Geometric volume controlled corneal refractive therapy contact lenses

Abstract

The present disclosure relates to a contact lens for treating myopia in a patient's eye, comprising a front surface; and a back surface having a semi-meridian, wherein the back surface defines: a central compression zone (CCZ) configured to contact the cornea to be treated, a volume control zone (VCZR1, VCZR2) at the periphery of the central compression zone (CCZ), a secondary compression zone (SCZ) configured to contact the cornea to be treated, wherein the secondary compression zone (SCZ) is at the periphery of the volume control zone (VCZR1, VCZR2), a peripheral relief zone (PRZ) at the periphery of the secondary compression zone (SCZ), a landing zone (LZ) configured to contact the cornea to be treated, wherein the landing zone (LZ) is at the periphery of the peripheral relief zone (PRZ), and an edge termination (ET) at the periphery of the landing zone (LZ).

Description

[0001] The present disclosure is a divisional application for an invention entitled “Contact lens for corneal refractive therapy with geometric volume controlled”, which entered the Chinese national phase on November 5, 2021 and has a national application number of 202180003258.5. Technical Field

[0002] The disclosed technology relates generally to contact lenses, and more particularly, some embodiments relate to contact lenses and non-surgical methods for reshaping the cornea of ​​an eye to treat vision defects. Background Art

[0003] Rigid contact lenses were first commercialized 60 years ago. The initial fitting concept quickly evolved into a double or triple arc design to facilitate the lens movement required for tear exchange in non-gas permeable lenses. This design necessitated blinking to move the lens to move a new tear layer from the tear meniscus at the lower eyelid to the underside of the lens. The simple lathes used during the first two decades of commercialization allowed the concentric curves to be joined without sharp junctions.

[0004] The central radius of the lens is selected relative to the central corneal curvature. Depending on the design principle, the base curve curvature radius can be equal to, greater than or less than the central corneal curvature. The radius of the first concentric zone (second arc) is always greater than the base curve curvature radius, and the radius of each successive zone around the central zone is correspondingly greater than the radius of the central zone. Lenses have traditionally had three or more zones. Typically, the radius of all zones outside the central visual zone is greater than the radius of the cornea below it. This is a requirement to facilitate lens movement and tear exchange.

[0005] These designed lenses exhibit up to 1.0 to 1.5 mm of movement with blinking motion and lateral eye movement. Patients need to adapt to get used to this lens movement. Edge design is also very important to achieve comfort and prevent eye and conjunctival damage.

[0006] The advent of gas permeable materials has reduced the need for the high degree of motion and radial and axial edge lift required by non-gas permeable lenses. Even so, traditional design concepts remain and are used with new materials. Over time, lenses have been designed to have smaller gaps. In the original designs, it was common to have a secondary curve radius of curvature approximately 1.4mm larger than the base curve radius of curvature, while in gas permeable designs, they tend to be 0.8mm larger than the base curve radius of curvature. The average difference in the base curve radius of curvature and the central corneal radius also tends to be in the shorter direction.

[0007] Over the past decade, the average overall lens diameter has also trended in the larger direction. As a result, modern gas permeable lenses are larger and fit more closely to the cornea. Early non-gas permeable lenses made of polymethyl methacrylate (PMMA) were designed to have axial edge lift approaching 100 microns, while modern lenses can have axial edge lift as low as 50 microns. Modern gas permeable lenses exhibit lens movement of approximately 0.25 mm or less, compared to 1.0 to 1.5 mm for early PMMA lenses.

[0008] Even so, contemporary design concepts and teachings continue to use concentric zone features and their corresponding adjustments. Lenses and design procedures reference the width and local radius of each zone. Educational programs adjust lenses by making the radius "flatter" or "steeper" and "narrower" or "wider." Because there is no generally available, precise metric for measuring the actual gap of a lens, and fit needs to be determined by observation with sodium fluorescein staining, assessment of fit is a learned art rather than a measurement-based science.

[0009] At the same time, the market demands effective time management in contact lens fitting. Waiting times must be reduced, and first-time fitting success rates are important indicators for improving clinical efficiency and optimizing channel economics. Lens fitting concepts must be simple and training must be reduced to achieve successful results.

[0010] The design of rigid gas permeable lenses for nocturnal corneal reshaping has been improved primarily by a rational fitting system in which the parameters of a predetermined zone are adjusted to control the vertex lens radius to vertex corneal radius relationship, the relationship between the mid-peripheral lens sagittal depth and the mid-peripheral corneal sagittal depth, and the alignment of the lens periphery to the peripheral cornea. Those skilled in the art know that the cornea is not rotationally symmetrical, but all commercial lens designs are rotationally symmetrical. The result of placing a rotationally symmetrical lens on a rotationally asymmetric cornea is lens decentration. Randomized treatment accuracy is also an undesirable result.

[0011] Extensive and sustained efforts have been made in the industry to match these rotationally asymmetric eyes with significant irregular height differences with rotationally symmetric lenses. In some cases, complex peripheral designs or dual sagittal height designs are used to accommodate orthogonal corneal height differences. It is necessary to achieve non-orthogonal height control by designing lenses with separate semi-meridian height control points. Each semi-meridian of the lens can be designed to have a predetermined height at a corresponding control point defined by its distance from the geometric center of the lens. The height or sagittal depth of each point from the geometric center of the back of the lens is determined by the topography below each eye at the same location and the design principle algorithm that describes the required sagittal depth relationship. These height differences are intended to correspond to the irregular height of the underlying cornea when the lens is applied to the eye.

[0012] Unfortunately, the standard design paradigm using concentric curves results in decentration of the lens, contact with the cornea somewhere near the corneal apex, randomization of tear volume under the second arc (reversed arc), and variable contact of the lens with the cornea in the alignment zone at the lens periphery. Second-generation night orthokeratology lenses induce higher order aberrations and do not accurately and consistently produce the mid-peripheral power required for sustained myopia control. Although attempts can be made to address corneal asymmetry using second-generation designs, the use of coaxial concentric radii of curvature is inherently self-limiting. The ability to achieve precision in fitting and experience consistency is questionable.

[0013] A third order polynomial is incorporated in the second zone of the third generation design, but the same limitations are still inherent. Manufacturers of third generation designs have not yet commercialized designs in which the semi-meridian varies the third order polynomial to produce rotationally asymmetric height, and the corresponding regulatory approvals do not include the use of separate semi-meridian height control. In addition, the third generation designs do not teach controlling the volume between the untreated cornea and the lens in the mid-periphery of the lens, having a controlled inward facing angle for the secondary compression zone of the lens, or having a secondary clearance zone to allow the mid-peripheral corneal contact area to compress the cornea.

[0014] The problem remains that even when third-generation lens designs address the specific sagittal depth of the semi-meridian, the skill level of the fitter must be very high and exhaustive trial sets or lens reordering are required to find the best fit. Summary of the invention

[0015] Embodiments of the apparatus and methods may include one or more of the following features. Some embodiments include a posterior surface of a contact lens shaped to define a geometrically controlled zone in at least a single semi-meridian of a space between the surface of the contact lens and an underlying corneal surface defined by a first radial position on the posterior surface and a second radial position on the posterior surface and the same radial position of a corneal surface to be treated. Some embodiments include a posterior surface of a contact lens having a predetermined inward-facing angle from a point of contact of a mid-peripheral portion of the lens with a corneal surface to be treated that forms a peripheral portion of the geometrically controlled zone in the space between the posterior surface of the contact lens and the underlying corneal surface.

[0016] In general, one aspect of the disclosure is characterized by a contact lens for reshaping a cornea to be treated in a patient's eye, comprising: a front surface; and a back surface having a semi-meridian, the back surface defining: a central compression zone configured to contact the cornea to be treated, a volume control zone at the periphery of the central compression zone, a secondary compression zone configured to contact the cornea to be treated, wherein the secondary compression zone is at the periphery of the volume control zone, a peripheral relief zone at the periphery of the secondary compression zone, a landing zone configured to contact the cornea to be treated, wherein the landing zone is at the periphery of the peripheral relief zone, and an edge terminal at the periphery of the landing zone.

[0017] Embodiments of the contact lens may include one or more of the following features. In some embodiments, the central compression zone is spherical. In some embodiments, the central compression zone is aspherical. In some embodiments, the diameter of the central compression zone is between 3.0 and 7.0 mm. In some embodiments, the volume control zone is defined by at least four geometric control points connected by one of the following: a spline, a polynomial, or a combination of a conical segment and an unbent segment, a fourth geometric control point CP2 is at the periphery of the third geometric control point CP1; a first geometric control point CP3 is at the periphery of the fourth geometric control point CP2; and a second geometric control point CP4 is configured to contact the cornea to be treated, wherein the second geometric control point CP4 is at the periphery of the first geometric control point CP3. In some embodiments, the third geometric control point CP1 of the volume control zone is positioned to have a z-axis spacing in the range of 5 to 80 microns from the cornea to be treated. In some embodiments, the fourth geometric control point CP2 of the volume control zone is positioned to have a z-axis spacing from the cornea to be treated, and the z-axis spacing defines a predetermined area between the back surface and the cornea to be treated in the volume control zone. In some embodiments, the first geometric control point CP3 of the volume control zone is positioned to define an extrusion angle between (i) a line connecting the first geometric control point CP3 and the second geometric control point CP4 and (ii) a horizontal line passing through the second geometric control point CP4. In some embodiments, the semi-chord radial distance of the second geometric control point CP4 is in the range of 2.6 mm to 5.2 mm. In some embodiments, the secondary compression zone has a width in the range of 0.2 mm to 0.8 mm. In some embodiments, the secondary compression zone is defined by a shape having at least one control point within the secondary compression zone, the shape being defined by one of the following: a spline; a polynomial; or a convex cone segment. In some embodiments, the peripheral relief zone is defined by at least one control point, the at least one control point being positioned to have a z-axis spacing from the cornea to be treated, the z-axis spacing being at least 6 microns per diopter in an attempt to reduce the central refractive error. In some embodiments, the peripheral relief zone has a width between 0.4 mm and 1.2 mm. In some embodiments, the peripheral landing zone is defined by a shape having at least one control point within the peripheral landing zone, the shape being defined by one of: a spline; a polynomial; a conical segment; an angled curved segment; or an angled uncurved segment. In some embodiments, the edge termination of the posterior surface begins at a radially peripheral most portion of the peripheral landing zone and connects to a peripheral outermost portion of the anterior surface; and the edge termination of the posterior surface is defined by: an ellipse, a conical segment, or a spline. In some embodiments, the volume control zone and the secondary compression zone are defined by a single spline.

[0018] In general, one aspect of the present disclosure is characterized by a method for defining a contact lens manufactured for a patient's eye, the method comprising: selecting, based on a corneal topography of the patient's eye: a base curve curvature radius of a central compression zone of the contact lens, a peripheral semi-meridian radial distance of the central compression zone of the contact lens, an area of ​​a volume control zone adjacent to the central compression zone, and a semi-chord radial distance of a secondary compression zone for contacting the eye's cornea to be treated, wherein the secondary compression zone is adjacent to and peripheral to the volume control zone; determining positions of a plurality of control points to define at least a width of the central compression zone, a shape of the volume control zone, a predetermined area produced by the volume control zone between a surface of the volume control zone and a surface of the cornea to be treated, a semi-meridian radial distance of the secondary compression zone, and an inward-facing angle formed at the apex of the secondary compression zone; and defining a semi-meridian of the posterior surface of the contact lens based on the plurality of control points.

[0019] Embodiments of the method may include one or more of the following features. Some embodiments include positioning a third of the control points at the geometric center of the contact lens and the corresponding geometric center of the cornea to be treated. Some embodiments include determining the base curve radius of curvature based on subjective refraction of the eye and corneal curvature or topography; selecting a half-chord radial distance of a fourth of the control points as the marginal termination of the central compression zone; and setting the sagittal depth of the fourth of the control points at the half-chord radial distance selected for the fourth of the control points at a sagittal depth of the selected base curve radius of curvature when the third of the control points is in contact with the underlying cornea to be treated. Some embodiments include selecting the half-chord radial distance of the first of the control points to separate a first region of the volume control zone from a second region of the volume control zone, the second region being located at the periphery of the first region of the volume control zone; and setting the sagittal depth of the first of the control points at a distance equal to that of a lens having a predetermined diopter treatment target radius when the lens is placed on an average cornea to be treated. Some embodiments include selecting a half-chord radial distance of a second one of the control points based on a desired mid-peripheral add power position, the half-chord radial distance of the second one of the control points being equal to the half-chord radial distance of the apex of the secondary compression zone. Some embodiments include selecting an extrusion angle of a peripheral portion of a second region of the volume control zone; and positioning a fifth one of the control points to define an extrusion angle with the second one of the control points. Some embodiments include determining a location of a sixth one of the control points based on the selected region of the volume control zone and based on a desired mid-peripheral add power. Some embodiments include determining an overall diameter of the contact lens based on a corneal diameter of a cornea to be treated; and determining a location of a seventh one of the control points based on the overall diameter of the contact lens. Some embodiments include determining an eighth one of the control points to define an inner portion of a landing zone for contacting the cornea to be treated based on a corneal topography of the eye, and determining a desired radial distance from the seventh one of the control points based on a desired radial width of the landing zone. Some embodiments include selecting a diameter of a ninth control point among the control points; selecting an area of ​​a peripheral relief zone between the secondary compression zone and the landing zone; and determining a sagittal depth of a ninth control point among the control points based on the selected area of ​​the peripheral relief zone, or based on a target treatment in diopters. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] According to one or more various embodiments, the present disclosure is described in detail with reference to the following drawings. The drawings are provided for illustration purposes only and merely depict typical or exemplary embodiments.

[0021] Figure 1is a plan view of a posterior surface of a contact lens provided in accordance with some embodiments of the disclosed technology.

[0022] Figure 2 Shown are semi-meridians defining the posterior surface of an exemplary contact lens provided in accordance with some embodiments of the disclosed technology.

[0023] Figure 3 is a flow chart illustrating an overview process for producing contact lenses for corneal reshaping in accordance with some embodiments of the disclosed technology.

[0024] Figure 4A and Figure 4B is a flow chart illustrating an overview process for defining contact lenses for corneal reshaping in accordance with some embodiments of the disclosed technology.

[0025] Figure 5 A block diagram of an exemplary computer system is depicted in which embodiments described in this disclosure may be implemented.

[0026] The drawings are not exhaustive and do not limit the disclosure to the precise forms disclosed. DETAILED DESCRIPTION

[0027] Embodiments of the disclosed technology provide corneal refractive therapy (CRT) contact lenses for nighttime corneal reshaping, and methods of defining CRT contact lenses using geometric volume control techniques. These techniques employ spline mathematics or other geometry to determine the surface profile of a contact lens at predetermined control points or nodes on the posterior surface of the lens, the predetermined control points or nodes being defined by their specified semi-chord radial distances from the center of the lens to the edge of the lens and their sagittal depths from a reference plane. Some embodiments employ a corneal topography map of each eye to apply an algorithm to determine the semi-meridian sagittal depth at each control point to allow empirical ordering and observational fitting of the eye for nighttime corneal reshaping. The described embodiments may empirically select the base curve radius of curvature of the lens, while also empirically selecting the surface height of the lens in each semi-meridian at a plurality of predetermined control points on the lens surface from the center of the lens to the edge of the lens, ensuring that the central corneal radius varies to correct existing myopia while producing the desired mid-peripheral add power and mid-peripheral add power location.

[0028] Figure 1 is a plan view of the back surface of a contact lens according to some embodiments of the disclosed technology. Figure 1 The posterior surface of the contact lens includes a plurality of annular zones, including a central compression zone (CCZ), a first region of the volume control zone (VCZR1), a second region of the volume control zone (VCZR2), a secondary compression zone (SCZ), a peripheral relief zone (PRZ), and a landing zone (LZ). Each of these zones will be described in detail below.

[0029] Figure 2 1 shows the semi-meridians defining the posterior surface of an exemplary contact lens according to some embodiments of the disclosed technology. Figure 2 In FIG, the semi-meridian of the contact lens is shown as a continuous solid line with multiple curves and control points CP. Figure 2 The cornea to be treated is also shown in dashed lines. The contact lens and the cornea to be treated are plotted on a grid in millimeters. However, Figure 2 Not drawn to scale. It should be understood that the specific values ​​of control point CP shown are given by way of example only, and that the control points of other semi-meridians of the contact lens and other contact lenses may have different values. If the eye were rotationally symmetric, then the contact lens could be manufactured using only the control points of a single semi-meridian. However, since the eye is not rotationally symmetric, a single contact lens may be manufactured using control points of multiple semi-meridians having different surface height dimensions.

[0030] refer to Figure 2 , the center of the cornea to be treated and the center of the contact lens are located at the origin of the grid. Figure 2 , the anterior portion of the cornea to be treated and the anterior surface of the contact lens (not shown) face downward, toward the bottom of the grid. As practiced by those skilled in the art of contact lens design and manufacture, the anterior surface can have a predetermined radius in the central visual zone to produce a predetermined lens power in combination with the posterior surface radius in the central zone. The anterior visual zone surface can be spherical, aspherical, a single radius, or multiple radii designed to produce multifocal refractive powers. The peripheral portion of the anterior surface can be designed to produce a constant thickness from the posterior surface, or can be designed to have a varying thickness from each corresponding posterior surface control point. The contact lens includes nine control points CP1-CP9 associated with the contact lens zone. However, in other embodiments, a different number of control points may be used.

[0031] The central compression zone (CCZ) contacts the cornea to be treated at its center and extends from control point CP1 at the center of the semi-meridian to control point CP2, which in this example is located at a semi-chord radial distance of approximately 2.5 mm.

[0032] The periphery of the central compression zone is the volume control zone, which extends to the control point CP4, which is located at a half-chord radial distance of about 4mm in this example. In this example, the volume control zone includes two areas. The first area of ​​the volume control zone (VCZR1) extends to the control point CP3, which is located at a half-chord radial distance of about 3mm in this example. The periphery of the first area of ​​the volume control zone is the second area of ​​the volume control zone (VCZR2), which includes control points CP6 and CP5 and extends to the control point CP4. In this example, the control points CP6 and CP5 are located at half-chord radial distances of about 3.4mm and 3.8mm respectively.

[0033] At the periphery of the second region of the volume control zone is the secondary compression zone (SCZ) where the contact lens again contacts the cornea to be treated. At the periphery of the secondary compression zone is the peripheral relief zone (PRZ) which includes control point CP9 and extends to control point CP8 which in this example is located at a half-chord radial distance of about 5 mm. In this example, control point CP9 is located at a half-chord radial distance of about 4.5 mm.

[0034] At the periphery of the peripheral relief zone is the landing zone (LZ) where the contact lens again contacts the cornea to be treated. The landing zone extends to control point CP7, which in this example is located at a half-chord radial distance of about 5.4 mm. The peripheral end of the landing zone marks the edge termination (ET) of the contact lens.

[0035] Spherical or aspherical base curves can be used in the central compression zone. Volumetric control zones, secondary compression zones, peripheral relief zones, and landing zones can be configured using circumferentially varying spline mathematics or other geometry to achieve the desired sagittal depth difference at defined control points along each semi-meridian. The height difference can be driven by topographic measurements of the cornea to be treated at each corresponding control point and in each semi-meridian of the cornea to be treated. The height difference between a point on the rear surface of the lens and a corresponding point on the surface of the cornea to be treated can be measured using the axial distance from the lens surface to the corneal surface or the radial distance from the lens surface to the corneal surface. The axial distance forms a line parallel to the axis of the lens, while the radial distance is in the direction of the center of rotation from the lens surface to the corneal surface of the corresponding eye. In a preferred embodiment, the axial distance from the lens surface to the surface of the cornea to be treated is used to calculate the height difference between the control point on the rear surface of the lens and the corresponding point on the corneal surface. The lens edge can be adjusted to produce a flat and circular, flat and non-circular, or non-flat and circular lens.

[0036] The contact lens of the present disclosure shows improved centration, optimal reduction of refractive myopia of the treated eye, and predetermined post-treatment mid-peripheral corneal add-on power and position. The volume control zone and the position and angle of the semi-chord radial distance formed by the secondary compression zone generate forces to produce the mid-peripheral add-on power and its position. The peripheral relief zone allows the secondary compression zone to compress and redistribute the corneal epithelium inward to the volume control zone. The uniformly aligned landing zone provides pressure that produces a central compression force and a compression force within the secondary compression zone. The landing zone height matches the height difference of the cornea to be treated in two or more semi-meridians, and the rotational asymmetry of the landing zone height provides optimal compression force, lens stability and improved lens centration. An edge terminal is added to the landing zone. The shape of the posterior surface of the contact lens is continuous and seamless to avoid any joint-induced trauma. In one embodiment, a cubic spline may be employed that places nodes at corresponding control points to produce a smooth, continuous and seamless surface with a predetermined area under each semi-meridian in the volume control zone and an extrusion angle inward from the secondary compression zone.

[0037] The contact lens is seamless because each zone begins at a local slope at the end of its central zone. The nodes of the volume control zone spline control the relative sagittal depth of the lens at defined control points along the posterior surface of the lens semi-meridian outside the central compression zone, and the control of the spline provides the shape of the surface. The centralmost portion of the spline is defined by the height and local slope at the chord of the visual zone junction, and the peripheralmost portion is defined by the desired height at each next peripheral control point in each semi-meridian. The local slope of the peripheralmost portion of the volume control zone is defined by the squeeze angle, with its apex at the deepest point of the secondary compression zone. The peripheralmost portion of the secondary compression zone is defined by the local slope of the centralmost portion of the peripheral relief zone; and the peripheralmost portion of the peripheral relief zone is defined by the centralmost portion of the landing zone. The edge termination begins at the height of the peripheralmost portion of the landing zone.

[0038] In some applications, lenses may be custom made for each eye. In other applications, a trial set may be made from which lenses may be selected. An exemplary trial set or kit may have one overall diameter (OAD; e.g., in the range of 10.5 mm to 11.5 mm), up to five base curve curvature radius increments (BCRIs), each with a single optic zone diameter and a volume control zone width, each with up to five volume control zones, each with three secondary compression zone depths, a peripheral relief zone, and a landing zone. The trial set would have 75 lenses (1 OAD × 5 BCR I × 5 VCZ zones × 3 SCZ depths). A lookup table or computer application may be generated to suggest a first trial lens by inputting subjective refraction and central keratometric or corneal topography collected by standard clinical testing.

[0039] The preferred empirical approach without a trial set and without a corneal topography map is to empirically design a first observation lens to be manufactured by using subjective refraction and standard corneal curvature to predict the base curve radius of curvature; using a treatment dose in diopters and average biometric data to predict the first and second areas of the volume control zone; using the treatment dose and average biometric data to predict the secondary compression zone depth; using a standard peripheral relief zone height; and using average biometric data to predict the local slope and sagittal depth of the central portion of the landing zone. The first lens designed empirically based on clinical data can be used as a observation lens for ordering a second lens. It should be noted that the first observation lens designed empirically is expected to include rotational asymmetry, which is based on the average biometric data revealing the asymmetry.

[0040] Figure 3 is a flow chart illustrating an overview process 300 for producing contact lenses for orthokeratology according to some embodiments of the disclosed technology. The elements of process 300 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, in parallel, omitted entirely, etc. Furthermore, process 300 may include other elements in addition to those presented.

[0041] refer to Figure 3 , process 300 may include performing clinical testing of the eye at 302. The clinical testing may include determining uncorrected visual acuity, refraction, binocular vision, peripheral refraction, eye health, corneal curvature, corneal diameter, corneal topography, eyelid position and aperture size, pupil size, etc.

[0042] Process 300 may include selecting constants and calculating lens parameters at 304. These parameters may include base curve radius of curvature, optic zone diameter, total diameter, mid-peripheral add power, semi-chord radial distance of the mid-peripheral add power center, lens power, and the like.

[0043] Process 300 may include calculating diameters and sagittal depths of contact lens posterior surface control points at 306. These calculations may be based on biometric average data, measured corneal topography, etc., or a combination thereof. These calculations are described in detail below. After performing these calculations, the anterior surface control points may be calculated, for example using a thickness rule or constant from one or more posterior surface control points to one or more anterior surface control points, and in the case of a multifocal optical device, etc., in conjunction with a desired front center radius or radius of curvature to produce the desired one or more lens powers.

[0044] Process 300 may include creating a cutting file and manufacturing a contact lens at 308. For example, a cutting file such as Figure 1The semi-meridian of the posterior surface of the contact lens is calculated using the control points shown in . The semi-meridian surface can be generated using splines, geometric segments, etc. or a combination thereof. The contact lens can be manufactured using standard wear-resistant hard gas permeable materials or similar materials in accordance with common and customary good manufacturing practices. For example, a non-polished computer numerical control lathe can be used to cut the contact lens. After cutting, the posterior surface of the contact lens can be profiled to determine that the completed posterior surface matches the expected shape.

[0045] Process 300 may include applying and evaluating a contact lens at 310. This may include capturing an image of the contact lens on the patient's eye. The image may be analyzed to evaluate the lens-eye relationship and measure the centering of the lens. The evaluation may include steps such as determining the lens power, measuring visual acuity, etc. Process 300 may end with wearing the contact lens at 312 and performing one or more subsequent evaluations.

[0046] Figure 4A and 4B 4 is a flow chart illustrating an overview process 400 for defining a contact lens for corneal reshaping according to some embodiments of the disclosed technology. The elements of process 400 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, in parallel, omitted entirely, etc. Furthermore, process 400 may include other elements in addition to those presented.

[0047] refer to Figure 4A , process 400 may include positioning control point CP1 at the geometric center of the lens to correspond to the geometric center of the cornea to be treated at 402. Process 400 may include determining a base curve curvature radius based on subjective refraction and corneal curvature of the eye to be treated, selecting a diameter of control point CP2 as the edge termination of the central compression zone CCZ, and setting a sagittal depth of control point CP2 at the selected diameter of control point CP2 at the sagittal depth of the selected base curve curvature radius at 404.

[0048] Process 400 may include selecting a diameter of control point CP3 at 406 to separate a first area of ​​the volume control zone from a second area of ​​the volume control zone at a periphery of the first area of ​​the volume control zone, and setting the sagittal depth of control point CP3 at a predetermined diopter distance from the vertex radius of the cornea to be treated. In one embodiment, the sagittal depth difference between CP3 and the cornea is intended to be constant and independent of the target treatment amount. In this embodiment, all treatment lenses will have the same sagittal depth difference with the underlying cornea at CP3 regardless of differences in target treatment or differences between the central corneal radius and the base curve curvature radius of the treatment lens. The second area of ​​the volume control zone is used to accommodate eyes with different mid-peripheral height differences, equalize the area below each semi-meridian, control the location of the additional corneal refractive power generated below the area, and improve lens centration. Circumferential balancing of the zone beneath each semi-meridian eliminates toric or double-sag fitting by allowing a non-complex base curve and circumferential height difference in the volume control zone to prevent the lens from burdening the shallow semi-meridian of the treated cornea and preventing z-axis tilt and decentration toward the deep semi-meridian of the cornea.

[0049] Process 400 may include selecting a diameter or a half-chord radial distance of a control point CP4 for a secondary compression zone at 408 based on the desired location of the mid-peripheral additional power. The sagittal depth of the secondary compression zone SCZ at control point CP4 depends on the sagittal height of the underlying cornea to be treated at control point CP4, which is the apex of the zone. The posterior surface advances to the next control point CP9 to determine the height of the peripheral relief zone PRZ. In one embodiment, the height of control point CP9 from the underlying cornea to be treated is determined by the central treatment amount in diopters. For example, the height of control point CP9 from the underlying cornea may be equal to 6 microns per diopter treatment. The peripheral relief zone then descends to control point CP8. The height of control point CP8 corresponds to the measured height of the cornea to be treated at the half-chord radial distance of the start of the landing zone LZ. The half-chord radial distance of control point CP8 is defined by the half-chord radial distance of control point CP7 and the minimum desired width between control points CP8 and CP7. In one embodiment, the half-chord radial distance of control point CP7 is defined by the measured horizontal corneal diameter. For example, the lens diameter can be selected to be 90% of the measured corneal diameter, and then the half-chord radial distance of control point CP7 is determined to be 45% of the corneal diameter. The desired half-chord width from control point CP8 to CP7 ranges from 0.8 to 1.6 mm. The edge termination ET at control point CP7 is then integrated into the sagittal depth of the lens at the outermost peripheral portion of the landing zone LZ. The sagittal depth of control point CP7 is selected based on the known eye contour and the preselected edge lift from the underlying cornea at the desired half-chord radial distance of control point CP7. For example, the desired preselected edge lift from the underlying cornea at control point CP7 can be 40 to 80 microns.

[0050] The spline of the secondary compression zone SCZ can start from the local slope of the last control point CP5 in the volume control zone spline, and can be calculated to produce an incident angle of the secondary compression zone SCZ on the lower cornea to be treated, which optimizes the movement of tissue inward into the volume control zone, referred to herein as the squeeze angle (SA). Process 400 may include selecting the squeeze angle of the peripheral portion of the second area of ​​the volume control zone at 410, and positioning control point CP5 to define the squeeze angle with control point CP4. The angle can be measured from a line perpendicular to the lens axis passing through control point CP4, or it can be measured from the local slope of the lower cornea at control point CP4. For example, the local slope of the cornea to be treated at control point CP4 can be measured to be 28 degrees, and the desired angle between the cornea to be treated and the back surface of the lens can be 5 degrees. Thus, the squeeze angle generated by the line connecting control point CP5 inward from the vertex at control point CP4 and the horizontal line passing through control point CP4 will be reported as 33 degrees from the horizontal line.

[0051] Reference now Figure 4B, process 400 may include, at 412, selecting an area of ​​the volume control zone based on the desired mid-peripheral add power to determine the location of control point CP6 to produce a desired area of ​​the volume control zone. When the lens is placed on the cornea to be treated, the volume control zone may be estimated to be equivalent to an area below the posterior surface of a second or third generation orthokeratology lens having a target treatment of 3.00 diopters. Typically, the radius of second and third generation CRT lenses is about 1.00 diopters longer than the target treatment. Therefore, the target or desired area of ​​the semi-meridian of the volume control zone may be estimated based on the area below a 4.00D longer radius of curvature lens on an average cornea, the lens having an average optic zone diameter and an average arc of reversal or return zone width; and an average arc of reversal radius of curvature or return zone depth. The target or desired total area below a single half-chord radial distance may include the total volume control zone from the center of the lens, control points CP1 to CP4, or from control points CP2 to CP4, or only the second area of ​​the volume control zone, control points CP3 to CP4. For example, for a third or fourth generation CRT lens having an optic zone diameter of 5.0 mm; a reverse arc width of 1.5 mm; and a base curve radius of curvature of 4.00 diopters (approximately 0.8 mm longer than the radius of the cornea to be treated), the area from control point CP2 to CP4 is estimated to be 1.58×104 square microns or 0.0158 square millimeters. The desired area in the semi-meridian will vary depending on the semi-chord radial distance of control points CP2, CP3, and CP4. Control point CP4 adjusts the semi-chord radial distance of the midpoint of the mid-peripheral power addition. The closer the desired mid-peripheral power addition is to the center of the lens, the shorter the semi-chord radial distance of control point CP4. When control points CP2 and CP3 remain constant, the shorter the semi-chord radial distance of control point CP4, the smaller the area of ​​the corresponding volume control zone. In one embodiment, the semi-chord radial distance of control point CP2 is maintained equal to or greater than 1.5 mm, and the semi-chord radial distance of control point CP3 is maintained equal to or greater than 2.2 mm. The reduced semi-meridian radial distance of control point CP4 reduces the semi-meridian radial distance of the midpoint of the post-treatment mid-peripheral add power. For a given semi-meridian radial distance of control point CP4, the larger the area within the volume control zone, the higher the mid-peripheral add power. It is to be understood that modulation of the semi-meridian radial distance of control point CP4 controls the radial position of the mid-peripheral add power, while the area between the posterior surface of the lens and the cornea to be treated within the volume control zone modulates the mid-peripheral add power. The semi-meridian radial distance of control point CP6 modulates the shape of the mid-peripheral add power.

[0052] Process 400 may include, at 414, determining an overall diameter of the contact lens based on the corneal diameter of the cornea to be treated, and determining a location of control point CP7 based on the overall diameter of the contact lens.

[0053] Process 400 may include determining, at 416, a control point CP8 based on a corneal topography of the eye and the location of control point CP7 to define a landing zone LZ that contacts the cornea to be treated. The circumferential height characteristics of the secondary compression zone SCZ and the landing zone LZ result in a circumferentially uniform edge lift, which is beneficial for improving centering and comfort. The semi-meridian sagittal depth control design may use different splines in at least one semi-meridian of at least one zone of the lens outside the visual zone. The magnitude of the sagittal depth difference may be specified around a nominal value, which is used for most normal eyes, or determined empirically from height data from a corneal topography map.

[0054] Process 400 may include selecting a diameter of control point CP9 at 418, selecting an area of ​​a peripheral relief zone between the secondary compression zone and the landing zone, and determining a sagittal depth of control point CP9 based on the selected area of ​​the peripheral relief zone. In an alternative embodiment, the sagittal depth of control point CP9 is determined based on the treatment goal of the corresponding eye. It is known to those skilled in the art that each diopter of treatment obtained causes the corneal vertex to retreat by approximately 6 microns. Control point CP9 can be placed at a position of 6 microns per diopter of the underlying cornea. For example, when 3.00D is the treatment goal, control point CP9 can be placed 18 microns from the underlying corneal surface when control points CP1, CP4 and CP8 are placed to contact the corneal surface. Larger gaps are considered acceptable, while smaller gaps may hinder treatment or require compression of the cornea across the entire lens surface from control points CP4 to CP7.

[0055] Table 1 below provides an example in which the semi-meridian corneal height at a control point at a semi-meridian radial distance is provided and the posterior surface sagittal depth is determined according to the method of one embodiment of the present disclosure.

[0056]

[0057]

[0058] Table 1

[0059] Process 400 may include defining the semi-chord radial distances and sagittal depths of the semi-meridians of the posterior surface of the contact lens based on control points CP1-CP9 at 420. After defining one or more semi-meridians, the contact lens may be manufactured, for example, as described above. These control point semi-meridian radial distances and corresponding depths are input information for a computer program product to complete the x, y, and z points required for the entire lens surface.

[0060] The technology of the present disclosure can be applied to the corneal shaping portion of a corneal rigid lens and the corneal shaping portion of a lens having a diameter greater than the cornea, including, for example, a scleral contact lens, a hybrid contact lens, and a soft contact lens. For embodiments where the lens has a diameter greater than the cornea, the edge terminal does not connect to the anterior surface at control point CP7. Instead, the terminal end of the peripheral landing zone connects to the next peripheral zone on the posterior surface, which extends beyond the diameter of the cornea in at least one semi-meridian.

[0061] Figure 5 A block diagram of an exemplary computer system 500 is depicted in which embodiments described in the present disclosure may be implemented. Computer system 500 includes a bus 502 or other communication mechanism for communicating information, and one or more hardware processors 504 coupled to bus 502 for processing information. Hardware processor(s) 504 may be, for example, one or more general purpose microprocessors.

[0062] Computer system 500 also includes a main memory 506, such as a random access memory (RAM), cache, and / or other dynamic storage device, coupled to bus 502 for storing information and instructions to be executed by processor 504. Memory 506 may also be used to store temporary variables or other intermediate information during the execution of instructions executed by processor 504. Such instructions, when stored in a storage medium accessible to processor 504, render computer system 500 into a special-purpose machine customized to perform the operations specified in the instructions.

[0063] Computer system 500 also includes a read only memory (ROM) 508 or other static storage device coupled to bus 502 for storing static information and instructions for processor 504. A storage device 510, such as a magnetic disk, optical disk, or USB thumb drive (flash drive), etc., is provided and coupled to bus 502 for storing information and instructions.

[0064] The computer system 500 may be coupled to a display 512, such as a liquid crystal display (LCD) (or touch screen), via the bus 502 to display information to a computer user. An input device 514, including alphanumeric and other keys, is coupled to the bus 502 for communicating information and command selections to the processor 504. Another type of user input device is a cursor control 516, such as a mouse, trackball, or cursor direction keys, for communicating direction information and command selections to the processor 504 and controlling cursor movement on the display 512. In some embodiments, the same direction information and command selections as cursor control may be achieved by receiving touches on a touch screen without a cursor.

[0065] The computer system 500 may include a user interface module for implementing the GUI, which may be stored in a mass storage device as executable software code executed by (one or more) computing devices. This module and other modules may include components, such as software components, object-oriented software components, class components and task components, processes, functions, properties, procedures, subroutines, program code segments, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays and variables, for example.

[0066] In general, the words "component", "engine", "system", "database", "data repository", etc. used herein may refer to logic embodied in hardware or firmware, or a collection of software instructions (possibly with entry and exit points), which are written in a programming language such as Java, C or C++. Software components can be compiled and linked into an executable program, installed in a dynamic link library, or can be written in an interpreted programming language such as BAS IC, Per l or Python. It should be appreciated that software components can be called from other components or from themselves, and / or can be called in response to detecting an event or interrupt. Software components configured for execution on a computing device can be provided on a computer-readable medium (such as a compact disc, digital video disc, flash drive, disk or any other tangible medium), or as a digital download (and can be initially stored in a compressed or installable format, which needs to be installed, decompressed or decrypted before execution). Such software code can be stored in part or in whole on a storage device of the executing computing device to be executed by the computing device. Software instructions can be embedded in firmware such as an EPROM. It should further be appreciated 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.

[0067] The computer system 500 may implement the techniques described in the present disclosure using custom hardwired logic, one or more AS ICs or FPGAs, firmware, and / or program logic, which in combination with the computer system makes the computer system 500 a special-purpose machine or programs the computer system 500 as a special-purpose machine. According to one embodiment, the techniques of the present disclosure are performed by the computer system 500 in response to (one or more) processors 504 executing one or more sequences of one or more instructions contained in the main memory 506. Such instructions may be read into the main memory 506 from another memory such as the storage device 510. Executing the sequence of instructions contained in the main memory 506 causes (one or more) processors 504 to perform the processing steps described in the present disclosure. In alternative embodiments, hardwired circuits may be used instead of software instructions or in combination with software instructions.

[0068] As used in this disclosure, the term "non-transitory media" and similar terms refer to any media that stores data and / or instructions that cause a machine to operate in a specific manner. Such non-transitory media may include non-volatile media and / or volatile media. Non-volatile media include, for example, optical or magnetic disks, such as storage device 510. Volatile media include dynamic memory, such as main memory 506. Common forms of non-transitory media include, for example, floppy disks, flexible disks, hard disks, solid-state drives, magnetic tapes or any other magnetic data storage media, CD-ROMs, any other optical data storage media, any physical media with patterns of holes, RAM, PROMs and EPROMs, FLASH-EPROMs, NVRAMs, any other memory chips or cartridges, and networked versions thereof.

[0069] Non-transitory media are distinct from but may be used in conjunction with transmission media. Transmission media participate in the transmission of information between non-transitory media. For example, transmission media include coaxial cables, copper wire, and optical fiber, including the wires that make up bus 502. Transmission media may also take the form of acoustic or light waves, such as those generated during radio wave and infrared data communications.

[0070] Computer system 500 also includes a communication interface 518 connected to bus 502. Communication interface 518 provides a two-way data communication connection to one or more local network links, and the local network link is connected to one or more local networks. For example, communication interface 518 can be an integrated service digital network (ISDN) card, a cable modem, a satellite modem, or a modem that provides a data communication connection to a corresponding type of telephone line. As another example, communication interface 518 can be a local area network (LAN) card to provide a data communication connection to a compatible LAN (or a WAN component that communicates with a WAN). A wireless link can also be implemented. In any such implementation, communication interface 518 sends and receives electrical, electromagnetic or optical signals that carry digital data streams representing various types of information.

[0071] A network link typically provides data communication to other data devices through one or more networks. For example, a network link may provide connectivity through a local network to a host or data device operated by an Internet Service Provider (ISP). The ISP, in turn, provides data communication services through the global packet data communication network now commonly referred to as the "Internet." Both local area networks and the Internet use electrical, electromagnetic, or optical signals that carry digital data streams. The signals through the various networks and the signals on the network link and through the communication interface 518 are example forms of transmission media that carry digital data to and from the computer system 500.

[0072] Computer system 500 can send messages and receive data, including program code, through the network(s), network links and communications interface 518. In the Internet example, a server can transmit code requested by an application program through the Internet, ISP, local area network and communications interface 518.

[0073] The received code may be executed by processor 504 as it is received, and / or stored in storage device 510 or other non-volatile storage for later execution.

[0074] Each process, method and algorithm described in the preceding sections may be embodied in a code component executed by one or more computer systems or computer processors including computer hardware, and may be fully or partially automated by it. One or more computer systems or computer processors may also support the execution of related operations in a "cloud computing" environment or as "software as a service" (SaaS). The process and algorithm may be implemented in part or in whole in a dedicated circuit. The various features and processes described above may be used independently of each other, or may be 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 embodiments. The methods and processes described in the present disclosure are also not limited to any particular order, and the blocks or states associated therewith may be executed in other appropriate orders, or may be executed in parallel, or in some other manner. Blocks or states may be added to or removed from the disclosed exemplary embodiments. The execution of certain operations or processes may be distributed among computer systems or computer processors, not just residing in a single computer, but may be deployed across multiple computers.

[0075] As used in the present disclosure, any form of hardware or a combination of hardware and software can be used to implement the circuit. For example, one or more processors, controllers, ASICs, PLAs, PALs, CPLDs, FPGAs, logic components, software routines or other mechanisms can be implemented to form the circuit. In an embodiment, the various circuits described in the present disclosure can be implemented as discrete circuits, or the functions and features described can be partially or completely shared between one or more circuits. Even if the various features or elements of the functions can be described or claimed separately as separate circuits, these features and functions can also be shared between one or more general circuits, and such a description will not require or imply the need for separate circuits to implement such functions or functions. In the case of using software to implement the circuit in whole or in part, such software can be implemented to operate together with a computing or processing system (e.g., computer system 500) that can perform the functions described relative to this.

[0076] The present disclosure also includes the following:

[0077] A contact lens for reshaping a cornea to be treated in an eye of a patient, comprising:

[0078] a front surface; and

[0079] A posterior surface having a semi-meridian, the posterior surface defining:

[0080] is configured to contact the central compression zone of the cornea to be treated,

[0081] The volume control zone around the central compression zone,

[0082] A secondary compression zone configured to contact a cornea to be treated, wherein the secondary compression zone is at a periphery of the volume control zone,

[0083] a peripheral relief zone at the periphery of said secondary compression zone,

[0084] a landing zone configured to contact a cornea to be treated, wherein the landing zone is peripheral to the peripheral relief zone, and

[0085] The edge terminates at the perimeter of the landing zone.

[0086] In some embodiments, the central compression zone is spherical.

[0087] In some embodiments, the central compression zone may also be aspherical.

[0088] In some embodiments, the diameter of the central compression zone is between 3.0 and 7.0 mm.

[0089] In some embodiments, the volume control region is defined by at least four geometric control points connected by one of:

[0090] Spline,

[0091] polynomial, or

[0092] Combination of conical segments and unbent segments,

[0093] The fourth geometric control point is located around the third geometric control point;

[0094] The first geometric control point is located at a periphery of the fourth geometric control point; and

[0095] The second geometric control point is configured to contact the cornea to be treated, wherein the second geometric control point is at a periphery of the first geometric control point.

[0096] In some embodiments, the third geometric control point of the volume control zone is positioned with a z-axis spacing in the range of 5 to 80 microns from the cornea to be treated.

[0097] In some embodiments, the fourth geometric control point of the volume control zone is positioned with a z-axis interval from the cornea to be treated, wherein the z-axis interval defines a predetermined area between the posterior surface and the cornea to be treated in the volume control zone.

[0098] In some embodiments, the first geometric control point of the volume control region is positioned to define an extrusion angle between (i) a line connecting the first control point and the second control point and (ii) a horizontal line passing through the second control point.

[0099] In some embodiments, the semi-chord radial distance of the second geometric control point is in the range of 2.6 mm to 5.2 mm.

[0100] In some embodiments, the secondary compression zone has a width in the range of 0.2 mm to 0.8 mm.

[0101] In some embodiments, the secondary compression zone is defined by a shape having at least one control point within the secondary compression zone, the shape being defined by one of:

[0102] Spline;

[0103] Polynomial; or

[0104] Convex cone section.

[0105] In some embodiments, the peripheral relief zone is defined by at least one control point positioned with a z-axis separation from the cornea to be treated of at least 6 microns per diopter in an attempt to reduce central refractive error.

[0106] In some embodiments, the peripheral relief zone has a width between 0.4 mm and 1.2 mm.

[0107] In some embodiments, the peripheral landing zone is defined by a shape having at least one control point within the peripheral landing zone, the shape being defined by one of:

[0108] Spline;

[0109] Polynomial;

[0110] Conical section;

[0111] An angled curved section; or

[0112] Angled unbent section.

[0113] In some embodiments, the edge termination of the rear surface begins at a radially outermost peripheral portion of the landing zone and connects to a peripheral outermost portion of the front surface; and

[0114] The edge termination of the rear surface is defined by:

[0115] oval,

[0116] Conical section or

[0117] Spline.

[0118] In some embodiments, the volume control zone and the secondary compression zone are defined by a single spline.

[0119] A method for defining a contact lens manufactured for an eye of a patient, the method comprising:

[0120] Select based on the corneal topography of the patient's eye:

[0121] the base curve radius of curvature of the central compression zone of the contact lens, the peripheral semi-meridian radial distance of the central compression zone of the contact lens,

[0122] an area of ​​the volume control zone adjacent to the central compression zone, and

[0123] a half-chord radial distance of a secondary compression zone for contacting a cornea of ​​an eye to be treated, wherein the secondary compression zone is adjacent to and peripheral to the volume control zone;

[0124] determining positions of a plurality of control points to define at least a width of the central compression zone, an area of ​​the volume control zone, a semi-meridian radial distance of the secondary compression zone, and an inward facing angle formed at an apex of the secondary compression zone; and

[0125] A semi-meridian of the posterior surface of the contact lens is defined according to the plurality of control points.

[0126] In some embodiments, the method further comprises:

[0127] A third of the control points is positioned at the geometric center of the contact lens and the corresponding geometric center of the cornea to be treated.

[0128] In some embodiments, the method further comprises:

[0129] Determining the base curve curvature radius according to the subjective optometry of the eye and the corneal curvature;

[0130] Selecting a semi-chord radial distance of a fourth control point among the control points as an edge terminal of the central compression zone; and

[0131] When the third of the control points contacts the underlying cornea to be treated, the sagittal depth of the fourth of the control points is set at the selected semi-chord radial distance of the fourth of the control points and at the sagittal depth of the selected base curve curvature radius.

[0132] In some embodiments, the method further comprises:

[0133] selecting a semi-chord radial distance of a first one of the control points to separate a first region of the volume control zone from a second region of the volume control zone, the second region being located at a periphery of the first region of the volume control zone; and

[0134] The sagittal depth of a first one of the control points is set at a distance equal to a distance of a lens having a predetermined diopter treatment target radius when the lens is placed on an average cornea to be treated.

[0135] In some embodiments, the method further comprises:

[0136] According to the desired mid-peripheral additional refractive power position, a semi-chord radial distance of a second control point among the control points is selected, and the semi-chord radial distance of the second control point is equal to the semi-chord radial distance of the vertex of the secondary compression zone.

[0137] In some embodiments, the method further comprises:

[0138] selecting an extrusion angle of a peripheral portion of a second region of the volume control zone; and

[0139] A fifth one of the control points is positioned to define an extrusion angle with a second one of the control points.

[0140] In some embodiments, the method further comprises:

[0141] The position of a sixth control point among the control points is determined according to the selected area of ​​the volume control zone and according to the desired mid-peripheral additional refractive power.

[0142] In some embodiments, the method further comprises:

[0143] Determining the overall diameter of the contact lens based on the corneal diameter of the cornea to be treated; and

[0144] A position of a seventh of the control points is determined based on an overall diameter of the contact lens.

[0145] In some embodiments, the method further comprises:

[0146] An eighth control point among the control points is determined based on the corneal topography of the eye to define an inner portion of a landing zone contacting the cornea to be treated, and a desired radial distance from the seventh control point among the control points is determined based on a desired radial width of the landing zone.

[0147] In some embodiments, the method further comprises:

[0148] Selecting a diameter of a ninth control point among the control points;

[0149] selecting an area of ​​the peripheral relief zone between the secondary compression zone and the landing zone; and

[0150] A sagittal depth of a ninth one of the control points is determined based on a selected area of ​​the peripheral relief zone or based on a target treatment in diopters.

[0151] As used in this disclosure, the term "or" may be interpreted in an inclusive or exclusive sense. In addition, descriptions of resources, operations, or structures in the singular should not be understood to exclude the plural. Unless otherwise explicitly stated or otherwise understood in the context of use, conditional language (such as "can," "would," "might," or "may," etc.) is generally intended to convey that some embodiments include, while other embodiments do not include, certain features, elements, and / or steps.

[0152] Unless expressly stated otherwise, the terms and phrases used herein and variations thereof should be construed as open ended, not restrictive. Adjectives such as "conventional," "traditional," "normal," "standard," "known," and terms of similar meaning should not be construed to limit the items described to those available in a given period of time or at a given time, but should be understood to encompass conventional, traditional, normal, or standard technology available or known at any time now or in the future. In some cases, the presence of expanded words and phrases such as "one or more," "at least," "but not limited to," or other similar phrases should not be construed as an intent or requirement to use a narrower context where such expanded phrases may not be present.

Claims

1. A contact lens for reshaping a cornea to be treated in an eye of a patient, comprising: front surface; as well as A posterior surface having a semi-meridian, the posterior surface defining: is configured to contact the central compression zone of the cornea to be treated, A volume control zone is formed around the central compression zone, wherein: The volume control region is defined by at least a first geometric control point (CP3) and a second geometric control point (CP4), wherein at least the first geometric control point (CP3) and the second geometric control point (CP4) are connected by at least one of a spline, a polynomial, a conic segment, and an unbent segment; The second geometric control point (CP4) is configured to contact the cornea to be treated, and the second geometric control point (CP4) is located at the periphery of the first geometric control point (CP3); as well as The first geometric control point (CP3) is positioned to define an extrusion angle between (i) a line connecting the first geometric control point (CP3) and the second geometric control point (CP4) and (ii) a horizontal line passing through the second geometric control point (CP4); A secondary compression zone configured to contact a cornea to be treated, wherein the secondary compression zone is at a periphery of the volume control zone, a peripheral relief zone at the periphery of said secondary compression zone, a landing zone configured to contact a cornea to be treated, wherein the landing zone is peripheral to the peripheral relief zone, and The edge terminates at the perimeter of the landing zone.

2. The contact lens of claim 1 wherein the central compression zone is spherical.

3. The contact lens of claim 1 wherein the central compression zone is aspherical.

4. The contact lens of claim 1 wherein the central compression zone has a diameter between 3.0 and 7.0 mm.

5. The contact lens of claim 1, wherein: The semi-chord radial distance of the second geometric control point (CP4) is in the range of 2.6 mm to 5.2 mm.

6. The contact lens of claim 1, wherein: The secondary compression zone has a width in the range of 0.2 mm to 0.8 mm.

7. The contact lens of claim 1, wherein: The secondary compression zone is defined by a shape having at least one control point within the secondary compression zone, the shape being defined by one of: Spline; Polynomial; a convex conical section; and Unbent section.

8. The contact lens of claim 1, wherein: The peripheral relief zone is defined by at least one control point positioned with a z-axis separation from the cornea to be treated of at least 6 microns per diopter in an attempt to reduce central refractive error.

9. The contact lens of claim 1, wherein: The peripheral relief zone has a width between 0.4 mm and 1.2 mm.

10. The contact lens of claim 1, wherein: The landing zone is defined by a shape having at least one control point within the landing zone, the shape being defined by one of: Spline; Polynomial; Conical section; an angled curved section; and Angled unbent section.

11. The contact lens of claim 1 , wherein: The edge termination of the rear surface begins at a radially outermost peripheral portion of the landing zone and connects to a peripheral outermost portion of the front surface; and The edge termination of the rear surface is defined by one of: oval, a cone section; and Spline.

12. The contact lens of claim 1, wherein: The volume control zone and the secondary compression zone are defined by a single spline.

13. A contact lens for reshaping a cornea to be treated in an eye of a patient, comprising: front surface; as well as A posterior surface having a semi-meridian, the posterior surface defining: is configured to contact the central compression zone of the cornea to be treated, A volume control zone is formed around the central compression zone, wherein: The volume control region is defined by at least a first geometric control point (CP3), a fifth geometric control point (CP5) and a second geometric control point (CP4), wherein at least the first geometric control point (CP3) and the second geometric control point (CP4) are connected by at least one of a spline, a polynomial, a conic segment and an unbent segment; The second geometric control point (CP4) is configured to contact the cornea to be treated, wherein the second geometric control point (CP4) is at the periphery of the first geometric control point (CP3); as well as The volume control zone includes a first region (VCZR1) and a second region (VCZR2), the first region (VCZR1) extends to the first geometric control point (CP3), the second region (VCZR2) extends to the second geometric control point (CP4), and the second region (VCZR2) includes the fifth geometric control point (CP5); The fifth geometric control point (CP5) is positioned to define an extrusion angle between (i) a line connecting the fifth geometric control point (CP5) inwardly from the vertex at the second geometric control point (CP4) and (ii) a horizontal line passing through the second geometric control point (CP4); A secondary compression zone configured to contact a cornea to be treated, wherein the secondary compression zone is at a periphery of the volume control zone, a peripheral relief zone at the periphery of said secondary compression zone, a landing zone configured to contact a cornea to be treated, wherein the landing zone is peripheral to the peripheral relief zone, and The edge terminates at the perimeter of the landing zone.

14. The contact lens of claim 13 wherein the central compression zone is spherical.

15. The contact lens of claim 13 wherein the central compression zone is aspherical.

16. The contact lens of claim 13, wherein the central compression zone has a diameter between 3.0 and 7.0 mm.

17. The contact lens of claim 13, wherein: The semi-chord radial distance of the second geometric control point (CP4) is in the range of 2.6 mm to 5.2 mm.

18. The contact lens of claim 13, wherein: The secondary compression zone has a width in the range of 0.2 mm to 0.8 mm.

19. The contact lens of claim 13, wherein: The secondary compression zone is defined by a shape having at least one control point within the secondary compression zone, the shape being defined by one of: Spline; Polynomial; a convex conical section; and Unbent section.

20. The contact lens of claim 13, wherein: The peripheral relief zone is defined by at least one control point positioned with a z-axis separation from the cornea to be treated of at least 6 microns per diopter in an attempt to reduce central refractive error.

21. The contact lens of claim 13, wherein: The peripheral relief zone has a width between 0.4 mm and 1.2 mm.

22. The contact lens of claim 13, wherein: The landing zone is defined by a shape having at least one control point within the landing zone, the shape being defined by one of: Spline; Polynomial; Conical section; an angled curved section; and Angled unbent section.

23. The contact lens of claim 13, wherein: The edge termination of the rear surface begins at a radially outermost peripheral portion of the landing zone and connects to a peripheral outermost portion of the front surface; and The edge termination of the rear surface is defined by one of: oval, a cone section; and Spline.

24. The contact lens of claim 13, wherein: The volume control zone and the secondary compression zone are defined by a single spline.

25. A contact lens for reshaping a cornea to be treated in an eye of a patient, comprising: front surface; as well as A posterior surface having a semi-meridian, the posterior surface defining: is configured to contact the central compression zone of the cornea to be treated, A volume control zone is formed around the central compression zone, wherein: The volume control region is defined by at least four geometric control points, the at least four geometric control points being connected by at least one of a spline, a polynomial, a conic segment, and an unbent segment; A fourth geometric control point (CP2) is located at the junction of the volume control area and the central compression area; The first geometric control point (CP3) controls the area between the cornea to be treated and the semi-meridian of the posterior surface, and the first geometric control point (CP3) is at the periphery of the fourth geometric control point (CP2); A second geometric control point (CP4) is configured to contact the cornea to be treated, wherein the second geometric control point (CP4) is at the periphery of the first geometric control point (CP3); and A sixth geometric control point (CP6) is positioned between the first geometric control point (CP3) and the second geometric control point (CP4) for defining a predetermined area between the cornea to be treated and the posterior surface semi-meridian.

26. The contact lens of claim 25, wherein: The second geometric control point (CP4) is positioned to adjust the half-chord radial distance of the midpoint of the mid-peripheral refractive power addition.

27. The contact lens of claim 26, wherein: The semi-meridian radial distance of the sixth geometric control point (CP6) is selected to modulate the shape of the mid-peripheral add power.

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