Contact lenses and methods relating thereto

Abstract

A contact lens (201) and a method of making such a lens are described. The lens (201) includes an optical zone (202). The optical zone (202) includes a central zone (205) having a first optical axis (219), a substantially radial curvature power, a substantially radial sagittal power, and a center of curvature on the first optical axis (219). The optical zone (202) includes an annular zone (203) having a radial curvature power of X at a point halfway across the width of the annular zone (203), where X is greater than the substantially radial curvature power. The annular zone (203) has an off-axis center of curvature a first distance from the optical axis (219) such that the annular zone (203) has a sagittal power of Y at a point halfway across its width, where Y is greater than the substantially radial sagittal power, and where Y is less than X.

Description

TECHNICAL FIELD

[0001] The present 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 use by presbyopes. The invention also relates to methods of manufacturing such lenses. BACKGROUND

[0002] Many people, including children and adults, require contact lenses to correct myopia (short-sightedness) and many adults can require lenses to correct presbyopia (age-related inability to accommodate and thus to focus on near objects).

[0003] Myopic eyes focus incoming light from distant objects at a position in front of the retina. As a result, light converges and diverges towards a plane in front of the retina and is out of focus when it reaches the retina. Conventional lenses for correcting myopia, e.g. spectacle lenses and contact lenses, reduce the convergence of incoming light from distant objects before it reaches the eye (for contact lenses) or cause it to diverge (for spectacle lenses) so that the focal point position is shifted onto the retina.

[0004] Presbyopia does not effectively change shape to accommodate near objects and so people with presbyopia are unable to focus on near objects. Conventional lenses for correcting presbyopia, e.g. spectacle lenses and contact lenses, include bifocal or progressive lenses which include a zone optimised for near vision and a zone optimised for distance vision. Presbyopia can also be treated using bifocal or multifocal lenses or single vision lenses in which a different prescription is provided for each eye, one eye being provided with a distance vision lens and one eye being provided with a near vision lens.

[0005] It has been proposed for several decades that the progression of myopia in children or young adults can be slowed or prevented by undercorrection, i.e. moving the focal point towards the retina but not completely onto the retina. However, this approach inevitably results in a decrease in distance vision compared to the vision obtained with lenses which fully correct myopia. Furthermore, it is now questionable whether undercorrection is effective in controlling developing myopia. A more recent approach to correcting myopia is to provide lenses which have both one or more zones which provide full correction for distance vision and one or more zones which undercorrect or deliberately induce myopic defocus. It has been proposed that this approach can prevent or slow the development or progression of myopia in children or young adults while providing good distance vision.

[0006] In the case of lenses having zones that provide defocus, the zone that provides full correction of hyperopia is often referred to as the base power zone and the zone that provides undercorrection or intentionally induces myopic defocus is often referred to as the myopic defocus zone or add power zone (because the power is more positive or less negative than the power of the hyperopic zone). The surface (usually the front surface) of the add power zone has a smaller radius of curvature than the hyperopic power zone and thus provides more positive or less negative power to the eye. The add power zone is designed to focus incoming parallel light (i.e., light from far away) in front of the retina (i.e., closer to the lens) in the eye, while the hyperopic power zone is designed to focus light and form an image at the retina (i.e., farther from the lens).

[0007] One type of contact lens known to reduce the progression of myopia is a bifocal contact lens available under the name MISIGHT (CooperVision, Inc.). This bifocal lens is different from bifocal or multifocal contact lenses configured to improve the vision of presbyopes, because the bifocal lens is configured with specific optical dimensions to enable the wearer to use the hyperopic correction (i.e., base power) to view both distant and near objects. The therapeutic zone of the bifocal lens with add power also provides a myopic defocus image at both the distance and near viewing distances.

[0008] While these lenses have been found to be beneficial in preventing or slowing the development or progression of myopia, the annular add power zone can cause unwanted visual side effects. Light focused by the annular add power zone in front of the retina diverges from the focal point to form a defocus ring at the retina. Thus, the wearer of these lenses can see a ring or "halo" surrounding the image formed on the retina, particularly for small and bright objects such as street lights and car headlights. Furthermore, in theory, the wearer can utilize the extra focal point in front of the retina created by the annular add power zone to focus on near objects, rather than using the natural accommodation of the eye (i.e., the instinct of the eye to change focus); in other words, the wearer can inadvertently use the lens in the same way as a presbyopic corrective lens, which is undesirable for young subjects.

[0009] Developments have been made that can be used to treat myopia, and are designed to eliminate the halos observed around the focused hyperopic image in the MISIGHT (CooperVision, Inc.) lens and other similar lenses described above. In these lenses, the annular zone is configured so that a single on-axis image is not formed in front of the retina, preventing this image from being used to avoid the need for eye accommodation for near distance targets. Specifically, a distant point source is imaged through the annular zone to an annular focal line at the near add power focal surface, resulting in a small spot size of light at the hyperopic focal surface, without a surrounding "halo" effect on the retina.

[0010] For the treatment of myopia, it is recognized that it can be beneficial to provide a lens that introduces additional myopic defocus. For the treatment of presbyopia, it can be beneficial to provide a lens that creates an extended depth of focus. SUMMARY

[0011] According to a first aspect, the disclosure provides a contact lens comprising an optical zone. The optical zone comprises a central zone having a first optical axis, a substantially radial curvature power, and a substantially radial sagittal power. The central zone has a center of curvature on the first optical axis. The optical zone comprises an annular zone, wherein at a point halfway across the annular zone, the annular zone has a radial curvature power of X, where X is greater than the substantially radial curvature power. The annular zone has an off-axis center of curvature a first distance from the optical axis. At a point halfway across its width, the annular zone has a radial sagittal power of Y, where Y is greater than the substantially radial sagittal power, and where Y is less than X.

[0012] According to a second aspect, the disclosure provides a method of manufacturing a lens. The method comprises forming the contact lens of the first aspect of the invention.

[0013] It will of course be appreciated that features described with reference to one aspect of the disclosure can be incorporated into other aspects of the disclosure. For example, the methods of the disclosure can incorporate features described with reference to the apparatus of the disclosure, and vice versa. BRIEF DESCRIPTION OF DRAWINGS

[0014] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which:

[0015] Figure 1A is a schematic top view of a contact lens providing a myopic defocus image to reduce progression of myopia;

[0016] Figure 1B is Figure 1A a side view of the contact lens of

[0017] Figure 2A is Figure 1Aray diagram of the lens of

[0018] Figure 2B light pattern at the near focal surface of the lens of Figure 1A

[0019] Figure 2C light pattern at the far focal surface of the lens of Figure 1A

[0020] Figure 3 is Figure 1A and 1B partial ray diagram of the lens of and circles indicating the radii of curvature of the central hyperopic zone (dotted line) and the annular add-on zone (dashed line) of the contact lens;

[0021] Figure 4A is a plot showing the variation of the radial sagittal power of the lens shown in Figure 1A and 1B

[0022] Figure 4B is a plot showing the variation of the radial curvature power of the lens shown in Figure 1A and 1B

[0023] Figure 5A is a top view of different contact lenses with non-coaxial optics;

[0024] Figure 5B is a side view of the contact lens of Figure 5A

[0025] Figure 6A ray diagram of the lens of Figure 5A and 5B

[0026] Figure 6B light pattern at the near focal surface of the lens of Figure 5A and 5B

[0027] Figure 6C light pattern at the far focal surface of the lens of Figure 5A and 5B

[0028] Figure 6D is Figure 5A and 5B

[0029] Figure 7A is a plot showing​​​​​​​​​Figure 5A and 5B a plot of the variation of the radial sagittal power of the lens shown in

[0030] Figure 7B is a plot showing Figure 5A and 5B a plot of the variation of the radial curvature power of the lens shown in

[0031] Figure 8A is a top view of a lens according to an embodiment of the disclosure;

[0032] Figure 8B is a side view of a contact lens of Figure 8A

[0033] Figure 9 is a partial ray diagram of the lens of Figure 8A and 8B a circle indicating the radius of curvature of the central distance zone (dashed line) and the annular add-on zone (dotted line) of the contact lens;

[0034] Figure 10A is a plot showing Figure 8A and 8B a plot of the variation of the radial curvature power of the lens shown in

[0035] Figure 10B is a plot showing Figure 8A and 8B a plot of the variation of the radial sagittal power of the lens shown in

[0036] Figure 11A is a ray diagram of the lens of Figure 8A and 8B

[0037] shows the light pattern at the far end focal surface of the lens of Figure 11B and Figure 8A 8B shows the light pattern at the first near end focal surface of the lens of

[0038] and Figure 11C Figure 8A and 8B

[0039] Figure 11D shows the light pattern at the second near end focal surface of the lens of Figure 8A and 8B

[0040] Figure 12A is a top view of a lens according to an embodiment of the disclosure, with a variation of the radial curvature power;

[0041] ​​​​Figure 12B is a side view of a contact lens of Figure 12A

[0042] Figure 13A is a schematic view of the lens of Figure 12A and 12B along with circles indicating the radii of curvature of the central distance zone (dashed line) and the annular addition zone (dotted line) of the contact lens;

[0043] Figure 13B is a schematic view of the lens of Figure 12A and 12B along with circles indicating the radii of curvature of the central distance zone (dashed line) and the annular addition zone (dotted line) of the contact lens;

[0044] Figure 14 is a schematic graph showing the sinusoidal variation of the radial power around the annular zone of the lenses shown in Figure 12A and 12B ;

[0045] Figure 15A is a schematic graph showing the sinusoidal variation of the power around the annular zone of the lenses according to embodiments of the present disclosure as a function of the angle Θ;

[0046] Figure 15B is a schematic graph showing the sawtooth variation of the power around the annular zone of the lenses according to embodiments of the present disclosure as a function of the angle Θ;

[0047] Figure 15C is a schematic graph showing the square wave variation of the power around the annular zone of the lenses according to embodiments of the present disclosure as a function of the angle Θ;

[0048] Figure 16 is a flowchart showing a method of designing a contact lens according to embodiments of the present disclosure; and

[0049] Figure 17 is a schematic view of a radial cross-section through a portion of three modelled lenses modelled using the method described in Figure 16 . DETAILED DESCRIPTION

[0050] ​According to a first aspect, the disclosure provides a contact lens. The lens includes an optical zone including a central zone having a first optical axis, a substantially radial curvature power and a substantially radial sagittal power, and a center of curvature on the first optical axis. The central zone has an annular zone. At a point halfway across the width of the annular zone, the annular zone has a radial curvature power of X. X is greater than the substantially radial curvature power. The annular zone has an off-axis center of curvature at a first distance from the optical axis, and such that at a point halfway across its width, the annular zone has a radial sagittal power of Y, where Y is greater than the substantially radial sagittal power, and where Y is less than X.

[0051] As used herein, the term contact lens refers to an ophthalmic lens that can be placed onto the anterior surface of an eye. It will be appreciated that such a contact lens will provide a clinically acceptable on-eye movement and not stick to one or both eyes of a person. The contact lens can be in the form of a corneal lens (e.g., a lens that rests on the cornea of an eye). The contact lens can be a soft contact lens, such as a hydrogel contact lens or a silicone hydrogel contact lens. The lens can be a lens for use in the prevention or slowing of the progression of myopia, which can be used to provide extended depth of focus to a myopic eye.

[0052] A contact lens according to the disclosure includes an optical zone. The optical zone encompasses the portion of the lens that has optical functionality. The optical zone is configured to be positioned over the pupil of an eye when in use. For a contact lens according to the disclosure, the optical zone includes a central zone and an annular zone (or zones) surrounding the central zone. The optical zone is surrounded by a peripheral zone. The peripheral zone is not part of the optical zone, but is external to the optical zone and above the iris when the lens is worn, and it provides mechanical functionality, for example, increasing the size of the lens, making the lens easier to handle, providing ballast to prevent rotation of the lens, and / or providing a shaping zone that improves the comfort of the lens wearer. The peripheral zone can extend to the edge of the contact lens.

[0053] A contact lens according to embodiments of the disclosure can include ballast to orient the lens when positioned on the eye of a wearer. Embodiments of the disclosure that incorporate ballast into a contact lens will rotate to a predetermined angle of repose under the action of the eyelids of a wearer when placed on the eye of the wearer; for example, the ballast can be a wedge and the rotation can be caused by the action of the eyelids on the wedge. It is well known in the art to ballast contact lenses to orient the contact lenses; for example, toric contact lenses are ballasted to orient the lens so that the ortho-cylindrical correction provided by the lens is correctly aligned with the astigmatism of the eye of the wearer. It is possible that a contact lens of the disclosure provides a particular benefit to a wearer in a given orientation. For example, a contact lens can provide a particular benefit to a wearer when the meridian of maximum add power is in a particular orientation.

[0054] The contact lens can be generally circular in shape and have a diameter from about 4 mm to about 20 mm. The optical zone can be generally circular in shape and can 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 zone has a diameter from 7 mm to 9 mm.

[0055] The first optical axis can be along the centerline of the lens. The central zone can focus light from a distant point object on the first optical axis to a point of light at a far focal plane on the first optical axis. The term surface as used herein does not refer to a physical surface, but rather to a surface that a point of focus from light from a distant object can be drawn. This surface is also referred to as the image plane (even though it can be a curved surface) or image shell. The eye focuses light onto a curved retina, and in a perfectly focusing eye, the curvature of the image shell would match the curvature of the retina, so the eye does not focus light onto a flat mathematical plane. However, in the art, the curved surface of the retina is often referred to as a plane.

[0056] The central zone can be generally circular in shape and can have a diameter between about 2 mm and 9 mm, and preferably can be between 2 mm and 7 mm. The central zone can be generally elliptical in shape. The annular zone can extend radially outwardly from the periphery of the central zone by between about 0.1 mm to 4 mm, preferably between about 0.5 mm and 1.5 mm. For example, the radial width of the annular zone can be from about 0.1 mm to about 4 mm, and preferably can be from about 0.5 mm to about 1.5 mm. The periphery of the central zone can define a boundary between the central zone and the annular zone, and thus the annular zone can be adjacent to the central zone.

[0057] The annular zone can be contiguous with the central zone. A blending zone can be provided between the central zone and the annular zone. The blending zone should not substantially affect the optics provided by the central zone and the annular zone, and the blending zone can have a radial width of 0.05 mm or less, but it can also be as wide as 0.2 mm, or in some embodiments as wide as 0.5 mm.

[0058] In the context of the present disclosure, the power of the central and annular zones of a lens can be defined as the radial curvature power, the circumferential curvature power, the mean curvature power (which is the average of the radial and circumferential curvature powers), the radial sagittal power, the circumferential sagittal power, and the mean sagittal power (which is the average of the radial and circumferential sagittal powers).

[0059] Curvature and sagittal power are defined as follows:

[0060] For a wavefront W, at a point at a radial distance r (pupil radius) from a line normal to the center of the wavefront, W(r) = A*r 2 where A is a function.

[0061] Wavefront curvature or curvature power Pc is a function of the second derivative of the wavefront. The wavefront slope or the slope-based power P S is a function of the first derivative of the wavefront and varies with the slope of the wavefront.

[0062] For a simple spherical lens, the curvature power P c is defined as:

[0063]

[0064] The slope-based power P S is defined as

[0065]

[0066] That is, for a simple lens (with paraxial assumption), P C = P S .

[0067] The radial curvature power is the curvature power in a direction extending radially outward from the center of curvature of the lens. The circumferential curvature power is the curvature power at a constant radial coordinate extending around the circumference of the lens. The mean curvature provides an average of the radial and circumferential curvature powers.

[0068] The radial sagittal power is the sagittal power in a direction extending radially outward from the center of the lens. The circumferential sagittal power is the sagittal power at a constant radial coordinate extending around the circumference of the lens.

[0069] The central zone can have the same curvature power as the sagittal power. This is referred to herein as the base curvature power, base sagittal power, or base power. The nominal power of the central zone will correspond to the marked power of the contact lens as provided on the contact lens packaging (but in practice it can not have the same value). This will be the average sagittal or average curvature power taken across the central zone. The measured power of the central zone is the average refractive curvature or sagittal power taken directly as a measurement across the central zone. This can be different from the nominal power.

[0070] For lenses used in myopia treatment, the base power will be negative or close to zero and the central zone will correct distance vision. The base power can be between 0.5 diopters (D) and -15.0 diopters. The base power can be from -0.25 D to -15.0 D.

[0071] The base power of the central zone can be generated by the curvature of the surface of the lens. The base power can be generated by the curvature of the front surface of the lens and / or the center of curvature of the back surface of the lens.

[0072] In the context of the present disclosure, the annular zone is a generally annular zone surrounding the optical zone. It can have a generally circular shape or a generally elliptical shape. It can completely surround the optical zone. It can partially surround the optical zone.

[0073] For embodiments of the present disclosure, the radial curvature power of the annular zone is greater than the base radial curvature power of the central zone.

[0074] The radial curvature power of the annular zone can be determined by the curvature of at least one surface of the annular zone. The radial curvature power of the annular zone can result from the curvature of the front surface and / or the back surface of the lens. The annular zone can have a greater curvature or a smaller radius of curvature than the central zone. The front surface of the annular zone can have a greater curvature or a smaller radius of curvature than the curvature of the central zone. Alternatively or additionally, the back surface of the annular zone can have a curvature that is greater than the curvature of the central zone.

[0075] The radial curvature power can vary across the annular zone. At a point halfway across the width of the annular zone, the radial curvature power of the annular zone is X. The radial curvature power will be a power that is more positive (or less negative) than the base radial curvature power. The net radial curvature power of the annular zone will be the sum of the base radial curvature power of the central zone and the radial curvature additional power of the annular zone. For example, if the base radial curvature power is -3.0 D and the radial curvature additional power of the annular zone is +4.0 D, then the net radial curvature power of the annular zone will be +1.0 D.

[0076] The value of X can be between +0.5 D and +20.0 D. The value of X can be +10.0 D greater than the base radial curvature power (i.e., the radial curvature additional power at a point halfway across the width of the annular zone can be +10.0 D). The value of X can be +11.0 D greater than the base radial curvature power (i.e., the radial curvature additional power at a point halfway across the width of the annular zone can be +11.0 D). The value of X can be +12.0 D greater than the base radial curvature power (i.e., the radial curvature additional power at a point halfway across the width of the annular zone can be +12.0 D).

[0077] The annular zone can be understood to be tilted relative to the central zone. As used herein, a tilt of the annular zone means a circularly symmetric tilt and not a lateral tilt. The annular zone is tilted about a curve that extends around the circumference of the lens such that the outer edge of the annular zone moves in a first direction and the inner edge of the annular zone moves in an opposite direction. Tiling the annular zone will change the radial sagittal power of the annular zone because that is a function of the first derivative of the wavefront, but will not change the radial curvature power of the annular zone, which is a function of the second derivative of the wavefront. Tiling the annular zone relative to the central zone will mean that the center of curvature of the annular zone is displaced from the first optical axis of the central zone by a first distance. The radial sagittal power of the annular zone can vary across the width of the annular zone, and in embodiments of the present disclosure. At a point halfway across the width of the annular zone, the radial sagittal power of the annular zone is Y. Y will be greater than the base radial sagittal power of the central zone, but Y will be less than X (the radial curvature power of the annular zone at a point halfway across the width of the annular zone). The radial sagittal power of the annular zone will be more positive than the sagittal power of the central zone. The net radial sagittal power of the annular zone will be the sum of the base radial sagittal power of the annular zone and the radial sagittal add power. The value of Y can be between +0.5 D and +10.0 D. The value of Y can be +2.0 D greater than the base radial sagittal power (i.e., the radial sagittal add power at a point halfway across the width of the annular zone can be +2.0 D). The value of Y can be +4.0 D greater than the base radial sagittal power (i.e., the radial sagittal add power at a point halfway across the width of the annular zone can be +4.0 D). The value of Y can be +3.0 D greater than the base radial sagittal power (i.e., the radial sagittal add power at a point halfway across the width of the annular zone can be +3.0 D).

[0078] Example combinations of values for X and Y are described below. Those skilled in the art will immediately appreciate that many other combinations of X and Y values fall within the scope of the present disclosure.

[0079] The value of X can be +10.0 D greater than the base radial curvature power (i.e., the radial curvature add power at a point halfway across the width of the annular zone can be +10.0 D), and the value of Y can be +2.0 D greater than the base radial sagittal power (i.e., the radial sagittal add power at a point halfway across the width of the annular zone can be +2.0 D).

[0080] The value of X can be +12.0 D greater than the base radial curvature power (i.e., the radial curvature add power at a point halfway across the width of the annular zone can be +12.0 D), and the value of Y can be +4.0 D greater than the base radial sagittal power (i.e., the radial sagittal add power at a point halfway across the width of the annular zone can be +4.0 D).

[0081] The value of X can be greater than the base radial curvature power by +10.0 D (i.e., the radial curvature additional power at a point halfway across the width of the annular zone can be +10.0 D), and the value of Y can be greater than the base radial sagittal power by +3.0 D (i.e., the radial sagittal additional power at a point halfway across the width of the annular zone can be +3.0 D).

[0082] The value of X can be greater than the base radial curvature power by +11.0 D (i.e., the radial curvature additional power at a point halfway across the width of the annular zone can be +11.0 D), and the value of Y can be greater than the base radial sagittal power by +3.0 D (i.e., the radial sagittal additional power at a point halfway across the width of the annular zone can be +3.0 D).

[0083] The value of X can be greater than the base radial curvature power by +12.0 D (i.e., the radial curvature additional power at a point halfway across the width of the annular zone can be +12.0 D), and the value of Y can be greater than the base radial sagittal power by +3.0 D (i.e., the radial sagittal additional power at a point halfway across the width of the annular zone can be +3.0 D).

[0084] The radial curvature power of the annular zone can be greater than the circumferential curvature power of the annular zone. The circumferential curvature power of the annular zone can be the same as the base circumferential curvature power. The circumferential sagittal power of the annular zone can be the same as the circumferential base sagittal power.

[0085] The radial sagittal power of the annular zone can be greater than the radial sagittal power of the central zone across the width of the annular zone. In known center hyperopic lens designs with an annular zone providing additional power, where the center of curvature of the annular zone coincides with the optical axis of the central zone (which can be referred to as an on-axis annular zone), the radial sagittal power of the annular zone is greater than the radial sagittal power of the central zone across the width of the annular zone. For known center hyperopic lens designs with an annular zone providing additional power, where the center of curvature of the annular zone is displaced away from the optical axis of the central zone (which can be referred to as an off-axis annular zone), due to the tilt of the annular zone relative to the central zone, the radial sagittal power of the annular zone can be lower than the radial sagittal power of the central zone at the innermost edge of the annular zone. The radial sagittal power can increase as the radial distance increases towards the outer edge of the annular zone. In these known designs, the annular zone can be radially tilted relative to the central zone such that the radial sagittal power at the midpoint of the width of the annular zone matches the radial sagittal power that the central zone would have if it were extended to said midpoint. The lens can have a radial sagittal power at the midpoint of the annular zone that matches the radial sagittal power that the central zone would have if it were extended outward to the midpoint.

[0086] The combined effect of the annular zone being tilted relative to the central zone and the small radius of curvature of the annular zone means that the radial sagittal power of the annular zone can be greater than the radial sagittal power of the central zone across the entire width of the annular zone. Alternatively, the sagittal power of the annular zone can fall towards the boundary between the central zone and the annular zone.

[0087] The radial sagittal power can increase radially outwards across the width of the annular region. The radial sagittal power can increase linearly radially outwards from the innermost edge of the annular region.

[0088] The radial curvature power can be constant along a given meridian radially outwards from the inner edge of the annular zone, or can increase along a given meridian radially outwards from the inner edge of the annular zone.

[0089] The radial curvature power can vary around the meridian of the annular zone between a minimum value X1 and a maximum value X2, where both X1 and X2 are greater than the base radial curvature power. Both X1 and X2 can be greater than the base curvature power. The radial curvature power can vary periodically around the annular zone. The variation can be defined by a sinusoidal, triangular, square or sawtooth waveform. The radial curvature power can vary continuously between X1 and X2. There can be a maximum value of the radial curvature power every 90°, every 45°, every 20° or every 10° around the circumference of the annular zone, defined by an angle Θ, where Θ varies between 0° and 360°. X1 can be between +0.5D and +10.0D. X2 can be between +2.0D and +20.0D.

[0090] Alternatively and / or additionally, the radial sagittal power of the annular zone can vary around the meridian of the annular zone between a maximum value Y1 and a minimum value Y2, where both Y1 and Y2 are greater than the base radial sagittal power. Both Y1 and Y2 can be greater than the base radial sagittal power. The radial sagittal power can vary periodically around the annular zone. The periodic variation of the radial sagittal power can vary around the entire annular zone or around a portion of the annular zone. The variation can be defined by a sinusoidal, triangular or sawtooth waveform. The radial sagittal power can vary continuously between Y1 and Y2. There can be a maximum radial sagittal power every 90°, every 45°, every 20° or every 10° around the circumference of the annular zone, defined by an angle Θ, where Θ varies between 0° and 360°. Y1 can be between +0.5D and +9.0D. Y2 can be between +2.0D and +19.0D.

[0091] In embodiments of the disclosure in which the radial curvature power of the annular zone varies between a minimum value Xl and a maximum value X2, both Xl and X2 can be greater than Y. In embodiments of the disclosure in which the radial sagittal power of the annular zone varies between a minimum value Yl and a maximum value Y2, both Yl and Y2 can be less than X. In embodiments of the disclosure in which the radial curvature power of the annular zone varies between a minimum value Xl and a maximum value X2, and the radial sagittal power of the annular zone varies between a minimum value Yl and a maximum value Y2, the variations in radial curvature power and radial sagittal power can be in phase or out of phase. At any meridian around the annular zone, the radial curvature power can be greater than the radial sagittal power. Both the radial sagittal power and the radius of curvature of the annular zone can vary with the meridian around the annular zone such that the radial curvature power of the lens remains constant, or approximately constant, as the meridian moves around the annular zone. For example, for a lens having a constant radial curvature power of +3.0 D, the radial sagittal power can vary between +2.0 D and +3.0 D as the meridian moves around the annular zone. For a zone having a radial sagittal power of +3.0 D, the radius of curvature of the annular zone would be centered on the first optical axis. For a zone having a radial sagittal power of +2.0 D, the center of curvature of the annular zone would be displaced away from the first optical axis, and the radius of curvature of the annular zone can change.

[0092] The contact lens can include 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 can have a radial curvature power of X, where X is greater than the base radial curvature power. Each of the at least two annular zones can have an off-axis center of curvature a first distance from the optical axis, such that at a point halfway across its width, the annular zone has a radial sagittal power of Y, where Y is greater than the base radial sagittal power, and where Y is less than X. Each annular zone can include any of the features of the annular zones described above. For embodiments having at least two concentric annular zones, each annular zone can have the same radial curvature power profile and the same radial sagittal power profile, or each concentric annular zone can have a different radial curvature power profile and / or radial sagittal power profile. For embodiments having at least two concentric annular zones, the annular zones can be separated by a zone having a base power (i.e., the same power as the central zone).

[0093] The contact lenses can include an elastomeric material, a silicone elastomeric material, a hydrogel material, or a silicone hydrogel material, or combinations thereof. As understood in the art of contact lenses, a hydrogel is a material that holds water in equilibrium and is free of silicone-containing chemicals. A silicone hydrogel is a hydrogel that includes silicone-containing chemicals. The hydrogel materials and silicone hydrogel materials as described in the context of the present disclosure have an equilibrium water content (EWC) of at least 10% to about 90% (wt / wt). In some embodiments, the hydrogel materials or silicone hydrogel materials have an EWC of from about 30% to about 70% (wt / wt). In contrast, the silicone elastomeric materials as described in the context of the present disclosure have a water content of from about 0% to less than 10% (wt / wt). Typically, the silicone elastomeric materials used in conjunction with the present methods or devices have a water content of from 0.1% to 3% (wt / wt). Examples of suitable lens formulations include those having the following United States Adopted Names (USAN): methafilcon 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, riorilcon A, delefilcon A, verofilcon A, kalifilcon A, and the like.

[0094] Alternatively, the lens can include, consist essentially of, or consist of a silicone elastomeric material. For example, the lens can include, consist essentially of, or consist of a silicone elastomeric material having a Shore A hardness of from 3 to 50. The Shore A hardness can be determined using conventional methods, as understood by one of ordinary skill in the art (e.g., using method DIN 53505). Other silicone elastomeric materials can be obtained, for example, from NuSil Technology or Dow Chemical Company.

[0095] According to a second aspect, the disclosure provides a method of manufacturing a lens. The method can include forming a contact lens, where the contact lens includes a central zone having a first optical axis, a base radial power, and a base tangential power, and centered on a center of curvature on the first optical axis. The lens includes an annular zone. The annular zone has a radial power of X. X is greater than the base radial power. The annular zone has an off-axis center of curvature at a first distance from the optical axis, and such that at a point halfway across its width, the annular zone has a radial tangential power of Y, where Y is greater than the base radial tangential power, and where Y is less than X.

[0096] The lens can include any of the features set forth above.

[0097] The method of manufacturing can include forming a female mold member having a concave lens forming surface and a male mold member having a convex lens forming surface. The method can include filling a gap between the female and male mold members with a bulk lens material. The method can further include curing the bulk lens material to form the lens.

[0098] The contact lens can be formed using a turning process. The lens can be formed by a mold casting process, a spin molding process, or a turning process, or a combination thereof. As understood by one of skill in the art, mold casting refers to modeling a lens by placing a lens forming material between a female mold member having a concave lens member forming surface and a male mold member having a convex lens member forming surface.

[0099] The method of manufacturing a lens can include designing a contact lens, where the designed lens is a lens according to an embodiment of the disclosure, and includes any of the features described above. The lens can be designed using modeling, which can be computer implemented modeling.

[0100] The method can include modeling a first contact lens. The first contact lens can have a central zone having a first optical axis. The central zone can have a base power and can be centered on a center of curvature in the first optical axis. The first contact lens can have an annular zone surrounding the central zone. The annular zone can have a radius of curvature centered on the first optical axis, where the curvature of the annular zone produces an additional power, where the net power of the annular zone is the sum of the base power and the additional power. The method can include modeling a second contact lens. The second contact lens can have the same central zone as the first contact lens. The central zone of the second lens can have the same base power as the first lens and can be centered on the center of curvature in the first optical axis. The second contact lens can have an annular zone surrounding the central zone. The annular zone of the second lens can have a radius of curvature centered on the first optical axis, and the curvature of the second annular zone of the second lens can produce an additional power that is greater than the additional power of the first contact lens. The net power of the second lens will be the sum of the base power and the additional power of the second lens. The net power of the second lens can be greater than the net power of the first lens. The method of designing a lens can include tilting the annular zone of the second lens within the model such that the outer circumference or outer edge of the annular zone matches the outer edge of the annular zone of the first lens while keeping the inner edge of the annular zone fixed. Tilting the annular zone of the second lens will move the center of curvature of the annular zone away from the first optical axis. Tilting the annular zone of the second lens will produce a third modeled lens, i.e., a tilted second lens. The third lens or tilted second lens will have an annular zone that produces the same net power as the un-tilted second contact lens but with an off-axis center of curvature.

[0101] The method of manufacturing a lens can include manufacturing a lens based on the third modeled contact lens, i.e., the tilted second lens. Since the lens based on the third modeled lens will have a higher curvature than the lens based on the first modeled lens, this lens can have a higher spherical aberration. The lens manufactured based on the third contact lens design can also have an extended depth of focus compared to the lens based on the first or second modeled lens.

[0102] Figure 1A A schematic top view showing a contact lens 1 using a treatment zone that provides myopic defocus images to reduce progression of myopia. Figure 1B A schematic top view showing a contact lens 1 using a treatment zone that provides myopic defocus images to reduce progression of myopia. Figure 1AA schematic side view of lens 1. 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 it easier to handle, providing ballast to prevent rotation of the lens 1, and providing a shaping area to improve the comfort of the wearer. Optical region 2 provides the optical functionality of lens 1 and includes an annular region 3 and a central region 5. 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 lens 1. The center of curvature of the central region 5 is located on the first optical axis 19. Figure 2A (As shown in the image). The annular region 3 has a radial curvature refractive power greater than the basic 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, such as... Figure 3 As shown in the diagram. 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 the diagram...) Figure 2A As shown, 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-end focal plane 13, and the focal point of the central region 5 is located on the far-end focal plane 17, which is further away from the rear surface of the lens. Figure 2C As shown, for a point source at infinity, the light rays focused through the central area 5 form a focused image 23 at the far focal plane 17. The light rays focused through the central area 5 also produce an unfocused, blurred spot 27 at the near focal plane 13.

[0103] like Figure 2B As shown, light focused through the annular region 3 forms a focused image 21 at the near-focus plane 13. The light focused through the annular region 3 diverges after the near-focus plane 13, and the diverging light produces an unfocused ring 25 at the far-focus 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.

[0104] Figure 4A It is a display Figure 1A and 1B The diagram 31 shown in the figure illustrates the variation of the radial and sagittal refractive power of lens 1. Figure 4B It is a display Figure 1A and 1B The diagram 33 shows the variation of the radial curvature refractive power of lens 1. Figure 4A and 4BThis illustrates the variation in 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.

[0105] Figure 5A A schematic top view showing another contact lens 101 with non-coaxial optics. Figure 5B yes Figure 5A A schematic side view of lens 101. Similar to... Figure 1A The lens 101 includes an optical region 102 that substantially 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 the lens 101 and includes an annular region 103 and a central region 105. The lens 101 has a fundamental radial curvature refractive power equal to a fundamental radial sagittal refractive power. The fundamental refractive power is generated by the radius of curvature of the surface of the lens 101. The center of curvature of the central region 105 is located on a first optical axis 119. Figure 6A (As shown in the image). 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 with... Figure 1A and 1B Compared to lens 1, for Figure 5A and 5B The lens 101 shown cannot define the curvature of the annular region 103 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 in Figure 6D As shown in the image. The annular region 103 is tilted relative to the central region 105, making it more inclined than... Figure 1A and 1B In the case of lens 1, the outer edge of the annular region 103 is higher than its inner edge (in Figure 5B (In the middle), this changes the radial sagittal refractive power of the annular region 103, but does not change the radial curvature refractive power of the annular region 103. For example... Figure 6D As shown, 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 smaller radius 106.

[0106] At the far focal surface 117, the light rays that travel through the central zone 105 are focused. The annular zone 103 acts as a beam stop, which results in a small spot size 133 of the light 124 at the far focal surface 117, as shown in Figure 6C .

[0107] At the near focal surface 113, a single image is not formed. As shown in Figure 6B , at the near focal surface 113, for a point source at infinity, the light rays that travel through the central zone 105 produce a blur circle 128, Figure 1A , 1B The lenses of FIGS. 2A, 2B are also so. However, the light rays from a distant point source that travel through the annular zone 103 produce a focal ring 122, as shown in Figure 6B , which surrounds the blur circle 128. Figure 6B The light pattern produced for a distant point source is shown. In contrast to the lens 1 of Figure 1A and 1B , Figure 5A and 5B The lens 101 does not produce a single image or on-axis image at the near focal surface 113, which can be used to avoid the need for the eye to accommodate for near objects. For an extended object at infinity, the focused image formed at the near focal surface 113 is a convolution of (i) the focused image of the extended object that would be obtained with a conventional lens having an optical power with an annular zone 103 and (ii) the optical transfer function representing the optical effect of the annular zone 103.

[0108] In contrast to the lens 1 of Figure 1A and 1B , there is no ring or "halo" effect at the far focal surface 117.

[0109] Figure 7A is a plot 131 showing the variation of the radial sagittal power of the lens 101 shown in Figure 5A and 5B , and Figure 7B is a plot 133 showing the variation of the radial curvature-based power of the lens shown in Figure 5A and 5B . Figure 7A and 7BThe variation in refractive power along the radial diameter of lens 101 is illustrated. 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, giving it an off-axis center of curvature. This tilt means that the radial sagittal refractive power is more negative at the boundary between the central region 105 and the annular region 103 than the radial sagittal refractive power in the central region, as illustrated by curve 135. The radial sagittal refractive power can increase with increasing radial distance toward the outer edge of the annular region 103.

[0110] Figure 8A A schematic top view of a contact lens 201 according to an embodiment of the present disclosure is shown. Similar to... Figure 1A and 1B Lens 1 and Figure 5A and 5B The lens 101 and lens 201 include 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 the lens 201 easier to handle, providing ballast to prevent rotation of the lens 201, and providing a shaping area to improve the comfort of the wearer of the lens 201. The optical region 202 provides the optical functionality of the lens 201 and includes an annular region 203 and a central region 205. The central region 205 of the 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 the lens 201. The center of curvature 244 of the central region 205 is located on the first optical axis 219. Figure 9 (As shown in the middle). 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.

[0111] At point A, which is halfway across the width of the ring-shaped region (at... Figure 8A and 8B (As indicated in the text), the radial curvature refractive power of the annular region has a value of approximately +3.5D. For Figure 8A and 8B The example lens 201 shown in the image exhibits a radial curvature refractive power that remains constant along all meridians around the annular region 203 for a given radial position. This means that the radial curvature refractive power will be constant along... Figure 8A and 8BThe dashed curve 241 shown has the same value; the dashed curve is a curve extending around the annular region 203 at a point halfway across the width of the annular region 203. In this exemplary embodiment of the present disclosure, X is approximately +3.5D. Similar to... Figure 5A and 5B The lens shown has an annular region 203 tilted relative to the central region 205, causing the center of curvature 243 of the annular region 203 to deviate from the first optical axis 219. This is in Figure 9 The diagram illustrates how tilting 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 increase along... Figure 8A and 8B The dashed curve 241 shown in the figure has the same value; it is a curve that extends around the annular region 203.

[0112] 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.

[0113] Figure 10A It is a display of cross Figure 8A and 8B The graph 231 shows the variation of the curvature refractive power of the radial diameter of lens 201. This graph 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 zone 205 and the annular zone 203 to the average of the circumferential and radial curvature refractive powers.

[0114] Figure 10B It is a display of cross Figure 8A and 8BThe plot 233 shows the variation of the sagittal power of the radial diameter of the lens 201. This plot 233 shows the average of the radial and the circumferential sagittal power. Across the central zone 205 of the lens 201, the sagittal power is constant and has a value of 0.0 D. At the boundary between the central zone 205 and the annular zone 203, the sagittal power of the annular zone 203 increases sharply due to the increase in the radial sagittal power, as indicated by the curve 237. The radial sagittal power increases in an approximately linear manner radially outward across the width of the annular zone 203. With the lens 201 shown in Figure 7A In contrast to the sagittal power curves shown in Figure 1A and 1B , there is no drop in the sagittal power at the boundary between the central zone 205 and the annular zone 203. This is because the annular zone 203 has been tilted with respect to the central zone in a manner that increases the radial sagittal power at the boundary between the central zone 205 and the annular zone 203. The increase in the sagittal power at the boundary between the central zone 205 and the annular zone 205 will not be as large as for a lens with an on-axis annular zone of additional power, such as the lens shown in

[0115] As shown in Figure 11A , for the lens 201 shown in Figure 8A and 8B , at the far focal surface 217, the light rays that travel through the central zone 205 will form a focused image 223, as shown in Figure 11B . The light rays that travel through the annular zone 203 will produce an unfocused ring 225 at the far focal surface 217. At the first near focal surface 218, for a point source at infinity, the light rays that travel through the central zone 205 will produce a first blur circle 227 and the light rays that travel through the annular zone 203 will produce a second blur circle 229, as shown in Figure 11C . At the second near focal surface 220, the light rays that travel through the central zone 205 will produce a third blur circle 231 and the light rays that travel through the annular zone 203 will produce a focused ring 233 that is located within the third blur circle 231, as shown in Figure 11D . Figure 12A A schematic top view of a contact lens 301 according to an embodiment of the disclosure is shown. Similar to Figure 8A and 8BLens 201 and 301 include 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. The 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 the 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 with the meridians surrounding the annular region 303. In this exemplary embodiment, the radial curvature refractive power is approximately constant as it extends radially outward along any meridian. Figure 12A and 12B The dashed line 341 indicates a curve extending around annular region 303, representing the halfway point of the width of the annular region. 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, exhibiting… Figure 14 The distribution is shown in the diagram. An angle θ is used to define the position around the circumference of the annular region 303, 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.

[0116] 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 exemplary embodiment, the radius of curvature of the annular region 303 varies with the meridian, and this produces a varying radial curvature refractive power. Figure 13A The diagram shows the radial diameter along which the radial curvature has its maximum value. Figure 12A In the line EE), the radius of curvature 306e of the annular region 303 will be the smallest ( Figure 13A ).like Figure 13BThe radius of curvature 306f of the annular zone 303 will be greatest at the point along the radial diameter (line F-F in Figure 12A

[0117] For this lens 301, the radial sagittal power has a constant value Y at a point halfway across the width of the annular zone 303, and a constant value around the central zone 305. Y is less than X, but Y is greater than the base power of the central zone 305 of the lens 301, as shown schematically in Figure 14

[0118] In other embodiments of the disclosure (not shown), the lens is similar to the lens shown and described in Figures 8A to 11D Figure 8A 8B The radial curvature power of the annular zone is about +10.0 D greater than the base radial curvature power of the central zone (i.e., the radial curvature add power is about +10.0 D), and the radial sagittal power of the annular zone is about +2.0 D greater than the base radial sagittal power of the central zone (i.e., the radial sagittal add power is about +2.0 D), as shown in

[0119] In other embodiments of the disclosure (not shown), the lens is similar to the lens shown and described in Figures 8A to 11D The radial curvature power of the annular zone is about +12.0 D greater than the base radial curvature power of the central zone (i.e., the radial curvature add power is about +12.0 D), and the radial sagittal power of the annular zone is about +4.0 D greater than the base radial sagittal power of the central zone (i.e., the radial sagittal add power is about +4.0 D) at a point A halfway across the width of the annular zone. Advantageously, this lens will exhibit a sharp increase in radial sagittal power at the boundary between the central zone and the annular zone. The increase in radial sagittal power can exceed +2.0 D. For lens wearers with a relatively small pupil diameter (e.g., young lens wearers), this sharp increase in radial sagittal power at the boundary between the central zone and the annular zone can improve the therapeutic effect of the annular zone.

[0120] In other embodiments of the disclosure (not shown), the lens is similar to the lens shown and described in Figures 8A to 11D Figure 8A 8B The radial curvature power of the annular zone is about +11.0 D greater than the base radial curvature power of the central zone (i.e., the radial curvature add power is about +11.0 D), and the radial sagittal power of the annular zone is about +3.0 D greater than the base radial sagittal power of the central zone (i.e., the annular zone radial sagittal add power is about +3.0 D) at a point A halfway across the width of the annular zone, as shown in ​​​​​​

[0121] In other embodiments of the disclosure (not shown), the lens is similar to the lens shown and described in Figures 8A to 11D but the radial curvature power of the annular zone is about +12.0 D greater than the base radial curvature power of the central zone (i.e., the radial curvature add power is about +12.0 D), and the radial sagittal power of the annular zone is about +3.0 D greater than the base radial sagittal power of the central zone (i.e., the radial sagittal add power is about +3.0 D) at a point A halfway across the width of the annular zone, as shown in Figure 8A and 8B In other embodiments of the disclosure (not shown), the lens is similar to the lens shown and described in but the radial curvature power of the annular zone is about +10.0 D greater than the base radial curvature power of the central zone (i.e., the radial curvature add power is about +10.0 D), and the radial sagittal power of the annular zone is about +3.0 D greater than the base radial sagittal power of the central zone (i.e., the radial sagittal add power is about +3.0 D) at a point A halfway across the width of the annular zone, as shown in

[0122] In other embodiments of the disclosure (not shown), the lens is similar to the lens shown and described in Figures 8A to 11D but the radial curvature power of the annular zone is about +12.0 D greater than the base radial curvature power of the central zone (i.e., the radial curvature add power is about +12.0 D), and the radial sagittal power of the annular zone is about +3.0 D greater than the base radial sagittal power of the central zone (i.e., the radial sagittal add power is about +3.0 D) at a point A halfway across the width of the annular zone, as shown in Figure 8A and 8B In other embodiments of the disclosure (not shown), the lens is similar to the lens shown and described in Figure 15A In other embodiments of the disclosure, the radial curvature power and the radial sagittal power can both vary with meridian around the annular zone. The variation in radial sagittal power can be in phase or out of phase with the variation in radial curvature power. At all points around the circumference of the annular zone, the radial sagittal power can be less than the radial curvature power, but greater than the base power of the central zone.

[0123] In other embodiments of the disclosure, the radial curvature power and the radial sagittal power can both vary with meridian around the annular zone. The variation in radial sagittal power can be in phase or out of phase with the variation in radial curvature power. At all points around the circumference of the annular zone, the radial sagittal power can be less than the radial curvature power, but greater than the base power of the central zone.

[0124] In other embodiments of the disclosure, the lens can include two or more concentric annular zones. For each of the annular zones, the annular zone has a radial curvature power of X at a point halfway across the width of the annular zone, where X is greater than the base radial curvature power. Each of the at least two annular zones can have an off-axis center of curvature a first distance from the optical axis, such that the annular zone has a radial sagittal power of Y at a point halfway across its width, where Y is greater than the base radial sagittal power, and where Y is less than X. Each concentric annular zone can be separated by a zone having the base power (i.e., the same power as the central zone).

[0125] In other embodiments of the disclosure, the lens can include two or more concentric annular zones. At least one of the annular zones is an annular zone as shown in Figure 5A and 6A for at least one of the other annular zones, the annular zone has a radial curvature power of X at a point halfway across the width of the annular zone, where X is greater than the base radial curvature power. Each of the at least two annular zones can have an off-axis center of curvature a first distance from the optical axis, such that at a point halfway across its width, the annular zone has a radial sagittal power of Y, where Y is greater than the base radial sagittal power, and where Y is less than X.

[0126] Figure 16 A method 501 of designing a contact lens is shown, where the lens is according to an embodiment of the disclosure. In a first step 503, the method involves modeling a first contact lens. The first contact lens has a central zone having a first optical axis. The central zone has a base power and is centered on a center of curvature on the first optical axis. In this example, the central zone of the first contact lens has a base power of -3.0D. The first contact lens has an annular zone surrounding the central zone. The annular zone has a radius of curvature centered on the first optical axis. The curvature of the annular zone creates an additional power. In this example, the annular zone has a curvature that creates an additional power of +2.0D. The net power of the annular zone is the sum of the base power and the additional power, and so in this example, the net power of the annular zone is -1.0D. In a second step 505, the method involves modeling a second contact lens. The second contact lens has the same central zone as the first contact lens, and so, in this example, the second contact lens has a base power of -3.0D. The second contact lens is also centered on a center of curvature on the first optical axis. The second contact lens has an annular zone surrounding the central zone. The annular zone of the second lens has a radius of curvature that is also centered on the first optical axis, but the curvature of the annular zone creates an additional power that is greater than the additional power of the first lens. In this example, the curvature of the second annular zone creates an additional power of +4.0D. The net power of the second lens is the sum of the base power and the additional power, and so in this example, the net power of the second lens is +1.0D. In a third step 507, the method includes tilting the annular zone of the second lens within the model so that the outer edge of the second annular zone matches the outer edge of the annular zone of the first lens, while keeping the inner edge of the second annular zone fixed. This creates a third lens (corresponding to the tilted second lens) that has an annular zone with the same net power as the untitled second lens. In this example, the third lens or tilted second lens has an annular zone with a net power of +1.0D, but with a center of curvature that is not on the first optical axis.

[0127] Figure 17is a schematic diagram of three modeled lenses 601, 603, 605 modeled as part of a method of designing the lenses described above. The three lenses share a common central zone 607 having a curvature centered on the first optical axis providing a base power of -3.0D. The first lens 601 has an annular zone 601a having a curvature that produces an additional power of +2.0D, such that the net power of the annular zone is -1.0D. The center of curvature of the annular zone 601a of the first lens 601 is centered on the first optical axis. The second lens 603 has an annular zone 603a having a curvature that produces an additional power of +4.0D, such that the net power of the annular zone is +1.0D. The center of curvature of the annular zone 603a of the second lens 603 is also centered on the first optical axis. The inner edge of the annular zone 601a of the first lens 601 and the inner edge of the annular zone 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 zone 605a of the third lens 605 has a curvature that produces an additional power of +4.0D, having the same additional power and the same net power as the second lens 603. The inner edge of the annular zone 605a of the third lens coincides with the same point 607 as the first lens 601 and the second lens 603, but the outer edge of the annular zone 605a of the third lens 605 has been tilted to coincide with the outer edge of the annular zone 601a of the first lens 601 at point 611. The annular zone 605a of the third lens 605 has a net power of +1.0D, but has a center of curvature that is not on the first optical axis.

[0128] Those of ordinary skill in the art will appreciate that features of the example embodiments can be combined in other embodiments falling within the scope of the present disclosure.

[0129] While in the foregoing specification this disclosure has been described in relation to certain embodiments thereof, and many details have been set forth for the purpose of illustration, it will be apparent to those skilled in the art that the disclosure is not limited to the embodiments described herein and that many modifications, changes, combinations, subcombinations, sub-combinations and variations can be used. It is therefore contemplated to cover in the appended claims all such modifications, changes, combinations, subcombinations, sub-combinations and variations as falling within the true scope of the disclosure. It is therefore intended that the disclosure not be limited to the described embodiments, but that it include all adaptations, modifications, combinations, sub-combinations, sub-combinations and variations that fall within the scope of the appended claims. Further, the scope of the appended claims is intended to cover all adaptations, modifications, combinations, sub-combinations, sub-combinations and variations that fall within the scope of the disclosure.

Claims

1. A contact lens comprising an optical region, wherein the lens includes: Central zone, wherein the central zone has basic refractive power; and The annular region, in which At a point halfway across the radial width of the annular region, the annular region has a radial curvature refractive power of X and a radial sagittal refractive power of Y, wherein both X and Y are greater than the fundamental refractive power, and wherein Y is less than X. Light rays traveling through the central region form a focused image at the far focal plane, while light rays traveling through the annular region form an unfocused ring at the far focal plane. At the first near-focal plane of the lens, which is closer to the far-focal plane than the far-focal plane, light rays traveling through the central region will produce a first blur circle, and light rays traveling through the annular region will produce a second blur circle; and At the second near-end focal plane, which is closer to the lens than the first near-end focal plane, light rays traveling through the central region will produce a third blur circle, and light rays traveling through the annular region will produce a focusing ring located within the third blur circle.

2. The contact lens of claim 1, wherein the fundamental refractive power of the central region is generated by the curvature of the anterior and / or posterior surfaces of the lens.

3. The contact lens according to claim 1 or 2, 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.

4. The contact lens according to claim 1 or 2, wherein at a point halfway across the radial width of the annular region, the annular region has a radial curvature refractive power approximately +10.0 D greater than the basic refractive power.

5. The contact lens according to claim 1 or 2, wherein the fundamental refractive power of the lens is between 0.5 D and -15.0 D.

6. The contact lens according to claim 1 or 2, wherein the lens comprises an elastomeric material, a hydrogel material, or a mixture thereof.

7. The contact lens according to claim 6, wherein the elastomer material is a silicone elastomer material.

8. The contact lens according to claim 6, wherein the hydrogel material is a silicone hydrogel material.

9. The contact lens according to claim 1 or 2, wherein the lens is formed using a turning process or a die-casting process.

10. The contact lens according to claim 1 or 2, wherein the central region is generally circular in shape and has a diameter between 2 mm and 7 mm, and the annular region extends radially outward from the periphery of the central region by between 0.1 mm and 4 mm.

11. The contact lens of claim 1 or 2, wherein the contact lens comprises at least two concentric annular regions, wherein for each of the at least two concentric annular regions: Light rays traveling through the central region form a focused image at the far focal plane, while light rays traveling through the annular region form an unfocused ring at the far focal plane. At the first near-focal plane of the lens, which is closer to the far-focal plane than the far-focal plane, light rays traveling through the central region will produce a first blur circle, and light rays traveling through the annular region will produce a second blur circle; and At the second near-end focal plane, which is closer to the lens than the first near-end focal plane, light rays traveling through the central region will produce a third blur circle, and light rays traveling through the annular region will produce a focusing ring located within the third blur circle.

12. A method of manufacturing a contact lens, the method comprising the step of designing the contact lens, wherein designing the contact lens includes: (a) Modeling a first contact lens, the first contact lens having: The central region, wherein the central region has a fundamental refractive power and a center of curvature on the first optical axis; and An annular region surrounding the central region, the annular region having a radius of curvature centered on the first optical axis, wherein the curvature of the annular region produces a first additional refractive power greater than the basic refractive power; (b) Modeling a second contact lens, wherein the second contact lens has the same central region as the first contact lens, and an annular region surrounding the central region, wherein the annular region has a radius of curvature centered on the optical axis, and the annular region produces a second additional refractive power greater than the first additional refractive power of the first contact lens; (c) Within the model, the annular region of the second contact lens is tilted such that the outer edge of the annular region matches the outer edge of the annular region of the first contact lens, thereby producing a third contact lens, wherein the annular region of the third contact lens has the second additional refractive power of the annular region of the second contact lens, but the center of curvature is at a first distance from the first optical axis.

13. The method of claim 12, further comprising manufacturing a lens based on the modeled third contact lens.

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