meridians of a front surface toric soft contact lens of the present invention.

[0030] [Figure 10] 1 depicts the 3D radius of curvature thickness profile of a front toric soft contact lens with a (-3D / -2.5DC x 60°) prescription designed using prior art methods.

[0031] [Figure 11] 1 shows the 3D radius of curvature thickness profile of a front toric soft contact lens with a (-3D / -2.5DC x 60°) prescription designed using the method of the present invention.

[0032] [Figure 12] 1 depicts cross-sectional radius of curvature thickness profiles along the vertical meridian of a front toric soft contact lens designed using (a) the prior art method (dotted line) and (b) the method of the present invention (solid line).

[0033] [Figure 13]FIG. 1 is a front view of a central near multifocal anterior toric soft contact lens of the present invention having substantially circular distance and near optical zones.

[0034] [Figure 14] FIG. 1 is a cross-sectional view of the optical zone radius of a front toric soft contact lens embodiment of the present invention, illustrating the steps of defining the optical power profile for a selected number of semi-meridians for the optical zone radius of a central near multifocal front toric soft contact lens disclosed herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] In this section, the present invention will be described in detail with reference to one or more methods, some of which are illustrated and supported in the accompanying drawings. The examples and embodiments are provided for illustration purposes and are not to be construed as limiting the scope of the present invention. The following description is provided with respect to methods that may share common characteristics and features of the present invention. It should be understood that one or more features of one method may be combined with one or more methods of other embodiments to form additional method embodiments of the front toric soft contact lens of the present invention.

[0036] The functional and structural information disclosed herein should not be construed as limiting in any way, but rather as a representative basis for teaching those skilled in the art the disclosed methods and variations of those methods in various ways to design, develop and manufacture toric soft contact lenses, and more specifically, front surface toric soft contact lenses.

[0037] 1 is a front view of a prior art posterior toric soft contact lens (100) comprised of a lens diameter (101), a non-circular optic zone (102), and a peripheral non-optically stabilized zone (103). The transition (104) between the non-circular optic zone (102) and the peripheral non-optically stabilized zone (103) of the posterior toric soft contact lens (100) does not have a defined blend and may result in the lens not being stabilized as desired, potentially resulting in reduced comfort and / or visual performance.

[0038] The elliptical shape and size of the non-circular optical zone (102) of the posterior toric soft contact lens (100) is according to its toric prescription, i.e., its sphere power, cylinder power, and cylinder axis. The major axis of the ellipse (106) represents the meridian with the largest radius of curvature and the most positive power. Its orientation defines the cylinder axis (105), which in this example is about 60°. The minor axis of the ellipse represents the meridian with the smallest radius of curvature, or the meridian with the most negative power, or the steepest meridian (107). The cylinder power of the lens is the power difference between the flat meridian (106) and the steepest meridian (107). The decentration of the posterior toric soft contact lens (100), or the ratio between the length of the minor axis and the length of the major axis of the elliptical or non-circular optical zone (102), increases with increasing cylindrical power and can cause further degradation of performance, especially for tilted cylindrical axes.

[0039] Although FIG. 1 provides an example of a prior art posterior toric soft contact lens (100), the same design limitations exist for prior art anterior toric soft contact lenses.

[0040] To overcome the design limitations of prior art front or back toric soft contact lenses having non-circular optical zones, a novel method for designing a front toric soft contact lens that provides a circular optical zone regardless of toric prescription, i.e., independent of the magnitude of the cylinder power and independent of the orientation of the axis of the cylinder, is provided.

[0041] 2 is a front view of a front toric soft contact lens (200) of the present invention, comprising a lens diameter (201), a substantially circular optic zone (202), a peripheral non-optically stabilized zone (203), and a blend zone (204) between the substantially circular optic zone (202) and the peripheral non-optically stabilized zone (203). The blend zone (204) provides a smooth blend and improves comfort and / or visual performance compared to current prior art front toric soft contact lenses.

[0042] The substantially circular optical zone (202) of the anterior toric soft contact lens (200) includes a meridian with the smallest radius of curvature, which is also the meridian of the greatest positive power or the steepest meridian (206), and a meridian with the greatest radius of curvature or the meridian with the smallest positive power or the flat meridian (207). In this embodiment, the orientation of the steepest meridian (206) defines the cylinder axis (205), which is approximately 60° in this example. The cylinder power of the lens is the power difference between the steepest meridian (206) and the flat meridian (207). As the cylinder power increases, the size and shape of the substantially circular optical zone (202) remains substantially the same, allowing for visual performance that is independent of the toric prescription.

[0043] The first few steps of an exemplary method of the present invention are illustrated in Figure 3, which is a cross-sectional view of the posterior surface of an embodiment of a front toric soft contact lens of the present invention. In this embodiment, the first step is to define the posterior surface of the front toric soft contact lens with a single curved aspheric surface (301) above a defined lens diameter or radius (step 2, 302) as disclosed herein.

[0044] In one alternative embodiment, the first few steps of an exemplary method of the present invention are illustrated in Figure 4, which is a cross-sectional view of the posterior surface of a front toric soft contact lens embodiment. In this embodiment, the first step is to define the central posterior surface using a spherical or aspheric curve (401) including the specification of a central posterior optical zone radius (402). Step 3 involves defining the lens radius (403) and at least one posterior peripheral curve (404). Appropriate blending is applied between these zones (401 and 404) to smooth out any sharp interfaces.

[0045] Step 4 of an exemplary method of the present invention is illustrated in Figure 5, which is a front view of the optic zone (501) of diameter (502) of a front toric soft contact lens embodiment of the present invention. This step involves selecting a plurality of semi-meridians (503) for the front optical zone diameter (502) of the front toric soft contact lens, preferably in uniform clockwise increments separated by an angle θ (504) as disclosed herein.

[0046] The next step of the exemplary method of the present invention is step 5 (605) illustrated in Figure 6, which depicts the optical power profile in the substantially circular optical zone of a front toric soft contact lens embodiment of the present invention, which involves defining the optical power profile for a selected plurality of semi-meridians in the front optical zone as disclosed herein. In Figure 6, the optical power profiles for the various semi-meridians (621-630, etc.) are plotted for a distinct angle θ as a function of the front optical zone radius (607) (i.e., distance from the center). In some embodiments, the selected plurality of semi-meridians may be between 12 and 400 semi-meridians, or between 10 and 300 semi-meridians, or between 8 and 240 semi-meridians. In some embodiments of the invention, the power difference between the least positive semi-meridian (630) and the most positive semi-meridian (621), also known as the cylinder, may be between 0.25DC and 5DC, between 0.5DC and 3DC, between 0.5DC and 6DC, or between 1DC and 4DC. In other embodiments of the invention, the power difference between the least positive semi-meridian (630) and the most positive (621), also known as the cylinder, may be at least 0.25DC, at least 1DC, at least 3DC, or at least 4DC. In some embodiments of the invention, the power profile across the selected semi-meridian may be configured to be spherical, aspheric, or polycurve.

[0047] Another set of steps of an exemplary method of the present invention is illustrated in Figure 7, which depicts thickness profiles (703a, 703b, 703c, 703d, etc.) along a radius (703) of a front toric soft contact lens embodiment of the present invention. The steps include step 6 of selecting a central thickness (706), step 7 of converting the semi-meridian power profiles (621-630) into semi-meridian thickness profiles (e.g., 707a and 707b) of the front optical zone radius (707) taking into account the contact lens material refractive index and adding, if necessary, a matching prism thickness difference to each selected semi-meridian thickness profile (e.g., 707a and 707b) of the front optical zone radius (707), step 9 of defining a blend zone width (711), step 10 of selecting a peripheral zone thickness profile (706) for each selected semi-meridian power profile (706) of the front optical zone radius (707), step 11 of selecting a blend zone width (712), step 12 of selecting a peripheral zone thickness profile (706) for each selected semi-meridian power profile (706) of the front optical zone radius (707), step 13 of selecting a blend zone width (713), step 14 of selecting a blend zone width (714), step 15 of selecting a blend zone width (715), step 16 of selecting a blend zone width (716), step 17 of selecting a blend zone width (717), step 18 of selecting a blend zone width (718), step 19 of selecting a blend zone width (719), step 20 of selecting a blend zone width (720), step 21 of selecting a blend zone width (720), step 22 of selecting a blend zone width (720), step 23 of selecting a blend zone width (720), step 24 of selecting a blend zone width (720), step 25 of selecting a blend zone The method includes or involves step 10 of defining a peripheral thickness profile (e.g., 712a and 712b) for a meridian (712) and step 11 of selecting the shape of a blend curve (e.g., 711a and 711b) to provide a substantially no-junction or smooth profile between the selected semi-meridians (e.g., 707a and 707b) and the selected peripheral zone thickness profiles (e.g., 712a and 712b) for the anterior toric soft contact lens anterior optical zone radius (707). The blend width may vary between the semi-meridians by stretching zone 711 and shortening peripheral zone 712 or vice versa.

[0048] The final step of the exemplary method of the present invention is illustrated in Figure 8, which is a cross-sectional view of a radius of a front toric soft contact lens embodiment of the present invention, and includes or involves generating a front surface sag profile (813) for a plurality of "n" semi-meridians selected for the radius of the front toric soft contact lens by adding the thickness profiles of the optic zone (707), blend zone (711), and peripheral zone (712) disclosed herein to the posterior surface profile (812).

[0049] A preferred exemplary method for designing a front toric soft contact lens according to an embodiment of the present invention may be based on another algorithm that includes at least in part a series of the following steps: (Step 1) Define a rotationally symmetric posterior surface profile for the front toric soft contact lens, which may be designed as either a single curved aspheric surface or a multi-curved set of conic sections. If necessary, i.e. when the rotationally symmetric posterior surface profile for the front toric soft contact lens is defined as a multi-curved surface, perform (Step 2) defining a posterior optical zone diameter, which is preferably larger than or similar to the front optical zone diameter of the front toric soft contact lens. (Step 3) Define a front toric soft contact lens diameter (or radius) and an appropriate posterior peripheral curve to achieve a target mean base curve. (Step 4) Select a front optical zone diameter and a number of semi-meridians for the front definition of the optical zone of the front toric soft contact lens. For example, the number of semi-meridians may be between 12 and 400. (Step 5) Calculate the required power profile for each semi-meridian of the optical zone, in this embodiment, based on the toric lens prescription of sphere, cylinder, cylinder axis, and spherical aberration. (Step 6) Select the lens material and the appropriate center thickness. (Step 7) Convert the multiple semi-meridian power profiles to thickness profiles based on the refractive index and center thickness of the selected material. (Step 8) Define the blend width between the anterior optical zone and the anterior non-optical peripheral stabilization zone. (Step 9) Define the peripheral thickness profile for each semi-meridian. (Step 10) Apply a blend curve along each semi-meridian to smoothly combine the optical zone thickness profile to the peripheral zone thickness profile. (Step 11) Add the calculated thickness profile of each semi-meridian to the posterior surface to generate the anterior profile along each semi-meridian. The selection of the peripheral thickness profile for each semi-meridian is defined in part by the selected stabilization method.The combination of the peripheral thickness profile along each semi-meridian may constitute one of the commonly used stabilization methods, or prismatic ballast, periballast, or dynamic stabilization, or other methods that can orient the lens on the eye. To facilitate manufacturing and provide acceptable on-eye comfort, appropriate edge profiles may be added to the anterior and posterior surface profiles. The anterior and posterior surface data points are converted into a format suitable for manufacturing the respective surfaces.

[0050] For example, Figure 9 represents the front surface sag profile data for three selected semi-meridians of a front surface toric soft contact lens of the present invention that can be used on a lathe to produce the front surface. However, the actual number of semi-meridians required to produce a front surface toric soft contact lens may range from 12 to 400. The density of data points along the semi-meridians may vary. In this embodiment, the data points are denser toward the edge of the lens. In other embodiments, the density may be the same across the semi-meridians.

[0051] The front toric soft contact lens designed using the method of the present invention offers two advantages over conventional toric soft contact lenses: (I) it allows a circular optical zone of appropriate diameter that can be maintained over all spherical, cylindrical, and axial prescriptions of the front toric soft contact lens, and / or (II) it allows a blend between the optical zone and the non-optical peripheral stabilization zone that can be optimized for each semi-meridian of the front toric soft contact lens for each individual prescription of the front toric soft contact lens. The smooth surface and thickness profile can be considered as an advantage for comfortable on-eye wear.

[0052] The three-dimensional thickness profile of a prior art front toric soft contact lens with a -3.00DS / -2.50DC x 60 degree axis prescription is shown in Figure 10. It has been found that the prior art methods produce non-circular or elliptical shaped optical zones (1001) that may not provide robust visual performance over the range of pupil diameters that a wearer may experience. Furthermore, the greater the cylinder power to be contained within a toric soft contact lens, the greater the deviation from a circular optical zone. At cylinder powers greater than 3DC, elliptical optical zones can result in significant visual performance issues.

[0053] Unlike the teachings of the prior art, the novel method of designing a front toric soft contact lens offers two distinct advantages: maintaining a circular optical zone (1101) regardless of the magnitude of the cylinder power of the front toric soft contact lens, and smoothly blending the optical zone with a peripheral non-optical stabilization zone for improved on-eye comfort. The three-dimensional thickness profile of a front toric soft contact lens designed at least in part using the method of the present invention is shown in Figure 11. The front toric soft contact lens of Figure 11 has a prescription of -3.00DS / -2.50DC x 60 degree axis.

[0054] Typically, the minimum optical zone diameter for soft contact lenses is about 8 mm, which corresponds to the maximum clinically relevant pupil diameter in scotopic-mesopic lighting conditions. The table below shows the expected change in optical zone diameter, i.e., short axis and long axis, of a prior art front toric soft contact lens with increasing cylinder power. At low cylinder powers, down to about -2.0 DC, the minimum optical zone diameter of 8 mm is maintained. However, at higher cylinder powers, the long axis optical zone diameter encroaches on the periphery of the soft contact lens, which is typically 14 mm in diameter, and therefore the short axis optical zone diameter must be shortened.

[0055] Thus, a prior art front toric soft contact lens having a cylinder power of -4.00 DC, for example, produces a minor axis optical zone diameter of 6.2 mm while maintaining a maximum major axis optical zone diameter of 13.6 mm, which is unacceptably small for visual performance in all lighting conditions. [Table 1]

[0056] In contrast, the novel design method of the present front toric soft contact lens allows the optic zone diameter to be maintained at substantially 8 mm regardless of the amount of cylinder power.

[0057] FIG. 12 shows an example of a vertical thickness profile of a prism-ballasted toric soft contact lens. The dashed line (1201) represents the radius of curvature thickness profile when the lens is designed using conventional anterior or posterior toric design methods. The solid line (1202) represents the radius of curvature thickness profile of the same lens prescription designed by the method of the present invention. It can be seen that the solid line is a smoother contour, maintaining an optical zone diameter of about 8 mm across both semi-meridians. In contrast, the dashed line is more irregular (i.e., undesirable surface relief) and the optical zone diameter is reduced to about 7 mm across this vertical meridian.

[0058] Although the exemplary embodiment of the present invention described in FIG. 12 includes implementing a front toric design using a prism ballast, the present design method of the front toric design can also be configured with various other stabilization techniques discussed in the prior art.

[0059] 13 is a front view of a central near multifocal front toric soft contact lens (1300) comprised of a lens diameter (1301), a substantially circular optic zone (1302), a peripheral non-optically stabilized zone (1303), and a blend zone (1304) between the substantially circular optic zone (1302) and the peripheral non-optically stabilized zone (1303). The blend zone (1304) provides a smooth blend, leading to improved comfort and / or visual performance compared to prior art front toric soft contact lenses.

[0060] The substantially circular optical zone (1302) of the central near multifocal front toric soft contact lens (1300) includes a concentric distance viewing zone (1308), a concentric intermediate viewing zone (1309), a central near viewing zone (1310), a meridian with the smallest radius of curvature, or the meridian with the greatest positive power, or the steep meridian (1306), and a meridian with the longest radius of curvature, or the meridian with the smallest positive power, or the flat meridian (1307). In this embodiment, the orientation of the steep meridian (1306) defines a cylinder axis (1305), which is approximately 60° in this example. The cylinder power of the lens is the power difference between the steep meridian (1306) and the flat meridian (1307). As the cylinder power increases, the size and shape of the substantially circular optical zone (1302) remains substantially the same, providing visual performance independent of the toric prescription.

[0061] FIG. 14 is a cross-sectional view of the optical zone radius of a central near multifocal front toric soft contact lens embodiment of the present invention, illustrating the steps of defining the optical power profile for a selected number of semi-meridians with respect to the optical zone radius of a central near multifocal front toric soft contact lens disclosed herein.

[0062] In FIG. 14, the power profiles of an exemplary central near multifocal front toric soft contact lens for various semi-meridians (1421-1430, etc.) are plotted for individual angles θ as a function of anterior optical zone radius (1407) (i.e., distance from center). Central distance and other power profiles providing multifocality are also envisioned and are considered to be within the scope and spirit of the present invention. In some embodiments, the selected plurality of semi-meridians may be 12-400 semi-meridians, or 10-300 semi-meridians, or 8-240 semi-meridians. In some embodiments of the present invention, the power difference between the least positive semi-meridian (1430) and the most positive semi-meridian (1421), also known as the cylinder power, may be 0.25DC-5DC, 0.5DC-3DC, 0.5DC-6DC, or 1DC-4DC. In other embodiments of the invention, the power difference, also known as cylinder power, between the least positive semi-meridian (1430) and the most positive semi-meridian (1421) may be at least 0.25 DC, at least 1 DC, at least 3 DC, or at least 4 DC.

[0063] The present invention describes a multifocal anterior toric soft contact lens (e.g., FIG. 13) that includes an anterior surface, a posterior surface, a central thickness, anterior and posterior optical zones having multiple semi-meridians and multiple optical power profiles, a peripheral stabilization zone circumscribing the optical zones, a blend zone between the anterior optical zone and the peripheral stabilization zone, and an edge. The multifocal front toric soft contact lens includes: (1) defining a diameter of the multifocal front toric soft contact lens; (2) defining a diameter of the optical zone; (3) defining a width of the blend zone for each semi-meridian; (4) defining a width of the peripheral stabilization zone for each semi-meridian; (5) defining a rotationally symmetric posterior surface of the multifocal front toric soft contact lens; (6) selecting a plurality of semi-meridians to define a multifocal front surface of the contact lens; (7) calculating a power profile along each of the plurality of semi-meridians of the multifocal front toric soft contact lens based on a prescription including a spherical power, a cylindrical power, an add power, a cylindrical axis, and a spherical aberration; (8) selecting a lens material and an appropriate central thickness of the front toric soft contact lens; and (9) calculating a curvature along each of the plurality of semi-meridians in the optical zone to achieve the power profile based on the refractive index of the lens material and the central thickness. (10) calculating a radial or axial thickness profile, where the radius of curvature thickness profile is defined at a plurality of discrete points selected along each of a plurality of semi-meridians in the optical zone; (11) applying a desired thickness profile to each of a plurality of semi-meridians in the peripheral stabilization zone; (12) applying a suitable blending algorithm to combine the optical zone and the peripheral stabilization zone such that the optical zone and the peripheral stabilization zone are substantially smooth along each of a plurality of semi-meridians; (13) applying the thickness profile along each of a plurality of semi-meridians onto the posterior surface to obtain anterior data points; (14) adding edges to the anterior and posterior surface profiles; and (15) converting the anterior and posterior surface data points into a format suitable for manufacturing the anterior and posterior surfaces.

[0064] Use of the present invention allows contact lens manufacturers to design front toric soft contact lenses by adding the calculated thickness profile exemplified in the various embodiments disclosed herein to any base curve, providing the freedom to maintain a circular optical zone, the shape of which is independent of the amount of cylindrical power contained within the front toric soft contact lenses of the present invention. More specifically, one method of the present invention provides a front toric soft contact lens characterized by an essentially circular optical zone.

[0065] In some embodiments, the anterior toric soft contact lens includes an anterior surface, a posterior surface, a central thickness, an optic zone having a power profile, a peripheral stabilization zone circumscribing the optic zone, a blend zone between the optic zone and the peripheral stabilization zone, and an edge. The contact lens includes: (1) defining a diameter of the contact lens; (2) defining a diameter of the optical zone; (3) defining a width of the blend zone; (4) defining a width of the peripheral stabilization zone; (5) defining a rotationally symmetric posterior surface of the contact lens; (6) selecting a plurality of semi-meridians to define a front surface of the contact lens; (7) calculating a power profile along each of the plurality of semi-meridians of the contact lens based on a prescription including a spherical power, a cylindrical power, a cylindrical axis, and a spherical aberration; (8) selecting a lens material and an appropriate central thickness of the contact lens; and (9) calculating a radius of curvature or an axial thickness profile along each of the plurality of semi-meridians in the optical zone to achieve the power profile based on the refractive index and central thickness of the lens material, the radius of curvature or axial thickness profile being selected along each of the plurality of semi-meridians in the optical zone. (10) adding a desired thickness profile to each of a plurality of semi-meridians in the peripheral stabilization zone to provide a prismatic ballast; (11) optimizing a blend zone between the optical zone and the peripheral stabilization zone for each of the plurality of semi-meridians; (12) applying a suitable blending algorithm to blend the optical zone and the peripheral stabilization zone such that the optical zone and the peripheral stabilization zone are substantially smooth along each of the plurality of semi-meridians; (13) adding a thickness profile along each of the plurality of semi-meridians onto the posterior surface to obtain anterior data points; (14) adding edges to the anterior and posterior surface profiles; and (15) converting the anterior and posterior surface data points into a format suitable for manufacturing the anterior and posterior surface profiles.

[0066] In some embodiments, the front toric soft contact lens may be configured such that the shape of the optic zone is substantially circular, which may be independent of the prescription sphere power, cylinder power, cylinder axis, or amount of spherical aberration.

[0067] In some embodiments, a front toric soft contact lens may be constructed such that the toric optical correction of the optical zone of the contact lens has two different target optical powers along two orientations that are not perpendicular to each other.

[0068] In other embodiments, the anterior toric soft contact lens may be defined with a rotationally symmetric posterior surface that may be designed as a single curve aspheric surface or a set of multi-curve aspheric surfaces.

[0069] In another exemplary embodiment, the present front toric soft contact lenses may be defined with a plurality of semi-meridians, the number of which may be between 12 and 400, or between 8 and 240.

[0070] In one embodiment, the front toric soft contact lens may have a spherical power defined on the optical zone that is between -10D and +10D, a cylinder power that is between -0.5DC and -3.5DC, a cylinder axis that is between 0 and 180 degrees, and a spherical aberration that is between -2D and +2D.

[0071] In another embodiment, the front toric soft contact lenses of the present invention are manufactured in a lens material having a refractive index between 1.38 and 1.5. In another embodiment, the front toric soft contact lenses of the present invention have a diameter between 13.5 mm and 15 mm. In another embodiment, the front toric soft contact lenses of the present invention have an optical zone diameter between 6 and 9 mm.

[0072] In another embodiment, the front toric soft contact lens of the present invention is designed with a number of discrete points of a selected density along each of a plurality of semi-meridians, the number of discrete points being at least 100, or at least 1000, or between 32 and 256, or between 256 and 10000.

[0073] In another embodiment, the front toric soft contact lenses of the present invention are defined with a rounded edge, a chisel edge, or a knife edge.

[0074] Some other embodiments are described in the example set below. Example Set A: Front Toric Soft Contact Lenses for Distance Vision Correction

[0075] The front toric soft contact lens includes an anterior surface, a posterior surface, a central thickness, an optic zone having multiple semi-meridians and multiple power profiles, a peripheral stabilization zone circumscribing the optic zone, a blend zone between the optic zone and the peripheral stabilization zone, and an edge. The multifocal front toric soft contact lens comprises: (1) defining a diameter of the front toric soft contact lens; (2) defining a diameter of the optical zone; (3) defining a width for a blend zone for each semi-meridian; (4) defining a width for a peripheral stabilization zone for each semi-meridian; (5) defining a rotationally symmetric posterior surface of the multifocal front toric soft contact lens; (6) selecting a plurality of semi-meridians to define a multifocal front surface of the contact lens; (7) calculating a power profile along each of the plurality of semi-meridians of the multifocal front toric soft contact lens based on a prescription including a spherical power, a cylindrical power, a cylindrical axis, and a spherical aberration; (8) selecting a lens material and an appropriate central thickness for the front toric soft contact lens; and (9) selecting a lens material and a suitable central thickness for the front toric soft contact lens at each of the plurality of semi-meridians in the optical zone to achieve the power profile based on the refractive index of the lens material and the central thickness. (10) calculating a radius of curvature or axial thickness profile along each of a plurality of semi-meridians in the optical zone, the radius of curvature thickness profile being defined at a plurality of discrete points selected along each of a plurality of semi-meridians in the peripheral stabilization zone; (11) applying a desired thickness profile to each of a plurality of semi-meridians in the peripheral stabilization zone; (12) optimizing a blend width between the optical zone and the peripheral stabilization zone for each of the plurality of semi-meridians; (13) applying the thickness profile along each of the plurality of semi-meridians onto the posterior surface to obtain anterior data points; (14) adding edges to the anterior and posterior surface profiles; and (15) converting the anterior and posterior surface data points into a format suitable for manufacturing the anterior and posterior surfaces.

[0076] The front toric soft contact lens of claim 1 of Example Set A, wherein the optical power profile along each of the plurality of semi-meridians provides the front toric soft contact lens for correcting distance vision.

[0077] The front toric soft contact lens of claim 1 in Example Set A, wherein the shape of the optic zone is substantially circular, said shape being independent of the prescription sphere power, cylinder power, add power, cylinder axis, or magnitude of spherical aberration.

[0078] The anterior toric soft contact lens of claim 1 of embodiment set A, wherein the rotationally symmetric posterior surface is designed as a single curved aspheric surface.

[0079] The front toric soft contact lens of claim 1 of embodiment set A, wherein the rotationally symmetric posterior surface is designed as a set of multi-curved aspheric surfaces.

[0080] The front toric soft contact lens of claim 1 of Example Set A, wherein the number of the plurality of semi-meridians is 12 to 400.

[0081] The front toric soft contact lens of claim 1 of Example Set A, wherein the number of the plurality of semi-meridians is 8 to 240.

[0082] The front toric soft contact lens of claim 1 of embodiment set A, wherein the spherical power defined on the optical zone is -10D to +10D, the cylindrical power is -0.5DC to -3.5DC, the cylindrical axis is 0 to 180 degrees, and the spherical aberration is -2D to +2D.

[0083] The front toric soft contact lens of claim 1 of Example Set A, wherein the refractive index of the lens material is 1.38 to 1.5.

[0084] The front toric soft contact lens of claim 1 of Example Set A, the diameter of the lens is 13.5 mm to 15 mm.

[0085] The front toric soft contact lens of claim 1 of Example Set A, wherein the circular optic zone diameter is 6-9 mm.

[0086] The front toric soft contact lens of claim 1 in embodiment set A, wherein the number of the plurality of discrete points of selected density along each of the plurality of semi-meridians is at least 100.

[0087] The front surface toric soft contact lens of claim 1 of embodiment set A, wherein the number of the plurality of discrete points of selected density along each of the plurality of semi-meridians is between 32 and 256.

[0088] The front toric soft contact lens of claim 1 in embodiment set A, wherein the number of the plurality of discrete points of selected density along each of the plurality of semi-meridians is 256-10,000.

[0089] The front toric soft contact lens of claim 1 of embodiment set A, wherein the edge is defined as a round edge.

[0090] The front toric soft contact lens of claim 1 in embodiment set A, wherein the edge is defined as a chisel edge.

[0091] The front toric soft contact lens of claim 1 of embodiment set A, wherein the edge is defined as a knife edge.

[0092] The front toric soft contact lens of claim 1 of Example Set A, wherein an axial thickness profile along each of a plurality of semi-meridians within the optical zone is used to achieve a refractive index profile. Example Set B: Multifocal anterior toric soft contact lenses

[0093] The multifocal anterior toric soft contact lens includes a front surface, a posterior surface, a central thickness, a front optical zone having multiple semi-meridians and multiple optical power profiles, a peripheral stabilization zone circumscribing the optical zone, a blend zone between the front optical zone and the peripheral stabilization zone, and an edge. The multifocal front toric soft contact lens includes: (1) defining a diameter of the multifocal front toric soft contact lens; (2) defining a diameter of the optical zone; (3) defining a width for a blend zone of each of a plurality of semi-meridians; (4) defining a width for a peripheral stabilization zone of each of the semi-meridians; (5) defining a rotationally symmetric posterior surface of the multifocal front toric soft contact lens; (6) selecting a plurality of semi-meridians to define a multifocal anterior surface of the contact lens; (7) calculating a power profile along each of a plurality of semi-meridians of the multifocal front toric soft contact lens based on a prescription including a spherical power, a cylindrical power, an add power, a cylindrical axis, and a spherical aberration; (8) selecting a lens material and an appropriate central thickness for the front toric soft contact lens; and (9) selecting a diameter of each of a plurality of semi-meridians in the optical zone to achieve the power profile based on the refractive index of the lens material and the central thickness. The method is configured using an algorithmic design method including, at least in part, a series of design steps: calculating a radius of curvature or axial thickness profile along a semi-meridian, the radius of curvature thickness profile being defined at a plurality of discrete points selected along each of a plurality of semi-meridians in the optical zone; (10) adding a desired thickness profile to each of a plurality of semi-meridians in the peripheral stabilization zone; (11) optimizing a blending zone between the optical zone and the peripheral stabilization zone for each of the plurality of semi-meridians; (12) applying a suitable blending algorithm to blend the optical zone and the peripheral stabilization zone substantially smoothly along each of the plurality of semi-meridians; (13) adding the thickness profile along each of the plurality of semi-meridians onto the posterior surface to obtain anterior data points; (14) adding edges to the anterior and posterior surface profiles; and (15) converting the anterior and posterior surface data points into a format suitable for manufacturing the anterior and posterior surfaces.

[0094] The multifocal front toric soft contact lens of claim 1 of embodiment set B, wherein the optical power profile along a plurality of semi-meridians results in a central near multifocal front toric soft contact lens.

[0095] The multifocal front toric soft contact lens of claim 1 of embodiment set B, wherein the optical power profile along a plurality of semi-meridians results in a central distance multifocal front toric soft contact lens.

[0096] A multifocal front toric soft contact lens according to one or more claims of Example Set B, wherein the shape of the optic zone is substantially circular, said shape being independent of the prescription sphere power, cylinder power, add power, cylinder axis, or magnitude of spherical aberration.

[0097] The multifocal anterior toric soft contact lens of one or more of the claims in Example Set B, wherein the rotationally symmetric posterior surface is designed as a single curved aspheric surface.

[0098] The multifocal anterior toric soft contact lens of one or more of the claims in embodiment set B, wherein the rotationally symmetric posterior surface is designed as a set of multi-curved aspheric surfaces.

[0099] The multifocal front toric soft contact lens of one or more claims of Example Set B, wherein the number of the plurality of semi-meridians is between 12 and 400.

[0100] The multifocal front toric soft contact lens of one or more of the claims in Example Set B, wherein the number of the plurality of semi-meridians is between 8 and 240.

[0101] A multifocal front toric soft contact lens according to one or more of the claims in Example Set B, wherein the spherical power defined on the optical zone is -10D to +10D, the cylindrical power is -0.5DC to -3.5DC, the cylindrical axis is 0 to 180 degrees, the add power is +0.5 to +3.5D, and the spherical aberration is -2D to +2D.

[0102] The multifocal anterior toric soft contact lens of one or more claims of Example Set B, wherein the refractive index of the lens material is between 1.38 and 1.5.

[0103] A multifocal anterior toric soft contact lens according to one or more claims of Example Set B, wherein the lens has a diameter between 13.5mm and 15mm.

[0104] The multifocal anterior toric soft contact lens of one or more of the claims in Example Set B, wherein the circular optic zone diameter is between 6 and 9 mm.

[0105] The multifocal anterior toric soft contact lens of one or more of the claims in Example Set B, wherein the number of the plurality of discrete points of selected density along each of the plurality of semi-meridians is at least 100.

[0106] The multifocal anterior toric soft contact lens of one or more of the claims in Example Set B, wherein the number of the plurality of discrete points of selected density along each of the plurality of semi-meridians is between 32 and 256.

[0107] The multifocal anterior toric soft contact lens of one or more of the claims in Example Set B, wherein the number of the plurality of discrete points of selected density along each of the plurality of semi-meridians is between 256 and 10,000.

[0108] The multifocal front toric soft contact lens of one or more of the claims in Example Set B, wherein the edge is defined as a round edge.

[0109] The multifocal front toric soft contact lens of one or more of the claims in Example Set B, wherein the edge is defined as a chisel edge.

[0110] The multifocal anterior toric soft contact lens of one or more of the claims in Example Set B, wherein the edge is defined as a knife edge.

[0111] A multifocal front toric soft contact lens of one or more of the claims in Example Set B, wherein an axial thickness profile along each of a plurality of semi-meridians within the optical zone is used to achieve a refractive index profile.

Claims

1. 1. A front toric soft contact lens comprising: an anterior surface, a posterior surface, a front optical zone having a central thickness, a plurality of semi-meridians and a plurality of optical power profiles, a peripheral stabilization zone circumscribing said optical zone, a blend zone between said anterior optical zone and said peripheral stabilization zone, and an edge, (1) defining the diameter of the front toric soft contact lens; (2) defining a diameter of the optical zone; (3) defining a width for the blending zone for each semi-meridian; (4) defining a width for the peripheral stabilization zone of each semi-meridian; and (5) defining a rotationally symmetric posterior surface of said anterior toric soft contact lens; (6) selecting a plurality of semi-meridians to define the anterior surface of the contact lens; (7) calculating a power profile along each of the semi-meridians of the front toric soft contact lens based on a prescription including a spherical power, a cylindrical power, a cylindrical axis, and a spherical aberration; (8) selecting a lens material and an appropriate center thickness of said front toric soft contact lens; (9) calculating a radius of curvature thickness profile or an axial thickness profile along the semi-meridians within the optical zone to achieve the optical power profile based on the refractive index of the lens material and the central thickness, the radius of curvature thickness profile being defined at a plurality of discrete points selected along each of the semi-meridians within the optical zone; (10) applying a desired thickness profile to each of the plurality of semi-meridians within the peripheral stabilization zone; and (11) optimizing the blend width between the optical zone and the peripheral stabilization zone for each of the plurality of semi-meridians; and (12) applying a suitable blending algorithm to blend the optical zone and the peripheral zone substantially smoothly along each of the plurality of semi-meridians; and (13) applying the thickness profile along each of the plurality of semi-meridians onto the posterior surface to obtain the anterior surface data points; (14) adding edges to the front profile and the back profile; (15) converting the front surface data points and the back surface data points into a format suitable for manufacturing the front surface and the back surface. The design method is configured using an algorithm that at least partially includes a series of design steps: Front toric soft contact lens.

2. the shape of the optical zone is substantially circular; the shape is independent of the magnitude of the prescription's sphere power, cylinder power, cylinder axis, or spherical aberration; 2. The front toric soft contact lens of claim 1.

3. The rotationally symmetric rear surface is designed as a single curved aspheric surface. The front toric soft contact lens according to one or more of claims 1-2.

4. The rotationally symmetric rear surface is designed as a set of multi-curved aspheric surfaces. The front toric soft contact lens according to one or more of claims 1-2.

5. the number of the plurality of semi-meridians is between 12 and 400; A front toric soft contact lens according to one or more of claims 1 to 4.

6. the number of the plurality of semi-meridians is between 8 and 240; A front toric soft contact lens according to one or more of claims 1 to 4.

7. the spherical power defined on the optical zone is between -10D and +10D, the cylinder power is between -0.5DC and -3.5DC, the cylinder axis is between 0 and 180 degrees, and the spherical aberration is between -2D and +2D; The front toric soft contact lens according to one or more of claims 1 to 6.

8. The refractive index of the lens material is 1.38 to 1.

5. A front toric soft contact lens according to one or more of claims 1 to 7.

9. the diameter of the lens is between 13.5 mm and 15 mm; The front toric soft contact lens according to one or more of claims 1 to 8.

10. The circular optical zone diameter is 6-9 mm. The front toric soft contact lens according to one or more of claims 1 to 9.

11. the number of the plurality of discrete points of the density selected along each of the plurality of semi-meridians is at least 100; A front toric soft contact lens according to one or more of claims 1 to 10.

12. the number of the plurality of discrete points of the density selected along each of the plurality of semi-meridians is between 32 and 256; The front toric soft contact lens according to one or more of claims 1 to 11.

13. the number of the plurality of discrete points of the density selected along each of the plurality of semi-meridians is between 256 and 10,000; The front toric soft contact lens according to one or more of claims 1 to 11.

14. The edge is defined as a rounded edge. The front toric soft contact lens according to one or more of claims 1 to 13.

15. The edge is defined as a chisel edge. The front toric soft contact lens according to one or more of claims 1 to 13.

16. The edge is defined as a knife edge. The front toric soft contact lens according to one or more of claims 1 to 13.

17. the axial thickness profile along each of the plurality of semi-meridians within the optical zone is used to achieve the optical power profile; The front toric soft contact lens according to one or more of claims 1 to 16.

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