Stable design of toric contact lenses based on a thickness gradient orthogonal to the eyelid margin

Abstract

Ophthalmic lenses are described herein. An exemplary ophthalmic lens may include a first surface. An exemplary ophthalmic lens may include a second surface disposed opposite the first surface and defining a volume of lens material between the first surface and the second surface. A thickness profile of the volume of lens material may be derived from one or more eyelid contours such that a thickness gradient of the volume of lens material is oriented substantially orthogonal to a target eyelid edge shape.

Description

Background Art

[0001] A wearer may wear a contact lens on an eye to improve vision. The performance of one type of contact lens may vary from one wearer to another. This type of contact lens may move more within the eye of a first wearer during use and move less within the eye of a second wearer during use. This type of contact lens may lack consistency in the location it lands on the wearer. Therefore, there is a need to improve the performance of contact lenses and to improve the consistency of contact lens performance across wearers. Summary of the invention

[0002] Ophthalmic lenses are described herein. An exemplary ophthalmic lens may include a first surface. An exemplary ophthalmic lens may include a second surface disposed opposite the first surface and defining a volume of lens material between the first surface and the second surface. A thickness profile of the volume of lens material may be derived from one or more eyelid contours such that a thickness gradient of the volume of lens material is oriented substantially orthogonal to a target eyelid edge shape.

[0003] Methods are described herein. An exemplary method may include determining one or more eyelid contours associated with one or more eyelids. An exemplary method may include determining a target eyelid margin shape based on the one or more eyelid contours. An exemplary method may include designing an ophthalmic lens based at least on the target eyelid margin shape, the ophthalmic lens comprising a first surface and a second surface disposed opposite the first surface, and defining a volume of lens material between the first surface and the second surface. A thickness profile of the volume of lens material may be derived from the one or more eyelid contours such that a thickness gradient of the volume of lens material is oriented substantially orthogonal to the target eyelid margin shape.

[0004] Methods are described herein. An exemplary method may include determining one or more eyelid contours associated with one or more eyelids. An exemplary method may include determining a target eyelid margin shape based on the one or more eyelid contours. An exemplary method may include designing an ophthalmic lens based at least on the target eyelid margin shape, the ophthalmic lens comprising a first surface and a second surface disposed opposite the first surface, and defining a volume of lens material between the first surface and the second surface. A thickness profile of the volume of lens material may be derived from the one or more eyelid contours such that a thickness gradient of the volume of lens material is oriented substantially orthogonal to the target eyelid margin shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The following drawings illustrate various examples discussed in the present disclosure generally by way of example and not by way of limitation. In the drawings:

[0006] Figure 1An example of an eye is shown where the upper and lower eyelid margins have been manually delineated and fitted by second order polynomials (dashed lines). The polynomials are defined relative to the centroid of an ellipse defined by the solid line, where the ellipse is fitted to selected points along the corneal edge.

[0007] Figure 2 A series of such images collected at the eye is shown, where the gaze angle is varied by 10° between adjacent images.

[0008] Figure 3 Eyelid shape data for the upper and lower eyelids of 102 right eyes are shown, whereby each line is a second order polynomial fit to a series of points traced along a photograph of the eyelid margin with the eye in first fixation.

[0009] Figure 4 Graphs are shown for the upper and lower eyelids, respectively, showing that the average eyelid margin shape is obtained by taking the median of all polynomials at each millimeter interval along the X-axis.

[0010] Figure 5 Shown are left and right 'flipped' and 'non-flipped' data plotted together on the same axis.

[0011] Figure 6 The averages of the flipped and non-flipped data are shown, whereby the average of the y-axis values ​​for each is taken per millimeter interval.

[0012] Figure 7 Shown are top-down "flipped" and "non-flipped" data plotted together on the same axis.

[0013] Figure 8 The results are shown as a three-dimensional array of data points.

[0014] Fig. 9 A "best fit" polynomial function for these data points using a formula of this form is shown.

[0015] Fig.10 A graph of an exemplary polynomial is shown, with shading representing the height (z-value) of the surface shape.

[0016] Fig.11 The thickness profile is shown with areas for the optic zone and lens edge cutouts.

[0017] Fig.12 A graph showing an exemplary designed image overlaid with an initial eyelid shape polynomial where the eyelid shape has been centered on the origin.

[0018] Fig.13 A model eye is shown, with arrows showing orthogonal vectors relative to the eyelid. DETAILED DESCRIPTION

[0019] Systems and methods for manufacturing contact lenses are described herein. A population may be selected. The population may include one or more of the following: race, age range, gender, etc. and / or any combination of the foregoing. Multiple left or right eye images associated with the population may be retrieved. The multiple images may be arranged so that the center of the cornea of ​​the eye in each image may be at the same vertical and horizontal position relative to the center of the cornea in the other images. In addition or alternatively, each image may be aligned relative to the center of the contact lens placed on the eye (measured or expected lens decentration). For example, if images are used at multiple gaze angles, the lens may move, i.e., slightly change its centering as the eye looks in different directions, so it may be better to make the alignment reference as the center of the lens rather than the center of the cornea. The multiple images can be used to extract eye shape data for the population. The extracted eye shape data can be used to design contact lenses for the population so that the contact lenses include a stable area. The stable area may include a gradient of a thickness profile that is at right angles to an expected eyelid edge shape, wherein the expected eyelid edge shape is based on the extracted shape data.

[0020] An ophthalmic lens is described herein. An exemplary ophthalmic lens may include a first surface. The first surface may have a circular shape. The first surface may have a non-circular shape.

[0021] An exemplary ophthalmic lens may include a second surface disposed opposite the first surface and defining a volume of lens material between the first surface and the second surface. The second surface may have a circular shape. The second surface may have a non-circular shape.

[0022] The thickness profile of the certain volume of lens material may be derived from one or more eyelid contours so that the thickness gradient of the certain volume of lens material is oriented to be substantially orthogonal to the target eyelid edge shape. The one or more eyelid contours may include biometric data associated with one or more of the position or shape of one or more eyelid edges in the upper eyelid edge or the lower eyelid edge of a group of eyes. The group may include one or more of race, age range, and gender. The one or more eyelid contours may include biometric data associated with a group of eyes in a target gaze position. The one or more eyelid contours may include biometric data associated with a group of eyes in multiple gaze positions.

[0023] The one or more eyelid contours may include biometric data associated with a group of eyes in one or more blink stages. The one or more eyelid contours may include biometric data associated with one or more of the position or shape of one or more eyelid edges in an upper eyelid edge or a lower eyelid edge of at least one eye. The one or more eyelid contours may include biometric data associated with at least one eye in a target gaze position. The one or more eyelid contours may include biometric data associated with at least one eye in multiple gaze positions.

[0024] An exemplary ophthalmic lens may include a stabilization zone defined in or on the volume of material. A thickness profile may be associated with the stabilization zone.

[0025] The target eyelid margin shape may be determined relative to a center of a cornea of ​​at least one eye. The thickness profile may be based on a plurality of images. The thickness profile may be defined at least in part by a polynomial equation. The polynomial equation may be a second order polynomial equation. The thickness profile may be symmetrical about a central vertical axis and / or a central horizontal axis.

[0026] A contact lens manufacturer may receive a plurality of images. Each of the plurality of images may include the left eye of an Asian female between the ages of twenty-four and fifty-four. The plurality of images may be arranged so that the center of the cornea of ​​the eye in each image may be at the same vertical and horizontal position relative to the center of the cornea in the other images. The plurality of images may be used to extract eye shape data, such as eyelid margin data, of an Asian female between the ages of twenty-four and fifty-four. The contact lens manufacturer may use the extracted eye shape data to design a contact lens for the left eye of an Asian female between the ages of twenty-four and fifty-four. The designed contact lens may include a stable region. The stable region may include a gradient of a thickness profile that is at right angles to an expected eyelid margin shape, wherein the expected eyelid margin shape is based on the extracted shape data.

[0027] Methods are described herein. An exemplary method may include determining one or more eyelid contours associated with one or more eyelids. The one or more eyelid contours may include biometric data associated with one or more of the position or shape of one or more eyelid edges in the upper eyelid margin or the lower eyelid margin of a group of eyes. The group may include one or more of race, age range, and gender. The one or more eyelid contours may include biometric data associated with a group of eyes in a target gaze position. The one or more eyelid contours may include biometric data associated with a group of eyes in multiple gaze positions.

[0028] The one or more eyelid contours may include biometric data associated with a group of eyes in one or more blink stages. The one or more eyelid contours may include biometric data associated with one or more of the position or shape of one or more eyelid edges in an upper eyelid edge or a lower eyelid edge of at least one eye. The one or more eyelid contours may include biometric data associated with at least one eye in a target gaze position. The one or more eyelid contours may include biometric data associated with at least one eye in multiple gaze positions.

[0029] An exemplary method may include determining a target eyelid margin shape based on one or more eyelid contours.The target eyelid margin shape may be determined relative to a center of a cornea of ​​at least one eye.

[0030] An exemplary method may include designing an ophthalmic lens based at least on a target eyelid margin shape, the ophthalmic lens comprising a first surface and a second surface disposed opposite the first surface, and defining a volume of lens material between the first surface and the second surface. The ophthalmic lens may include a stabilization zone defined in or on the volume of material. One or more of the first surface and the second surface may include a circular shape. One or more of the first surface and the second surface may include a non-circular shape.

[0031] The thickness profile of the volume of lens material may be derived from one or more eyelid contours such that a thickness gradient of the volume of lens material is oriented substantially orthogonal to a target eyelid edge shape. The thickness profile may be associated with a stabilization zone. The thickness profile may be based on a plurality of images. The thickness profile may be defined at least in part by a polynomial equation. The polynomial equation may be a second order polynomial equation. The thickness profile may be symmetric about a central vertical axis and / or a central horizontal axis.

[0032] A contact lens manufacturer may receive a plurality of images. Each of the plurality of images may include the right eye of an Asian female between the ages of twenty-four and fifty-four. The plurality of images may be arranged so that the center of the cornea of ​​the eye in each image may be at the same vertical and horizontal position relative to the center of the cornea in the other images. The plurality of images may be used to extract eye shape data, such as eyelid margin data, of an Asian female between the ages of twenty-four and fifty-four. The contact lens manufacturer may use the extracted eye shape data to design a contact lens for the right eye of an Asian female between the ages of twenty-four and fifty-four. The designed contact lens may include a stable region. The stable region may include a gradient of a thickness profile that is at right angles to an expected eyelid margin shape, wherein the expected eyelid margin shape is based on the extracted shape data.

[0033] Methods are described herein. An exemplary method may include determining one or more eyelid contours associated with one or more eyelids. The one or more eyelid contours may include biometric data associated with one or more of the position or shape of one or more eyelid edges in the upper eyelid margin or the lower eyelid margin of a group of eyes. The group may include one or more of race, age range, and gender. The one or more eyelid contours may include biometric data associated with a group of eyes in a target gaze position. The one or more eyelid contours may include biometric data associated with a group of eyes in multiple gaze positions.

[0034] The one or more eyelid contours may include biometric data associated with a group of eyes in one or more blink stages. The one or more eyelid contours may include biometric data associated with one or more of the position or shape of one or more eyelid edges in an upper eyelid edge or a lower eyelid edge of at least one eye. The one or more eyelid contours may include biometric data associated with at least one eye in a target gaze position. The one or more eyelid contours may include biometric data associated with at least one eye in multiple gaze positions.

[0035] An exemplary method may include determining a target eyelid margin shape based on one or more eyelid contours.The target eyelid margin shape may be determined relative to a center of a cornea of ​​at least one eye.

[0036] An exemplary method may include designing an ophthalmic lens based at least on a target eyelid margin shape, the ophthalmic lens comprising a first surface and a second surface disposed opposite the first surface, and defining a volume of lens material between the first surface and the second surface. The ophthalmic lens may include a stabilization zone defined in or on the volume of material. One or more of the first surface and the second surface may include a circular shape. One or more of the first surface and the second surface may include a non-circular shape.

[0037] The thickness profile of the volume of lens material may be derived from one or more eyelid contours such that a thickness gradient of the volume of lens material is oriented substantially orthogonal to a target eyelid edge shape. The thickness profile may be associated with a stabilization zone. The thickness profile may be based on a plurality of images. The thickness profile may be defined at least in part by a polynomial equation. The polynomial equation may be a second order polynomial equation. The thickness profile may be symmetric about a central vertical axis and / or a central horizontal axis.

[0038] A contact lens manufacturer may receive an image of an eye. The image may be used to extract eye shape data of the eye, such as eyelid margin data. The contact lens manufacturer may use the extracted eye shape data to design a contact lens for the eye. The designed contact lens may include a stabilization zone. The stabilization zone may include a gradient of a thickness profile that is at right angles to an expected eyelid margin shape, wherein the expected eyelid margin shape is based on the extracted shape data.

[0039] Disclosed herein is a toric lens stabilization design in which a thickness map is derived from eyelid positions from a population of eyes such that the thickness gradient of the lens is oriented orthogonal to the 'average' eyelid edge shape.

[0040] Disclosed herein are systems and / or methods for improving the rotational performance of a toric lens with greater stability over time and greater consistency in settled position on different eyes.

[0041] A novel method for designing or optimizing the design of a contact lens that is intended to be rotationally stable on the eye is described below.

[0042] The method can be used for round or non-round contact lenses.

[0043] The design process can include obtaining biometric data about the position and shape of the upper and lower eyelid margins for a group of eyes. The position and shape of the upper and lower eyelid margins are analyzed with the eyes in a natural gaze position (i.e., primary eye position, looking straight ahead, not squinting or opening the eyelids). The shape and position of the eyelid margins are determined relative to the position of the cornea or the position of the contact lens worn on the eye. Image analysis software is used to depict the upper and lower eyelid margins by selecting a number of points along the eyelid margins. A polynomial or similar function can then be used to fit the selected points to mathematically describe the shape and position of the eyelid margins relative to a predetermined landmark (e.g., relative to the center of the cornea). Figure 1 An example of an eye is shown where the upper and lower eyelid margins have been manually delineated and fitted by second order polynomials (dashed lines). The polynomials are defined relative to the centroid of an ellipse defined by the solid line, where the ellipse is fitted to selected points along the corneal edge.

[0044] In addition to collecting this data in first fixation (i.e., eyes looking straight ahead), eyelid margin biometric data may also be collected with the eyes viewing with varying degrees of peripheral fixation. For example, the position and shape of the eyelid (relative to the cornea or a contact lens worn on the eye) may be collected with the eye rotated in certain horizontal, vertical, or oblique directions while maintaining a natural eyelid posture (i.e., not tilted or "not wide open"). Figure 2A series of such images collected at the eye is shown, where the gaze angle is varied by 10° between adjacent images.

[0045] Such images may be collected for a single eye or a group of eyes. Such a group of eyes may relate to a representative group of a particular region, or a representative group of eyes of a particular race, age range, gender, or a combination of these.

[0046] In addition to collecting images in multiple gaze directions, multiple images can also be collected during different phases of a natural blink (eg, using high-speed video recording).

[0047] Where images are collected in multiple gaze directions, an averaging process may be applied to the eyelid shape data so that an "average" eyelid margin shape is obtained (i.e., an average eyelid margin shape in multiple gaze directions). The averaging may involve averaging the polynomial coefficients over all images, or some other mathematical averaging technique. The averaging may involve weighting each of the images differently, for example, a weighting function may be used whereby images that the eye is closer to first gaze are weighted more heavily in the averaging function than images that the eye is viewing with extreme peripheral vision. Such a weighting function may be obtained from data showing the distribution of time that the eye spends looking in different gaze directions.

[0048] Similarly, when collecting data for a group of eyes, the eyelid margin shape data over multiple eyes may be averaged. This may be done by averaging polynomial coefficients or some other mathematical averaging technique. As described above, averaging the shape data over multiple eyes may be done before or after averaging the data in multiple gaze directions.

[0049] A stable design of the contact lens can then be derived from the eyelid margin shape data. This can be done by defining a thickness profile of the lens stability zone, the goal being to generate a thickness profile such that the gradient of thickness is perpendicular (ie, normal) to the mean eyelid margin.

[0050] In other words, the thickness profile of the lens (when positioned on the eye in its nominal orientation) is defined relative to the position and shape of the eyelid margin so that the gradient of the thickness profile (the direction of maximum slope) is at right angles to the average eyelid margin shape.

[0051] Instead of average eyelid shape data, or in combination with the average, mathematical interpolation can be used to create a continuous lens thickness profile over a range of eyelid margin shapes.

[0052] Certain areas of the lens are excluded from the stabilization zone, including the central optical zone and the peripheral lens edge. The design is blended with these areas by using blending zones.

[0053] Alternatively, a unique stabilized lens design may be created for each eye (or for each gaze angle of a single eye), and the thicknesses of these designs may be averaged to create a final single stabilized design. A weighting function may be used during this averaging process, for example, giving greater weight to designs created from images where the eye is closer to the first gaze.

[0054] Instead of averaging data across multiple eyes, a unique lens stabilization profile can be created for each individual eye, whereby the shape of the stabilization zone can be customized based on the shape and position of the eyelid in one or more gaze directions for that eye.

[0055] Averaging can also be applied so that the final lens stable design has mirror symmetry about a central vertical or horizontal axis, or can have both vertical and horizontal symmetry. In these cases, the design can be determined by averaging the thickness profiles at all symmetry points.

[0056] Below is an example of how unidirectional data can be processed and averaged across multiple eyes in first fixation to obtain a "population average" design. For example, Figure 3 Eyelid shape data is shown, whereby each line is a second order polynomial fit to a series of points depicted along a photograph of the eyelid margin with the eye in first fixation. Millimeter scale photographs were also taken so that the scale of the image (mm / pixel) is known, and the position and shape of the eyelid are described in millimeters. The origin (0,0) is referenced to the center of the cornea. All eyes used in the collection of this data were right eyes (i.e., left eyes were not included in this particular data set, however the design process can be generalized to the collection of left eye data).

[0057] Eyelid edge delineation and polynomial fitting were performed using custom image analysis software in MATLAB. The camera used to collect eyelid shape information was selected so that the resulting image was a true representation of the eyelid shape in space. Image dewarping or correction for lens aberrations or geometric distortions (e.g., pincushion or barrel distortion) may be applied.

[0058] For the upper and lower eyelids separately, the average eyelid margin shape was obtained by taking the median of all polynomials at each millimeter interval along the X-axis. Figure 4 Graphs are shown for the upper and lower eyelids, respectively, showing that the average eyelid margin 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, by taking Figure 3 The y value is determined by taking the median of all y values ​​of the polynomial for the upper eyelid as shown. A similar process is followed for the lower eyelid.

[0059] So that the final lens design can be bilaterally symmetric, the data is "flipped" left-right about the y-axis. The "flipped" and non-flipped data are then averaged by taking the average of the flipped and non-flipped y values ​​at each position. The resulting "averaged" data is therefore symmetric about the y-axis.

[0060] Figure 5 Shown are left and right 'flipped' and 'non-flipped' data plotted together on the same axis.

[0061] Figure 6 The averages of the flipped and non-flipped data are shown, whereby the average of the y-axis values ​​for each is taken at every millimeter interval. For example, to ensure that the final design is symmetrical from top to bottom about the x-axis, the data is flipped again, this time about the x-axis. Figure 7 Shown are top-down "flipped" and "non-flipped" data plotted together on the same axis.

[0062] The lens thickness design is then generated as follows:

[0063] - Select points along the line shown in the figure above at intervals of millimeters (from -8mm to +8mm on the x-axis, i.e. -8mm, -7mm, -6mm, etc.).

[0064] - For the line representing the average upper eyelid margin shape (both mirrored and non-mirror), these points are given a z-coordinate value of 1.

[0065] For example, the point coordinates of the upper eyelid edge shape are:

[0066] - Point 1 (x, y, z) = (-8, [y value at x = -8], 1)

[0067] - Point 2 (x, y, z) = (-7, [y value at x = -7], 1)

[0068] - Point 3 (x, y, z) = (-6, [y value at x = -6], 1)

[0069] -etc……

[0070] For the line representing the average lower eyelid edge shape (both mirrored and non-mirror), these points are given a z-coordinate value of 0. For example, the point coordinate values ​​for the lower eyelid edge shape are:

[0071] - Point 1 (x, y, z) = (-8, [y value at x = -8], 0)

[0072] - Point 2 (x, y, z) = (-7, [y value at x = -7], 0)

[0073] - Point 3 (x, y, z) = (-6, [y value at x = -6], 0)

[0074] -etc……

[0075] The result is a three-dimensional array of data points, such as Figure 8 Using the MATALB curve fitting tool, the data points were then fitted with a "best fit" polynomial surface of degree 2 defined by the following function:

[0076] z=a+b*x^2+x*y^2

[0077] Fig. 9 A "best fit" polynomial function for these data points using this form of the formula is shown. The polynomial surface shape is fit to the data points using a least squares algorithm. The resulting values ​​for the coefficients a, b and c are determined from this.

[0078] Instead of using a second order polynomial as described herein, a higher order polynomial or some other mathematical function that defines the surface shape can be used. This polynomial can then be used to represent the thickness profile of the stable region of the contact lens, where the local maximum of the polynomial (the central high point at (x, y) = [0, 0]) represents the thickest part of the lens.

[0079] Fig.10 Another graph of this polynomial is shown, where the shading represents the height (z-value) of the surface shape. This "thickness map" can then be used as the basis for generating a lens thickness profile in the stable region of the design. The central optical zone of the lens will be excluded, as will the peripheral lens edge where the thickness of the lens decreases to zero. The stable region of the lens will be blended with these features in the "blending zone" area to make the design a continuous 3D surface.

[0080] Fig.11 Thickness profiles are shown with rough cutouts for the optical zone and lens edge. The optical zone is "cut out" by removing data from the central 8mm circle. The lens edge and beyond are roughly "cut out" by removing any data that falls outside of an ellipse with a horizontal diameter of 15.5mm and a vertical diameter of 14.0mm.

[0081] An exemplary ophthalmic lens may include a first surface and a second surface disposed opposite the first surface, and defining a volume of lens material between the first surface and the second surface. The thickness profile of the volume of lens material may be derived from one or more eyelid contours such that a thickness gradient of at least a portion of the volume of lens material is oriented orthogonal to a target eyelid edge shape. The one or more eyelid contours may include biometric data associated with one or more of the positions or shapes of one or more eyelid edges in an upper eyelid edge or a lower eyelid edge of a group of eyes. The one or more eyelid contours may include biometric data associated with a group of eyes in a target gaze position. The one or more eyelid contours may include biometric data associated with a group of eyes in a plurality of gaze positions. The one or more eyelid contours may include biometric data associated with a group of eyes in one or more blinking phases. The one or more eyelid contours may include biometric data associated with one or more of the positions or shapes of one or more eyelid edges in an upper eyelid edge or a lower eyelid edge of at least one eye. The one or more eyelid contours may include biometric data associated with at least one eye in a target gaze position. The one or more eyelid profiles may include biometric data associated with at least one eye in a plurality of gaze positions. The thickness profile may be associated with a stabilization zone. The portion of the volume of lens material may include an annular volume disposed between an edge of the ophthalmic lens and an optical zone radius. The optical zone radius may be between 3 mm and 5 mm from a center of the ophthalmic lens. The portion of the volume of lens material may include an annular volume including a radial region excluding a region between a terminal edge of the ophthalmic lens and a radius of 1 micron to 300 microns from the terminal edge of the ophthalmic lens.

[0082] To visualize the shape of this design in relation to the initial eyelid margin data, Fig.12 A graph showing the final design image overlaid with the initial eyelid shape polynomial.

[0083] As mentioned above, this is one example of how eyelid shape data can be used to create a lens design. Better techniques can be developed through discussions with people who have a high level of expertise in mathematics, topology, data analysis, and 3D modeling.

[0084] Instead of the described examples, a more optimized design approach may involve one or more of the following:

[0085] - A high degree polynomial function, or other mathematical function for fitting the eyelid shape data.

[0086] - Reference the eyelid shape function to the center of the contact lens worn on the eye (ie so that the origin of the axis is at the center of the contact lens) rather than the center of the cornea.

[0087] -Different techniques for combining eyelid shape data from different images, whereby they can be combined by taking the average or median of the function coefficients, the average of the function values ​​over certain areas, or averaging the "slope / gradient" function of the surface shape generated by the eyelid shape data.

[0088] The above techniques can also be used to create a customized stabilization design for an individual eye, rather than an "average" design across multiple eyes.

[0089] For example, an ophthalmic lens may include a first surface and a second surface disposed opposite the first surface and defining a volume of lens material between the first surface and the second surface. The thickness profile of the volume of lens material is derived from one or more eyelid contours, such that the thickness gradient of the volume of lens material is oriented substantially orthogonal to the target eyelid edge shape, such as Fig.13 Substantially orthogonal can include orthogonal angles and angles that are + / - 20 degrees from orthogonal.

[0090] As another example, a method for creating a stable design for a toric lens may include determining the eyelid edge shape (OD) of a group of right eyes. The upper eyelid edge shape and the lower eyelid edge shape may be plotted in two dimensions using a Cartesian coordinate system. For each eyelid, the "average" (median) eyelid edge position at each plotted X position may be determined. The eyelid shapes may be mirrored about the y-axis (i.e., flipped left to right) so that they are left-right symmetrical so that the data represents the average of the right eye (OD) and the left eye (OS). The mirrored data and the non-mirrored data may be plotted together. For each eyelid, the average (average or median) of the non-mirrored data and the mirrored data may be determined. The updated data may be centered on the origin, then mirrored about the X-axis (i.e., flipped up and down - so that the final design may be "bidirectional"), and the two sets of data may be plotted together. A thickness mapping function may be generated by treating these lines as equal thickness contours. The gradient of the function at any point along the contour line is perpendicular to the line. The lens thickness at the data points along each line can be adjusted so that they have the same Z value (height) in a three-dimensional Cartesian coordinate system so that they are effectively considered points along the contour line. A data point can be added at (x, y) = (0, 0) where the height (Z value) is greater than the Z value assigned to the contour line. The best fitting quadratic polynomial in x and y can then be determined. Data within the central 8mm diameter (the area of ​​the contact lens optical zone) and any data outside the ellipse with a horizontal diameter of 15.5mm and a vertical diameter of 14mm can be filtered out (for elliptical lenses with these horizontal and vertical diameters, outside the "edge"). To show the design associated with the original data, an image can be drawn with the original cap shape overlaid with transparency.

Claims

1. A contact lens comprising: a first surface; and a second surface disposed opposite the first surface and defining a volume of lens material between the first surface and the second surface, the volume of lens material having a varying thickness; The first surface and the second surface are joined at a common circular peripheral lens edge; as well as an optical zone located within said common circular peripheral lens edge; wherein a polynomial is used to represent a thickness profile of the contact lens, the thickness profile being symmetrical about a central vertical axis and / or a central horizontal axis, a local maximum of the polynomial representing a thickest portion of the contact lens, and wherein a target upper eyelid margin shape is depicted by selecting a number of points along an eyelid margin extracted from data from one or more images of one or more eyelid contours that are fit to a curve using a predetermined best fit polynomial and fitting the selected points using the polynomial, and wherein a thickness gradient is constructed as the direction of the maximum slope of the maximum thickness profile along its length such that the thickness gradient is oriented orthogonal to the target upper eyelid margin shape; and wherein said maximum thickness profile extends continuously across said contact lens except in said optic zone and at said common circular peripheral lens edge.

2. The contact lens according to claim 1, wherein: The data from the one or more eyelid contours includes biometric data associated with one or more of the position or shape of one or more eyelid edges in the upper eyelid margins or lower eyelid margins of a group of eyes.

3. The contact lens of claim 1, wherein: The data from the one or more eyelid contours includes biometric data associated with a group of eyes in a target gaze position.

4. The contact lens of claim 1, wherein: The data from the one or more eyelid contours includes biometric data associated with a group of eyes in multiple gaze positions.

5. The contact lens of claim 1, wherein: The data from the one or more eyelid contours includes biometric data associated with a group of eyes in one or more blink stages.

6. The contact lens of claim 1, wherein: The data from the one or more eyelid contours includes biometric data associated with one or more of the position or shape of one or more of an upper eyelid margin or a lower eyelid margin of at least one eye.

7. The contact lens of claim 1, wherein: The data from the one or more eyelid contours includes biometric data associated with at least one eye in a target gaze position.

8. The contact lens of claim 1, wherein: The data from the one or more eyelid contours includes biometric data associated with at least one eye in a plurality of gaze positions.

9. The contact lens of claim 1, wherein: A portion of the volume of lens material includes an annular volume disposed between an edge of the contact lens and a radius of the optic zone.

10. The contact lens of claim 9, wherein: The optical zone radius is between 3 mm and 5 mm from the center of the contact lens.

11. The contact lens of claim 1 , wherein: A portion of the volume of lens material includes an annular volume that excludes a radial region between an edge of the contact lens and a radius of 1 micron to 300 microns from the edge of the contact lens.

12. A method for designing a contact lens comprising: obtaining data from one or more images of one or more eyelid contours associated with one or more eyelids; determining a target upper eyelid margin shape by fitting the data to a curve using a predetermined best fit polynomial; Designing a contact lens comprising a first surface and a second surface disposed opposite the first surface and defining a volume of lens material having a varying thickness therebetween, and a circular peripheral lens edge and an optic zone within the circular peripheral lens edge; wherein a polynomial is used to represent the thickness profile of the contact lens, the thickness profile being symmetric about a central vertical axis and / or a central horizontal axis, a local maximum of the polynomial represents the thickest portion of the contact lens, and wherein the target upper eyelid margin shape is depicted by selecting a number of points along the eyelid margin extracted from data from one or more images of one or more eyelid contours and fitting the selected points using the polynomial, and wherein the maximum thickness profile of the contact lens extends across the contact lens except in the optical zone and at the circular peripheral lens edge, and wherein a thickness gradient is constructed as the direction of the maximum slope of the maximum thickness profile along its length such that the thickness gradient is oriented orthogonal to the target upper eyelid margin shape.

13. The method according to claim 12, wherein: The data from the one or more eyelid contours includes biometric data associated with one or more of the position or shape of one or more eyelid edges in the upper eyelid margins or lower eyelid margins of a group of eyes.

14. The method according to claim 12, wherein: The data from the one or more eyelid contours includes biometric data associated with a group of eyes in a target gaze position.

15. The method according to claim 12, wherein: The data from the one or more eyelid contours includes biometric data associated with a group of eyes in multiple gaze positions.

16. The method according to claim 12, wherein: The data from the one or more eyelid contours includes biometric data associated with a group of eyes in one or more blink stages.

17. The method according to claim 12, wherein: The data from the one or more eyelid contours includes biometric data associated with one or more of the position or shape of one or more of an upper eyelid margin or a lower eyelid margin of at least one eye.

18. The method according to claim 12, wherein: The data from the one or more eyelid contours includes biometric data associated with at least one eye in a target gaze position.

19. The method according to claim 12, wherein: The data from the one or more eyelid contours includes biometric data associated with at least one eye in a plurality of gaze positions.

20. The method of claim 12, further comprising defining a stabilization zone in or on the volume of material, wherein the thickness profile is associated with the stabilization zone.

21. The method according to claim 12, wherein: A portion of the volume of lens material includes an annular volume disposed between an edge of the contact lens and a radius of the optic zone.

22. The method according to claim 21, wherein: The optical zone radius is between 3 mm and 5 mm from the center of the contact lens.

23. The method according to claim 12, wherein: A portion of the volume of lens material includes an annular volume that excludes a radial region between an edge of the contact lens and a radius of 1 micron to 300 microns from the edge of the contact lens.

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