Systems, methods, and apparatus for non-deformation and translation and rotation stable contact lens

Abstract

Generally, one aspect of the present disclosure features a soft contact lens for an eye of a patient, the soft contact lens comprising: an anterior surface; and a posterior surface, the posterior surface comprising: a central optical zone defined by a base arc according to a vertex radius of curvature of a cornea of the eye; at least one peripheral corneal region on the periphery of the central optical region, and a sclera landing region on the periphery of the peripheral corneal region, the sclera landing region having a circumferentially asymmetric height.

Description

Technical Field

[0001] The disclosed technology relates generally to ophthalmic devices, and more particularly, some embodiments relate to a soft contact lens and a method for determining posterior and anterior geometries of a soft contact lens. Background Art

[0002] Soft contact lenses were commercialized more than 40 years ago. The initial design concepts quickly evolved into double-curve and single-curve designs in an attempt to facilitate the lens movement required for tear exchange in lenses made of materials with low oxygen permeability. Lens movement during blinking is necessary to allow a new layer of tears to move from the tear meniscus at the lower eyelid to under the lens. Spin casting, molding, and simple turning used in the first two decades of commercialization allowed for a central base curve and concentric peripheral curves with a longer radius of curvature than the central base curve. Lens thickness varies from 0.04 mm to 0.2 mm, and lens diameters range from 13.0 mm to 16.0 mm.

[0003] The central radius of curvature of the lens, also called the base radius, is selected to be substantially longer than the central radius of curvature of the eye to be fitted. The radius of the first concentric zone (second arc) is always greater than the base radius, and the radius of each zone of the periphery is also respectively greater than the radius of the zone just inside it, and the radius of curvature of each zone is relatively longer outward. Historically, lenses have one to three zones. Generally speaking, the radius of curvature of all zones outside the central optical zone is longer than the radius of curvature of the cornea below and inside it. This is a requirement to promote lens movement and tear exchange.

[0004] Even though each arc is longer than the radius of curvature of the cornea beneath it, the sagittal depth of the entire lens is deeper than the sagittal depth of the eye to which it is fitted due to the decentration of the cornea. The deeper sagittal depth of the entire lens is sometimes referred to as the "band factor". The relatively low modulus of a soft lens allows the lens to stretch or overhang circumferentially to accommodate the geometric diversity of the eye population being fitted.

[0005] These designed lenses demonstrate blink movement and lateral eye movement. The lens movement is approximately 1.0 mm. Edge design is also very important to achieve comfort and prevent trauma to the eye and palpebral conjunctiva.

[0006] The advent of more breathable silicone hydrogel materials has reduced the need for high mobility. Lower modulus materials, improved molding processes, and smoother surface modifications have resulted in thinner and more flexible lens products. The manufacturing cost per lens has decreased, making daily disposable or single-use lenses possible.

[0007] Optical design has also evolved from only spherical lens refractive power to toric lenses to correct astigmatic refractive errors, and to bifocal and multifocal refractive powers to correct presbyopia with or without refractive errors. The development of vibration-free computer numerical control lathe machining has demonstrated the ability to impart sub-micron features on the lens surface and the surface smoothness that does not require post-polishing of the lens by diamond turning the lathe.

[0008] The high level of commercial success of low-cost molded lenses has brought the cost of consumer contact lenses to a low and stable level. An undesired effect is that eyes that cannot achieve vision correction through the optical and geometric parameters of these disposable lenses are relatively lacking in their suitable high-oxygen-permeable soft contact lenses. This category is referred to as "irregular corneal astigmatism" because the cornea is the main contributor to higher-order aberrations. However, this use can be extended to correct higher-order aberrations caused by irregularities in the optical system of the eye, including other optical components of the eye, which reduce the modulation transfer function of the eye.

[0009] Rigid gas-permeable scleral lenses and hybrid lenses are addressing this target market, while custom soft lenses cannot meet the need to deliver sufficient oxygen to the cornea and have a low enough manufacturing cost to allow for at least monthly lens replacement. Part of the reason for not meeting the monthly replacement commodity cost requirement is due to the need to turn each lens. At the same time, compared with scleral and hybrid lenses, disposable custom soft lenses are understood to be more favored by patients due to their relative ease in terms of lens application, lens removal, lens cost, and the convenience of lens disposability.

[0010] The inability to meet the oxygen delivery requirement is the lack of materials that can be turned and have a high enough oxygen permeability for the required lens thickness for the desired optical correction. Although materials science can address the availability of turnable materials with higher oxygen permeability, the manufacturing cost is expected to be too high to meet the monthly replacement pricing established by the market.

[0011] Lens design is a remaining problem to be solved in this disclosure. Lenses for optical correction to correct higher-order aberrations, even high-amplitude low-order refractive errors, and presbyopia need to avoid lens deformation, require the centering of the optical components on the visual axis, and the stability of rotational and translational orientations. This disclosure meets these needs.

[0012] Market dynamics require effective time management in the fitting of contact lenses. Chairtime must be reduced, and the first-pass success rate is an important metric for productivity in this field. One advantage of the systems, methods, and devices of this disclosure is the improvement of the method for selecting parameters for the final lens and the reduction of the chairtime required to obtain an appropriate lens prescription.

[0013] Another market factor lies in the alignment of changes in the curriculum of eye care professionals with the integration of disease treatment. The time allowed in the curriculum for contact lens education and training has been continuously decreasing. Basic training is the goal of the program, while specialized training is considered post-graduate practice. Therefore, the concept of lens prescription must be simple and must require less training to achieve successful results.

[0014] The ophthalmic industry continues to evolve with the technology of instruments for measuring eye morphology. The practice of scleral contact lenses has taught the use of topography, tomography, and impression scanning to understand eye morphology. These techniques are used to predict the shape or geometry of the posterior surface of scleral contact lenses. In the same way, these techniques can be used to assist in the design of soft lenses for different purposes such as reducing lens distortion, assisting in rotational alignment, assisting in translation and orientation stability, and improving the centration of the lens on the visual axis.

[0015] U.S. Patents 8,388,130 and 8,083,346 teach methods for controlling lens distortion and using corneal topography to determine the posterior lens surface of an eye with irregular corneal astigmatism. Even so, these patents do not teach the use of eye morphology to control lens distortion or the combination of the eye morphology geometry of the posterior lens surface with the rotational stability features of the anterior surface. The disclosures of U.S. Patents 8,388,130 and 8,083,346 are hereby incorporated by reference in their entirety.

[0016] The present disclosure provides a system and method for fabricating a predicatelens using eye morphology data, observing the lens orientation when the predicatelens is worn, and measuring the residual low-order and high-order aberration morphology, thereby producing a final lens having additional anterior surface stability features and a surface morphology for correcting refractive errors.

[0017] There is a product opportunity for fully molded lenses with a product cost that allows monthly replacement, which incorporate eye morphology-guided posterior surface geometry and an anterior surface with additional rotational stability features and personalized or customized refractive correction.

[0018] Although attempts have been made to manufacture customized soft lenses by diamond turning, the materials and methods of manufacture do not meet clinical and market requirements. The present disclosure provides a system, method, and apparatus that provide a means for at least monthly replacement for correcting irregular corneal astigmatism, high-order aberrations caused by irregularities in the optical system of the eye, and for correcting presbyopia. SUMMARY OF THE INVENTION

[0019] Due to the lack of oxygen permeability and high manufacturing costs, custom soft lenses have not been able to gain a significant market share. Even so, the market demand for custom soft lenses is expected to increase because corneal cross-linking has become the standard of care for the initial diagnosis of keratoconus. The incidence of severe keratoconus has decreased, and the prevalence of severe irregular corneal astigmatism is expected to shift to a mild to moderate level. These factors, combined with post-refractive surgery ectasia and post-traumatic ectasia, support the need for systems, methods, and devices for correcting irregular corneal astigmatism with custom soft lenses.

[0020] The fitting goals for custom soft contact lenses for irregular corneal astigmatism include a lens diameter that extends approximately 1.5 mm beyond the corneal limbus onto the bulbar conjunctiva, a peripheral lens-eye fit that spares the sclera from excessive edge lift and avoids trauma, a peripheral uniform edge strain below the level of inducing central lens deformation, a translational lens movement of less than 0.2 mm, an orientation instability of less than + / - 5 degrees, and an optical centration within 0.5 mm of the visual axis.

[0021] Four forces affect the positioning of the lens on the eye and the dynamics of the lens with respect to translational and rotational movement. These forces are mass gravity, eyelid interaction, negative pressure from capillary attraction, and strain forces generated by lens deformation due to the mismatch between the shape and volume of the lens and the shape and volume of the eye.

[0022] Mass gravity varies with the specific gravity of the lens material and the total diameter, thickness, and mass of the lens. Eyelid interaction varies with the anatomical shape of the underside of the upper eyelid, the position of the eyelid relative to the corneo-scleral junction, the width of the interpalpebral space, the diameter of the lens, the thickness profile of the lens periphery, and the coefficient of friction of the lens surface.

[0023] Negative pressure or capillary attraction is a function of the surface area of the lens, the relative parallelism of the posterior lens surface to the underlying eye surface, and the thickness of the post-lens tear film. Hydrophobic surface attraction, while separate from negative pressure, increases the adhesion of the lens to the eye. Increasing negative pressure is understood to counteract the forces of mass gravity and eyelid interaction.

[0024] Positive edge strain has been reported to be necessary for retaining a soft contact lens on the cornea. It is well known that commercial soft contact lenses are deeper than the underlying eye at the chord length of their total diameter, while the lens shows a gap from the corneal apex that is less than the amount of the sagittal depth of the entire lens from the sagittal dimension of the underlying eye. The result is the generation of stress at the periphery of the lens, which generates strain energy within the lens.

[0025] The sagittal depth of the human eye is rotationally asymmetric at a chord diameter equal to the corneal diameter and even more so outside the cornea. The rotational asymmetry is understood to increase with distance from the corneal center, and the difference between the deepest meridian and the shallowest meridian of the eye can reach 600 microns or more. In addition, it should be understood that the deepest meridian of the eye and the shallowest meridian of the eye are not separated by 90 degrees. It is expected that this difference in sagittal depth creates a difference in marginal strain, which in turn creates deformation, thus causing a new set of higher-order aberrations in the optical path of the soft contact lens.

[0026] Asymmetric marginal strain may also affect the positioning of the lens relative to the other forces described above. Superior-nasal-inferior-temporal rotation is a common observation in toric contact lenses, which are designed to correct regular corneal astigmatism and incorporate non-rotating features such as prism ballast, double slab off, and asymmetric thin and thick zones. A significant percentage of right lenses known to have rotation-stabilizing features rotate counterclockwise, while left lenses are known to rotate clockwise. Unfortunately, the amount and direction of rotation are different for all eyes. Even with orientation-stabilizing features, clinical observations of the direction and degree distribution of rotation have led to the LARS convention, which is used to teach the means of observing and communicating the position and degree of the lens, and the degree is used to compensate for the axis position of the cylindrical correction of the contact lens. LARS stands for Left Add Right Subtract. Left is the clockwise direction and right is the counterclockwise direction. Professionals are thus trained to add the clockwise angular position of the lens to the cylindrical axis and subtract the degree from the cylindrical axis for the counterclockwise positioning of the lens.

[0027] One theory of this common lens rotation pattern is that eyelid interaction and asymmetric marginal strain forces act together to produce lens rotation. These forces balance at the angle where the lens rotation is stable. Fortunately, the lens rotation angle is usually sufficiently repeatable for a single eye to allow the cylindrical power after axis modification to be effective in correcting regular astigmatism. In addition, rotationally symmetric soft contact lenses show lens decentration in the inferotemporal direction. Unfortunately, the visual axis of the human eye is usually nasal to the geometric center of the cornea. Therefore, the optical center of the soft contact lens needs to be moved in the opposite direction to the nasal position of the cornea where the visual axis is located. The mismatch between the mass gravity and the posterior shape of the contact lens is considered to be the main force causing inferotemporal decentration of the soft contact lens.

[0028] The technical embodiments of the present disclosure provide a novel system, method, and device for solving multiple unmet needs, for treating irregular corneal astigmatism and associated higher-order aberrations, and for successfully commercializing disposable custom soft contact lenses. The same system, method, and device can be applied to improve soft contact lenses for presbyopia, peripheral defocus optics for myopia control, and the management of higher-order aberrations from the optical structures of the eye.

[0029] Generally, one aspect of the present disclosure features an ophthalmic device worn on the ocular surface that contacts the cornea, bulbar conjunctiva, and the inner side of the eyelids. The device can be applied to and worn on the surface of the eye so as to provide optimal vision, comfort, and health for the user's eye and appendages due to its design, materials, manufacturing, and method of parameter selection.

[0030] In some embodiments, the posterior surface of the soft contact lens is empirically designed based on biometric average data of known eye shapes combined with routine and customary clinical measurements. In other embodiments, the anterior surface parameters are selected from clinical observations and measurements, where the initial lens has known parameters applied to the eye surface. In other embodiments, instrumentation techniques for measuring the ocular surface morphology, at least the inner side of the upper eyelid, and the position of the eyelid relative to the corneoscleral junction can be used to design the posterior and anterior surfaces of the lens.

[0031] The problem solved by the present disclosure is the management of forces that affect the deformation, centration, translation, and rotational stability of soft contact lenses to allow for optimized refractive correction and the resulting optimal contact lens corrected vision.

[0032] In some embodiments, the device is a soft contact lens with a novel posterior surface morphology that reduces asymmetric edge strain and utilizes the asymmetry of the human eye to enhance lens centration and rotational stability, and is combined with one or more anterior surface rotational stability designs selected from clinical measurements of one or more of the interpalpebral space or palpebral fissure, eyelid position, and posterior eyelid anatomical shape.

[0033] In some embodiments, the present disclosure teaches the measurement of eye morphology and a method for correcting errors caused by fixation-based instrumentation to provide corrected eye morphology; using the corrected eye morphology to select a predicted posterior surface morphology of a soft contact lens; applying the predicted soft contact lens and observing its centration, orientation, orientation stability, and translational mobility; measuring residual low-order and high-order aberrations with the predicted lens in place; using at least one of the dimensions of the palpebral fissure, eyelid position, and anatomical shape of the inner side of the upper eyelid to select anterior surface lens stability features; and the creation of a cutting file for the final lens or for the mold for molding the final lens.

[0034] In general, one aspect of the present disclosure features a soft contact lens for a patient's eye, the soft contact lens including: a front surface; and a rear surface, the rear surface including: a central optical zone defined by a base curve selected according to the vertex curvature radius of the eye's cornea; a peripheral corneal zone peripheral to the central optical zone, and a scleral landing zone peripheral to the peripheral corneal zone, where if a fixation-based instrument is used, the scleral landing zone has a shape derived from the corrected ocular morphology, or if non-fixation-based tomography, imprinting, or scanning is used to measure the ocular morphology, the scleral landing zone has a shape derived from the ocular morphology data.

[0035] Embodiments of personalized or customized soft contact lenses may include one or more of the following features: the base curve of the central optical zone is defined by at least one of a spherical radius, an aspherical radius with a conic constant, a toric surface, a multifocal shape, or a rotationally asymmetric shape. In some embodiments, the peripheral corneal zone and the scleral landing zone are defined by a spline having a plurality of knots and / or control points. In some embodiments, the peripheral corneal zone is defined by an outermost knot and an innermost knot; where when the base curve radius is shorter than a predetermined length, the sagittal depth of the outermost knot is shallower than that of the innermost knot relative to the innermost knot along the semi-chord length diameter extended to the outermost knot along the base curve; and where when the base curve radius is greater than the predetermined length, the sagittal depth of the outermost knot is deeper than that of the innermost knot relative to the innermost knot along the semi-chord length diameter extended to the outermost knot along the base curve. In some embodiments, the predetermined length is 8.0 mm. In some embodiments, the scleral landing zone is circumferentially specific in height, but is transformed into an optimally fitted radial tangent controlled by an angle.

[0036] In some embodiments, the scleral landing zone is circumferentially asymmetric and its circumferential height varies proportionally to the ocular morphology of the expected eye. The ocular morphology can be determined by fixation-based techniques, including optical coherence tomography instruments or instruments employing Scheimpflug imaging or fringe topography or similar scanning-based techniques. The ocular morphology can be measured using laser scanning as described in U.S. Patent Publication No. 20220313081, by scanning an impression, scanning the eye wearing a contact lens with reference marks as described in U.S. Patent 11,762,219, or by other means. The disclosures of U.S. Patent Publication No. 20220313081 and U.S. Patent 11,762,219 are incorporated herein by reference in their entireties.

[0037] In some embodiments, the entire posterior surface region; the central optical zone, the peripheral corneal zone, and the scleral zone are highly specific at each point. Regarding the central optical zone, the resulting lack of a conventional spherical arc for the optics of the lens can be compensated for using anterior surface wavefront-guided optics generated by conventional and customary techniques. In this embodiment, customization can be performed in each zone.

[0038] In this embodiment, the lens does not have a detectable posterior zone. Instead, the posterior surface of the lens is coordinated with the eye surface, and the entire posterior surface of the lens is shaped to match the morphology of the eye surface. In a typical lens, the posterior surface has an optical zone, which is usually spherical or sometimes toric. In this embodiment, the posterior surface shape is equivalent to the eye surface to eliminate or minimize soft material deformation and improve or contribute to lens stability. This is particularly useful in irregular corneal shapes. Subsequently, the anterior surface optics can be derived from wavefront aberration measurements and placed on the visual axis by using image capture of the lens reference or other methods to determine the registration of the higher-order aberration characteristics of the lens relative to the visual axis position.

[0039] In some embodiments, the scleral zone of the posterior surface can be altered by increasing or decreasing the angle of the lens surface from its edge inward. Modulation of the radial angle can be used to produce uniform edge strain, or in combination with circumferentially modulating the lens thickness or by other means to assist in producing uniform edge strain.

[0040] Those skilled in the art well understand that the visual axis does not pass through the geometric center of the cornea. Instead, it is known that the Kappa angle is formed by the height of the angle, which is the separation between the geometric center of the cornea and the point on the cornea through which the visual axis passes. Fixation-based instruments produce incorrect eye morphology due to the rotation of the eye at the angular measure of the Kappa angle. The effect of the error due to Kappa angle rotation is greatest in the horizontal meridian, where the Kappa angle can be greater than or less than 5 degrees and smaller in the vertical meridian, and in the vertical meridian, the visual axis can pass through the cornea approximately 1 degree below the geometric center. The Kappa angle varies from eye to eye due to the position distribution of the fovea centralis and the nodal point of the eye and the position and refractive power distribution of the eye's optical elements.

[0041] The present disclosure teaches standardizing the data from these fixation-based instruments to correct eye morphology measurements due to eye rotation during measurement.

[0042] A method for correcting the sagittal depth value provided by a fixation-based instrument can be a manual measurement by calibrating the image perpendicular to the geometric axis rather than the visual axis, or by adding or subtracting a calculation of the height of a triangle using the base length of the triangle and the apex angle through a conventional tangent equation, or by applying a calculation of the derived constant of each chord diameter and the mean of the Kappa angle. The base length of the triangle is the eye depth from the corneal vertex to the chord line determined for sagittal depth measurement. The angle is the Kappa angle. The first Purkinje image or reflection image on the anterior cornea provides a reasonable estimated position for the visual axis. In severely irregular corneas or corneas with displaced ectasia, the first Purkinje image does not represent the visual axis, but the image is displaced due to the displaced position of the corneal vertex. In these cases, the visual axis can be estimated by using any one of the pupil centers from photopic, mesopic, or scotopic illumination conditions or the mean of all pupil centers for some selected conditions, and the geometric center of the cornea can be derived from limbus-to-limbus, white-to-white distance, or anterior chamber angle-to-angle measurements.

[0043] The final difference between the geometric center and the visual axis results in two independent planes: the geometric plane and the visual axis plane. When the optical center of the lens is aligned with the geometric plane, it results in visual axis misalignment, so the visual axis and the optical center of the lens are misaligned, and optical aberrations are expected to occur. To correct the misalignment of the visual axis with the optical center of the lens, a second-order tilt is applied to make the visual axis plane perpendicular to the optical center plane. After tilting the visual axis plane, the optical center can be decentered to the visual axis position.

[0044] Traditionally, a large anterior optical zone has been used to address the moving and centering lens dynamics as well as pupil size to provide an optical device that does not bisect the pupil. As the size of the anterior optical zone increases, the lens thickness also increases. For plus-powered optics, the central optical device thickness increases while the peripheral optical device thickness decreases, and for minus-powered optics, the opposite is true. For prism optics, the lens thickness increases at the prism base and thins at the prism apex. The large optical zone adds an undesirable additional mass to the lens, further resulting in a mass gravitational effect. Additionally, the increased thickness of the anterior optical device causes the anterior lens surface to rise, creating more posterior eyelid interactions, which can have an adverse effect on lens dynamics. In the case of an ideal stable lens using the features described herein, the high-order aberration optics can be sized to achieve the maximum natural scotopic pupil to minimize the undesirable effects on lens position and translational movement. Thus, custom-sizing the lens optics minimizes the mass gravitational effect and minimizes the interaction of the posterior eyelid with the thicker optical structure, thereby further stabilizing the lens. In some embodiments, the application of the principles of visual axis plane alignment and decentration of the optical center can be applied to further optimize the translational and rotational positioning, stability, and optical correction of the eye.

[0045] Anterior lens stabilizing features include asymmetric thin and thick zones that can be customized by interpalpebral space, eyelid position, and eyelid dynamic movement. The superior thin zone and / or inferior thin zone can be customized by eyelid position to minimize eyelid interaction. The nasal and / or temporal thick zones can be customized by eyelid position and morphology of the primary eye position. A smoothing algorithm can be applied to smooth the anterior surface of the lens, which can further minimize the zone junction thickness and abrupt shapes to minimize eyelid-lens interaction.

[0046] The circumferential shape of the scleral landing zone of a soft contact lens is selected to produce uniform edge strain to reduce central lens deformation, improve lens centration, and enhance orientation stability of soft contact lenses with or without anterior rotational stabilization features.

[0047] In general, one aspect of the present disclosure is characterized by a method for defining the shape of the back surface of a soft contact lens for a patient's eye, the method comprising: defining a base curve of a central optical zone of the soft contact lens according to a vertex curvature radius of the cornea of ​​the eye; defining at least one peripheral corneal zone periphery of the optical zone; and defining a scleral landing zone periphery of at least one peripheral corneal zone according to correct eye morphology data.

[0048] Embodiments of the method may include one or more of the following features. Some embodiments include defining a base curve of the central optical zone according to at least one of a spherical radius, an aspherical radius with a conic constant, a torus, a multifocal shape, or a rotationally asymmetric shape. Some embodiments include defining a peripheral corneal zone and a scleral landing zone according to a spline having a plurality of nodes and / or control points. In some embodiments, the peripheral corneal zone is defined according to an outermost node and an innermost node; wherein when the base curve radius is shorter than a predetermined length, the sagittal depth of the outermost node is shallower than the innermost node relative to the innermost node at a half-chord diameter extending along the base curve to the outermost node; and wherein when the base curve radius is greater than a predetermined length, the sagittal depth of the outermost node is deeper than the innermost node relative to the innermost node at a half-chord diameter extending along the base curve to the outermost node. In some embodiments, the predetermined length is 8.0 mm.

[0049] Some embodiments include defining a scleral landing zone based on corrected ocular shape data obtained by an algorithm that corrects for errors caused by ocular rotation due to the kappa angle using a fixation-based ocular shape instrument. Other embodiments include defining a scleral landing zone from a modification of a non-fixation-based ocular shape measurement technique to produce uniform circumferential edge strain, thereby reducing central lens deformation, improving lens centration, and enhancing the orientation stability of a soft contact lens with or without anterior rotation stability features. Generally, one aspect of the present disclosure features a soft contact lens for a patient's eye, the soft contact lens including: a front surface; and a rear surface including: a central optical zone defined by a base curve selected based on the vertex curvature radius of the cornea of the eye; at least one peripheral corneal zone peripheral to the central optical zone, and a scleral landing zone peripheral to the peripheral corneal zone, the scleral landing zone having a circumferentially asymmetric height.

[0050] Embodiments of the soft contact lens may include one or more of the following features. In some embodiments, the base curve of the central optical zone is defined by at least one of a spherical radius, an aspherical radius with a conic constant, a toroid, a multifocal shape, or a rotationally asymmetric shape. In some embodiments, at least one of the peripheral corneal zone and the scleral landing zone is defined by a spline having a plurality of knots and / or control points. In some embodiments, the peripheral corneal zone is defined by an outermost knot and an innermost knot; when the base curve radius is shorter than a predetermined length, the sagittal depth of the outermost knot is shallower than the innermost knot relative to the innermost knot along the semi-chord length diameter extended to the outermost knot along the base curve; and when the base curve radius is greater than a predetermined length, the sagittal depth of the outermost knot is deeper than the innermost knot relative to the innermost knot along the semi-chord length diameter extended to the outermost knot along the base curve.

[0051] In some embodiments, the predetermined length of the base curve radius is 8.0 mm. In other embodiments, the predetermined length of the base curve radius may be greater than or less than 8.0 mm. In some embodiments, the scleral landing zone is defined by a corrected ocular shape from fixation-based ocular tomography. In some embodiments, the corrected ocular shape adjusts the circumferentially asymmetric height to correct for errors caused by the deviation of the point of intersection of the visual axis with the cornea from the geometric center of the cornea to define the asymmetric sagittal depth of the scleral landing zone. In some embodiments, the scleral landing zone is rotationally asymmetric in sagittal depth to improve lens centration, regulate edge strain, reduce deformation of the optical zone, and enhance orientation positioning and stability. In some embodiments, the scleral landing zone is rotationally asymmetric in thickness to regulate edge strain, reduce deformation of the optical zone, and enhance orientation positioning and stability. In some embodiments, the front surface includes a rotation stability feature determined by measuring at least one of the palpebral fissure, the position of the upper eyelid, and the posterior anatomical shape of the upper eyelid.

[0052] Another aspect of the present disclosure features a method for defining the posterior surface shape and the anterior surface shape of a soft contact lens for a patient's eye. The method includes: defining the base curve of the central optical zone of the soft contact lens according to the vertex curvature radius of the eye's cornea; defining a peripheral corneal zone at the periphery of the central optical zone; defining a scleral landing zone at the periphery of the peripheral corneal zone according to ocular morphological data that is not affected by the rotation of the eye during measurement; selecting or manufacturing a predicted lens having the defined base curve, peripheral corneal zone, and scleral landing zone; applying the predicted lens and measuring the lens registration with respect to the pupil center or visual axis, as well as the translational and orientation stability; defining an anterior stability feature based on at least one of the palpebral fissure, the position of the upper eyelid, and the posterior anatomical shape of the upper eyelid; and, with the predicted lens in place, defining the anterior optical zone based on at least one of subjective refraction, spherical-cylindrical refraction, pupil size, and on-eye aberration measurement.

[0053] Embodiments of the method may include one or more of the following features. Some embodiments include defining the base curve of the central optical zone according to at least one of a spherical radius, an aspherical radius with a conic constant, a toric surface, a multifocal shape, and a rotationally asymmetric shape. Some embodiments include defining the peripheral corneal zone and the scleral landing zone according to a spline curve having a plurality of knots and / or control points. Some embodiments include defining the peripheral corneal zone according to the outermost knot and the innermost knot; wherein when the base curve radius is shorter than a predetermined length, the sagittal depth of the outermost knot is shallower than that of the innermost knot relative to the innermost knot along the semi-chord length diameter extended to the outermost knot along the base curve; and wherein when the base curve radius is greater than the predetermined length, the sagittal depth of the outermost knot is deeper than that of the innermost knot relative to the innermost knot along the semi-chord length diameter extended to the outermost knot along the base curve. In some embodiments, the predetermined length is 8.0 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In accordance with one or more different embodiments, the present disclosure is described in detail with reference to the following drawings. The drawings are provided for illustrative purposes only and depict typical or example embodiments.

[0055] Figure 1 is a front view schematic diagram of a soft contact lens according to some embodiments of the technology of the present disclosure.

[0056] Figure 2 is a cross-sectional schematic diagram of the posterior surface of a soft contact lens according to some embodiments of the technology of the present disclosure.

[0057] Figure 3A is a schematic diagram of a short-radius base curve in a central optical zone with a shallow peripheral corneal zone according to some embodiments of the technology of the present disclosure.

[0058] Figure 3BSchematic illustration of a long radius base curve in a central optical zone with a deep peripheral corneal zone according to some embodiments of the present disclosure technology.

[0059] Figure 4A 、 4B 4C and 4D show optical coherence tomography images with normal eye rotation since the visual axis passes through the nasal side of the corneal geometric center.

[0060] Figure 5 Table of sagittal depth values measured without correcting for eye rotation caused by the kappa angle and sagittal depth values measured after correcting the kappa angle according to some embodiments of the present disclosure technology.

[0061] Figure 6 Schematic illustration of the common superonasal-inferotemporal view for a rotationally symmetric back surface toric contact lens for correcting astigmatism.

[0062] Figure 7 Schematic illustration of the principal non-orthogonal asymmetric height of the human eye measured by a fixation-based instrument.

[0063] Figure 8A 、 8B And 8C are schematic illustrations of three front surface rotational stability features described as double thin zones, prism draping, and asymmetric thin and thick zones.

[0064] Figure 9 Schematic illustration of a final soft contact lens according to some embodiments of the present disclosure technology, which is an orientation marker for verifying lens registration with the pupil center and lens orientation.

[0065] Figure 10 Flow schematic illustration of the overall process for producing a soft contact lens according to some embodiments of the present disclosure technology.

[0066] Figure 11 Flow schematic illustration of the overall process for defining the shape of the back surface of a soft contact lens for a patient's eye according to some embodiments of the present disclosure technology.

[0067] Figure 12 Block diagram depicting an example computer system in which embodiments described herein may be implemented.

[0068] The drawings are not exhaustive and do not limit the present disclosure to the exact form of the present disclosure. Detailed Description

[0069] Some embodiments of the disclosed technology provide a lens having at least three posterior regions: a central optical zone, a peripheral corneal zone, and a scleral landing zone. Various embodiments ensure corneal alignment by empirically selecting a base curve radius in the central optical zone that is close to the radius of curvature of the underlying cornea; provide the peripheral corneal zone using corneal topography or biometric average elevation data; and provide a rotationally asymmetric scleral landing zone to produce uniform edge strain and / or a rotationally asymmetric peripheral lens thickness, thereby reducing central lens distortion, improving lens centration, and enhancing the orientation stability of a soft contact lens with or without anterior rotation stability features.

[0070] Embodiments of the disclosed technology can provide soft contact lenses for wear on the anterior eye surface, methods for selecting lens parameters, and methods for manufacturing lenses. These techniques can employ spline mathematics, Bézier curves, or other geometries to determine the surface profile of the contact lens at predetermined control points or nodes on the posterior surface, which are defined by the specified semi-chord diameter distances of the contact lens from the lens center to the lens edge and the sagittal depth of the contact lens from a reference plane. Some embodiments utilize corneal topography and / or ocular tomograms of each eye to apply algorithms to determine the semi-meridian sagittal depths at one or more control points, thereby allowing for predictive empirical lens fitting and selection of observed eye parameters to determine preferred anterior surface stability features.

[0071] In some embodiments, the base curve radius of the optical zone is selected using the vertex radius of curvature of the cornea measured by a standard keratometer or the reference sphere or best-fit sphere measured by corneal topography. To correct for higher-order aberrations or irregularities of the anterior corneal surface, the base curve geometry can be spherical, toric, aspheric using a conic constant, multifocal, or rotationally asymmetric.

[0072] In some embodiments, the posterior lens surface is designed to match the morphology of the eye surface. Unlike traditional soft contact lenses having an optical zone that is typically spherical or sometimes toric on the posterior surface, this embodiment does not have a defined posterior optical zone. Instead, it has a shape that matches the morphology of the anterior eye surface. This feature helps to eliminate or minimize soft material distortion and helps to improve or facilitate lens stability. Optical correction can be managed by aberration measurement, and the anterior surface is designed to place low-order and higher-order aberration features coincident with or centered on the visual axis. A fiducial or other method can be employed to determine the position of the lens relative to the visual axis while measuring low-order and higher-order aberrations. The resulting embodiments can include wavefront-guided optics for vision correction on the anterior lens surface of the lens and / or a posterior surface that does not have a traditional spherical or toric optical zone.

[0073] In addition, the peripheral corneal region can be empirically determined using the height data of corneal topography, or can be empirically determined using the radius of the base curve or the effective radius of the base curve. The algorithm can employ an inverse relationship, where the shorter the base curve radius, the shallower the node is set at the peripheral azimuth of the peripheral corneal region; conversely, the longer the base curve radius, the deeper the node is set at the peripheral azimuth of the peripheral corneal region.

[0074] In some embodiments, the peripheral corneal region is defined by a spline that has a first node at the junction of the peripheral corneal region and its medial optical zone and has the local slope of the optical zone. At least one medial node normalizes the height of the lens surface inversely proportional to the base curve radius as described above, and the last node joins the scleral landing zone at the starting point of the scleral landing zone with the local slope at that point. The sagittal depth of each node of each meridian of the peripheral corneal region can be determined by ocular tomography to produce the most uniform lens-eye fit.

[0075] In some embodiments, after measuring the sagittal depth of at least one meridian at a predetermined chord diameter outside the cornea, the shape of the scleral landing zone is guided by biometric average data. For example, a measurement of the average sagittal depth of the full horizontal meridian at a chord of 14 mm can be provided. Then, the biometric average ocular morphology of the population of eyes to be treated can be combined with the known sagittal depth of the individual eye to select a predictive lens for observation and measurement, thereby generating the final lens.

[0076] In other embodiments, the full-eye morphology can be measured with a fixation-based instrument, and an algorithm can be applied to correct for errors caused by eye rotation due to the visual axis not passing through the geometric center of the cornea; and, the corrected ocular morphology can be used to select or generate a predictive lens for observation and measurement.

[0077] In some embodiments, scanning of an impression, direct scanning of an eye with landmarks (as taught in U.S. Patent Publication No. 20220313081), or scanning of a reference contact lens with detectable markers (e.g., as described in U.S. Patent No. 11,762,219) can be used to generate ocular morphology data, which is used to select or generate a predictive lens for observation and measurement.

[0078] In some embodiments, the ocular morphology data can be used to generate a lens whose sagittal depth in the peripheral corneal region and the scleral landing zone in each meridian corresponds one-to-one with the corrected ocular morphology measured in the same meridian. In other embodiments, the peripheral corneal region can be designed to have a smaller gap or excessive sagittal depth in at least one meridian; and, in other embodiments, the scleral landing zone can be designed to have an expected deviation from the measured or corrected ocular morphology data.

[0079] In some embodiments, an intentional deviation of the posterior lens shape from the corrected or measured eye shape in at least one meridian can be employed to counteract at least one of mass gravity, eyelid interaction forces, or negative pressure, or to increase or decrease the edge strain in at least one semi-meridian in order to use strain energy to move the lens position or counteract another force causing lens deformation.

[0080] In some embodiments, the thickness profile of the outer periphery of the contact lens is intentionally varied circumferentially to adjust the edge strain in each semi-meridian. Strain management based on the outer peripheral lens thickness is achieved by selectively designing thick or thin semi-meridians, sectors, or quadrants to create regions of greater edge strain or edge strain elimination. Thereby, lens deformation caused by edge strain can be reduced, predictability and consistency of orientation positioning can be achieved, and orientation stability can be enhanced.

[0081] In some embodiments, the total diameter of the lens can be selected based on the horizontal visible iris diameter or the corneal diameter. The diameter range can be from 13.0 mm to 22.0 mm. A fixed diameter between 14.0 and 16.0 mm can be selected. For example, a total diameter of 14.8 mm may be able to accommodate a large distribution of human eyes.

[0082] In some embodiments of the present disclosure, the soft contact lens can have a base curve radius ranging from 5.0 mm to 12 mm, an optical zone diameter in the range of 5.0 mm to 10.0 mm, a peripheral corneal zone width in the range of 0.2 mm to 2.0 mm; and a scleral landing zone width in the range of 1.0 mm to 2.5 mm.

[0083] In some embodiments, a preferred oxygen permeability is 100×10 -11 (cm 2 / sec)(mL O2) / (mL×mm Hg) or higher for a silicone hydrogel material. A medium to low modulus is optimal, and relatively low radial and linear expansion coefficients allow for the imparting of submicron high-order aberration correction features, which will be more predictably used for their optical purposes.

[0084] In some embodiments, a silicone elastomer material including various polydimethylsiloxanes can be used. For example, a material named Lemafocon A can be used in the United States, which has a measured oxygen permeability Dk = 778×10 -11 ((cm 2 / sec)(mLO2) / (mL×mm Hg). It is known that silicone elastomer materials have near-zero radial and linear expansion coefficients, can be easily molded to submicron precision, and allow for a thicker lens profile due to their ultra-high oxygen permeability.

[0085] In some embodiments, the lens is designed and converted into a cutting file for direct diamond turning. For example, an Optoform or DAC computer numerical control lathe can use the cutting file to act on the front surface, back surface, and edge to turn the lens material blank completely into a finished lens.

[0086] In some embodiments, the lens may have a coordination zone before the lens edge terminus, and the resulting lens may be planar and circular. In other embodiments, an asymmetric edge file can be generated, and the resulting lens can be non-planar and / or non-circular. The edge can exhibit an asymmetry similar to the outermost peripheral orientation of the scleral landing zone in its sagittal depth and thus closely match the ocular morphology of the measured eye.

[0087] In some embodiments, at each meridian in the scleral landing zone of the soft lens of the present disclosure, when deviating from the circumferential sagittal depth, the edge terminus can be designed to remain non-planar.

[0088] Figure 1 A plan view of a soft contact lens 100 according to some embodiments of the technology of the present disclosure is shown. Referring Figure 1 , the soft contact lens 100 can have at least three zones and at least three nodes on the back surface. The most central zone is the central optical zone OZ, which has a surface shape that, when combined with the front surface shape, achieves the optical correction of the eye. The back surface shape of the central optical zone can be spherical, aspherical with a conic constant, toric, multifocal with two or more radii of curvature, or rotationally asymmetric to correct corneal irregularities or higher-order aberrations. The central optical zone OZ can have a fixed diameter or a diameter that varies with its radius of curvature. The periphery of the central optical zone is bounded by the node 1 (k1) in each semi-meridian. The region outside the periphery of the central optical zone OZ can be the peripheral corneal zone PCZ.

[0089] The peripheral corneal zone PCZ can be bounded by the node 2 (k2) in its peripheral orientation. The height of k2 is modulated as a function of the base curve radius, where the shorter the base curve radius, the shallower k2 is placed, and the longer the base curve radius, the deeper k2 is placed. For example, for a base curve radius of 8.00 mm, when extending this base curve along the same radius of curvature, 8.00 mm, to the chord length diameter of K2, the sagittal depth of k2 does not deviate from the extended surface; while when the base curve radius is decreased from 8.00 mm and extended along the corresponding radius of curvature to the K2 chord length radius, k2 can rise above the extended surface; and as the base curve radius increases from 8.00 mm, k2 can drop below the surface extended along the corresponding radius of curvature to the k2 chord length diameter.

[0090] In some embodiments, the shape of the peripheral corneal zone can be determined by corneal topography or tomography. In this way, the posterior surface morphology can be adapted to the peripheral cornea in each meridian. The adaptation or near adaptation in each meridian may be superior to the empirical adjustment of the nodal point 2 (K2), and it is expected that the use for the posterior surface of the lens can achieve the purpose of further reducing lens deformation, improving lens centration, and enhancing the rotational stability of the soft lens.

[0091] The outer peripheral zone of the peripheral corneal zone is the scleral landing zone SLZ. The scleral landing zone is bounded in its outer peripheral orientation by the nodal point 4 (k4) forming the edge terminus, and has at least one nodal point 3 (k3) at its maximum depth point within this zone. The scleral landing zone SLZ can be formed as part of a cubic spline, basis spline, or Bessel function, etc. generated by the positions of a series of nodal points. According to the present disclosure, the sagittal depths of the nodal points k2, k3, and k4 can be estimated first by corrected or measured eye morphology data.

[0092] It should be understood that Figure 1 the embodiments of

[0093] Figure 2 A cross-sectional view of the posterior surface of a soft lens 200 according to some embodiments of the present disclosure is shown. Referring to Figure 2 , the nodal points k1-k4 for the lower part of the eye are shown, as well as the zones OZ, PCZ, and SLZ. The upper part of the eye can be described in a similar manner.

[0094] Figure 3A A short base curve radius in the central optical zone OZ with a shallow peripheral corneal zone PCZ according to some embodiments of the present disclosure is shown. The peripheral corneal zone PCZ is bounded in its inner or central orientation by the nodal point 1 (k1), and in its outer peripheral orientation by the nodal point 2 (k2). Figure 3BShows a long base curve radius in the central optical zone OZ with a deep peripheral corneal zone PCZ according to some embodiments of the disclosed technology. The peripheral corneal zone PCZ is bounded medially or centrally by node 1 (k1) and laterally by node 2 (k2). The height of node 2 (k2) is modulated as a function of the base curve radius OZ, where the shorter the base curve radius, the shallower k2 is placed, and the longer the base curve radius OZ, the deeper k2 is placed. It should be understood that the embodiments of FIG. 3 can be used in whole or in part in combination with other embodiments described herein. For example, for a base curve radius of 8.00 mm, extending the base along the same radius of curvature, 8.00 mm, to the chord diameter of K2, the sagittal depth of k2 does not deviate from the extended surface; while when the base curve radius is decreased from 8.00 mm and extended along the corresponding radius of curvature to the chord radius of K2, k2 can rise above the extended surface; and as the base curve radius increases from 8.00 mm, k2 can drop below the surface extended along the corresponding radius of curvature to the chord diameter of k2. Additionally, the sagittal depth of k2 in each meridian can be determined by corneal topography or ocular tomography.

[0095] Figure 4A Shows an optical coherence tomography image of the horizontal meridian of the right eye and depicts the normal temporal rotation of the eye due to the nasal passage of the visual axis through the corneal geometric center. The ophthalmic convention is to label the nasal horizontal orientation of the right eye, also the 3 o'clock position, as zero degrees and the temporal horizontal orientation as 180 degrees. Thus, the superior vertical orientation is 90 degrees and the inferior vertical orientation is 270 degrees. Notes P1, P2, and P3 refer to points on lines L2 and L3. P1 is the midpoint of baseline L1, at which midpoint the eye has a chord diameter for measuring the sagittal depth with a prescribed or expected value. P3 is the intersection point of the visual axis position as it passes through the anterior corneal surface. P2 is the geometric center of the cornea. The vertex of the angle formed by lines P1 - P2 and P1 - P3 is P1 on L1. This angle represents the Kappa angle. L2 is formed by connecting P1 and P2. L3 is formed by connecting P1 and P3. L2, L3, L4, L5, L6, and L7 are reference lines for measuring the sagittal depth at the base chord L1. In this example, L1 has a length of 14.8 mm. L5 is orthogonal to L3, and L6 and L7 are orthogonal to L5. In this construction representing a fixation-based instrument, the sagittal depth of the nasal orientation of this right eye is represented by L7 and presents a value of 3.105 mm, and the sagittal depth of the temporal orientation of this right eye is represented by L6 and presents a value of 4.045 mm. Note that since the visual axis is nasal to the geometric axis, this right eye is rotated temporally (i.e., to the right), resulting in the length of L6 appearing substantially greater than L7.

[0096] Figure 4B and 4CRespectively represent similar images and measurement results of the uncorrected sagittal depth in the 45 - 225 degree meridian and the 90 - 270 degree meridian of the same eye. When the meridian moves away from the horizontal meridian marked as 0 - 180 and shown in Figure 4A , the angular deviation between L2 and L3 decreases.

[0097] Continuing to refer to Figure 4D , line L5 is generated perpendicular to line L2 instead of L3, and lines L6 and L7 are generated perpendicular to line L5 to measure the adjusted sagittal depth, thereby attempting to correct the rotation of the eye and achieve a corrected measurement of the sagittal depth of the eye from the corneal geometric center and compensate for the rotation of the eye. Note that the corrected sagittal depth is substantially different from the sagittal depth measured when the eye is positioned due to the Kappa angle.

[0098] Figure 5 is a table of the sagittal depth values measured without correcting for the rotation of the eye due to the Kappa angle and the sagittal depth values measured after correcting the Kappa angle. Figure 6 Shows the superior - nasal - inferior - temporal view common for rotationally symmetric posterior - surface toric contact lenses with anterior - surface rotation - stabilizing features for correcting astigmatism. In Figure 6 , the superior - nasal - inferior - temporal views of lenses 602 and 604 are indicated by the arrows at 606 and 608.

[0099] Figure 7 Shows the main non - orthogonal non - symmetric heights of the human eye reported in the literature and obtained by using fixation - based tomographic techniques. In Figure 7 , the iris is shown at 702 and the pupil is shown at 704. Figure 7 The inner - ring numbers with notes represent angles in ophthalmic convention. According to this convention, zero degrees is at the 3 o'clock position, the degrees increase counter - clockwise, 90 degrees is at 12 o'clock, 180 degrees is at 9 o'clock, and 270 degrees is at 6 o'clock. These data are for the right eye, and zero degrees is the nasal position while 180 degrees is the temporal position.

[0100] The outer - ring values are the corresponding average depths of the sample of 32 right eyes measured in microns. These data indicate that the shallowest sector of this right - eye sample is in the region from zero to 330 degrees, while the deepest sector is between 210 and 270 degrees. It is worth noting that the deepest and shallowest regions of the eye presented by these data are not 90 degrees apart and vary by up to 387 microns.

[0101] Figure 8A , 8B and 8C show three anterior - surface rotation - stabilizing features. Figure 8A Shows the prism ballast, where at 802, the lens is thin near the top, thick near the bottom, and beveled at the bottom. Figure 8BShows a double thin zone, where the lens is beveled at the top 804 and the bottom 806. Figure 8C Shows a lens having an asymmetric zone including a thin zone 808 and two thick zones 810.

[0102] Figure 9 Shows a final soft contact lens according to some embodiments of the present disclosure technology, which has an orientation mark 812 for checking the registration of the lens with the pupil center and the lens orientation. The orientation marks 812 can be located on a circle 814, and two orientation marks 812 are located at the bottom. However, any configuration of orientation marks can be used.

[0103] Figure 10 Is a flowchart showing an overall process 1000 for producing a soft contact lens according to some embodiments of the present disclosure technology. The elements of process 1000 are presented in one arrangement. However, it should be understood that one or more elements of the process can be performed in a different order, in parallel, completely omitted, etc. In addition, process 1000 can include other elements in addition to those presented.

[0104] Reference Figure 10 , process 1000 can include performing a clinical test of the eye at 1002. The clinical test can include determining uncorrected visual acuity, refraction, binocular vision, eye health, corneal curvature, corneal diameter, corneal topography, eyelid position and palpebral fissure size, pupillometry, observing the lens-eye fitting of a predicted soft contact lens for known parameters, etc.

[0105] Process 1000 can include selecting constants and calculating lens parameters at 1004. These parameters can include base curve radius, optical zone diameter, total diameter, peripheral corneal zone width, sagittal depth of k2, transverse and sagittal positions of k3, scleral landing zone width, sagittal depth of k4, lens refractive power, etc.

[0106] The parameters of the front surface of the lens can be derived in a conventional and customary manner and can be calculated manually from the input data, or more efficiently calculated using a computer program product through the following steps: a) increasing one or more front optical zone curvature radii or Zernike polynomials to jointly generate the desired low-order and high-order aberration lens powers with the back surface of the optical zone and the post-lens tear lens; b) selecting the front optical zone diameter as a function of the lens refractive power to control the center thickness and junction thickness; c) applying a thickness rule to the remaining annular zones outside the front optical zone to produce a thickness distribution that manages lens deformation, lens breakage, and eyelid-lens relationship to optimize comfort.

[0107] Process 1000 may include calculating at 1006 the diameters and sagittal depths of the nodes of the posterior surface of the contact lens. These calculations may be based on biometric average data, measured or corrected corneal topography, ocular tomography, etc., or combinations thereof. These calculations are described in detail below. After these calculations, the nodes of the anterior surface may be calculated, for example, from one or more posterior surface control points to one or more anterior surface control points using thickness rules or constants, in combination with one or more desired anterior central radii of curvature, to produce one or more desired lens refractive powers, etc. in the case of a multifocal lens, etc.

[0108] Process 1000 may include selecting at 1008 anterior rotation stability features. These features may be selected based on at least one of the interpalpebral or palpebral fissure dimensions, the anatomical shape of the posterior surface of the upper eyelid, and the eyelid position.

[0109] Process 1000 may include generating at 1010 a cutting file for the lens or for a set of male and female mold combinations and fabricating the contact lens. For example, the nodes may be used to calculate the semi-meridians of the posterior surface of the contact lens, such as as Figure 2 shown. Splines, geometric line segments, etc., or combinations thereof may be used to generate the semi-meridian surface. The contact lens may be fabricated from a breathable soft lens material, etc., using normal and customary good manufacturing practices. For example, a non-polishing computer numerical control lathe may be used to cut the contact lens or mold. After cutting, a morphological inspection of the mold or contact lens or posterior surface may be performed to determine that the finished posterior and anterior surfaces match the expected shape. A mold material may be selected that has a glass transition temperature higher than that required to cure the polymer selected for the lens substrate. In addition, the mold material must exhibit no delay in polymerization and no chemical bonding with the lens material during polymerization.

[0110] Process 1000 may include applying and evaluating at 1012 a predicted contact lens. This may include capturing an image of the contact lens worn on the patient's eye. The image may be analyzed to evaluate the lens-eye fit and to measure lens centration, lens orientation, and translational and orientation stability. The evaluation may include steps such as determining in-lens refraction, in-lens aberration measurement, measuring visual acuity, etc. Process 1000 may end at 1014 by distributing the final contact lens and performing one or more follow-up evaluations.

[0111] Figure 11 is a flow chart showing an overall process 1100 for defining the shape of the posterior surface of a soft contact lens for a patient's eye according to some embodiments of the disclosed technology. The elements of process 1100 are presented in one arrangement. However, it should be understood that one or more elements of the process may be performed in a different order, performed in parallel, omitted entirely, etc. In addition, process 1000 may include other elements in addition to those presented.

[0112] Reference Figure 11 ,Process 1100 may include defining, at 1102, the base curve of the central optical zone of a custom soft contact lens based on the apical radius of the eye's cornea. The base curve of the central optical zone may be defined based on at least one of a spherical radius of curvature, an aspherical radius of curvature with a conic constant, a toric surface, a multifocal shape, or a rotationally asymmetric shape.

[0113] Process 1100 may include defining, at 1104, the peripheral corneal zone peripheral to the central optical zone. Process 1100 may include defining the circumferential sagittal depth of each meridian of the scleral landing zone peripheral to the peripheral corneal zone. The peripheral corneal zone and the scleral landing zone may be defined based on a spline having multiple knots in each semi-meridian. Process 1100 may include defining, at 1106, the scleral landing zone peripheral to the peripheral corneal zone.

[0114] The peripheral corneal zone may be defined based on the outermost knot and the innermost knot. When the base curve radius is shorter than a predetermined length, the sagittal depth of the outermost knot is shallower than that of the innermost knot relative to the semi-chord length diameter extending along the base curve to the outermost knot; and wherein, when the base curve radius is greater than the predetermined length, the sagittal depth of the outermost knot is deeper than that of the innermost knot relative to the semi-chord length diameter extending along the base curve to the outermost knot. In some embodiments, the predetermined length is 8.0 mm.

[0115] In some embodiments, the peripheral corneal zone is rotationally asymmetric. In some embodiments, at least two meridians are separated by greater than or less than 90 degrees, and the knots at the node 2 (k2) and the outermost azimuth of the peripheral corneal zone exhibit different sagittal depths.

[0116] According to some embodiments of the present disclosure, Table 1 shows the clinical measurements that can be used to determine the parameters of the soft contact lens of the present disclosure, and these previous clinical data can be combined to determine additional parameters. Clinical observations of lens centration, lens angular orientation, and orientation stability help to evaluate a predictive lens having posterior asymmetry height in the scleral landing zone and in some embodiments in the peripheral corneal zone and / or the central optical zone.

[0117]

[0118]

[0119] Table 1

[0120] In one embodiment, the horizontal visible iris diameter or corneal diameter can be the first clinical measurement used to determine the total diameter of a soft contact lens. The total diameter can be calculated mathematically or determined through a look-up table as shown in Table 1. The total diameter can be used as a base parameter to select the sagittal depth of the predicted lens for viewing, the chord diameter of node 4 (k4), and the node position on the front surface of the lens to generate the thickness profile of the lens.

[0121] The vertex curvature radius of the cornea or the best-fit sphere or reference sphere from an automated corneal topographer can be the second clinical measurement and is used to derive the base curve radius of the posterior optical zone of the soft contact lens. In one embodiment, the base curve radius can be calculated to be 0.2 mm longer than the vertex curvature radius or the best-fit or reference sphere. The derived base curve radius can in turn be used to calculate the posterior optical zone diameter and the sagittal depth of node 2 from the geometric center plane of the back surface of the soft contact lens.

[0122] Measuring the sagittal depth of the eye in at least one meridian at a preselected chord diameter and combining the clinical measurement with biometric mean data can be used to generate the height of the scleral landing zone and, in some cases, also the height of the peripheral corneal zone. Alternatively, in some embodiments, fixation-based ocular tomography such as optical coherence tomography, Scheimpflug technology, etc. can be used to measure the ocular morphology. A correction algorithm can be used to reduce errors from kappa angle positioning. In some embodiments, scanning of an ocular morphology impression, or direct scanning of the eye with markers, or scanning of a predicted lens with reference markers or scanning of fiducial points with known positions can be used to evaluate the ocular morphology. The ocular morphology data can then be used to generate the posterior height of the scleral landing zone and, in some embodiments, the posterior heights of the peripheral corneal zone and the optical zone.

[0123] The lens power of a predicted soft contact lens can be empirically calculated through subjective refraction and by combining the subjective refraction with the selected base curve radius and the measured vertex curvature radius of the cornea. Alternatively, in-lens refraction can be performed by placing a prefabricated predicted soft contact lens with a known base curve radius and power on the eye, and the final lens power can be determined by combining the in-lens refraction with the base curve radius of the predicted lens, the power of the predicted lens, and a new base curve radius obtained from the vertex curvature radius of the cornea. In some embodiments, spherical-cylindrical in-lens refraction or in-lens aberration measurement can be employed to determine the final low-order and high-order aberration corrections of a soft lens for correcting irregular astigmatism.

[0124] The final lens diopter parameters can be used to determine a single radius of curvature, multiple radii of curvature, or a rotationally asymmetric surface shape in the anterior optical zone. The lens diopter generated by the posterior optical zone radius of curvature, the anterior optical zone radius of curvature, and the refractive index of the material can be used to determine the anterior optical zone diameter to control the harmonic mean thickness of the soft contact lens within the anterior optical zone.

[0125] Table 2 presents steps for determining posterior surface parameter values as examples of embodiments of the soft contact lenses of the present disclosure. The diameter is determined by the corneal diameter of the eye observed with a predictive lens, and the clinical measurements of the predictive lens at that diameter with known parameter values are used to determine the final set of lens parameters. Table 2 presents sample design rules and nominal values of the lens parameters as an example of an embodiment of the soft contact lenses of the present disclosure.

[0126]

[0127]

[0128] Table 2

[0129] In some embodiments, a computer program product can be used to accept input fields including corneal diameter, corneal vertex radius of curvature, registration of translational and orientation with the pupil axis or visual axis, and spectacle-eye fitting observations of a predictive lens with known parameters, parameters of the predictive lens, and subjective refraction or in-spectacle refraction of a lens with known parameters, or in-spectacle aberration measurement. The computer program product can use clinical measurements and lens parameters derived from the clinical measurements to calculate the final soft lens parameters to calculate the final posterior and anterior lens parameters and the cutting file for production.

[0130] Figure 12 A block diagram of an example computer system 1200 in which embodiments described herein can be implemented is depicted. The computer system 1200 includes a bus 1202 or other communication mechanism for conveying information, and one or more hardware processors 1204 coupled to the bus 1202 for processing information. The hardware processor 1204 can be, for example, one or more general-purpose microprocessors.

[0131] The computer system 1200 also includes a main memory 1206, such as random access memory (RAM), cache, and / or other dynamic storage devices, coupled to the bus 1202 for storing information and instructions to be executed by the processor 1204. The main memory 1206 can also be used to store temporary variables or other intermediate information during execution of instructions to be executed by the processor 1204. When stored in a storage medium accessible to the processor 1204, such instructions cause the computer system 1200 to become a special-purpose machine customized to perform the operations specified in the instructions.

[0132] The computer system 1200 also includes a read-only memory (ROM) 1208 or other static storage device coupled to the bus 1202 for storing static information and instructions for the processor 1204. A storage device 1210, such as a magnetic disk, optical disk, or USB thumb drive (flash drive), is provided and coupled to the bus 1202 for storing information and instructions.

[0133] The computer system 1200 can be coupled via the bus 1202 to a display 1212, such as a liquid crystal display (LCD) (or touch screen), for displaying information to a computer user. An input device 1214, including alphanumeric and other keys, is coupled to the bus 1202 for communicating information and command selections to the processor 1204. Another type of user input device is a cursor control 1216, such as a mouse, trackball, or cursor direction keys, for communicating direction information and command selections to the processor 1204 and for controlling cursor movement on the display 1212. In some embodiments, the same direction information and command selections as for the cursor control can be implemented via receiving touches on the touch screen in the absence of a cursor.

[0134] The computing system 1200 can include a user interface module to implement the GUI, which can be stored in the mass storage device as executable software code executed by the (one or more) computing devices. By way of example, this and other modules can include components such as software components, object-oriented software components, class components, and task components, processes, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables.

[0135] Generally, the terms "component", "engine", "system", "database", "data store", etc., as used herein, may refer to logic implemented in hardware or firmware, or to a collection of software instructions that may have entry and exit points and are written in a programming language such as Java, C, or C++. Software components may be compiled and linked into an executable program, installed in a dynamic link library, or may be written in an interpreted programming language such as BASIC, Perl, or Python. It will be understood that software components may be callable from other components or from themselves, and / or may be called in response to detected events or interrupts. Software components configured to execute on a computing device may be provided on a computer-readable medium, such as a compact disc, digital video disc, flash drive, magnetic disk, or any other tangible medium, or as a digital download (and may initially be stored in a compressed or installable format that requires installation, decompression, or decryption before execution). Such software code may be stored, in whole or in part, on the memory device of the executing computing device for execution by the computing device. Software instructions may be embedded in firmware, such as an EPROM. It should also be understood that hardware components may include connected logic units, such as gates and flip-flops, and / or may include programmable units, such as programmable gate arrays or processors.

[0136] Computer system 1200 may implement the techniques described herein using custom hardwired logic, one or more ASICs or FPGAs, firmware, and / or program logic that, in combination with the computer system, cause or program computer system 1200 to be a special-purpose machine. According to one embodiment, the techniques herein are performed by computer system 1200 in response to one or more sequences of one or more instructions contained in main memory 1206 being executed by (one or more) processors 1204. These instructions may be read from another storage medium, such as storage device 1210, into main memory 1206. Executing the sequence of instructions contained in main memory 1206 causes (one or more) processors 1204 to perform the processing steps described herein. In an alternative embodiment, hardwired circuitry may be used in place of or in combination with software instructions.

[0137] As used herein, the term "non-transitory medium" and like terms refer to any medium that stores data and / or instructions that cause a machine to operate in a particular manner. Such non-transitory media can include non-volatile media and / or volatile media. Non-volatile media includes, for example, optical or magnetic disks, such as storage device 1210. Volatile media includes dynamic memory, such as main memory 1206. Common forms of non-transitory media include, for example, floppy disk, flexible disk, hard disk, solid state drive, magnetic tape, or any other magnetic data storage medium, CD-ROM, any other optical data storage medium, any physical medium with hole patterns, RAM, PROM, and EPROM, FLASH-EPROM, NVRAM, any other memory chip or cartridge, and networked versions thereof.

[0138] A non-transitory medium is different from a transmission medium, but can be used in combination with a transmission medium. A transmission medium participates in transferring information between non-transitory media. For example, a transmission medium includes coaxial cables, copper wire, and fiber optics, including the wires that comprise bus 1202. A transmission medium can also take the form of acoustic or light waves, such as those generated during radio-wave and infrared data communications.

[0139] Computer system 1200 also includes a network interface 1218 coupled to bus 1202. Network interface 1218 provides a two-way data communication coupling to one or more network links connected to one or more local networks. For example, network interface 1218 can be an Integrated Services Digital Network (ISDN) card, cable modem, satellite modem, or a modem that provides a data communication connection to a corresponding type of telephone line. As another example, network interface 1218 can be a Local Area Network (LAN) card to provide a data communication connection to a compatible LAN (or WAN components to communicate with a WAN). A wireless link can also be implemented. In any such implementation, network interface 1218 sends and receives electrical, electromagnetic, or optical signals that carry digital data streams representing various types of information.

[0140] Network links typically provide data communication to other data devices through one or more networks. For example, a network link can provide a connection through a local network to a host computer or to a data device operated by an Internet Service Provider (ISP). The ISP, in turn, provides data communication services through the now commonly referred to global packet data communication network called the "Internet". Both local area networks and the Internet use electrical, electromagnetic, or optical signals that carry digital data streams. Signals through various networks and signals on the network link and through network interface 1218, which carry digital data to and from computer system 1200, are example forms of a transmission medium.

[0141] The computer system 1200 can send messages and receive data, including program code, via a network, network link, and network interface 1218. In an Internet example, a server can send request code for an application via the Internet, an ISP, a local network, and network interface 1218.

[0142] The received code can be executed by the processor 1204 when it is received, and / or stored in the storage device 1210 or other non-volatile storage device for later execution.

[0143] Each process, method, and algorithm described in the foregoing sections can be implemented in code components executed by one or more computer systems or computer processors including computer hardware, and be automated fully or partially by the same. One or more computer systems or computer processors can also operate to support the execution of relevant operations in a "cloud computing" environment or as "software as a service" (SaaS). These processes and algorithms can be implemented partially or fully in dedicated circuitry. The various features and processes described above can be used independently of each other or combined in various ways. Different combinations and sub-combinations are intended to fall within the scope of the present disclosure, and certain method or process blocks may be omitted in some implementations. The methods and processes described herein are also not limited to any particular order, and the blocks or states associated therewith can be executed in a suitable other order, or can be executed in parallel, or in some other way. Blocks or states can be added to or removed from the exemplary embodiments of the present disclosure. The execution of certain operations or processes can be distributed among computer systems or computer processors, not only residing within a single machine but also deployed across multiple machines.

[0144] As used herein, circuitry can be implemented using any form of hardware or a combination of hardware and software. For example, one or more processors, controllers, ASICs, PLAs, PALs, CPLDs, FPGAs, logic components, software routines, or other mechanisms can be implemented to constitute circuitry. In an implementation, the various circuits described herein can be implemented as discrete circuits, or the functions and features can be shared partially or fully among one or more circuits. Even though the various features or elements of functionality may be described or claimed separately as individual circuits, these features and functionality can be shared among one or more common circuits, and this description will not require or imply the need for separate circuits to implement such features or functionality. In cases where circuitry is implemented fully or partially using software, such software can be implemented to operate with a computing or processing system (such as computer system 1100) capable of executing the functions described thereof.

[0145] As used herein, the term "or" may be interpreted in an inclusive or exclusive sense. Additionally, a description of a resource, operation, or structure in the singular should not be construed as excluding a plurality. Unless specifically stated otherwise or otherwise understood within the context in which it is used, conditional language (such as "can," "able," "may," or "could") generally is intended to convey that certain embodiments include certain features, elements, and / or steps, while other embodiments do not include those features, elements, and / or steps.

[0146] Unless otherwise expressly stated, the terms and phrases used herein and their variants should be construed as open-ended rather than limiting. Adjectives such as "conventional," "traditional," "normal," "standard," "known," and terms of similar import should not be construed as limiting the item described to a given time period or to items available at a given time, but rather should be read to cover conventional, traditional, normal, or standard techniques that are available or known now or at any time in the future. In some instances, the presence of expansive words and phrases such as "one or more," "at least," "but not limited to," or other similar phrases should not be read to imply that a narrower case is intended or required in instances where such expansive phrases may be absent.

Claims

1. A soft contact lens for a patient's eye, the soft contact lens comprising: A front surface; And A back surface, the back surface comprising: A central optical zone defined by a base curve according to the vertex curvature radius of the eye's cornea; At least one peripheral corneal zone outside the central optical zone, and A scleral landing zone outside the peripheral corneal zone, the scleral landing zone having a circumferentially asymmetric height.

2. The soft contact lens according to claim 1, wherein: The base curve of the central optical zone is defined by at least one of a spherical radius, an aspherical radius with a conic constant, a toric surface, a multifocal shape, or a rotationally asymmetric shape.

3. The soft contact lens according to claim 1, wherein: The at least one peripheral corneal zone and the scleral landing zone are defined by a spline having a plurality of nodes and / or control points.

4. The soft contact lens according to claim 3, wherein: The peripheral corneal zone is defined by an outermost node and an innermost node; When the base curve radius is shorter than a predetermined length, the sagittal depth of the outermost node is shallower than that of the innermost node relative to the innermost node along the semi-chord length diameter extended to the outermost node along the base curve; And When the base curve radius is greater than a predetermined length, the sagittal depth of the outermost node is deeper than that of the innermost node relative to the innermost node along the semi-chord length diameter extended to the outermost node along the base curve.

5. The soft contact lens according to claim 4, wherein: The predetermined length of the base curve radius is 8.0 mm.

6. The soft contact lens according to claim 1, wherein: The scleral landing zone is defined by a corrected eye shape from fixation-based ocular tomography.

7. The soft contact lens according to claim 6, wherein: The corrected eye shape adjusts the circumferentially asymmetric height to correct the error caused by the deviation between the point where the visual axis intersects the cornea and the geometric center of the cornea, thereby defining the asymmetric sagittal depth of the scleral landing zone.

8. The soft contact lens according to claim 6, wherein: The scleral landing zone is rotationally asymmetric in sagittal depth to improve lens centration, adjust edge strain, reduce optical zone distortion, and enhance orientation positioning and stability.

9. The soft contact lens according to claim 6, wherein: The scleral landing zone is rotationally asymmetric in thickness to adjust edge strain, reduce optical zone distortion, and enhance orientation positioning and stability.

10. The soft contact lens according to claim 1, wherein: The front surface includes a rotationally stable feature determined by measuring at least one of the palpebral fissure, the position of the upper eyelid, and the posterior anatomical shape of the upper eyelid.

11. A method for defining the back surface shape and front surface shape of a soft contact lens for a patient's eye, the method comprising: Defining a base curve of a central optical zone of the soft contact lens according to the vertex curvature radius of the cornea of the eye; Defining a peripheral corneal zone outside the central optical zone; Defining a scleral landing zone outside the peripheral corneal zone according to ocular shape data that is not affected by the rotation of the eye during measurement; Select or fabricate a predictive lens having the defined base curve, peripheral corneal zone, and scleral landing zone; Apply the predictive lens and measure the registration and orientation stability of the lens relative to the pupil center or visual axis; Define an anterior stability feature based on at least one of the palpebral fissure, upper eyelid position, and posterior upper eyelid anatomical shape; And With the predictive lens in place, define the anterior optical zone based on at least one of subjective refraction, spherocylindrical overrefraction, pupil size, and on-lens aberration measurement.

12. The method according to claim 11, further comprising: Define the base curve of the central optical zone according to at least one of a spherical radius, an aspherical radius with a conic constant, a toric surface, a multifocal shape, and a rotationally asymmetric shape.

13. The method according to claim 11, further comprising: Define the peripheral corneal zone and the scleral landing zone according to a spline curve having a plurality of knots and / or control points.

14. The method according to claim 13, further comprising: Define the peripheral corneal zone according to the outermost knot and the innermost knot; When the base curve radius is shorter than a predetermined length, the sagittal depth of the outermost knot is shallower than that of the innermost knot relative to the innermost knot at the semi-chord length diameter along the base curve extended to the outermost knot; And When the base curve radius is greater than a predetermined length, the sagittal depth of the outermost knot is deeper than that of the innermost knot relative to the innermost knot at the semi-chord length diameter along the base curve extended to the outermost knot.

15. The method according to claim 14, wherein: The predetermined length is 8.0 mm.

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