HK40107115A - Contact lenses and methods relating thereto - Google Patents

Description

Contact lenses and methods related to them

Technical Field

This invention relates to contact lenses. The invention particularly (but not exclusively) relates to contact lenses for slowing the progression of myopia. The invention also particularly (but not exclusively) relates to contact lenses for presbyopia. The invention further relates to methods of manufacturing such lenses.

Background Technology

Many people (including children and adults) need contact lenses to correct myopia (short-sightedness), and many adults may need lenses to correct presbyopia (age-related maladaptation and therefore inability to focus on near objects).

Myopic eyes focus incident light from distant objects onto a point in front of the retina. Therefore, the light converges and diverges towards the plane in front of the retina, becoming out of focus by the time it reaches the retina. Conventional lenses used to correct myopia (e.g., spectacle lenses and contact lenses) reduce the convergence of incident light from distant objects before it reaches the eye (for contact lenses) or cause it to diverge (for spectacle lenses), shifting the focal point to the retina.

Presbyopia does not effectively reshape itself to accommodate near objects, thus making it difficult for people with presbyopia to focus on near objects. Conventional lenses used to correct presbyopia (e.g., spectacle lenses and contact lenses) include bifocal or progressive lenses, which contain zones optimized for near vision and zones optimized for distance vision. Bifocal or multifocal lenses or monofocal lenses (where a different prescription is provided for each eye, one eye with a distance vision lens and the other with a near vision lens) can also be used to treat presbyopia.

Decades ago, it was proposed that undercorrection—that is, moving the focal point towards but not completely onto the retina—could slow or prevent the progression of myopia in children or young adults. However, this method inevitably leads to decreased distance vision compared to the vision achieved with lenses that fully correct myopia. Furthermore, the effectiveness of undercorrection in controlling developing myopia is now questionable. A more recent method for correcting myopia involves providing lenses with one or more zones that provide full correction for distance vision and one or more zones that are undercorrected or intentionally induce myopic defocus. This method has been proposed to prevent or slow the development or progression of myopia in children or young adults while providing good distance vision.

In lenses with zones that provide defocus, the zone providing full correction for distance vision is typically called the base power zone, while the zone providing undercorrection or intentionally inducing myopic defocus is typically called the myopic defocus zone or add power zone (because its refractive power is more positive or less negative than that of the hyperopic zone). The surface of the add power zone (usually the anterior surface) has a smaller radius of curvature than the hyperopic power zone and therefore provides more positive or less negative refractive power to the eye. The add power zone is designed to focus incident parallel light (i.e., light from a distance) in front of the retina (i.e., closer to the lens), while the hyperopic power zone is designed to focus light and form an image at the retina (i.e., farther from the lens).

One known type of contact lens that reduces the progression of myopia is a bifocal contact lens purchased under the name MISIGHT (CooperVision, Inc.). This bifocal lens differs from bifocal or multifocal contact lenses designed to improve vision in presbyopic individuals because it is configured with specific optical dimensions to allow the adaptable person to use hyperopic correction (i.e., basic refractive power) to see both distant and near objects. The treatment area of the bifocal lens with additional refractive power also provides a myopic defocused image at both far and near viewing distances.

While these lenses have been found to be beneficial in preventing or slowing the development or progression of myopia, the annular additional refractive zone can cause unwanted visual side effects. Light focused through the annular additional refractive zone in front of the retina diverges from the focal point to form a defocusing ring at the retina. Therefore, wearers of these lenses may see a ring or "halo" around the image formed on the retina, especially for small, bright objects such as streetlights and car headlights. Furthermore, theoretically, wearers could use the extra focal point in front of the retina created by the annular additional refractive zone to focus on near objects, rather than using the eye's natural adaptation (i.e., the eye's instinct to change focus); in other words, wearers might inadvertently use the lenses in the same way as they would with presbyopic lenses, which is undesirable for younger subjects.

Developed for the treatment of myopia, and designed to eliminate the halo effect observed around the focused distance image in MISIGHT (CooperVision, Inc.) lenses and other similar lenses described above, are further developed lenses. In these lenses, the annular zone is configured such that a single coaxial image is not formed in front of the retina, thus preventing this image from being used to avoid the eye's adaptation to near objects. Specifically, a distant point light source is imaged through the annular zone onto the annular focal line at the near additional refractive power focal plane, resulting in a small spot size of light at the far-sighted focal plane, without the surrounding "halo" effect on the retina.

To treat myopia, it is recognized that providing lenses that introduce additional myopic defocus can be beneficial. To treat presbyopia, providing lenses that produce a longer depth of focus can be beneficial.

Summary of the Invention

According to a first aspect, this disclosure provides a contact lens comprising an optical region. The optical region includes a central region having a first optical axis, a fundamental radial curvature refractive power, and a fundamental radial-sagittal refractive power. The central region has a center of curvature on the first optical axis. The optical region includes an annular region, wherein at a point halfway across the annular region, the annular region has a radial curvature refractive power of X, wherein X is greater than the fundamental radial curvature refractive power. The annular region has an off-axis center of curvature at a first distance from the optical axis. At a point halfway across its width, the annular region has a radial-sagittal refractive power of Y, wherein Y is greater than the fundamental radial-sagittal refractive power and wherein Y is less than X.

According to a second aspect, this disclosure provides a method for manufacturing a lens. The method includes forming a contact lens according to the first aspect of the invention.

It will be understood, of course, that features described with respect to one aspect of this disclosure may be incorporated into other aspects of this disclosure. For example, the methods of this disclosure may be incorporated into features described with reference to the apparatus of this disclosure, and vice versa.

Attached Figure Description

Embodiments of the invention will now be described by way of example only, with reference to the accompanying schematic diagrams, wherein:

Figure 1A is a schematic top view of a contact lens that provides a myopic defocus image to reduce the progression of myopia.

Figure 1B is a side view of the contact lens in Figure 1A;

Figure 2A is a ray diagram of the lens in Figure 1A;

Figure 2B shows the light pattern at the near-focal plane of the lens in Figure 1A formed by a distant point source;

Figure 2C shows the light pattern at the far focal plane of the lens in Figure 1A formed by a distant point source;

Figure 3 is a partial ray diagram of the lens in Figures 1A and 1B, and circles indicating the radius of curvature of the central hyperopic zone (dotted line) and the annular additional zone (dashed line) of the contact lens.

Figure 4A is a plot showing the variation of radial sagittal refractive power of the lens shown in Figures 1A and 1B;

Figure 4B is a plot showing the variation of the radial curvature refractive power of the lens shown in Figures 1A and 1B;

Figure 5A is a top view of different contact lenses with non-coaxial optics;

Figure 5B is a side view of the contact lens in Figure 5A;

Figure 6A is a ray diagram of the lens in Figures 5A and 5B;

Figure 6B shows the light pattern at the near-focal plane of the lenses in Figures 5A and 5B formed by a distant point source.

Figure 6C shows the light pattern at the far focal plane of the lens in Figures 5A and 5B formed by a distant point source.

Figure 6D is a partial ray diagram of the lens in Figures 5A and 5B, and circles indicating the radii of curvature of the central hyperopic zone (dotted line) and the annular additional zone (dashed line) of the contact lens.

Figure 7A is a plot showing the variation of radial and sagittal refractive power of the lens shown in Figures 5A and 5B;

Figure 7B is a plot showing the variation of the radial curvature refractive power of the lens shown in Figures 5A and 5B;

Figure 8A is a top view of a lens according to an embodiment of the present disclosure;

Figure 8B is a side view of the contact lens in Figure 8A;

Figure 9 is a partial ray diagram of the lens in Figures 8A and 8B, and circles indicating the radius of curvature of the central hyperopic zone (dotted line) and the annular additional zone (dashed line) of the contact lens.

Figure 10A is a plot showing the variation of the radial curvature refractive power of the lens as shown in Figures 8A and 8B;

Figure 10B is a plot showing the variation of radial sagittal refractive power of the lens shown in Figures 8A and 8B;

Figure 11A is a ray diagram of the lens in Figures 8A and 8B;

Figure 11B shows the light pattern at the far focal plane of the lens in Figures 8A and 8b formed by a distant point source.

Figure 11C shows the light pattern at the first near-end focal plane of the lens in Figures 8A and 8B formed by a distant point source;

Figure 11D shows the light pattern at the second near-end focal plane of the lenses in Figures 8A and 8B formed by a distant point source;

Figure 12A is a top view of a lens according to an embodiment of the present disclosure, having a variation in radial curvature refractive power;

Figure 12B is a side view of the contact lens in Figure 12A;

Figure 13A is a schematic diagram of the lens in Figures 12A and 12B taken along line E-E, and circles indicating the radii of curvature of the central hyperopic zone (dotted line) and the annular additional zone (dashed line) of the contact lens.

Figure 13B is a schematic diagram of the lens in Figures 12A and 12B taken along line F-F, and circles indicating the radii of curvature of the central hyperopic zone (dotted line) and the annular additional zone (dashed line) of the contact lens.

Figure 14 is a schematic diagram showing the variation of radial curvature refractive power around the annular region of the lens shown in Figures 12A and 12B as a function of angle θ.

Figure 15A is a schematic graph illustrating the sinusoidal variation of refractive power around the annular region of a lens according to an embodiment of the present disclosure with respect to angle θ.

Figure 15B is a schematic diagram illustrating the zigzag variation of refractive power around the annular region of a lens according to an embodiment of the present disclosure with respect to angle θ.

Figure 15C is a schematic graph showing the square wave refractive power around the annular region of a lens according to an embodiment of the present disclosure as a function of angle θ;

Figure 16 is a flowchart illustrating a method for designing contact lenses according to an embodiment of the present disclosure; and

Figure 17 is a schematic diagram of a radial cross-section through a portion of three modeled lenses modeled using the method described in Figure 16.

Detailed Implementation

According to a first aspect, this disclosure provides a contact lens. The lens includes an optical region comprising a central region having a first optical axis, a fundamental radial curvature refractive power and a fundamental radial sagittal refractive power, and a center of curvature on the first optical axis. The central region has an annular region. At a point halfway across the width of the annular region, the annular region has a radial curvature refractive power of X. X is greater than the fundamental radial curvature refractive power. The annular region has an off-axis center of curvature at a first distance from the optical axis, such that at a point halfway across its width, the annular region has a radial sagittal refractive power of Y, wherein Y is greater than the fundamental radial sagittal refractive power and wherein Y is less than X.

As used herein, the term contact lens refers to an ophthalmic lens that can be placed on the anterior surface of the eye. It will be understood that this contact lens will provide clinically acceptable supraocular movement without sticking to one or both eyes. Contact lenses may be in the form of corneal lenses (e.g., lenses that rest on the cornea of the eye). Contact lenses may be soft contact lenses, such as hydrogel contact lenses or silicone hydrogel contact lenses. Lenses may be lenses used to prevent or slow the development or progression of myopia, and said lenses may be used to provide extended depth of focus to the myopic eye.

The contact lens according to this disclosure includes an optical region. The optical region encompasses a portion of the lens that has optical functionality. The optical region is configured to be positioned above the pupil of the eye during use. For the contact lens according to this disclosure, the optical region includes a central region and an annular region (or several regions) surrounding the central region. The optical region is surrounded by a peripheral region. The peripheral region is not part of the optical region, but is located outside the optical region and above the iris when the lens is worn, and it provides mechanical functions, for example, increasing the size of the lens to make it easier to handle, providing ballast to prevent lens rotation, and/or providing a shaping area to improve the comfort of the lens wearer. The peripheral region may extend to the edge of the contact lens.

Contact lenses according to embodiments of this disclosure may include a bearing to orient the lens when it is positioned on the wearer's eye. Embodiments of this disclosure incorporating a bearing in the contact lens will rotate to a predetermined angle of repose under the action of the wearer's eyelids when placed on the wearer's eye; for example, the bearing may be a wedge and the rotation may be caused by the action of the eyelids on the wedge. Bearing contact lenses to orient them is well known in the art; for example, toroidal contact lenses are bearing to orient the lens so that the orthogonal cylindrical correction provided by the lens is correctly aligned with the astigmatism of the wearer's eye. It is possible that contact lenses of this disclosure provide a specific benefit to the wearer in a given orientation. For example, a contact lens may provide a specific benefit to the wearer when the maximum additional refractive power meridian is in a particular orientation.

The contact lens may be generally circular in shape and have a diameter from about 4 mm to about 20 mm. The optical region may be generally circular in shape and have a diameter from about 2 mm to about 10 mm. In some embodiments, the contact lens has a diameter from 13 mm to 15 mm, and the optical region has a diameter from 7 mm to 9 mm.

The first optical axis may lie along the centerline of the lens. The central zone focuses light from a distant point object on the first optical axis to a point of light at the distal focal plane on the first optical axis. As used herein, the term "surface" does not refer to a physical surface, but rather to a surface from which the focused point can be drawn. This surface is also referred to as the image plane (even if it may be curved) or the image shell. The eye focuses light onto the curved retina, and in a perfectly focusing eye, the curvature of the image shell would match the curvature of the retina, so the eye would not focus light onto a flat mathematical plane. However, in this field, the curvature of the retina is generally referred to as a plane.

The central region may be generally circular and may have a diameter between approximately 2 mm and 9 mm, preferably between 2 mm and 7 mm. The central region may also be generally elliptical. The annular region may extend radially outward from the periphery of the central region by approximately 0.1 mm to 4 mm, preferably between approximately 0.5 mm and 1.5 mm. For example, the radial width of the annular region may be between approximately 0.1 mm and approximately 4 mm, preferably between approximately 0.5 mm and approximately 1.5 mm. The periphery of the central region may define the boundary between the central region and the annular region, and thus the annular region may be adjacent to the central region.

The annular region may be adjacent to the central region. A hybrid region may be provided between the central region and the annular region. The hybrid region should not substantially affect the optics provided by the central region and the annular region, and the hybrid region may have a radial width of 0.05 mm or less, but it may also be as wide as 0.2 mm, or in some embodiments as wide as 0.5 mm.

In the context of this disclosure, the refractive power of the central and annular regions of a lens can be defined as radial curvature refractive power, circumferential curvature refractive power, mean curvature refractive power (which is the average of radial and circumferential curvature refractive power), radial sagittal refractive power, circumferential sagittal refractive power, and mean sagittal refractive power (which is the average of radial and circumferential sagittal refractive power).

Curvature and sagittal refractive power are defined as follows:

For a wavefront W, at a point at a radial distance r (pupil radius) from the line normal to the center of the wavefront, W(r) = A* ^r² , where A is a function.

Wavefront curvature, or curvature-based refractive power P _{_c} , is a function of the second derivative of the wavefront. Wavefront slope, or slope-based refractive power P_{_S}, is a function of the first derivative of the wavefront and varies with the slope of the wavefront.

For a simple spherical lens, the curvature refractive power _Pc is defined as:

The refractive power P _{_S} based on the slope is defined as follows:

That is, for a simple lens (with the paraxial assumption), _PC = _PS .

Radial curvature refractive power is the refractive power of the lens extending radially outward from the center of curvature. Circumferential curvature refractive power is the refractive power of the lens at a constant radial coordinate, extending around the circumference of the lens. Mean curvature provides the average value of both radial and circumferential curvature refractive powers.

Radial sagittal refractive power is the sagittal refractive power extending radially outward from the center of the lens. Circumferential sagittal refractive power is the sagittal refractive power at a constant radial coordinate, extending around the circumference of the lens.

The central zone may have the same curvature refractive power as the sagittal refractive power. This is referred to herein as the fundamental curvature refractive power, fundamental sagittal refractive power, or fundamental refractive power. The nominal refractive power of the central zone will correspond to the labeled diopter of the contact lens as provided on the contact lens packaging (but may not actually have the same value). This will be the mean sagittal or mean curvature refractive power obtained across the central zone. The measured refractive power of the central zone is the directly measured mean refractive curvature or sagittal refractive power obtained across the central zone. This may differ from the nominal refractive power.

For lenses used in myopia treatment, the basic refractive power will be negative or close to zero, and the central area will correct distance vision. The basic refractive power can be between 0.5 diopters (D) and -15.0 diopters. The basic refractive power can range from -0.25D to -15.0D.

The fundamental refractive power in the central zone can be generated by the curvature of the lens surface. The fundamental refractive power can be generated by the curvature of the anterior surface of the lens and/or the center of curvature of the posterior surface of the lens.

In the context of this disclosure, the annular region is a generally annular region surrounding the optical region. It may have a generally circular shape or a generally elliptical shape. It may completely surround the optical region. It may partially surround the optical region.

In embodiments of this disclosure, the radial curvature refractive power of the annular region is greater than the basic radial curvature refractive power of the central region.

The radial curvature refractive power of the annular region can be determined by the curvature of at least one surface of the annular region. The radial curvature refractive power of the annular region can be generated by the curvature of the anterior and/or posterior surfaces of the lens. The annular region may have a larger curvature or a smaller radius of curvature compared to the central region. The anterior surface of the annular region may have a larger curvature or a smaller radius of curvature compared to the curvature of the central region. Alternatively or additionally, the posterior surface of the annular region may have a curvature greater than that of the central region.

The radial curvature refractive power varies across the annular zone. At a point halfway across the width of the annular zone, the radial curvature refractive power of the annular zone is X. The radial curvature refractive power will be a more positive (or less negative) refractive power than the basic radial curvature refractive power. The net radial curvature refractive power of the annular zone will be the sum of the basic radial curvature refractive power of the central zone and the radial curvature additional refractive power of the annular zone. For example, if the basic radial curvature refractive power is -3.0D and the radial curvature additional refractive power of the annular zone is +4.0D, then the net radial curvature refractive power of the annular zone will be +1.0D.

The value of X can be between +0.5D and +20.0D. The value of X can be +10.0D greater than the basic radial curvature refractive power (i.e., the radial curvature-added refractive power at a point halfway across the width of the annular region can be +10.0D). The value of X can be +11.0D greater than the basic radial curvature refractive power (i.e., the radial curvature-added refractive power at a point halfway across the width of the annular region can be +11.0D). The value of X can be +12.0D greater than the basic radial curvature refractive power (i.e., the radial curvature-added refractive power at a point halfway across the width of the annular region can be +12.0D).

The annular region can be understood as tilted relative to the central region. As used herein, tilting of the annular region means a circular, symmetrical tilt rather than a lateral tilt. The annular region tilts about a curve extending around the circumference of the lens, such that the outer edge of the annular region moves in a first direction and the inner edge of the annular region moves in the opposite direction. Tilting the annular region will change the radial sagittal refractive power of the annular region, as this is a function of the first derivative of the wavefront, but will not change the radial curvature refractive power of the annular region, which is a function of the second derivative of the wavefront. Tilting the annular region relative to the central region will mean that the center of curvature of the annular region is shifted away from the central region by a first optical axis by a first distance. The radial sagittal refractive power of the annular region can vary across the width of the annular region and in embodiments of this disclosure. At a point halfway across the width of the annular region, the radial sagittal refractive power of the annular region is Y. Y will be greater than the basic radial sagittal refractive power of the central region, but Y will be less than X (the radial curvature refractive power of the annular region at a point halfway across the width of the annular region). The radial sagittal refractive power of the annular region will be more positively biased than the sagittal refractive power of the central region. The net radial-sagittal refractive power of the annular region will be the sum of the basic radial-sagittal refractive power and the radial-sagittal additional refractive power of the annular region. The value of Y can be between +0.5D and +10.0D. The value of Y can be +2.0D greater than the basic radial-sagittal refractive power (i.e., the radial-sagittal additional refractive power at the point halfway across the width of the annular region can be +2.0D). The value of Y can be +4.0D greater than the basic radial-sagittal refractive power (i.e., the radial-sagittal additional refractive power at the point halfway across the width of the annular region can be +4.0D). The value of Y can be +3.0D greater than the basic radial-sagittal refractive power (i.e., the radial-sagittal additional refractive power at the point halfway across the width of the annular region can be +3.0D).

The following describes example combinations of values for X and Y. Those skilled in the art will immediately understand that many other combinations of X and Y values fall within the scope of this disclosure.

The value of X can be +10.0D greater than the basic radial curvature refractive power (i.e., the radial curvature additional refractive power at a point halfway across the width of the annular region can be +10.0D), and the value of Y can be +2.0D greater than the basic radial sagittal refractive power (i.e., the radial sagittal additional refractive power at a point halfway across the width of the annular region can be +2.0D).

The value of X can be +12.0D greater than the basic radial curvature refractive power (i.e., the radial curvature additional refractive power at a point halfway across the width of the annular region can be +12.0D), and the value of Y can be +4.0D greater than the basic radial sagittal refractive power (i.e., the radial sagittal additional refractive power at a point halfway across the width of the annular region can be +4.0D).

The value of X can be +10.0D greater than the basic radial curvature refractive power (i.e., the radial curvature additional refractive power at a point halfway across the width of the annular region can be +10.0D), and the value of Y can be +3.0D greater than the basic radial sagittal refractive power (i.e., the radial sagittal additional refractive power at a point halfway across the width of the annular region can be +3.0D).

The value of X can be +11.0D greater than the basic radial curvature refractive power (i.e., the radial curvature additional refractive power at a point halfway across the width of the annular region can be +11.0D), and the value of Y can be +3.0D greater than the basic radial sagittal refractive power (i.e., the radial sagittal additional refractive power at a point halfway across the width of the annular region can be +3.0D).

The value of X can be +12.0D greater than the basic radial curvature refractive power (i.e., the radial curvature additional refractive power at a point halfway across the width of the annular region can be +12.0D), and the value of Y can be +3.0D greater than the basic radial sagittal refractive power (i.e., the radial sagittal additional refractive power at a point halfway across the width of the annular region can be +3.0D).

The radial curvature refractive power of the annular region can be greater than the circumferential curvature refractive power of the annular region. The circumferential curvature refractive power of the annular region can be the same as the basic circumferential curvature refractive power. The circumferential sagittal refractive power of the annular region can be the same as the basic circumferential sagittal refractive power.

Across the width of the annular region, the radial sagittal refractive power of the annular region can be greater than that of the central region. In a known central hyperopic lens design with an annular region providing additional refractive power, where the center of curvature of the annular region coincides with the optical axis of the central region (this may be referred to as a coaxial annular region), the radial sagittal refractive power of the annular region across the width of the annular region will be greater than that of the central region. For a known central hyperopic lens design with an annular region providing additional refractive power, where the center of curvature of the annular region is shifted away from the optical axis of the central region (this may be referred to as an off-axis annular region), due to the tilt of the annular region relative to the central region, at the innermost edge of the annular region, the radial sagittal refractive power of the annular region may be lower than that of the central region. The radial sagittal refractive power can increase with increasing radial distance toward the outer edge of the annular region. In these known designs, the annular region can be radially tilted relative to the central region such that the radial sagittal refractive power at the midpoint of the width across the annular region matches the radial sagittal refractive power that the central region would have if it extended to said midpoint. The lens can have a radial sagittal refractive power at the midpoint of the annular zone that matches the radial sagittal refractive power that the central zone would have as it extends outward to the midpoint.

The combined effect of the annular region's tilt relative to the central region and its small radius of curvature means that the radial sagittal refractive power of the annular region can be greater across the entire width of the annular region than the radial sagittal refractive power of the central region. Alternatively, the sagittal refractive power of the annular region may decrease towards the boundary between the central and annular regions.

The radial sagittal refractive power increases radially outward across the width of the annular region. The radial sagittal refractive power can increase linearly from the innermost edge of the annular region outward.

The radial curvature refractive power can be constant radially outward from the inner edge of the annular region along a given meridian, or it can be increased radially outward from the inner edge of the annular region along a given meridian.

The radial curvature refractive power varies between a minimum value X1 and a maximum value X2 along the meridian around the annular region, where both X1 and X2 are greater than the basic radial curvature refractive power. Both X1 and X2 can be greater than the basic curvature refractive power. The radial curvature refractive power can vary periodically around the annular region. This variation can be defined by a sine wave, triangular wave, square wave, or sawtooth wave. The radial curvature refractive power can vary continuously between X1 and X2. The position around the circumference of the annular region is defined by an angle θ, where θ varies between 0° and 360°, and there may be maximum values of radial curvature refractive power every 90°, every 45°, every 20°, or every 10°. X1 can be between +0.5D and +10.0D. X2 can be between +2.0D and +20.0D.

Alternatively and/or additionally, the radial sagittal refractive power of the annular region may vary between a maximum value Y1 and a minimum value Y2 along the meridian around the annular region, where both Y1 and Y2 are greater than the basic radial sagittal refractive power. Both Y1 and Y2 may be greater than the basic radial sagittal refractive power. The radial sagittal refractive power may vary periodically around the annular region. This periodic variation of the radial sagittal refractive power may occur around the entire annular region or around a portion of the annular region. The variation can be defined by a sine wave, triangular wave, or sawtooth wave. The radial sagittal refractive power may vary continuously between Y1 and Y2. The position around the circumference of the annular region is defined by an angle θ, where θ varies between 0° and 360°, and there may be maximum radial sagittal refractive power every 90°, every 45°, every 20°, or every 10°. Y1 may be between +0.5 and +9.0D. Y2 may be between +2.0 and +19.0D.

In embodiments of this disclosure, the radial curvature refractive power of the annular region varies between a minimum value X1 and a maximum value X2, where both X1 and X2 can be greater than Y. In embodiments of this disclosure, the radial sagittal refractive power of the annular region varies between a minimum value Y1 and a maximum value Y2, where both Y1 and Y2 can be less than X. In embodiments of this disclosure, the radial curvature refractive power of the annular region varies between a minimum value X1 and a maximum value X2, and the radial sagittal refractive power of the annular region varies between a minimum value Y1 and a maximum value Y2; the variations in radial curvature refractive power and radial sagittal refractive power can be in phase or out of phase. At any meridian around the annular region, the radial curvature refractive power can be greater than the radial sagittal refractive power. Both the radial sagittal refractive power and the radius of curvature of the annular region can vary with the meridians around the annular region, such that the radial curvature refractive power of the lens remains constant, or approximately constant as it moves around the annular region. For example, for a lens with a constant radial curvature power of +3.0D, the radial sagittal power can vary between +2.0D and +3.0D as the meridian moves around the annular region. For the region with a radial sagittal power of +3.0D, the radius of curvature of the annular region will be centered on the first optical axis. For the region with a radial sagittal power of +2.0D, the center of curvature of the annular region will shift away from the first optical axis, and the radius of curvature of the annular region can change.

A contact lens may comprise at least two concentric annular zones. For each of the at least two annular zones, at a point halfway across the width of the annular zone, the annular zone may have a radial curvature refractive power of X, where X is greater than a fundamental radial curvature refractive power. Each of the at least two annular zones may have an off-axis curvature center at a first distance from the optical axis, such that at a point halfway across its width, the annular zone has a radial sagittal refractive power of Y, where Y is greater than a fundamental radial sagittal refractive power and where Y is less than X. Each annular zone may comprise any of the features of an annular zone described above. For embodiments having at least two concentric annular zones, each annular zone may have the same radial curvature refractive power distribution and the same radial sagittal refractive power distribution, or each concentric annular zone may have different radial curvature refractive power distributions and/or radial sagittal refractive power distributions. For embodiments having at least two concentric annular zones, the annular zones may be distinguished by having a fundamental refractive power (i.e., the same refractive power as the central zone).

Contact lenses may include elastomer materials, silicone elastomer materials, hydrogel materials, or silicone hydrogel materials, or combinations thereof. As understood in the field of contact lenses, a hydrogel is a material that maintains water in equilibrium and is free of silicone-containing chemicals. A silicone hydrogel is a hydrogel containing silicone-containing chemicals. The hydrogel materials and silicone hydrogel materials described in the context of this disclosure have an equilibrium water content (EWC) of at least 10% to about 90% (wt/wt). In some embodiments, the hydrogel material or silicone hydrogel material has an EWC of from about 30% to about 70% (wt/wt). In contrast, silicone elastomer materials described in the context of this disclosure have a water content of from about 0% to less than 10% (wt/wt). Typically, silicone elastomer materials used in conjunction with this method or apparatus have a water content of from 0.1% to 3% (wt/wt). Examples of suitable lens formulations include those with the following US Generic Drug Names (USANs): metafilcon A, ocufilcon A, ocufilcon B, ocufilcon C, ocufilcon D, omafilcon A, omafilcon B, comfilcon A, enfilcon A, stenfilcon A, fanfilcon A, etafilcon A, senofilcon A, senofilcon B, senofilcon C, narafilcon A, narafilcon B, balafilcon A, samfilcon A, lotrafilcon A, lotrafilcon B, somofilcon A, riofilcon A, delefilcon A, verofilcon A, kalifilcon A, and similar.

Alternatively, the lens may comprise, be substantially composed of, or be composed of a silicone elastomer material. For example, the lens may comprise, be substantially composed of, or be composed of a silicone elastomer material having a Shore A hardness from 3 to 50. The Shore A hardness can be determined using conventional methods, as understood by one of ordinary skill in the art (for example, method DIN 53505). Other silicone elastomer materials may be available, for example, from NuSil Technology or Dow Chemical Company.

According to a second aspect, this disclosure provides a method of manufacturing a contact lens. The method may include forming a contact lens, wherein the contact lens includes a central region having a first optical axis, a fundamental curvature refractive power, and a fundamental sagittal refractive power, and centered on a center of curvature on the first optical axis. The lens includes an annular region. The annular region has a radial curvature refractive power of X. X is greater than the fundamental radial curvature refractive power. The annular region has an off-axis center of curvature at a first distance from the optical axis, such that at a point halfway across its width, the annular region has a radial sagittal refractive power of Y, wherein Y is greater than the fundamental radial sagittal refractive power, and wherein Y is less than X.

The lens may include any of the features described above.

The manufacturing method may include forming a female mold component having a concave lens forming surface and a male mold component having a convex lens forming surface. The method may include filling the gap between the female and male mold components with a bulk lens material. The method may further include curing the bulk lens material to form a lens.

Contact lenses can be formed using turning processes. Lenses can be formed using molding, spinning, or turning processes, or combinations thereof. As understood by those skilled in the art, molding refers to modeling a lens by placing lens-forming material between a master mold part having a concave lens component forming surface and a male mold part having a convex lens component forming surface.

A method of manufacturing a lens may include designing a contact lens, wherein the designed lens is a lens according to embodiments of the present disclosure and includes any of the features described above. Modeling (which may be computer-implemented modeling) can be used to design the lens.

The method may include modeling a first contact lens. The first contact lens may have a central region having a first optical axis. The central region may have a fundamental refractive power and be centered on a center of curvature on the first optical axis. The first contact lens may have a ring-shaped region surrounding the central region. The ring-shaped region may have a radius of curvature centered on the first optical axis, wherein the curvature of the ring-shaped region produces an additional refractive power, and wherein the net refractive power of the ring-shaped region is the sum of the fundamental refractive power and the additional refractive power. The method may include modeling a second contact lens. The second contact lens may have the same central region as the first contact lens. The central region of the second lens may have the same fundamental refractive power as the first lens and be centered on a center of curvature on the first optical axis. The second contact lens may have a ring-shaped region surrounding the central region. The ring-shaped region of the second lens may have a radius of curvature centered on the first optical axis, and the curvature of the second ring-shaped region of the second lens may produce an additional refractive power greater than the additional refractive power of the first contact lens. The net refractive power of the second lens will be the sum of the fundamental refractive power and the additional refractive power of the second lens. The net refractive power of the second lens can be greater than that of the first lens. A method for designing the lens may include tilting the annular region of the second lens within a model such that the outer circumference or outer edge of the annular region matches the outer edge of the annular region of the first lens, while keeping the inner edge of the annular region fixed. Tilting the annular region of the second lens will shift the center of curvature of the annular region away from the first optical axis. Tilting the annular region of the second lens will produce a third modeled lens, i.e., the tilted second lens. The third lens, or the tilted second lens, will have an annular region, which produces the same net refractive power as the untilted second contact lens, but with an off-axis center of curvature.

Methods of manufacturing lenses may include manufacturing lenses based on a modeled third contact lens (i.e., a tilted second lens). Because a lens based on a third modeled lens will have a higher curvature than a lens based on a first modeled lens, it can have higher positive spherical aberration. Lenses designed and manufactured based on a third contact lens may also have a longer depth of focus compared to lenses based on a first or second modeled lens.

Figure 1A shows a schematic top view of a contact lens 1 using a treatment area that provides a myopic defocus image to reduce the progression of myopia. Figure 1B shows a schematic side view of the lens 1 of Figure 1A. The lens 1 includes an optical region 2 that substantially covers the pupil and a peripheral region 4 located above the iris. The peripheral region 4 provides mechanical functions, including increasing the size of the lens to make the lens 1 easier to handle, providing ballast to prevent rotation of the lens 1, and providing a shaping zone to improve the comfort of the wearer of the lens 1. The optical region 2 provides the optical functionality of the lens 1 and includes an annular region 3 and a central region 5. The lens 1 has a fundamental radial curvature refractive power, which is equal to the fundamental radial sagittal refractive power. The fundamental refractive power is generated by the radius of curvature of the surface of the lens 1. The center of curvature of the central region 5 is located on a first optical axis 19 (shown in Figure 2A). The annular region 3 has a radial curvature refractive power greater than the fundamental radial curvature refractive power. The radial curvature refractive power of the annular region 3 is provided by the radius of curvature 6 of the annular region 3, which is smaller than the radius of curvature 7 of the central region 5, as shown in Figure 3. The center of curvature of the annular region 3 is located on the first optical axis 19. The annular region 3 has a greater refractive power than the central region 5. As shown in Figure 2A, the focal point 11 of the annular region 3 and the focal point 15 of the central region 5 share a common optical axis 19. The focal point 11 of the annular region 3 is located on the near focal plane 13, and the focal point of the central region 5 is located on the far focal plane 17, which is further away from the rear surface of the lens. As shown in Figure 2C, for a point source at infinity, the light rays focused by the central region 5 form a focused image 23 at the far focal plane 17. The light rays focused by the central region 5 also produce an unfocused blurred spot 27 at the near focal plane 13.

As shown in Figure 2B, the light rays focused through the annular region 3 form a focused image 21 at the near-end focal plane 13. The light rays focused through the annular region 3 diverge after the near-end focal plane 13, and the diverging light rays produce an unfocused ring 25 at the far-end focal plane 17. As discussed above, the unfocused ring image 25 can cause the wearer of lens 1 to see a "halo" around the focused distance image.

Figure 4A is a plot 31 showing the variation of radial sagittal refractive power of lens 1 shown in Figures 1A and 1B, and Figure 4B is a plot 33 showing the variation of radial curvature refractive power of lens 1 shown in Figures 1A and 1B. Figures 4A and 4B show the variation of refractive power along the radial diameter of lens 1. For this lens 1, since the annular region 3 has a greater refractive power than the central region 5, and since the annular region 3 has a coaxial center of curvature, the radial sagittal refractive power across the annular region 3 (indicated by curve 35) is greater than that across the central region 5. The radial curvature refractive power across the annular region 3 (indicated by curve 37) is also greater than that across the central region 5.

Figure 5A shows a schematic top view of another contact lens 101 with non-coaxial optics. Figure 5B is a schematic side view of the lens 101 of Figure 5A. Similar to lens 1 of Figure 1A, lens 101 includes an optical region 102 that generally covers the pupil and a peripheral region 104 located above the iris. The peripheral region 104 provides mechanical functions, including increasing the size of the lens to make it easier to handle, providing ballast to prevent rotation of the lens 101, and providing a shaping area to improve the comfort of the wearer. The optical region 102 provides the optical functionality of lens 101 and includes an annular region 103 and a central region 105. Lens 101 has a fundamental radial curvature refractive power, which is equal to the fundamental radial sagittal refractive power. The fundamental refractive power is generated by the radius of curvature of the surface of lens 101. The center of curvature of the central region 105 is located on a first optical axis 119 (shown in Figure 6A). The annular region 103 has a radial curvature refractive power greater than the basic radial curvature refractive power. The radial curvature refractive power of the annular region 103 is provided by the radius of curvature of the annular region 103, which is smaller than the radius of curvature of the central region 105. However, compared to lens 1 in Figures 1A and 1B, for lens 101 shown in Figures 5A and 5B, the curvature of the annular region 103 cannot be defined by a single sphere, and the center of curvature of the annular region 103 is not located on the first optical axis 119. This is shown in Figure 6D. The annular region 103 is tilted relative to the central region 105, such that, compared to lens 1 in Figures 1A and 1B, the outer edge of the annular region 103 is higher than its inner edge (in Figure 5B). This changes the radial sagittal refractive power of the annular region 103, but does not change the radial curvature refractive power. As shown in Figure 6D, the front surface of the central region 105 defines a portion of the surface of a sphere with a larger radius 107. The front surface of the annular region 103 defines a curved annular surface with a small radius of 106.

At the far focal plane 117, light rays traveling through the central region 105 are focused. The annular region 103 acts as a beam blocker, which results in a small spot size 133 of light 124 at the far focal plane 117, as shown in Figure 6C.

No single image is formed at the near focal plane 113. As shown in Figure 6B, at the near focal plane 113, for a point source at infinity, light rays traveling through the central region 105 produce a blur circle 128, as is the case with the lenses in Figures 1A, 1B, 2A, and 2B. However, light rays from a distant point source traveling through the annular region 103 produce a focusing ring 122, as shown in Figure 6B, which surrounds the blur circle 128. Figure 6B shows the light pattern produced for a distant point source. Compared to the lens 1 in Figures 1A and 1B, the lens 101 in Figures 5A and 5B does not produce a single image or a coaxial image at the near focal plane 113, which can be used to avoid the need for the eye to adapt to near objects. For a distant extended object, the focused image formed at the near focal plane 113 is (i) the convolution of the focused image of the extended object obtained using a conventional lens with the optical refractive power of the annular region 103 and (ii) the optical transfer function representing the optical effect of the annular region 103.

Compared with lens 1 in Figures 1A and 1B, no ring or "halo" effect was observed at the far focal plane 117.

Figure 7A is a plot 131 illustrating the variation in radial sagittal refractive power of lens 101 shown in Figures 5A and 5B, and Figure 7B is a plot 133 illustrating the variation in refractive power based on radial curvature of lens 101 shown in Figures 5A and 5B. Figures 7A and 7B illustrate the variation in refractive power along the radial diameter of lens 101. For this lens 101, since the annular region 103 has greater refractive power than the central region 105, this means that the radial curvature refractive power across the annular region 103 (indicated by curve 137) is greater than that across the central region 105. However, the annular region 103 is tilted relative to the central region 105, resulting in an off-axis center of curvature for the annular region 103. The tilt of the annular region 103 relative to the central region 105 means that the radial sagittal refractive power is more negative at the boundary between the central region 105 and the annular region 105 than the radial sagittal refractive power in the central region, as shown by curve 135. The radial sagittal refractive power increases with increasing radial distance toward the outer edge of the annular region 103.

Figure 8A shows a schematic top view of a contact lens 201 according to an embodiment of the present disclosure. Similar to lens 1 of Figures 1A and 1B and lens 101 of Figures 5A and 5B, lens 201 includes an optical region 202 that substantially covers the pupil and a peripheral region 204 located above the iris. The peripheral region 204 provides mechanical functions including increasing the size of the lens to make lens 201 easier to handle, providing ballast to prevent rotation of lens 201, and providing a shaping area to improve the comfort of the wearer of lens 201. The optical region 202 provides the optical functionality of lens 201 and includes an annular region 203 and a central region 205. The central region 205 of lens 201 has a fundamental radial curvature refractive power that is equal to a fundamental radial sagittal refractive power. In this exemplary embodiment of the present disclosure, the fundamental radial curvature refractive power of the central region is 0.0D, which is equal to the fundamental radial sagittal refractive power of the central region 205. This fundamental refractive power is generated by the radius of curvature of the surface of lens 201. The curvature center 244 of the central region 205 is located on the first optical axis 219 (shown in Figure 9). The annular region 203 has a radial curvature refractive power greater than the basic radial curvature refractive power. The radial curvature refractive power of the annular region 203 is provided by the radius of curvature of the annular region 203, which is smaller than the radius of curvature of the central region 205.

At point A, halfway across the width of the annular region (indicated in Figures 8A and 8B), the radial curvature refractive power of the annular region has a value of approximately +3.5D. For the example lens 201 shown in Figures 8A and 8B, for a given radial position, the radial curvature refractive power is constant along all meridians around the annular region 203. This means that the radial curvature refractive power will have the same value along the dashed curve 241 shown in Figures 8A and 8B, which is a curve extending around the annular region 203 at a point halfway across the width of the annular region 203. In this example embodiment of the present disclosure, X is approximately +3.5D. Similar to the lens shown in Figures 5A and 5B, the annular region 203 of lens 201 is tilted relative to the central region 205, such that the center of curvature 243 of the annular region 203 is offset from the first optical axis 219. This is shown in Figure 9. Inclining the annular region 203 relative to the central region 205 reduces the radial sagittal refractive power at the boundary between the central region 205 and the annular region 203. At point A, halfway across the width of the annular region 203, the radial sagittal refractive power has a value Y, which is greater than the basic radial sagittal refractive power but less than X. For this example embodiment, Y is approximately +2.25D for a given radial position, and the radial sagittal refractive power is constant along all meridians around the annular region 203. This means that the radial sagittal refractive power will have the same value along the dashed curve 241 shown in Figures 8A and 8B, which is a curve extending around the annular region 203.

At the far focal plane 217, light rays traveling through the central region 205 are focused. Light rays traveling through the annular region 203 are guided toward the sagittal additional focal plane 218.

Figure 10A is a plot 231 showing the variation of curvature refractive power across the radial diameter of lens 201 shown in Figures 8A and 8B. This plot 231 shows the average values of radial and circumferential curvature refractive power. Across the central zone 205, the curvature refractive power of lens 201 is constant and approximately zero. At the boundary between the central zone 205 and the annular zone 203, the curvature refractive power shows a sharp increase, as indicated by curve 235. This is attributed to the increase in radial curvature refractive power. The circumferential curvature refractive power will not change significantly at the boundary between the central zone 205 and the annular zone 203, but the radial curvature refractive power will increase, and therefore the average curvature refractive power (indicated by curve 235) will increase at the boundary between the central zones 205 to the average of the circumferential and radial curvature refractive powers.

Figure 10B is a plot 233 showing the variation of sagittal refractive power across the radial diameter of lens 201 shown in Figures 8A and 8B. This plot 233 shows the average values of radial and circumferential sagittal refractive power. Across the central region 205 of lens 201, the sagittal refractive power is constant and has a value of 0.0D. At the boundary between the central region 205 and the annular region 203, the sagittal refractive power of the annular region 203 increases sharply due to the increase in radial sagittal refractive power, as indicated by curve 237. The radial sagittal refractive power increases radially outward across the width of the annular region 203 in an approximately linear manner. Compared with the sagittal refractive power curve shown in Figure 7A for a lens with annular region 203 having off-axis additional refractive power, there is no decrease in sagittal refractive power at the boundary between the central region 205 and the annular region 203. This is because the annular region 203 has been tilted relative to the central region in a manner that increases the radial sagittal refractive power at the boundary between the central region 205 and the annular region 203. The increase in sagittal refractive power at the boundary between the central zone 205 and the annular zone 205 will not be as large as that of lenses with an annular zone having additional coaxial refractive power (for example, as shown in Figures 1A and 1B).

As shown in Figure 11A, for the lens 201 shown in Figures 8A and 8B, at the distal focal plane 217, light rays traveling through the central region 205 will form a focused image 223, as shown in Figure 11B. Light rays traveling through the annular region 203 will produce an unfocused ring 225 at the distal focal plane 217. At the first near focal plane 218, for a point source at infinity, light rays traveling through the central region 205 will produce a first blur circle 227, and light rays traveling through the annular region 203 will produce a second blur circle 229, as shown in Figure 11C. At the second near focal plane 220, light rays traveling through the central region 205 will produce a third blur circle 231, and light rays traveling through the annular region 203 will produce a focused ring 233 located within the third blur circle 231, as shown in Figure 11D. Figure 12A shows a schematic top view of a contact lens 301 according to an embodiment of the present disclosure. Similar to lens 201 in Figures 8A and 8B, lens 301 includes an optical region 302 that substantially covers the pupil and a peripheral region 304 located above the iris. The peripheral region 304 provides mechanical functions, including increasing the size of the lens to make it easier to handle, providing ballast to prevent rotation of the lens 301, and providing a shaping area to improve the comfort of the wearer. The optical region 302 provides the optical functionality of the lens 301 and includes an annular region 303 and a central region 305. Lens 301 has a fundamental radial curvature refractive power equal to a fundamental radial sagittal refractive power. In this exemplary embodiment of the present disclosure, the fundamental radial curvature refractive power of the central region is -2.0D, and the fundamental radial sagittal refractive power of the central region is -2.0D. The fundamental refractive power is generated by the radius of curvature of the surface of lens 301. The center of curvature of the central region 305 is located on a first optical axis. The annular region 303 has a radial curvature refractive power greater than the fundamental radial curvature refractive power. The radial curvature refractive power of the annular region 303 varies along the meridians surrounding the annular region 303. In this example embodiment, the radial curvature refractive power is approximately constant as it extends radially outward along any meridian. Along a curve extending around the annular region 303 at halfway across the width of the annular region, indicated by the dashed line 341 in Figures 12A and 12B, the radial curvature refractive power varies between a minimum value X1 and a maximum value X2. Both X1 and X2 are greater than the fundamental curvature refractive power of the central region 305. X1 is +2.0D and X2 is +10.0D. The radial curvature refractive power varies sinusoidally around the annular region, with the distribution shown in Figure 14. The position around the circumference of the annular region 303 is defined using an angle θ, where θ varies between 0° and 360°. For this example embodiment, the radial curvature refractive power has a maximum value of X2 at points halfway across the width of the annular region 303 every 180°, such that the radial curvature at points A and C is X2. The radial curvature refractive power has a minimum value of X1 at points halfway across the width of the annular region 303 every 180°, such that the radial curvature at points B and D is X1.

The radial curvature refractive power of the annular region 303 is generated by the curvature of the surface of the annular region 303. At all points around the annular region 303, the radius of curvature of the annular region 303 is smaller than the radius of curvature 307 of the central region 305. At all points around the annular region 303, the annular region 303 has an off-axis center of curvature. In this example embodiment, the radius of curvature of the annular region 303 varies with the meridian, and this produces a varying radial curvature refractive power. As shown in Figure 13A, along the radial diameter where the radial curvature has a maximum value (line E-E in Figure 12A), the radius of curvature 306e of the annular region 303 will be the minimum (Figure 13A). As shown in Figure 13B, along the radial diameter where the radial curvature has a minimum value (line F-F in Figure 12A), the radius of curvature 306f of the annular region 303 will be the maximum.

For this lens 301, the radial sagittal refractive power has a constant value Y at a point halfway across the width of the annular region 303, and a constant value around the annular region 305. Y is less than X, but greater than the fundamental refractive power of the central region 305 of the lens 301, as schematically shown in Figure 14.

In other embodiments of this disclosure (not shown), the lens is similar to the lens shown and described in Figures 8A to 11D, but at point A, halfway across the width of the annular region (as shown in Figures 8A and 8B), the radial curvature refractive power of the annular region is approximately +10.0D compared to the basic radial curvature refractive power of the central region (i.e., the radial curvature additional refractive power is approximately +10.0D), and the radial sagittal refractive power of the annular region is approximately +2.0D compared to the basic radial sagittal refractive power of the central region (i.e., the radial sagittal additional refractive power is approximately +2.0D).

In other embodiments of this disclosure (not shown), the lens is similar to the lens shown and described in Figures 8A to 11D, but at point A, halfway across the width of the annular zone, the radial curvature refractive power of the annular zone is approximately +12.0D compared to the basic radial curvature refractive power of the central zone (i.e., the additional radial curvature refractive power is approximately +12.0D), and the radial sagittal refractive power of the annular zone is approximately +4.0D compared to the basic radial sagittal refractive power of the central zone (i.e., the additional radial sagittal refractive power is approximately +4.0D). Advantageously, this lens will exhibit a sharp increase in radial sagittal refractive power at the boundary between the central and annular zones. The increase in radial sagittal refractive power may exceed +2.0D. For lens wearers with relatively small pupil diameters (e.g., young lens wearers), this sharp increase in radial sagittal refractive power at the boundary between the central and annular zones can improve the therapeutic effect of the annular zone.

In other embodiments of this disclosure (not shown), the lens is similar to the lens shown and described in Figures 8A to 11D, but at point A, halfway across the width of the annular region (as shown in Figures 8A and 8B), the radial curvature refractive power of the annular region is approximately +11.0D compared to the basic radial curvature refractive power of the central region (i.e., the radial curvature additional refractive power is approximately +11.0D), and the radial sagittal refractive power of the annular region is approximately +3.0D compared to the basic radial sagittal refractive power of the central region (i.e., the radial sagittal additional refractive power of the annular region is approximately +3.0D).

In other embodiments of this disclosure (not shown), the lens is similar to the lens shown and described in Figures 8A to 11D, but at point A, halfway across the width of the annular region (as shown in Figures 8A and 8B), the radial curvature refractive power of the annular region is approximately +12.0D compared to the basic radial curvature refractive power of the central region (i.e., the radial curvature additional refractive power is approximately +12.0D), and the radial sagittal refractive power of the annular region is approximately +3.0D compared to the basic radial sagittal refractive power of the central region (i.e., the radial sagittal additional refractive power of the annular region is approximately +3.0D).

In other embodiments of this disclosure (not shown), the lens is similar to the lens shown and described in Figures 8A to 11D, but at point A, halfway across the width of the annular region (as shown in Figures 8A and 8B), the radial curvature refractive power of the annular region is approximately +10.0D compared to the basic radial curvature refractive power of the central region (i.e., the radial curvature additional refractive power is approximately +10.0D), and the radial sagittal refractive power of the annular region is approximately +3.0D compared to the basic radial sagittal refractive power of the central region (i.e., the radial sagittal additional refractive power is approximately +3.0D). In other embodiments of this disclosure, the lens may have an annular region with radial curvature refractive power varying with the meridian in a stepped or zigzag manner. The variation may be periodic or non-periodic. Peaks in radial curvature refractive power may exist every 180°, every 90°, every 20°, every 10°, or every 5°. The periodic variation of radial refractive power is illustrated in Figures 15A to C by way of example; it can be a variation of radial sagittal or curvature refractive power.

In other embodiments of this disclosure, both radial curvature refractive power and radial sagittal refractive power may vary along the meridian around the annular region. Variations in radial sagittal refractive power may be in phase or out of phase with variations in radial curvature refractive power. At all points around the circumference of the annular region, radial sagittal refractive power may be less than radial curvature refractive power, but greater than the fundamental refractive power of the central region.

In other embodiments of this disclosure, the lens may comprise two or more concentric annular zones. For each of the annular zones, at a point halfway across the width of the annular zone, the annular zone has a radial curvature refractive power of X, where X is greater than a fundamental radial curvature refractive power. Each of at least two annular zones may have an off-axis curvature center at a first distance from the optical axis, such that at a point halfway across its width, the annular zone has a radial sagittal refractive power of Y, where Y is greater than a fundamental radial sagittal refractive power and where Y is less than X. Each concentric annular zone can be distinguished by having a fundamental refractive power (i.e., the same refractive power as the central zone).

In other embodiments of this disclosure, the lens may comprise two or more concentric annular regions. At least one of the annular regions is the annular region shown in Figures 5A and 6A, and for at least one of the other annular regions, at a point halfway across the width of the annular region, the annular region has a radial curvature refractive power of X, where X is greater than a fundamental radial curvature refractive power. Each of at least two annular regions may have an off-axis curvature center at a first distance from the optical axis, such that at a point halfway across its width, the annular region has a radial sagittal refractive power of Y, where Y is greater than a fundamental radial sagittal refractive power and where Y is less than X.

Figure 16 illustrates a method 501 for designing a contact lens, wherein the lens is a lens according to an embodiment of the present disclosure. In a first step 503, the method involves modeling a first contact lens. The first contact lens has a central area having a first optical axis. The central area has a fundamental refractive power and is centered on a center of curvature on the first optical axis. In this example, the central area of the first contact lens has a fundamental refractive power of -3.0D. The first contact lens has an annular area surrounding the central area. The annular area has a radius of curvature centered on the first optical axis. The curvature of the annular area produces additional refractive power. In this example, the annular area has a curvature that produces an additional refractive power of +2.0D. The net refractive power of the annular area is the sum of the fundamental refractive power and the additional refractive power, and therefore in this example, the net refractive power of the annular area is -1.0D. In a second step 505, the method involves modeling a second contact lens. The second contact lens has the same central area as the first contact lens, and therefore, in this example, the second contact lens has a fundamental refractive power of -3.0D. The second contact lens is also centered on the center of curvature on the first optical axis. The second contact lens has an annular region surrounding the central area. The annular region of the second lens also has a radius of curvature centered on the first optical axis, but the curvature of the annular region produces an additional refractive power greater than that of the first lens. In this example, the curvature of the second annular region produces an additional refractive power of +4.0D. The net refractive power of the second lens is the sum of the basic refractive power and the additional refractive power, and therefore in this example, the net refractive power of the second lens is +1.0D. In the third step 507, the method includes tilting the annular region of the second lens within the model such that the outer edge of the second annular region matches the outer edge of the annular region of the first lens, while keeping the inner edge of the second annular region fixed. This produces a third lens (corresponding to the tilted second lens) with an annular region having the same net refractive power as the untilted second lens. In this example, the third lens or the tilted second lens has a net refractive power of +1.0D, but has an annular region not centered on the first optical axis.

Figure 17 is a schematic diagram of three modeled lenses 601, 603, and 605, modeled as part of the method for designing the lenses described above. The three lenses share a common central region 607, which has a curvature centered on a first optical axis providing a basic refractive power of -3.0D. The first lens 601 has an annular region 601a, which has a curvature that produces an additional refractive power of +2.0D, resulting in a net refractive power of -1.0D for the annular region. The center of curvature of the annular region 601a of the first lens 601 is centered on the first optical axis. The second lens 603 has an annular region 603a, which has a curvature that produces an additional refractive power of +4.0D, resulting in a net refractive power of +1.0D for the annular region. The center of curvature of the annular region 603a of the second lens 603 is also centered on the first optical axis. The inner edges of the annular region 601a of the first lens 601 and the inner edges of the annular region 603a of the second lens 603 coincide at point 607. The third lens 605 is a tilted version of the second lens 603. The annular region 605a of the third lens 605 has a curvature that produces an additional refractive power of +4.0D, and has the same additional refractive power and the same net refractive power as the second lens 603. The inner edge of the annular region 605a of the third lens coincides with point 607, the same as that of the first lens 601 and the second lens 603, but the outer edge of the annular region 605a of the third lens 605 is tilted to coincide with the outer edge of the annular region 601a of the first lens 601 at point 611. The annular region 605a of the third lens 605 has a net refractive power of +1.0D, but has a curvature center that is not on the first optical axis.

Those skilled in the art will understand that the features of these exemplary embodiments can be combined in other embodiments falling within the scope of this disclosure.

While references have been made in the foregoing description to elements or components having known obvious or foreseeable equivalents, such equivalents are incorporated herein as if individually stated. Reference should be made to the claims used to determine the true scope of this disclosure, which should be construed as covering any such equivalents. The reader will also understand that elements or features of this disclosure described as advantageous, convenient, or similar are optional and do not limit the scope of the independent claims. Furthermore, it should be understood that such selected elements or features, while potentially beneficial in some embodiments of this disclosure, may not be desired and therefore may not be present in other embodiments.

Claims (19)

1. A contact lens, the lens including an optical region comprising: The central region has a first optical axis, a fundamental radial curvature refractive power, a fundamental radial sagittal refractive power, and a center of curvature on the first optical axis; and The annular region, in which At a point halfway across the width of the annular region, the annular region has a radial curvature refractive power of X, where X is greater than the fundamental radial curvature refractive power, and The annular region has an off-axis curvature center at a first distance from the optical axis, such that at a point halfway across its width, the annular region has a radial sagittal refractive power of Y, where Y is greater than the basic radial sagittal refractive power and where Y is less than X. 2. The contact lens according to any of the preceding claims, wherein the radial sagittal refractive power of the annular region is greater than the radial sagittal refractive power of the central region over the width of the annular region. 3. The contact lens according to any of the preceding claims, wherein the radial sagittal refractive power of the annular region increases radially outward across the width of the annular region. 4. The contact lens according to any of the preceding claims, wherein X is between +0.5D and +20.0D. 5. The contact lens according to any of the preceding claims, wherein Y is between +0.5D and +10.0D. 6. The contact lens according to any of the preceding claims, wherein the radial curvature refractive power varies between a minimum value X1 and a maximum value X2 along the meridian around the annular region. 7. The contact lens of claim 6, wherein both X1 and X2 are greater than the basic radial curvature refractive power. 8. The contact lens according to claim 6 or claim 7, wherein the radial curvature refractive power varies periodically around the annular region. 9. The contact lens of claim 8, wherein the periodic variation is defined by a sine wave, a triangular wave, or a sawtooth wave. 10. The contact lens according to any of the preceding claims, wherein the radial sagittal refractive power of the annular region varies between a maximum value Y1 and a minimum value Y2 along the meridian surrounding the annular region. 11. The contact lens of claim 10, wherein both Y1 and Y2 are greater than the basic radial-sagittal refractive power. 12. The contact lens according to claim 10 or claim 11, wherein the radial sagittal refractive power varies periodically around the annular region. 13. The contact lens of claim 12, wherein the variation is defined by a sine wave, a triangular wave, or a sawtooth wave. 14. The contact lens according to any of the preceding claims, wherein the fundamental refractive power of the lens is between 0.5D and -15.0D. 15. The contact lens according to any of the preceding claims, wherein the fundamental refractive power of the central region is generated by the curvature of the anterior and/or posterior surfaces of the lens. 16. The contact lens according to any of the preceding claims, wherein the radial curvature refractive power of the annular region is generated by the curvature of the anterior and/or posterior surfaces of the lens. 17. The contact lens according to any of the preceding claims, wherein the lens comprises an elastomer material, a silicone elastomer material, a hydrogel material, or a silicone hydrogel material or a mixture thereof. 18. The contact lens according to any of the preceding claims, wherein the lens is formed using a turning process or a die-casting process. 19. A method of manufacturing a contact lens, the method comprising: Forming a contact lens according to any of the preceding claims.