Toric contact lenses employing stabilization mechanism to minimize effect of asymmetric eyelid deviations in fixed orientation and related design methods

Abstract

A toric contact lens employing a stabilization mechanism to minimize the effect of asymmetric eyelid deviations on a fixed orientation of the toric contact lens and related design methods. The toric contact lens includes stabilizing regions each disposed on a horizontal side of a lens perimeter of the contact lens between a central optical region of the contact lens and a lens rim. To minimize the effect of asymmetric deviation of the patient wearer's eyelid on alignment of the toric contact lens with the major meridian of the eye, the portion of the contour line in the stabilization region configured to intersect the upper eyelid edge when worn is oriented to a target upper eyelid edge shape of a target upper eyelid of a normal patient wearer. In this manner, the stable region of the toric contact lens is more desensitized to any asymmetric shape of the wearer's eyelid.

Description

Field of the Invention

[0001] The present disclosure relates to the field of ophthalmic lenses for astigmatic patients. More specifically, the present disclosure relates to toric contact lenses that include a stabilization mechanism to maintain the contact lens relatively stable in the eye, thereby maintaining the alignment of the corrective optical power in the lens along two principal meridians. Background of the Invention

[0002] Common conditions that result in decreased visual acuity include myopia (i.e., nearsightedness) and hyperopia (i.e., farsightedness), for which corrective lenses in the form of glasses or rigid or soft contact lenses are required. These conditions are generally described as an imbalance between the length of the eye and the focusing of the optical elements of the eye. Myopic eyes focus light in front of the retinal plane and hyperopic eyes focus light behind the retinal plane. Myopia typically develops because the axial length of the eye grows longer than the focal length of the optical components of the eye; i.e., the eye grows too long. Hyperopia typically develops because the axial length of the eye is too short relative to the focal length of the optical components of the eye. Patients suffering from these conditions can correct their vision with spherical contact lenses having an appropriate lens spherical optical power.

[0003] Astigmatism is an optical or refractive defect in which an individual's vision is blurred because the eye is unable to focus a point target into a focused image on the retina. Astigmatism is caused by a non-rotationally symmetric curvature of the refractive surfaces of the eye, including the cornea and the lens. For example, Figure 1A FIG. shows an astigmatic eye 100 that includes a cornea 102 that is steeper in one direction than in another direction, such that the refractive surface of the cornea 102 is not rotationally symmetric. In other words, one or more of the refractive surfaces of the cornea 102 are more curved or steeper along a principal meridian relative to another orthogonal principal meridian, thereby having different amounts of optical power and wavefront aberrations along different meridians. This causes the image 104 to stretch into a double-line focus 106 rather than focusing to a single point. Figure 1B The non-astigmatic eye 108 shown has a cornea 110 that has a rotationally symmetric refractive surface, such that the image 112 focuses to a single point 114.

[0004] Hard or rigid gas permeable contact lenses can be used to correct corneal astigmatism. In such cases, a fluid or tear lens may be present between the posterior surface of the rigid contact lens and the cornea. This fluid or tear lens conforms to or assumes the shape of the back surface of the contact lens. In other words, since the refractive index of the fluid or tear lens almost matches that of the cornea, the corneal scatter rate can be optically canceled or reduced. In these cases, a toric lens will usually not be required. However, rigid gas permeable contact lenses and hard contact lenses are generally less comfortable than soft or hydrogel contact lenses. Since soft or hydrogel contact lenses wrap around the cornea, there is usually no fluid lens and the tear is more closely analogous to a film. In this case, a toric lens design is required.

[0005] A toric lens is an optical element that has two different optical powers in two orientations perpendicular to each other. In essence, a toric lens has a spherical surface with one optical power for correcting myopia or hyperopia and a cylindrical surface with one optical power for correcting astigmatism built into a single lens. These optical powers are created using curvatures that are preferably maintained relative to the eye in different angular orientations. Toric lenses can be used in glasses, intraocular lenses, and contact lenses. The toric lens used in glasses or intraocular lenses is held fixed relative to the eye by the spectacle frame or haptics, thus always providing optimal vision correction. However, toric contact lenses tend to rotate on the eye, thus temporarily providing sub-optimal vision correction. Therefore, toric contact lenses also include means for relatively stably holding the contact lens on the eye when the wearer blinks or looks around. A toric contact lens needs to accomplish two things, namely, rotate into the proper orientation in the eye upon insertion and maintain that orientation during wear.

[0006] The maintenance of the orientation of a toric contact lens on the eye is usually accomplished by mechanical means. For example, "prism stabilization", including decentration or tilting of the anterior surface of the contact lens relative to the back surface, thickening of the lower contact lens periphery, formation of depressions or protrusions on the contact lens surface, and truncation of the contact lens edge are methods that have been used.

[0007] In addition, "static stabilization" has been used, in which a contact lens is stabilized by using a "stabilization" zone. The stabilization zone is an area at the periphery of the contact lens having a thickness distribution in which the thickness increases or decreases as the case may be. Generally, the stabilization zone is located in the periphery of the contact lens and is symmetric about the vertical axis and / or the horizontal axis. For example, the stabilization zone may include an effective zone as a stabilization point, the stabilization point including a thickness gradient and being positioned at a central position on either side of the optical zone and centered along the 0-180 degree axis of the contact lens, as shown, for example, in U.S. Patent No. 11,281,024. In another example, a single thick stabilization zone located at the bottom of the contact lens may be designed, the single thick stabilization zone providing a weight effect similar to prism stabilization, but also incorporating an area of increasing thickness from top to bottom in order to utilize the upper eyelid force to stabilize the contact lens. It is important to note that earlier technical literature utilized the term "dynamic stabilization" to denote what is referred to here as static stabilization. The terms static stabilization and dynamic stabilization may be used interchangeably.

[0008] Thus, when designing the shape of a toric contact lens having a stabilization zone, the thickness distribution of the stabilization zone and its effective zone may be based on the patient's eyelids being in contact with the stabilization zone to force the rotational orientation and stabilization of the toric contact lens. This is shown in Figure 2 the model eye 200. As Figure 2 shown, the patient's eye 200 is fitted with a toric contact lens 202. The upper eyelid 204 and lower eyelid 206 of the eye 202, and more specifically their respective upper eyelid edges 208 and lower eyelid edges 210, will contact the contact lens 202 as a function of the movement of the upper eyelid 204 and lower eyelid 206. Depending on the gradient of the stabilization zones 212, 214 as a function of the movement or blink of the upper eyelid 204 and / or lower eyelid 206, the eyelids 204, 206 will encounter an area of increasing thickness in the stabilization zones 212, 214 (e.g., in their effective zones) of the toric contact lens 202. As the eyelids 204, 206 move between different effective zones of the stabilization zones 212, 214 of the toric contact lens 202 where the thickness decreases to where the thickness increases (as shown by the arrow directions in Figure 2 ), the resistance between the eyelids 204, 206 to the toric contact lens 202 increases. The pressure imbalance between the lens 202 and the effective zones in the stabilization zones 212, 214 on the peripheral region of the lens 202 causes the lens 202 to orient itself relative to the eyelid edges 208, 210 of the eye 200 in which the lens 202 is present. The orientation of the toric contact lens 202 will track (i.e., register with) the shape of the eyelid edges 208, 210 and follow their shape because the rotational alignment of the toric contact lens 202 is driven by the shape of the eyelids 204, 206 through the stabilization zones 212, 214.

[0009] However, the shapes of the eyelids 204, 206 and their eyelid margins 208, 210 can vary widely between different patients. For example, some eyelids slope downward on the nasal side while others slope downward temporally. In either of these cases, if the eye is astigmatic, the eyelid margin is asymmetric with respect to the eye and its principal meridians. If the eyelid margin is asymmetric with respect to its eye, a toric contact lens having a stable zone presented to such an eye will also have a tilt / rotation with an asymmetric deviation from symmetric alignment on the eye. This causes the corrective power in the toric contact lens to be misaligned with one or both of the principal meridians of the eye. In a toric contact lens, alignment of the corrective powers for the two principal meridians of the eye with the principal meridians of the eye is important for correcting astigmatic vision.

[0010] An example of a toric contact lens that includes a stable zone to provide rotational stability in the eye is found in U.S. Patent No. 11,327,341B2 to Straker. Straker discloses a toric contact lens that includes a stable zone where the contour line of the effective zone is designed to be parallel to the eyelid margin such that the thickness gradient of the stable zone is substantially orthogonal to the eyelid margin. SUMMARY

[0011] Aspects disclosed herein include a toric contact lens that employs a stabilization mechanism to minimize the effect of asymmetric eyelid deviation on the fixed orientation of the toric contact lens. Related design methods for such toric contact lenses are also disclosed. The toric contact lens is designed to correct the vision of an astigmatic eye that has a spherical power correction requirement for correcting refractive error and a cylindrical power correction requirement for correcting astigmatism. The toric contact lens includes a stable zone that is each disposed on a horizontal side of the lens periphery of the contact lens between the central optical zone of the contact lens and the lens edge. Each stable zone has a thickness distribution that defines a plurality of contour lines, each contour line having a varying thickness between a first front surface of the contact lens and a second back surface of the contact lens. The stable zones are designed to contact the eyelid margins of the patient wearer's eyelids. As the eyelid moves from a decreasing thickness to an increasing thickness across the stable zone, the eyelid experiences an increasing force and pressure. This contact and the pressure generated between the eyelid and the stable zone force the rotational orientation of the contact lens to be oriented to the principal meridians of the eye at insertion and to maintain that orientation during wear. Ideally, the rotational orientation of the toric contact lens is aligned with the principal meridians of the eye. However, the shapes and asymmetries of the eyelids and eyelid margins of the patient wearer can vary widely between different patients. Since the stable zones track the shapes of the asymmetrically shaped eyelids and eyelid margins, this can result in misalignment of the toric contact lens with the principal meridians of the eye.

[0012] Thus, in an exemplary aspect, to minimize the effect of the asymmetric deviation of the eyelids of a patient wearer on the alignment of the toric contact lens with the principal meridians of the eye, the portion of the contour line in the stabilization zone that is configured to intersect the eyelid margin of the patient wearer is oriented to the target eyelid margin shape of the target eyelid of a typical patient wearer. For example, this can be achieved by compressing the intersecting portion of the contour line in the stabilization zone to be less concentric with the circumference of the lens. In one example, the first designated contour line in the stabilization zone is configured to be substantially contained within the open-eye rest boundary of the target eyelid margin and is provided at a thickness between approximately 73% - 80% of the meridional thickness difference (i.e., the difference between the horizontal meridional thickness and the vertical meridional thickness). The thickness of the first designated contour line in the stabilization zone within the aforementioned thickness range of the meridional thickness difference has been found to still allow the orientation and stabilization of the toric contact lens to be affected by the eyelids of the wearer, whose eyelids can have an asymmetric shape for rotational orientation, but not to be overly affected by the asymmetry of the wearer's eyelid shape. This is because, when the first designated contour line in the stabilization zone is configured to be substantially contained within the open-eye rest boundary of the target eyelid margin during wear, the orientation of the toric contact lens can be mainly affected by the lower and / or upper points on either side of the corresponding asymmetrically shaped upper eyelid and / or lower eyelid of the patient wearer. This can avoid or reduce the over-rotation of the toric contact lens beyond the horizontal meridian alignment due to the asymmetric shape of the eyelid and its eyelid margin. This is because the first designated contour line in the stabilization zone is oriented to be substantially contained within the open-eye rest boundary of the target eyelid margin during wear, which can reduce the pressure imbalance between the two sides of the eyelid in contact with the corresponding stabilization zone in the lens. In this way, the stabilization zone of the toric contact lens is more desensitized to any asymmetric shape of the wearer's eyelid.

[0013] In other exemplary aspects, each stabilizing zone has an effective zone that includes a portion of the contour lines that define the thickness gradient of the stabilizing zone. The effective zone is designed such that the eyelid edges of the patient wearer's eyelids are configured to move across the effective zone during wear and encounter the thickness gradient of the stabilizing zone to rotationally orient the toric contact lens. This portion of the contour lines within the effective zone can be shaped to be less concentric with the circumference of the lens to more closely approximate the shape of the target eyelid edge presented to the effective zone. This can also provide enhanced tracking and registration of the contact lens orientation to the shape of the eyelid edges of the patient wearer's eyelids. In still other exemplary aspects, the thickness gradient of the effective zone can also be designed to be substantially orthogonal to the target eyelid edge shape of the eyelid intended to contact the effective zone. This can provide an optimized influence of the forces and resulting pressures from the interaction of the eyelid edges of the patient wearer with the toric contact lens to affect rotation and stabilization, while minimizing the interaction between the eyelid edges and the effective zone of the stabilizing zone to minimize the effect of asymmetric deviations of the patient wearer's eyelid shape.

[0014] In this regard, in an exemplary aspect, a toric contact lens is disclosed. The toric contact lens includes a first surface and a second surface opposite the first surface, the toric contact lens having a horizontal thickness difference between the first surface and the second surface along a horizontal central axis, and a vertical thickness difference between the first surface and the second surface along a vertical central axis orthogonal to the horizontal central axis. The toric contact lens further includes: an optical zone disposed around an optical axis intersecting the horizontal central axis and the vertical central axis, and a lens periphery surrounding the optical zone and extending between the optical zone and the lens edge. The lens periphery includes: a first stabilization zone on a first side of the lens periphery between the optical zone and the lens edge, the first stabilization zone having a first thickness distribution including a plurality of first contour lines, each of the plurality of first contour lines having a varying thickness between the first surface and the second surface; and a second stabilization zone on a second side of the lens periphery opposite the first side, the second stabilization zone between the optical zone and the lens edge, the second stabilization zone having a second thickness distribution including a plurality of second contour lines, each of the plurality of second contour lines having a varying thickness between the first surface and the second surface. Wherein, a first contour line among the plurality of first contour lines is oriented to a target upper eyelid edge shape of an average patient wearer, the first contour line among the plurality of first contour lines is configured to be substantially contained within a stationary boundary of the target upper eyelid edge, having a first thickness between approximately 73% and 80% of a meridian thickness difference that is a difference between the horizontal thickness difference and the vertical thickness difference, and a second contour line among the plurality of second contour lines is oriented to the target upper eyelid edge shape, the second contour line among the plurality of second contour lines is configured to be substantially contained within the stationary boundary of the target upper eyelid edge, having a second thickness between approximately 73% and 80% of the meridian thickness difference.

[0015] In another exemplary aspect, a method of manufacturing a toric contact lens is disclosed. The method includes forming a lens from a volume of lens material, the lens including a first surface and a second surface opposite the first surface; the lens having a horizontal thickness difference between the first surface and the second surface along a horizontal central axis, and a vertical thickness difference between the first surface and the second surface along a vertical central axis orthogonal to the horizontal central axis. The method of manufacturing a toric contact lens further includes: an optical zone disposed about an optical axis that intersects the horizontal central axis and the vertical central axis, and a lens periphery that surrounds the optical zone and extends between the optical zone and the lens edge; the lens periphery including: a first stabilization zone on a first side of the lens periphery between the optical zone and the lens edge, the first stabilization zone having a first thickness distribution that includes a plurality of first contour lines, each of the plurality of first contour lines having a varying thickness between the first surface and the second surface; and a second stabilization zone on a second side of the lens periphery opposite the first side, the second stabilization zone being between the optical zone and the lens edge, the second stabilization zone having a second thickness distribution that includes a plurality of second contour lines, each of the plurality of second contour lines having a varying thickness between the first surface and the second surface. Wherein, a first contour line of the plurality of first contour lines is oriented to a target upper eyelid edge shape of a typical patient wearer, the first contour line of the plurality of first contour lines is configured to be substantially contained within a stationary boundary of the target upper eyelid edge, having a first thickness between approximately 73% - 80% of a meridional thickness difference that is the difference between the horizontal thickness difference and the vertical thickness difference, and a second contour line of the plurality of second contour lines is oriented to the target upper eyelid edge shape, the second contour line of the plurality of second contour lines is configured to be substantially contained within the stationary boundary of the target upper eyelid edge, having a second thickness between approximately 73% - 80% of the meridional thickness difference.

[0016] Additional features and advantages will be set forth in the detailed description which follows, and in part will be obvious to those skilled in the art from that description, or may be learned by practice of the aspects as described in the written description and its claims and the drawings.

[0017] It should be understood that the foregoing general description and the following detailed description are both exemplary and intended to provide an overview or framework for understanding the nature and characteristics of the claims.

[0018] The drawings are included to provide a further understanding, and are incorporated into and constitute a part of this specification. The drawings illustrate one or more aspects and, together with the description, serve to explain the principles and operations of the various aspects. Description of the Drawings

[0019] The above and other features and advantages of the present disclosure will become apparent from the following more particular description of the preferred embodiments of the present disclosure as illustrated in the accompanying drawings.

[0020] Figure 1A and Figure 1B are schematic views of a normal eye and an astigmatic eye, respectively;

[0021] Figure 2 shows a model eye fitted with a toric contact lens having a stabilization zone configured to engage the eyelids of the eye to orient the toric contact lens relative to the principal meridians of the eye;

[0022] Figure 3 shows eyelid shape data of the upper and lower eyelids of the right eye, where each line is a polynomial fit to a series of points traced along a photograph of the eyelid margin, with the eye in a first medium;

[0023] Figure 4A and Figure 4B show the full-thickness distribution and local thickness distribution of an exemplary toric contact lens, the exemplary toric contact lens showing a stabilization zone having a varying thickness on each side of the optical zone of the lens with respect to the vertical meridian, where the stabilization zone includes an effective zone having a contour line oriented to the target eyelid margin shape of the target eyelid of a typical patient wearer or an improved stabilization in a wearer with asymmetric eyelids;

[0024] Figure 5A and Figure 5B are side-by-side diagrams of the local thickness distribution plots in Figure 4B and Figure 4B respectively;

[0025] Figure 6 is a graph showing an exemplary thickness distribution along the vertical central axis of the toric contact lens in Figure 4A compared to the toric contact lens in Figure 5B where the toric contact lens includes a stabilization zone including an effective zone having a contour line oriented to the target eyelid margin shape of the target eyelid of a typical patient wearer or an improved stabilization in a wearer with asymmetric eyelids;

[0026] Figure 7 shows a drawing of an exemplary design image covered with an initial cap-shaped polynomial;

[0027] Figure 8 shows drawings for the upper and lower eyelids respectively, showing that the average eyelid margin shape is obtained by taking the median of all polynomials at intervals of one millimeter along the X-axis, and the shape has been centered at the origin;

[0028] Figure 9 shows the left and right “flipped” and “non - flipped” eyelid shape data plotted together on the same axis;

[0029] Figure 10 shows the average values of the “flipped” and “non - flipped” eyelid shape data, whereby the average value of the Y - axis value for each is taken at intervals of every millimeter;

[0030] Figure 11 shows the top - down “flipped” and “non - flipped” eyelid shape data plotted together on the same axis; and

[0031] Figure 12A and Figure 12B is a flow chart showing an exemplary process for designing a toric contact lens having a stabilization zone, the stabilization zones each having a varying thickness on each side of the optical zone of the lens with respect to the vertical meridian, wherein the stabilization zone includes an effective zone having a contour line that is oriented to the target eyelid edge shape of the target eyelid of an average patient wearer or improved stabilization in wearers with asymmetric eyelids, the toric contact lens including but not limited to Figure 4A and Figure 4B the toric contact lenses in. DETAILED DESCRIPTION

[0032] Aspects disclosed herein include toric contact lenses that employ a stabilization mechanism to minimize the effect of asymmetric eyelid deviation on the rotational orientation of the toric contact lens. Related design methods for such toric contact lenses are also disclosed. The toric contact lens is designed to correct the vision of an astigmatic eye that has a spherical power correction requirement for correcting refractive error and a cylindrical power correction requirement for correcting astigmatism. The toric contact lens includes stabilization zones that are each disposed on a horizontal side of the lens periphery of the contact lens between the central optical zone of the contact lens and the lens edge. The stabilization zones each have a thickness distribution that defines a plurality of contour lines, each contour line having a varying thickness between a first front surface of the contact lens and a second back surface of the contact lens. The stabilization zones are designed to contact the eyelid edge of the eyelid of a patient wearer. As the eyelid moves from a decreasing thickness to an increasing thickness across the stabilization zone, the eyelid experiences increasing force and pressure. This contact and the pressure generated between the eyelid and the stabilization zone force the rotational orientation of the contact lens to be oriented to the principal meridian of the eye upon insertion and to maintain that orientation during wear. Ideally, the rotational orientation of the toric contact lens is aligned with the principal meridian of the eye. However, the shape variations and asymmetries of the eyelids and eyelid edges of patient wearers can vary widely between different patients. Since the stabilization zones track the shape of the asymmetrically shaped eyelids and eyelid edges, this can lead to misalignment of the toric contact lens with the principal meridian of the eye.

[0033] Thus, in an exemplary aspect, to minimize the effect of the asymmetric deviation of the eyelids of a patient wearer on the alignment of the toric contact lens with the principal meridians of the eye, the portion of the contour line in the stabilization zone that is configured to intersect the eyelid margin of the patient wearer is oriented to the target eyelid margin shape of the target eyelid of an average patient wearer. For example, this can be achieved by compressing the intersecting portion of the contour line in the stabilization zone to be less concentric with the circumference of the lens. In one example, the first specified contour line in the stabilization zone is configured to be substantially contained within the open-eye rest boundary of the target eyelid margin and is provided at a thickness between approximately 73% - 80% of the meridional thickness difference (i.e., the difference between the horizontal meridional thickness and the vertical meridional thickness). The thickness of the first specified contour line in the stabilization zone within the aforementioned thickness range of the meridional thickness difference has been found to still allow the orientation and stabilization of the toric contact lens to be affected by the wearer's eyelids, which may have an asymmetric shape for rotational orientation, but not be overly affected by the asymmetry of the wearer's eyelid shape. This is because, when the first specified contour line in the stabilization zone is configured to be substantially contained within the open-eye rest boundary of the target eyelid margin during wear, the orientation of the toric contact lens can be mainly affected by the lower and / or upper points on either side of the corresponding asymmetric-shaped upper eyelid and / or lower eyelid of the patient wearer. This can avoid or reduce the over-rotation of the toric contact lens beyond the horizontal meridian alignment due to the asymmetric shape of the eyelid and its eyelid margin. This is because the first specified contour line in the stabilization zone is oriented to be substantially contained within the open-eye rest boundary of the target eyelid margin during wear, which can reduce the pressure imbalance between the two sides of the eyelid in contact with the corresponding stabilization zone in the lens. In this way, the stabilization zone of the toric contact lens is more desensitized to any asymmetric shape of the wearer's eyelid.

[0034] In this regard, to illustrate the variation and potential asymmetry of the eyelid margin shape among groups, Figure 3 . Figure 3 FIG. 300 is a diagram showing eyelid shape data 302, 304 for a population of the corresponding upper and lower eyelids of the right eye. The eyelid shape data 302, 304 are shown as corresponding multiple lines 306, 308, which show the shape of the eyelid margins of the population of the upper and lower eyelids. Each line 306, 308 is a second-order polynomial fit to a series of points traced along a photograph of the eyelid margin, where the eye is in a first gaze. As Figure 3As shown, according to lines 306, 308 corresponding to eyelid shape data 302, 304, the shape of the eyelid margin can vary greatly among different individuals in a population. For example, some eyelid margin shapes slope downward on the nasal side due to the corresponding eyelid sloping downward on the nasal side, while other eyelid margin shapes slope downward temporarily. In either of these cases, if the eye has astigmatism, the eyelid margin is asymmetric with respect to the eye and its principal meridians, such as the vertical meridian 310 and the horizontal meridian 312. If the eyelid margin is asymmetric with respect to its eye, a toric contact lens having a stable region presented to such an eye will also have an inclination / rotation with an asymmetric deviation from the symmetric alignment on the eye with respect to the vertical meridian 310 and / or the horizontal meridian 312. This causes the corrective optical power in the toric contact lens to be misaligned with one or both of the principal meridians of the eye. In a toric contact lens, it is important for the corrective optical power for the two principal meridians of the eye to be aligned with the principal meridians of the eye for correcting astigmatic vision.

[0035] To provide a toric contact lens that can orient itself to be substantially aligned with the principal meridians of the worn eye, even if the worn eye has an asymmetric eyelid shape, there is provided Figure 4A and Figure 4B the toric contact lens 400 in Figure 4A is a diagram showing the thickness distribution of an exemplary toric contact lens 400 having a first stable region 402 and a second stable region 404. Figure 4B is a close-up view of the upper left portion of the first stable region 402 of the toric contact lens 400, showing additional details of the thickness distribution of the first stable region 402, which also applies to the second stable region 404. Return reference Figure 4A , the toric contact lens 400 also has a thin region 407 outside the first stable region 402 and the second stable region 404. The thin region 407 has an upper region B and a lower region B' that intersect the vertical central axis V of the toric contact lens 400 1 The first stable region 402 and the second stable region 404 of the toric contact lens 400 are each configured to connect with the eyelids of the patient wearer's eye to improve the stable and alignment of the toric contact lens substantially with the principal meridians of the eye, even if the eyelid shape is asymmetric. An asymmetric eye shape is an eye shape in which the eyelids are not symmetric with respect to the vertical meridian of the eye. In this example, reference Figure 4A , the first stable region 402 and the second stable region 404 are symmetric with respect to the vertical central axis V of the toric contact lens 400 1Symmetry. The first stabilization zone 402 and the second stabilization zone 404 include a thickness distribution shown by a contour line that is configured to intersect a target upper eyelid margin 406 and a target lower eyelid margin 408 according to the average eyelid edge shape of the eyelids of an average patient wearer, and that still substantially orients the toric contact lens to the principal meridians of the eye even considering that the eyelid edge shape of the patient wearer is asymmetric.

[0036] In this regard, as discussed in more detail below, the designated first contour line 410(1) and second contour line 412(1) in each of the corresponding first stabilization zone 402 and second stabilization zone 404 have a thickness between approximately 73% - 80% of the meridional thickness difference (i.e., the difference in thickness between the horizontal central axis H 1 thickness difference and the vertical central axis V 1 thickness difference), and the designated first contour line and second contour line in each of the corresponding first stabilization zone and the second stabilization zone are configured to be substantially contained within the target open-eye rest boundaries ("rest boundaries") 414, 416 of the corresponding target upper eyelid margin 406 and target lower eyelid margin 408. The thickness of the designated first contour line 410(1) and second contour line 412(1) in the first stabilization zone 402 and the second stabilization zone 404 within the aforementioned thickness range of the meridional thickness difference has been found to still allow the orientation and stabilization of the toric contact lens 400 to be affected by the asymmetrically shaped eyelids of the patient wearer for rotational orientation, but not to be overly affected by any asymmetry in the shape of the patient wearer's eyelids. This is because, when the designated first contour line 410(1) and second contour line 412(1) in the corresponding first stabilization zone 402 and second stabilization zone 404 are configured to be substantially contained within the target rest boundaries 414, 416 of the target eyelid margins 406, 408 during wear, the orientation of the toric contact lens 400 can be primarily affected by the lower or upper points on either side of the corresponding asymmetrically shaped upper and lower eyelids of the patient wearer. This can avoid or reduce over-rotation of the toric contact lens 400 beyond horizontal meridian alignment in the worn eye due to the asymmetric shape of the patient wearer's eyelids and their eyelid edges. This is because, with the designated first contour line 410(1) and second contour line 412(1) in the corresponding first stabilization zone 402 and second stabilization zone 404 being oriented to be substantially contained within the target rest boundaries 414, 416 of the target eyelid margins 406, 408, the pressure imbalance between the two sides of the eyelids of the patient wearer that contact the corresponding first stabilization zone 402 and second stabilization zone 404 in the toric contact lens 400 can be reduced. In this way, the first stabilization zone 402 and the second stabilization zone 404 of the toric contact lens 400 are more desensitized to any asymmetric shape of the patient wearer's eyelids.

[0037] Continuing reference Figure 4A , the toric contact lens 400 is a lens material 401, which includes a first surface 418 and a second surface 420 opposite to the first surface 418. The toric contact lens 400 has a horizontal thickness difference between the first surface 418 and the second surface 420 along the horizontal central axis H 1 . In this example, the horizontal thickness difference is 0.365 millimeters (mm), and this horizontal thickness difference is the thickness difference between the lens edge 422 of the toric contact lens 400 and the maximum thickness along the horizontal central axis H in the first stable region 402 and the second stable region 404 1 . The toric contact lens 400 also has a vertical thickness difference between the first surface 418 and the second surface 420 along the vertical central axis V 1 orthogonal to the horizontal central axis H 1 . In this example, the vertical thickness difference is 0.19 mm, and this vertical thickness difference is the thickness difference between the lens edge 422 of the toric contact lens 400 and the maximum thickness along the vertical central axis V 1 . The toric contact lens 400 further includes an optical zone 424 disposed around the center, and this center is the optical axis C 1 intersecting the vertical central axis V 1 and the horizontal central axis H 1 . The toric contact lens 400 further includes a lens periphery 426, which is outside the optical zone 424 and surrounds the optical zone, and extends between the optical zone 424 and the lens edge 422

[0038] Continuing reference Figure 4A , the first stable region 402 is on the first left side of the lens periphery 426 between the optical zone 424 and the lens edge 422. The first stable region 402 has a first thickness distribution, which includes a plurality of first contour lines 410(1)-410(5). Each of the plurality of first contour lines is at the thickness that varies between the first surface 418 and the second surface 420 of the toric contact lens 400, and each of the plurality of first contour lines is shown to have different thickness measurement values in millimeters. It should be noted that the first contour lines 410(1)-410(5) are not hard transitions in the first stable region 402, but imaginary lines showing the specific thickness in the specific contour region of the first stable region 402. The first stable region 402 has a first thickness distribution with varying thickness. In this example, the plurality of first contour lines 410(1)-410(5) are at the corresponding thicknesses of 0.23 mm, 0.16 mm, 0.25 mm, 0.28 mm, and 33 mm

[0039] The second stabilization zone 404 is on the second right side of the lens periphery 426 between the optical zone 424 and the lens edge 422. The second stabilization zone 404 has a second thickness distribution that includes a plurality of second contour lines 412(1)-412(5), which are also each at the thickness of the toric contact lens 400 that varies between the first surface 418 and the second surface 420, and each of the second contour lines is shown having different thickness measurements in millimeters. Note that the second contour lines 412(1)-412(5) are not hard transitions in the second stabilization zone 404, but are imaginary lines showing the specific thickness in a specific contour area of the second stabilization zone 404. The second stabilization zone 404 has a second thickness distribution with varying thickness. In this example, the plurality of second contour lines 412(1)-412(5) have respective thicknesses of 0.23 mm, 0.16 mm, 0.25 mm, 0.28 mm, and 33 mm. This is because, in this example, the first stabilization zone 402 and the second stabilization zone 404 are 1 symmetrical to each other about the vertical central axis V 1 such that the corresponding first contour lines 410(1)-410(5) and the second contour lines 412(1)-412(5) are also 1 symmetrical to each other about the vertical central axis V. In this example, the first stabilization zone 402 and the second stabilization zone 404 do not intersect the vertical central axis V

[0040] Continue to refer to Figure 4A, the first stabilization zone 402 includes a first upper active zone 428(1) and a second lower active zone 428(2), each of which is configured to intersect a corresponding upper eyelid margin and a left side of the lower eyelid margin of the worn eye. The first upper active zone 428(1) and the second lower active zone 428(2) intersect a portion of the first contour lines 410(1)-410(5), which is configured to intersect a corresponding upper eyelid margin and a left side of the lower eyelid margin of the worn eye to orient and stabilize the toric contact lens 400 to the eye of the patient wearer. The first upper active zone 428(1) and the second lower active zone 428(2) each have a thickness gradient with an increasing thickness. The thickness difference is shown by the thickness variation of the first contour lines 410(1)-410(5), where the thickness varies from a thickness of 0.16 mm to a maximum thickness of 0.365 mm, providing a thickness difference of 0.205 mm. In this example, the thin zone 407 has a maximum thickness of 0.2 mm and a thickness variation of 0.2 mm to the lens edge 422. The first upper active zone 428(1) and the second lower active zone 428(2) surround the thickness gradient of the first stabilization zone 402 such that when the upper eyelid and the lower eyelid intersect and begin to move across the first upper active zone 428(1) and the second lower active zone 428(2), the upper eyelid and the lower eyelid of the patient wearer will encounter an increasing thickness across the thickness gradient, which will result in resistance. The pressure imbalance between the upper active zone 428(1) and the upper eyelid of the patient wearer causes the toric contact lens 400 to orient itself relative to the upper eyelid margin of the upper eyelid of the patient wearer. Similarly, the pressure imbalance between the lower active zone 428(2) and the lower eyelid of the patient wearer may cause the toric contact lens 400 to orient itself relative to the lower eyelid margin of the lower eyelid of the patient wearer.

[0041] Continuing reference Figure 4A, the second stabilization zone 404 includes a first upper active zone 430(1) and a second lower active zone 430(2), each of which is configured to intersect a corresponding upper eyelid margin and the right side of the lower eyelid margin of the worn eye. The first upper active zone 430(1) and the second lower active zone 430(2) intersect a portion of the second contour line 412(1)-412(5), and this portion of the second contour line is configured to intersect the corresponding upper eyelid margin and the left side of the lower eyelid margin of the worn eye to orient and stabilize the toric contact lens 400 to the eye of the patient wearer. The first upper active zone 430(1) and the second lower active zone 430(2) each have a thickness gradient with an increasing thickness. The thickness difference is shown by the thickness variation of the second contour line 412(1)-412(5), where the thickness variation ranges from a thickness of 0.16 mm to a maximum thickness of 0.365 mm, providing a thickness difference of 0.205 mm. The first upper active zone 430(1) and the second lower active zone 430(2) enclose the thickness gradient of the second stabilization zone 404, such that when the upper eyelid and the lower eyelid intersect and begin to move across the first upper active zone 430(1) and the second lower active zone 430(2), the upper eyelid and the lower eyelid of the patient wearer will encounter an increasing thickness across the thickness gradient, which will result in resistance. The pressure imbalance between the upper active zone 428(1) and the upper eyelid of the patient wearer causes the toric contact lens 400 to orient itself relative to the upper eyelid margin of the upper eyelid of the patient wearer. Similarly, the pressure imbalance between the lower active zone 430(2) and the lower eyelid of the patient wearer can cause the toric contact lens 400 to orient itself relative to the lower eyelid margin of the lower eyelid of the patient wearer.

[0042] Thus, in this example, the orientation of the toric contact lens 400 will track (i.e., register with) the shape of the eyelid margins of the upper eyelid and / or the lower eyelid and follow the shape of the eyelid margins of the patient wearer, because the rotational alignment of the toric contact lens 400 is driven by the first stabilization zone 402 and the second stabilization zone 404 based on the eyelid shape. However, the shapes of the eyelids and the eyelid margins of patients can vary greatly among different patients. For example, some eyelids slope downward on the nasal side, while others slope downward temporarily. In either of these cases, if the eye has astigmatism, the eyelid margin is asymmetric with respect to the eye and its principal meridians. If the eyelid margin is asymmetric with respect to its eye, the toric contact lens with a stabilization zone presented to such an eye will also have an inclination / rotation with an asymmetric deviation from the symmetric alignment on the eye. This causes the corrective optical power in the toric contact lens to be misaligned with one or both of the principal meridians of the eye. In a toric contact lens, it is important for the corrective optical power for the two principal meridians of the eye to be aligned with the principal meridians of the eye for correcting astigmatic vision.

[0043] Thus, in this example, in order to minimize the effect of the asymmetric deviation of the eyelids of the patient wearer on the alignment of the toric contact lens 400 in Figure 4A and Figure 4B with the principal meridians of the eye, the active zones 428(1), 428(2), 430(1), 430(2) that are configured to intersect the respective upper eyelid edges and lower eyelid edges of the upper eyelid and lower eyelid of the patient wearer, and their respective first contour lines 410(1)-410(5) and second contour lines 412(1)-412(5) are oriented to the target eyelid edge shape of the target eyelids of an average patient wearer. In this way, the active zones 428(1), 428(2), 430(1), 430(2) will be primarily affected by the lower or upper points on either side of the respective asymmetrically shaped upper and lower eyelids of the patient wearer. In this regard, the designated first contour line 410(1) in the first upper active zone 428(1) of the first stabilization zone 402 is oriented to the target eyelid edge shape of the target upper eyelid edge 406 of an average patient wearer, and the designated first contour line in the first upper active zone of this first stabilization zone is configured to be substantially contained within the target rest boundary 414 of the target eyelid edge. Moreover, in this example, the designated second contour line 412(1) in the first upper active zone 430(1) of the second stabilization zone 404 is oriented to the target eyelid edge shape of the target upper eyelid edge 406 of an average patient wearer, and the designated second contour line in the first upper active zone of this second stabilization zone is configured to be substantially contained within the target rest boundary 414 of the target eyelid edge. The designated first contour line 410(1) and second contour line 412(1) are shaped in their respective upper active zones 428(1), 430(1) to be substantially parallel to the target upper eyelid edge 406 in the region of the upper eyelid edge where they are configured to intersect in the patient wearer. The other first contour lines 410(2)-410(5) and second contour lines 412(2)-412(5) may also be shaped in their respective upper active zones 428(1), 430(1) to be substantially parallel to the target upper eyelid edge 406 in the region of the upper eyelid edge where they are configured to intersect in the patient wearer. This can provide enhanced tracking and registration of the toric contact lens 400 orientation to the shape of the eyelid edges of the eyelids of a patient wearer with asymmetrically shaped eyelids.

[0044] ​​​​Moreover, in this example, the specified first contour line 410(1) defines a first thickness in the first stable region 402, and the first thickness in this first stable region is between approximately 73% - 80% of the meridian thickness difference which is the difference between the horizontal thickness difference and the vertical thickness difference. The specified first contour line 410(1) travels more towards the superonasal quadrant B than the superotemporal quadrant A to be substantially kept within the target eyelid edge 406. Thus, in a patient wearer, the first contour line 410(1) of the toric contact lens 400 will more greatly affect the orientation of the toric contact lens 400 in the worn eye. And in this example, the first contour line 410(1) is not substantially the shape of the target upper eyelid edge 406. Thus, in a patient wearer of the toric contact lens 400, the asymmetric interaction between the patient's eyelid and the thickness difference may cause a counterclockwise rotation of the toric contact lens 400 and a non-zero average fixation location. And in this example, the first contour line 410(1) is not substantially the shape of the target upper eyelid edge 406.

[0045] The specified second contour line 412(1) defines a second thickness in the second stable zone 404, and this second thickness in the second stable zone is also between approximately 73% - 80% of the meridional thickness difference which is the difference between the horizontal thickness difference and the vertical thickness difference. It should be noted that the thicknesses of the specified first contour line 410(1) and second contour line 412(1) in the first stable zone 402 and the second stable zone 404 are within the aforementioned thickness range of the meridional thickness difference, and it has been found that they still allow the orientation and stability of the toric contact lens 400 to be affected by the asymmetrically shaped eyelids of the patient wearer for rotational orientation, but will not be overly affected by any asymmetry in the shape of the patient wearer's eyelids. This is because, when the first specified first contour line 410(1) and second contour line 412(1) in the corresponding first stable zone 402 and second stable zone 404 are configured to be substantially contained within the target stationary boundaries 414, 416 of the target eyelid edges 406, 408 during wear, the orientation of the toric contact lens 400 can be mainly affected by the lower or upper points on either side of the corresponding asymmetrically shaped upper and lower eyelids of the patient wearer. This can avoid or reduce the over-rotation of the toric contact lens 400 in the worn eye beyond the horizontal meridian alignment due to the asymmetric shapes of the patient wearer's eyelids and eyelid edges. This is because, since the specified first contour line 410(1) and second contour line 412(1) in the corresponding first stable zone 402 and second stable zone 404 are oriented to be substantially contained within the target stationary boundaries 414, 416 of the target eyelid edges 406, 408, the pressure imbalance between the two sides of the eyelid of the patient wearer in contact with the corresponding first stable zone 402 and second stable zone 404 in the toric contact lens 400 can be reduced. In this way, the first stable zone 402 and the second stable zone 404 of the toric contact lens 400 are more insensitive to any asymmetric shape of the patient wearer's eyelids.

[0046] In this example, the first thickness of the specified first contour line 410(1) and second contour line 412(1) is 0.23 mm between the first surface 418 and the second surface 420. Along the horizontal central axis H 1 The horizontal thickness difference between the first surface 418 and the second surface 420 is 0.365 millimeters (mm), and this horizontal thickness difference is the thickness difference between the lens edge 422 of the toric contact lens 400 and the maximum thickness along the horizontal central axis H in the first stable zone 402 and the second stable zone 404. Along the vertical central axis V orthogonal to the horizontal central axis H 1 1 of the vertical central axis V 1The vertical thickness difference between the first surface 418 and the second surface 420 is 0.19 mm. Thus, in this example, the meridian thickness difference between the horizontal thickness difference and the vertical thickness difference is 0.175 (i.e., 0.365 mm - 0.19 mm). The specified first contour line 410(1) and the second contour line 412(1) have a thickness of 0.23 mm. Thus, the specified first contour line 410(1) and the second contour line 412(1) with a thickness of 0.23 mm are the vertical central axis V 1 and the horizontal central axis H 1 The 77% of the thickness difference between them is as follows:

[0047] 77% = 0.365 Horizontal Thickness Difference - 0.23mm Contour Line

[0048] (0.365 horizontal thickness difference - 0.19 vertical thickness difference)

[0049] As discussed above, Figure 4A and Figure 4BThe first contour lines 410(1)-410(5) and the second contour lines 412(1)-412(5) in the corresponding effective regions 428(1), 428(2), 430(1), 430(2) are oriented to substantially match the shape of the corresponding target eyelid edges 406, 408 at their intersections to provide improved orientation and stability of the toric contact lens 400 in the worn eye. Since the shapes of the target eyelid edges 406, 408 are non-concentric with the lens rim 422, in this example, this is partially achieved by changing the shape and orientation of the specified first contour line 410(1) and the second contour line 412(1) in the corresponding effective regions 428(1), 428(2), 430(1), 430(2) to be substantially non-concentric with the lens rim 422. In this example, each of the first contour lines 410(1)-410(5) and the second contour lines 412(1)-412(5) in the corresponding effective regions 428(1), 428(2), 430(1), 430(2) can be designed to be substantially non-concentric with the lens rim 422. Moreover, in this example, the effective regions 428(1), 430(1), 430(2) are designed such that the thickness gradient is in the direction of the maximum slope along its length, and the thickness gradient is structured such that it is oriented orthogonally to the shape of the target upper eyelid edge 406. This can further minimize the interaction between the eyelid edges of the patient wearer and the effective regions 428(1), 430(1) of the corresponding first and second stabilization regions 402, 404 of the toric contact lens 400 across the patient population, and reduce the average lens orientation to the surface normal of the toric contact lens 400. This can provide an optimized effect of the forces and resulting pressures from the interaction of the eyelid edges of the patient wearer with the toric contact lens 400 to affect rotation and stability, while minimizing the interaction between the eyelid edges and the effective regions 428(1), 430(1) of the corresponding first and second stabilization regions 402, 404 to minimize the effect of the asymmetric deviation of the eyelid shape of the patient wearer.

[0050] Figure 5A and Figure 5B are respectively Figure 4A side-by-side diagrams of the thickness distributions between the first surface 418 and the second surface 420 of the toric contact lens 400 and the first surface 518 and the second surface 520 of another exemplary toric contact lens 500. As Figure 5B shown, the thickness of the specified first contour line 510(1) is 0.23 mm, which is the thickness in the toric contact lens 500 at the vertical central axis V 1 and the horizontal central axis H 177% of the thickness difference between them, which is substantially lower than the target upper eyelid edge 406 in the active zone 528(1). The designated first contour line 510(1) with a thickness of 0.23 mm travels across the target upper eyelid edge 406 in the upper nasal quadrant A, and the upper nasal quadrant A is on the upper temporal quadrant B. Thus, in a patient wearer, the first contour line 510(1) of the toric contact lens 500 will more greatly affect the orientation of the toric contact lens 500 in the worn eye and is more vulnerable to misalignment with the principal meridians of a patient wearer with an asymmetric eyelid shape. And in this example, Figure 5B the first contour line 510(1) of the toric contact lens 500 in is substantially not the shape of the target upper eyelid edge 406. Thus, in a patient wearer of the toric contact lens 500, the asymmetric interaction between the patient's eyelid and the thickness difference will likely cause a counterclockwise rotation of the toric contact lens 500 and a non-zero average fixation location.

[0051] In addition, it has been found that Figure 4A a toric contact lens similar to the design of the toric contact lens 400 in can recover from an initial incorrect rotation. The toric contact lens 400 continues to stably rotate back to its horizontal central axis H 1 orientation, which is substantially oriented to the horizontal meridian of the patient wearer's eye, not only when the eyelid blinks actively but also when the eye remains open. From this observation, it can be concluded that when the wearer's eye is open, the thickness gradient from the vertical thickness difference in the lower region B' and the upper region B of the toric contact lens 400, which is normally covered by the eyelid, can provide a shorter stabilization time and further reduce the average fixation error due to the improvement of the lens-eyelid interaction for those specific regions of the toric contact lens 400. Along the vertical central axis V 1 the introduction of the vertical thickness difference can also provide or maintain the performance of the toric contact lens 400 for the eyelid geometries of a wider range of patient wearers that further descend from the average eyelid profile.

[0052] In this regard, Figure 4A the toric contact lens 400 in (also shown in the local view in Figure 5A ) and Figure 5B the vertical thickness difference distribution between the toric contact lens 500 in is shown in the graph 600 in Figure 6 . Figure 6 The graph 600 in shows the exemplary thickness distribution (in mm) (Y-axis) along the vertical central axis V 1 , V 2 , which is the distance compared to Figure 5B the toric contact lens 500 in Figure 4Athe corresponding optical axis C of the corresponding toric contact lens 400 therein 1 、C 2 as a function of the radius (X-axis). As Figure 6 shown, in order to achieve a thickness gradient in the upper region B and the lower region B' of the toric contact lens 400, the peak thickness has been positioned radially inwards on the vertical central axis V of the toric contact lens 400 1 and, in Figure 6 is closer to the optical axis C Figure 5B than in the toric contact lens 500 in 1 (as shown by curve 604). Figure 6 The graph 600 in Figure 4A shows a comparison of the cross-sectional thickness distribution along the vertical central axis V of the toric contact lens 400 in 1 with the cross-sectional thickness distribution along the vertical central axis V of the toric contact lens 500 in Figure 5B . 2

[0053] As discussed above, Figure 4A the shapes and orientations of the specified first contour line 410(1) and second contour line 412(1) in the corresponding effective zones 428(1), 428(2), 430(1), 430(2) of the toric contact lens 400 in Figure 6 are substantially non-concentric with the shapes of the target eyelid edges 406, 408, because the shapes of the target eyelid edges 406, 408 are non-concentric with the lens rim 422. In this regard, as Figure 4A shown, in this example, for the toric contact lens 400 in 1 the peak thickness point P 1 appears at a radial distance of approximately 5.25 mm, while for the toric contact lens 500 in Figure 5B the peak thickness point P 2 is 6.5 mm. At the corresponding peak thickness points P 2 、P 1 、P 2 and the corresponding lens rims 422, 522 of the corresponding toric contact lenses 400, 500 (see also Figure 5A and Figure 5B ), the values of the offset points defining the spline curves at each vertical central axis V 1 、V 2 are at the corresponding vertical central axes V 1 、V 2 ​An offset is added starting from either side of Figure 4A This can be verified at point B in the toric contact lens 400 in Figure 5B where the 0.16 mm contour line is radially offset inwards from the lens edge 422, while in Figure 4A the 0.16 mm contour line in the toric contact lens 500 in Figure 6 is largely concentric with the outer diameter of its lens edge 522. By offsetting the 0.16 mm contour line in the active areas 428(1), 428(2) of the toric contact lens 400 in

[0054] inward as shown in Figure 4A

[0055] Figure 7 the shape of the 0.16 mm contour line in the active areas 428(1), 428(2) and 430(1), 430(2) is substantially the same as the shape of the target upper eyelid edge 406, so that the orientation of the toric contact lens 400 is affected by the target upper eyelid edge 406. Figure 7 Figure 7 is the drawing 700 of the final design image, overlaid with upper eyelid shape data 702 and lower eyelid shape data 704 in the form of polynomial curves 706, 708 across a patient population. This is an example of how eyelid shape data is used to determine the corresponding average target eyelid edges 406, 408 to create Figure 4A the design of the toric contact lens 400 in

[0056] Another technique can be developed through discussions with high - level expertise in mathematics, topology, data analysis, and 3D modeling. Instead of the described examples, another design approach may involve one or more of the following:

[0057] - Higher - order polynomial functions, or other mathematical functions for fitting eyelid shape data.

[0058] - Referencing the eyelid shape function to the center of a contact lens worn on the eye (i.e., such that the origin of the axis is at the center of the contact lens) rather than the center of the cornea.

[0059] - Different techniques for combining eyelid shape data from different images, whereby they can be combined by taking the mean or median of the function coefficients, the mean of the function values in certain regions,

[0060] or taking the mean of the "slope / gradient" function of the surface shape generated from the eyelid shape data.

[0061] In one example, for the upper and lower eyelids respectively, the average target eyelid edge shape is obtained by taking the median of all polynomials at each millimeter interval along the Figure 7 X - axis of Plot 700. Figure 8 Plot 800 shows the upper eyelid shape data 802 and lower eyelid shape data 804 for the corresponding upper and lower eyelids respectively, showing that the average eyelid edge shape is obtained by taking the median of all polynomials at each millimeter interval along the X - axis. At each millimeter interval on the X - axis, the Y - axis value is determined by taking the median of all Y - axis values of the upper eyelid polynomials. A similar process is followed for the lower eyelid.

[0062] Such that the final lens design can be left - right symmetric, with the data being "flipped" left - right about the Y - axis. Figure 9 Plot 900 shows the left - right "flipped" upper eyelid shape data 902 and lower eyelid shape data 904 and the "non - flipped" upper eyelid shape data 802 and lower eyelid shape data 804 plotted together on the same axis for the upper and lower eyelids. Then the "flipped" and "non - flipped" data are averaged by taking the mean of the "flipped" and "non - flipped" Y - axis values at each position. Thus, the resulting "average" data is symmetric about the Y - axis. In this regard, Figure 10 is Figure 9 Plot 1000 shows the means 1002, 1004 of the "flipped" upper eyelid shape data 902 and lower eyelid shape data 904 and the "non - flipped" upper eyelid shape data 802 and lower eyelid shape data 804 in Figure 11Drawing 1100 shows the upper "flipped" eyelid shape data 902 and the lower "flipped" eyelid shape data 904, as well as the upper "non-flipped" eyelid shape data 802 and the lower "non-flipped" eyelid shape data 804, plotted together on the same axis.

[0063] Figure 12A and Figure 12B is a flowchart showing an exemplary process 1200 for designing a toric contact lens having a stabilization zone, each stabilization zone having a varying thickness on each side of the optical zone of the lens with respect to the vertical meridian, wherein the stabilization zone includes an effective zone having a contour line that is oriented to the target eyelid edge shape of the target eyelid of an average patient wearer or an improved stabilization in a wearer with asymmetric eyelids. Such toric contact lenses can include, but are not limited to Figure 4A and Figure 4B the toric contact lens 400 in Figure 12A and Figure 12B Process 1200 in

[0064] In this regard, as Figure 12A shown, the first step in process 1200 can be to form the lens 400 from a volume of lens material 401 ( Figure 12A the block 1202 in Figure 12A ). The lens 400 can include a first surface 418 and a second surface 420 opposite the first surface 418 ( 1 the block 1204 in 1 ). The lens 400 has a horizontal thickness difference between the first surface 418 and the second surface 420 along the horizontal central axis H 1 and a vertical thickness difference between the first surface 418 and the second surface 420 along the vertical central axis V Figure 12A orthogonal to the horizontal central axis H ( 1 the block 1206 in 1 ). The lens 400 has an optical zone 424 1 arranged around the optical axis C Figure 12A that intersects the horizontal central axis H Figure 12A and the vertical central axis V ( Figure 12Ain the frame 1212). The first stabilization zone 402 has a first thickness profile that includes a plurality of first contour lines 410(1)-410(5), each of the plurality of first contour lines at a thickness varying between a first surface 418 and a second surface 420( Figure 12A in the frame 1214).

[0065] As Figure 12B shown, the lens 400 also has a second stabilization zone 404 on a second side of the lens perimeter 426 opposite the first side, the second stabilization zone 404 being between the optical zone 424 and the lens edge 422( Figure 12B in the frame 1216). The second stabilization zone 404 has a second thickness profile that includes a plurality of second contour lines 412(1)-412(5), each of the plurality of contour lines at a thickness varying between a first surface 418 and a second surface 420( Figure 12B in the frame 1218). The first contour line 410(1) of the plurality of first contour lines 410(1)-410(5) is oriented to the shape of the target upper eyelid edge 406 of the target upper eyelid of an average patient wearer, the first contour line of the plurality of first contour lines being configured to be substantially contained within the target rest boundary of the target upper eyelid edge 406, having a first thickness between approximately 73%-80% of the meridional thickness difference between the horizontal thickness difference and the vertical thickness difference( Figure 12B in the frame 1220). The second contour line 412(1) of the plurality of second contour lines 412(1)-412(5) is oriented to the shape of the target upper eyelid edge 406, the second contour line of the plurality of second contour lines being configured to be substantially contained within the target rest boundary of the target upper eyelid edge, having a second thickness between approximately 73%-80% of the meridional thickness difference( Figure 12B in the frame 1222).

[0066] Note that the aspects described above are with respect to exemplary contact lens systems, contact lens pairs, and individual contact lenses, but note that such examples are not limited to contact lenses, but may apply to any type of lens and related lens systems and lens pairs.

[0067] It should be noted in particular that the lens designs of the present disclosure can be incorporated into many different contact lenses formed from many materials. Specifically, the lens designs of the present disclosure can be used in any of the contact lenses described herein, including but not limited to daily wear soft contact lenses, rigid gas permeable contact lenses, bifocal contact lenses, toric contact lenses, and hybrid contact lenses. Additionally, while the present disclosure has been described with respect to contact lenses, it should be noted in particular that the concepts of the present disclosure can be used for spectacle lenses, intraocular lenses, corneal inlays, and onlays.

[0068] It should be understood that the present disclosure is not limited to the specific aspects disclosed, and modifications and other aspects are intended to be included within the scope of the appended claims and their equivalents. Although specific terms are employed herein, these terms are used in a general and descriptive sense only and not for purposes of limitation. Upon reading the following description in light of the accompanying drawings, those skilled in the art will understand the concepts of the present disclosure and will recognize applications of these concepts that are not specifically set forth herein. The aspects set forth below represent the necessary information for those skilled in the art to practice the present disclosure and illustrate the best mode of practicing the present disclosure. It should be understood that these concepts and applications fall within the scope of the present disclosure and the appended claims. In light of the foregoing description and the teachings presented in the related drawings, many modifications and other embodiments of the present disclosure set forth herein will come to mind to those skilled in the art to which the present disclosure pertains. Although the aspects shown and described are believed to be the most practical and specific aspects disclosed, modifications and other aspects are intended to be included within the scope of the appended claims. It is apparent that those skilled in the art may make changes to the specific designs and methods described and shown and use such variations without departing from the spirit and scope of the invention.

Claims

1. A toric contact lens comprising: a first surface and a second surface opposite to the first surface; The lens has a horizontal thickness difference between the first surface and the second surface along a horizontal central axis, and has a vertical thickness difference between the first surface and the second surface along a vertical central axis orthogonal to the horizontal central axis; an optical zone disposed around an optical axis intersecting the horizontal central axis and the vertical central axis; and a lens periphery surrounding the optical zone and extending between the optical zone and the lens edge, the lens periphery comprising: a first Stabilization Zone on a first side of the lens periphery between the Optical Zone and the lens edge, the first Stabilization Zone having: a first thickness profile, the first thickness profile comprising a plurality of first contour lines, the plurality of first contour lines each at a thickness that varies between the first surface and the second surface; and a second stabilization zone on a second side of the lens periphery opposite the first side, the second stabilization zone being between the optical zone and the lens edge, the second stabilization zone having: a second thickness profile, the second thickness profile comprising a plurality of second contour lines, the plurality of second contour lines each being at a thickness that varies between the first surface and the second surface; and in: a first contour line of the plurality of first contour lines being oriented to a target upper eyelid margin shape of a target upper eyelid of a typical patient wearer, the first contour line of the plurality of first contour lines being configured to be substantially contained within a stationary boundary of the target upper eyelid margin and having a first thickness between about 73%-80% of a meridian thickness difference of a difference between the horizontal thickness difference and the vertical thickness difference; and a second contour line of the plurality of second contour lines being oriented to the target upper eyelid margin shape, the second contour line of the plurality of second contour lines being configured to be substantially contained within the stationary boundary of the target upper eyelid margin, Having a second thickness between approximately 73%-80% of the meridian thickness difference.

2. The contact lens according to claim 1, wherein: The target upper eyelid margin shape is asymmetric about the vertical center axis.

3. The contact lens of claim 1 , wherein: The first stabilization zone does not intersect the horizontal central axis; and The second stability zone does not intersect the horizontal central axis.

4. The contact lens of claim 1, wherein: The first stabilization zone and the second stabilization zone are symmetrical to each other about the horizontal center axis.

5. The contact lens of claim 1, wherein: The first stabilization zone includes a first effective zone intersecting the plurality of first contour lines, the first effective zone being configured to intersect an upper eyelid margin of a wearer patient; and The second stabilization zone includes a second effective zone that intersects the plurality of second contour lines, the second effective zone being configured to intersect the upper eyelid margin of the wearer patient.

6. The contact lens of claim 5, wherein: The first active region has a first thickness gradient across the plurality of first contour lines; and The second active region has a second thickness gradient across the plurality of second contour lines.

7. The contact lens of claim 6, wherein: The first thickness gradient of the first effective zone is in a direction substantially orthogonal to the target upper eyelid margin shape; and The second thickness gradient of the first stabilization zone is in a direction substantially orthogonal to the target upper eyelid margin shape.

8. The contact lens of claim 5, wherein: The first contour line in the first effective area is substantially parallel to the target upper eyelid margin shape; and The second contour line in the second effective area is substantially parallel to the target upper eyelid margin shape.

9. The contact lens of claim 5, wherein: Each of the plurality of first contour lines in the first effective area is substantially parallel to the target upper eyelid margin shape; and Each of the plurality of second contour lines in the second effective area is substantially parallel to the target upper eyelid margin shape.

10. The contact lens of claim 5, wherein: Each of the plurality of first contour lines in the first effective area is substantially not concentric with the lens edge; and Each of the plurality of second contour lines in the second effective area is substantially not concentric with the lens edge.

11. The contact lens of claim 5, wherein: Each of the plurality of first contour lines outside the first effective area is substantially not concentric with the lens edge; and Each of the plurality of second contour lines outside the second effective area is substantially not concentric with the lens edge.

12. The contact lens of claim 6, wherein: The first active area and the second active area are symmetrical to each other about the vertical center axis.

13. The contact lens of claim 12, wherein: The first stabilization region further includes a third effective region having the first thickness gradient across the plurality of first contour lines; The second stabilization region further includes a fourth active region having the second thickness gradient across the plurality of second contour lines; The first effective area and the third effective area are symmetrical to each other about the horizontal central axis; and The second active area and the fourth active area are symmetrical to each other about the horizontal center axis.

14. The contact lens of claim 1, wherein: a third contour line of the plurality of first contour lines being oriented to a target lower eyelid margin shape of a target lower eyelid of a typical patient wearer, the third contour line of the plurality of first contour lines being configured to be substantially contained within a stationary boundary of the target lower eyelid margin and having a first thickness between about 73%-80% of a meridian thickness difference of a difference between the horizontal thickness difference and the vertical thickness difference; and A fourth contour line among the plurality of second contour lines is oriented to the target lower eyelid edge shape, and the fourth contour line among the plurality of second contour lines is constructed to be substantially contained within the static boundary of the target lower eyelid edge, having a second thickness between approximately 73%-80% of the meridian thickness difference.

15. The contact lens of claim 1, wherein: The first thickness is approximately 77% of the meridian thickness difference; and The second thickness is approximately 77% of the meridian thickness difference.

16. The contact lens of claim 1, wherein: The first contour line defines a thickness of 0.23 millimeters (mm) between the first surface and the second surface of the lens; and The second contour line defines a thickness of 0.23 mm between the first surface and the second surface of the lens.

17. The contact lens of claim 1, wherein: The first thickness profile varies from 0.2 millimeters (mm) thickness to 0.365 mm thickness between the first surface and the second surface of the lens; and The second thickness profile varies from 0.2 mm thickness to 0.365 mm thickness between the first surface and the second surface of the lens.

18. The contact lens of claim 1, wherein: The first thickness distribution has a first maximum thickness of 0.365 millimeters (mm) between the first surface and the second surface of the lens; and The second thickness distribution has a second maximum thickness of 0.365 mm between the first surface and the second surface of the lens.

19. The contact lens of claim 1 further comprising thin zones contained in a lower region and an upper region of the lens, the thin zones being outside the first stabilization zone and outside the second stabilization zone.

20. The contact lens of claim 18, wherein: The first thickness profile varies from 0.2 millimeters (mm) thickness to 0.365 mm thickness between the first surface and the second surface of the lens; The second thickness profile varies from 0.2 mm thickness to 0.365 mm thickness between the first surface and the second surface of the lens; and The thin area variation has a third maximum thickness of 0.2 millimeters (mm).

21. The contact lens of claim 1, wherein: The target upper eyelid margin shape is derived from data from one or more images of one or more eyelid contours of the patient.

22. A method of manufacturing a toric contact lens according to claim 1, comprising: A lens is formed from a volume of lens material, the lens comprising: a first surface and a second surface opposite to the first surface; The lens has a horizontal thickness difference between the first surface and the second surface along a horizontal central axis, and has a vertical thickness difference between the first surface and the second surface along a vertical central axis orthogonal to the horizontal central axis; an optical zone disposed about an optical axis intersecting the horizontal central axis and the vertical central axis; and a lens periphery surrounding the optical zone and extending between the optical zone and the lens edge, the lens periphery comprising: a first Stabilization Zone on a first side of the lens periphery between the Optical Zone and the lens edge, the first Stabilization Zone having: a first thickness profile, the first thickness profile comprising a plurality of first contour lines, the plurality of first contour lines each at a thickness that varies between the first surface and the second surface; and a second stabilization zone on a second side of the lens periphery opposite the first side, the second stabilization zone being between the optical zone and the lens edge, the second stabilization zone having: a second thickness profile, the second thickness profile comprising a plurality of second contour lines, the plurality of second contour lines each being at a thickness that varies between the first surface and the second surface; and in: a first contour line of the plurality of first contour lines being oriented to a target upper eyelid margin shape of a target upper eyelid of a typical patient wearer, the first contour line of the plurality of first contour lines being configured to be substantially contained within a stationary boundary of the target upper eyelid margin and having a first thickness between about 73%-80% of a meridian thickness difference of a difference between the horizontal thickness difference and the vertical thickness difference; and A second contour line among the plurality of second contour lines is oriented to the target upper eyelid margin shape, and the second contour line among the plurality of second contour lines is configured to be substantially contained within the static boundary of the target upper eyelid margin, having a second thickness between approximately 73%-80% of the meridian thickness difference.

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