Ophthalmic lenses containing spatially modulated optical power profiles

Abstract

The ophthalmic lens has a central zone and a peripheral zone. The central zone has a first region characterized by a substantially constant first optical power, and a second region located radially outside the first region, having positive and negative deviations of power as a function of radial position with respect to the substantially constant first optical power. The peripheral zone is located radially outside the central zone. The peripheral zone has positive and negative deviations with respect to the mean optical power, and the mean optical power increases as a function of radius from the first optical power.

Description

Technical Field

[0001] Methods and devices for reducing or eliminating myopia progression, including an ophthalmic lens, and more particularly, methods and devices for reducing or eliminating myopia progression, including an ophthalmic lens having a spatially varying optical power profile, are provided.

Background Art

[0002] Myopia is a condition of the eye in which an object at a distance (e.g., more than 6 meters) is focused in front of the retina, thereby causing visual impairment. Myopia is typically corrected by the use of an ophthalmic lens having a negative power sufficient to focus distant objects on the center of the retina, while near objects can be focused on the central region of the retina by accommodation of the eye's crystalline lens.

[0003] Most commonly, myopia occurs when axial eye growth is excessive, resulting in an imbalance between the axial length of the eye and its refractive power. Myopia is typically a progressive disorder associated with a gradual elongation of the eye. Many undesirable conditions that can potentially lead to vision loss (e.g., retinal detachment and glaucoma) can result from the elongation of the eye resulting from progressive myopia.

[0004] The increase in axial length of the eye in growing animals is controlled by a feedback mechanism that occurs within the eye, such that it is now generally accepted that the focus of light entering the eye can be adjusted to the central region of the retina (i.e., within approximately 2 degrees from the visual axis). In emmetropic eyes, this mechanism functions well, and the axial length and refractive power of the eye are balanced, thereby allowing the focus of light to be adjusted to the central region of the retina as the eye's axis grows; however, in myopic eyes, the elongation is excessive, and in hyperopic eyes, the elongation is insufficient, and in both cases, light that is not focused on the central region of the retina is projected.

[0005] Several theories exist regarding the ocular feedback mechanism, and any or all of them may contribute to the progression of myopia in a given patient. According to one theory, the axial position of the peripheral image controls the growth of the eye axis. More specifically, under this theory, when peripheral hyperopic defocus is caused by the peripheral focal plane of the eye being located behind (i.e., posteriorly) the retina, a stimulus is generated that promotes an increase in eye length.

[0006] Conventional single-vision eyeglasses or contact lenses correct myopic defocus in the central retina but may induce hyperopic defocus in the periphery, thereby stimulating axial growth. Furthermore, in children with myopia, peripheral hyperopic defocus can occur during close-up work due to delayed accommodation (i.e., insufficient accommodation). That is, because the eye does not fully accommodate, a hyperopically out-of-focus image exists at the periphery of the retina, stimulating the eyeball to grow in order to achieve focus.

[0007] Conventionally, to address peripheral hyperopic defocus, multi-zone ocular lenses for controlling myopia progression have a peripheral zone with a refractive add power offset relative to the central zone of the lens, shifting the focal plane in front of (i.e., forward of) the peripheral retina.

[0008] Lenses designed to control peripheral focus are constructed so that visual rays (i.e., rays that form a perceptible visual image) pass primarily only through the central zone of such a multizone lens, while the peripheral zone is located radially outside the central zone, directing myopically shifted light outside the central visual area of ​​the retina. Thus, when the central zone is configured for monofocus, given normal eye accommodation, only the image formed by the central zone is focused onto the retina, while light passing through the peripheral zone is focused in front of the retina. At a given time, the image formed by the central zone can be of a distant or near object, depending on the state of the eye's accommodation.

[0009] A multizone lens with a peripheral zone having an add power offset relative to the central zone is understood to be different from a multizone bifocal (or multifocal) contact lens, where the central and outer zones of the lens are above the pupil, and a visually significant amount of visual light is blocked by both the central and outer zones. In a bifocal lens, because the outer zone has a different power than the central zone, visual light from the central and outer zones always forms two images on the center of the retina (one corresponding to a distant object and the other to a near object, as determined by the focal power of the zones). Typically, bifocal (or multifocal) lenses are worn by wearers with presbyopia (i.e., non-accommodative), and the wearer's nervous system is required to distinguish information about the associated images.

[0010] According to another theory regarding the eye's feedback mechanism, myopia progression is caused by, or enhanced by, a lack of uniform focus orientation in the peripheral visual field. In other words, as light travels axially relative to the retina, the size and / or shape of the caustics changes, resulting in anterior retinal blurring being different from posterior retinal blurring. Under this theory, such heterogeneity provides a directional signal that causes eyeball growth.

[0011] Lenses that provide peripheral myopia defocus have been shown to be effective in achieving myopia progression suppression for some wearers, but others do not achieve the desired suppression. Furthermore, some wearers using conventional peripheral myopia defocus lenses experience impaired vision due to disturbances (e.g., glare and halos) resulting from stray light passing through the peripheral zone of the lens. [Overview of the project] [Problems that the invention aims to solve]

[0012] The lack of effectiveness for wearers of conventional lenses designed to suppress myopia progression using peripheral zone add power offset is thought to be due to the fact that conventional lenses cannot adequately address multiple or all factors of growth (e.g., hyperopic peripheral imaging and uneven focus orientation). [Means for solving the problem]

[0013] Aspects of the present invention relate to a multi-zone eye lens comprising a central zone for forming an image on the central retina and a peripheral zone having a power profile that provides an add power offset relative to the central zone.

[0014] The central zone comprises a radially inner portion having substantially constant optical power and a radially outer portion having an average power that is substantially equal to constant power but varies (as a function of radial position) relative to substantially constant power due to a spatially modulated power profile. The peripheral zone, which also has a spatially modulated power profile, has an average power that increases as a function of radial position from a value equal to substantially constant power at the central-peripheral zone interface to a value greater than substantially constant power at the outer edge of the peripheral zone. The term "average optical power" should be understood as analogous to the DC component of optical power as a function of radius, when optical power as a function of radius is considered as an electrical signal; and the variation in optical power should be understood as analogous to the AC component of optical power as a function of radius.

[0015] As described above, the optical power in the radially outer portions of the peripheral and central zones has a spatially modulated power profile. In the radially outer portions of the central zone, spatial modulation occurs as alternating positive and negative deviations of the optical power for a substantially constant power; in the peripheral zone, spatial modulation occurs as alternating positive and negative deviations for an increasing average power. Typically, the deviations in the radially outer portions of the central and peripheral zones form a continuous power profile.

[0016] Since progressive myopia most commonly affects children and young adults, the diameter of the central zone of the lens according to embodiments of the present invention can be greater than about 3 mm to reasonably ensure that the central zone is larger than the pupil of a typical wearer under photopic conditions. However, as is understood in the art, due to the presence of what is known as the Stiles-Crawford effect, rays that pass closer to the outer radius portion of the image-forming area of ​​the eye (also called "peripheral rays") have less visual importance than rays that travel closer to the center of the pupil. Therefore, the central zone does not need to be larger than the pupil diameter of the eye to be effective. Taking the Stiles-Crawford effect into account, it is desirable that the radius of the central zone of the lens is typically no more than 1 mm smaller than or greater than the radius of the pupil of the wearer's eye (e.g., 2 mm in diameter).

[0017] As is understood in the art, lenses are typically not custom-made for the wearer. Therefore, lenses can be designed such that the central zone diameter of the lens is not more than 1 mm smaller than the normal (i.e., average) pupil diameter of the eyes of any selected population.

[0018] Aspects of the present invention relate to an ophthalmic lens comprising a central zone and a peripheral zone. The central zone comprises a first region characterized by a substantially constant first optical power, and a second region located radially outside the first region, having positive and negative deviations of power as a function of radial position with respect to the substantially constant first optical power. The peripheral zone is located radially outside the central zone, and the peripheral zone has positive and negative deviations as a function of radial position with respect to the average optical power, the average optical power increasing as a function of radius from a substantially constant first optical power.

[0019] In some embodiments, a substantially constant first optical power in the first region, positive and negative deviations in the second region as a function of radius, and positive and negative deviations in the peripheral zone constitute a power profile without discontinuities in power.

[0020] In some embodiments, the diameter of the central zone is at least 2 mm or at least 3 mm. The central zone and / or the peripheral zone may be rotationally symmetric.

[0021] The lens may be a contact lens or another type of lens.

[0022] The positive and negative deviations of the power of at least one of the second region and the peripheral zone may be periodic as a function of the radius.

[0023] In some embodiments, in the plot of the power profile, the region above the average power enclosed by a constant first power and a positive deviation is less than 20% different from the region below the average power enclosed by the constant first power and a negative deviation.

[0024] In some embodiments, the (maximum) deviation amplitude with respect to the average optical power of the peripheral zone is equal to the (maximum) deviation amplitude with respect to the substantially constant first power in the second region. In some embodiments, the positive and negative deviations in the peripheral zone have an amplitude in the range of 0.5 to 12.0 diopters.

[0025] The average optical power in the peripheral zone may increase linearly.

[0026] In some embodiments, the positive and negative deviations in the second region (of the central zone) and the peripheral zone are determined by fluctuations in the surface curvature.

[0027] Any embodiment of the above lens structure can be embodied as a contact lens or any other ophthalmic lens.

[0028] These and other aspects of the invention will become apparent by considering the following detailed description and the appended claims.

[0029] As used herein, the terms "greater" and "additive power offset" mean that a specified value (e.g., optical power) is positive or negative relative to a specified reference value. For example, the peripheral power may be greater than the central zone power. Alternatively, the peripheral power may be described as having an additive power offset relative to the central zone power.

[0030] One indicator of the uniformity of blur during focus passage (i.e., the point spread function) is the blur log orientation slope (BLOS), which measures how the size and shape of the caustic change as the rays forming the caustic travel axially. As will be further clarified below, a smaller value of BLOS indicates higher uniformity of the blur orientation during focus passage.

[0031] For example, BLOS is calculated as described by Qiuzhi et al. in Through-Focus Optical Characteristics of Monofocal and Bifocal Soft Contact Lenses Across The Peripheral Visual Field in The Authors Ophthalmic & Physiological Optics 38(2018). The subject matter of the said paper is incorporated herein by reference in its entirety. BLO can be determined based on a calculation using the rays forming the caustic or a calculation using the pixels forming the caustic when the pixel calculation is weighted based on pixel intensity, and pixels with greater intensity are given proportionally greater weight, which corresponds to the optical energy measured by each pixel. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] [Figure 1A] Schematic plan view of an example of an ophthalmic lens according to an aspect of the present invention [Figure 1B]Schematic cross-sectional view of the lens in Figure 1A, taken along line IB-1B in Figure 1A. [Figure 2A] This figure shows one embodiment of the power profile of an ophthalmic lens having spatial modulation of optical power in part of the central zone and the peripheral zone. [Figure 2B] This figure illustrates examples of power profile characteristics that can be modified to balance myopia progression suppression effectiveness, visual acuity, and wearer comfort. [Figure 3A] A graph showing the effect of changes in wave amplitude on normalized visual acuity (i.e., normalization relative to the eyeglass baseline). [Figure 3B] Graph showing the effect of changes in wave amplitude in peripheral myopic defocus. [Figure 3C] Graph showing the effect of changes in wave amplitude on blur orientation gradient (BLOS). [Figure 4A] A graph showing the effect of changes in the gradient of the average power within the peripheral zone in normalized visual acuity. [Figure 4B] Graph showing the effect of changes in the gradient of average power within the peripheral zone in peripheral myopia defocus. [Figure 4C] Graph showing the effect of changes in the gradient of average power within the peripheral zone in BLOS. [Figure 5A] This diagram illustrates the effect of changes in the width (i.e., radius) of the central zone portion where there is no periodic deviation in power in normalized visual acuity. [Figure 5B] This diagram illustrates the effect of changes in the width (i.e., radius) of the central zone portion without periodic power deviations in peripheral myopic defocus. [Figure 5C] This diagram illustrates the effect of changes in the width (i.e., radius) of the central zone portion of BLOS where there is no periodic power deviation. [Modes for carrying out the invention]

[0033] Aspects of the present invention will be further described with reference to specific examples. These examples are given for illustrative purposes only and should not be understood as being intended to limit the scope of the claims to any particular example.

[0034] Figures 1A and 1B are schematic diagrams of an example of an ophthalmic lens according to an embodiment of the present invention; Figure 2A is a graph of an example of a power profile for use in an ophthalmic lens, in which the optical power in part of the central zone and the peripheral zone is spatially modulated according to an embodiment of the present invention.

[0035] The ophthalmic lens 100 comprises an optical axis OA, a central zone 110, and a peripheral zone 120. In the illustrated embodiment, the central and peripheral zones are rotationally symmetric, and the lens has an optical axis OA that coincides with the mechanical axis of the lens, although deviations from such arrangement are possible. Furthermore, although the ophthalmic lens 100 is shown as a contact lens, lenses according to embodiments of the present invention may be embodied as other types of ophthalmic lenses. For example, the lens may be a corneal inlay, a corneal onlay, or an intraocular lens.

[0036] The central zone 110 comprises a first region 110a characterized by a substantially constant first optical power CP, and a second region 110b located radially outside the first region 110a, having positive and negative power deviations 111a, 111b as a function of radial position with respect to the substantially constant first power CP.

[0037] The first region 110a typically has a power that is constant within manufacturing tolerances and in the presence of any spherical aberration. The first region 110a is designed to achieve optimal visual acuity correction using prior art. Typically, achieving optimal visual acuity correction means that the central zone is corrected for distance visual acuity.

[0038] The second region 110b has positive and negative power deviations 111a, 111b as functions of radial position for a substantially constant first power. The radial power profile in the second zone includes at least one maximum value 112a and at least one minimum value 112b. That is, the power is modulated as a function of radial position to achieve a power that is radially variable in magnitude along the second region. The deviations may occur in a pattern of a particular period.

[0039] The deviations 111a and 111b function to provide the wearer with an expanded depth of focus, thus reducing accommodative lag and eye fatigue. Furthermore, the deviations 111a and 111b may contribute to reducing factors that lead to progressive myopia. For example, the presence of a deviation in the central zone contributes to peripheral myopic defocus for light entering the eye at a certain angle to the optical axis.

[0040] As mentioned above, progressive myopia most commonly affects children and young adults; therefore, the diameter of the central zone 110 of the lens according to embodiments of the present invention can typically be larger than about 3 mm to reasonably ensure that the central zone is larger than the wearer's pupil under photopic conditions. However, according to the Stiles-Crawford effect, rays passing near the edge of the image-forming portion of the eye have less visual importance as they progress toward the retina than rays traveling closer to the center of the pupil; therefore, the central zone does not need to be larger than the pupil diameter of the eye to be effective. Considering the Stiles-Crawford effect, it is typically desirable that the central zone is not more than 1 mm smaller than the diameter of the pupil of the wearer's eye. For example, the central zone may have a diameter of at least 2.0 mm, or at least 3.0 mm, or at least 4.0 mm. The diameter of the central zone is typically in the range of 2.5 to 6.0 mm and is (partially) selected to reduce or avoid visual impairment in a given population under selected lighting conditions.

[0041] The peripheral zone 120 is located radially outside the central zone 110, and the peripheral zone has positive deviations 121a and negative deviations 121b with respect to the mean optical power IP, the mean optical power IP increases as a function of radius from the first power CP. While it is typically advantageous for the peripheral zone to be radially outside the central zone in all azimuth angles, the peripheral zone 120 may be located radially outside the central zone over substantially all 360 degrees of azimuth angles. The peripheral zone has an mean power that increases as a function of radial position. The deviation amplitude (also referred to herein as wave amplitude) in the peripheral zone 120 may be the same as or different from the wave amplitude in the second region 110b.

[0042] The optical power across the central-peripheral zone interface changes continuously, thereby avoiding power discontinuities and any visual impairments associated with them (i.e., improper induction of light to the visual portion of the retina). As shown in the embodiment of Figure 2A, the average optical power may increase linearly as a function of radial position; however, in some embodiments, the peripheral zone may have one or more regions where the optical power increases relatively large or small. It will be understood that the increase in power of the peripheral zone relative to the central zone addresses a contributing factor to progressive myopia, namely peripheral hyperopic defocus.

[0043] Radial power can be varied using changes in surface curvature or refractive index. Similar to the second region 110b of the central region, the radial power profile of the peripheral zone 220 includes at least one maximum value 122a and at least one minimum value 122b. That is, the power is radially modulated and achieves a power whose magnitude varies along the peripheral zone. Deviations can occur periodically (i.e., in a repeating pattern with a fixed period) or aperiodically.

[0044] Positive and negative deviations are embodied as sinusoidal patterns in optical power relative to the first power CP and average power IP, but it will be understood that other deviation patterns may be used. For example, positive and negative deviations may be embodied as sinusoidal shapes approximated by triangular patterns or linear portions. Typically, it is advantageous that the optical power is continuous as a function of radial position from the optical axis OA to the outer boundary of the peripheral zone. The amplitude of the deviation may be constant as a function of radial position, or it may increase and / or decrease as a function of radial position. Typically, it is advantageous that the region above the constant power CP and average optical power IP encompassed by the positive deviation is substantially equal to the region below the constant power CP and average optical power IP curve encompassed by the negative deviation (e.g., difference of less than 20% or difference of less than 10%), which contributes to the uniformity of the defocus blur produced by lens 100.

[0045] Figure 2B shows examples of power profile characteristics that can be varied to balance myopia progression suppression, visual acuity, and wearer comfort (i.e., the wearer being able to comfortably wear the lens for extended periods). As illustrated, various characteristics of the power profile of a lens having spatially modulated central and peripheral zones can be selected, as described with reference to Figure 2A, to achieve myopia progression suppression while maintaining sufficient visual acuity (perceived by the wearer) and wearer comfort. As will be discussed in more detail below, myopia progression suppression and visual acuity can be tested using eye models in optical design software and / or by clinical trials. For example, lens design variables of a lens according to an embodiment of the present invention and their effects on visual performance include: • Radius of the central zone region 210a with substantially constant power CP - Increasing the radius generally increases visual acuity but decreases the depth of focus of the lens. • Wave Amplitude (WA) - Increased wave amplitude in the central zone increases depth of focus but decreases visual acuity. Increased WA in the peripheral zone increases peripheral myopic defocus and decreases BLOS. • Increasing the gradient SL of the average power IP in the peripheral zone increases peripheral defocus, but does not have a significant effect on BLOS, visual acuity, or depth of field within the gradient range shown in Figures 4A-4C. • The radial range of the second region 210b of the central zone has a periodic deviation in power - by increasing the width of this portion of the central zone (at the expense of the peripheral zone), the depth of focus is increased, thereby addressing accommodative lag, but peripheral myopia shift is limited. The strength of myopia suppression versus lens wearer comfort can be influenced by selecting the waveform (attenuation as a function of radial position, rise as a function of radial position, a combination of attenuation and rise, etc.) and wave frequency—the maximum and minimum values ​​of the periodic deviation (as a function of radial position). As mentioned above, according to the Styles-Crawford effect, light from radial positions farther from the visual axis has less visual impact; however, such light can still provide suppression of myopia progression. Therefore, in some designs, it may be desirable to increase the deviation amplitude as a function of radial position. Furthermore, the waveform and frequency can influence light scattering and the presence of any halos perceived by the wearer.

[0046] The power deviation relative to a substantially constant power in the central zone, or to an increasing average optical power in the peripheral zone, typically has a maximum amplitude in the range of about 0.5 diopters to about 12.0 diopters or about 2.0 diopters to about 10.0 diopters. Embodiments shown in Figures 2A and 2B may have rotationally symmetric central and peripheral zones, or may have circumferential variations in optical power.

[0047] The performance of an ophthalmic lens design can be modeled using ray tracing software such as OpticStudio from Zemax LLC (Kirkland, WA), by placing the contact lens design within or on a model eye. For example, the contact lens can be positioned on a model eye such as the Arizona eye, or on a representation of one or more measurement eyes of a human subject. In one embodiment (hereinafter referred to as Embodiment 1), the rated contact lens design has the following parameters: The surrounding zones enclose the central zone. The deviation waveform is sinusoidal, with a uniform peak amplitude across the second region of the central zone and the peripheral zones. Wave amplitude = 4.0D Wave period=0.89mm The gradient of the average power in the surrounding zone = 4.4 D / mm Center zone radius = 2.0 mm Radius of the central zone where there is no periodic deviation in power = 0.668 mm Center zone average power = -3.0D Peripheral zone outer radius = 4.5mm.

[0048] To obtain a given lens design, the lens center thickness, as well as the back radius and cone value, were fixed, while the front surface was fitted with an aspherical surface whose radius, cone, and surface parameters were varied to obtain a selected power profile.

[0049] To demonstrate the effect of multiple parameters on the performance of each, the performance was calculated for a given parameter while the remaining parameters were kept constant and the given parameter was varied over a certain range. To obtain the data for each figure discussed below, Embodiment 1 was modeled by placing the lens of Embodiment 1 on the cornea of ​​each of 90 eye models. Each model was identified using ophthalmic measurements performed under photopic conditions from individuals without presbyopia, and the outputs calculated from each of the 90 modeled eyes were averaged. In particular, calculations were performed for an object located at infinity using 589 nm light and a lens with a refractive index of 1.4 (at 589 nm). Figures 3A-3C, 4A-4C, and 5A-5C show the effects of changes in wave amplitude, the gradient of average power in the peripheral zone, and the width of the unmodulated zone, respectively.

[0050] Figures 3A to 3C are graphs showing the effects of changes in wave amplitude on visual acuity, peripheral myopic defocus, and blur orientation gradient (BLOS), respectively, over wave amplitudes ranging from 0 to 8 diopters. In each of Figures 3A to 3C, parameters other than wave amplitude are maintained as described in Embodiment 1.

[0051] Figure 3A is a graphical representation of logMAR visual acuity as a function of wave amplitude. A decrease in normalized logMAR visual acuity of 0.02 corresponds to the loss of a single letter (i.e., a single target) on a standard Snellen's target. Figure 3A shows that even with an amplitude of 8D, the amount of decrease in logMAR visual acuity corresponds to only a single letter in one row on a standard Snellen's target.

[0052] Figure 3B is a graphical representation of peripheral myopia defocus as a function of wave amplitude for a series of three field angles. The peripheral myopia defocus values ​​corresponding to the wave amplitude of 0D represent the effective values ​​of peripheral myopia defocus for each of the three field angles in the absence of periodic positive and negative deviations; the peripheral myopia defocus values ​​corresponding to the wave amplitude of 8D represent the effective values ​​of peripheral myopia defocus in the presence of relatively large periodic positive and negative deviations for each field angle. For each field angle, it is clear that periodic fluctuations provide a significant contribution to peripheral myopia defocus. The wave amplitude of 8D provides approximately 2.3 diopters of peripheral myopia defocus at a 25-degree field angle, approximately 1.4 diopters at a 20-degree field angle, and approximately 1.2 diopters at a 15-degree field angle for a power profile without a positive slope in peripheral power. It should be noted that the field of view angles defined in Figures 3B and 3C (and other figures below) are measured relative to the corneal optical axis when light rays are incident on the outer surface of an ophthalmic optical system (e.g., the outer surface of the contact lens in systems including contact lenses, or the outer surface of the cornea in systems including corneal inlays).

[0053] Figure 3C is a graphical representation of BLOS as a function of wave amplitude for a series of seven field angles. The BLOS value corresponding to wave amplitude 0D represents the effective value of BLOS when there are no periodic positive and negative deviations for various angles; the BLOS value corresponding to wave amplitude 8D represents BLOS when relatively large periodic (positive and negative) deviations exist for each of the field angles. For all field angles, BLOS decreases monotonically as a function of increasing wave amplitude. Periodic deviations also provide the lens with an expanded depth of field, thereby significantly reducing BLOS at the 0-degree field of view.

[0054] Therefore, from Figures 3A to 3C, it is clear that increasing wave amplitude is effective in increasing peripheral defocus and reducing BLOS, but does not significantly impair visual acuity.

[0055] Figures 4A to 4C are graphs showing the effect of changes in the average power gradient in the peripheral zone on visual acuity, peripheral myopia defocus, and BLOS, respectively, over the range of 0 to 6 D / mm. In each of Figures 4A to 4C, parameters other than the average power gradient in the peripheral zone are maintained as described in Embodiment 1.

[0056] Figure 4A is a graphical representation of visual acuity as a function of the gradient of mean peripheral power. Figure 4A shows that even with a gradient of 6 D / mm, the decrease in logMAR visual acuity is significantly smaller than the decrease corresponding to the loss of a single letter on a standard Snellen chart. Thus, it is clear that an increase in the gradient of mean peripheral power does not significantly impair visual acuity.

[0057] Figure 4B is a graphical representation of peripheral myopia defocus as a function of the gradient of mean peripheral power for a series of three field of view angles. The peripheral myopia defocus value corresponding to the mean peripheral power gradient of 0 D / mm represents the effective value of peripheral myopia defocus when there is no positive gradient in peripheral power (i.e., mean peripheral power is equal to the average power in the central zone), while the peripheral myopia defocus value corresponding to the mean power gradient of 6 D / mm represents the effective value of peripheral myopia defocus in the presence of a relatively large gradient. For each field of view angle, it is clear that the mean power gradient provides a significant contribution to peripheral myopia defocus, especially at larger field of view angles. A gradient of 6 D / mm provides approximately 3.6 diopters of peripheral myopia defocus at a 25-degree field of view angle, approximately 2 diopters at a 20-degree field of view angle, and approximately 1 diopter at a 15-degree field of view angle for a power profile without a positive gradient in peripheral power.

[0058] Figure 4C is a graphical representation of BLOS as a function of the mean peripheral power gradient for a series of seven field of view angles. The BLOS value corresponding to a gradient of 0 D / mm represents the effective value of BLOS when there is no gradient in the mean peripheral power; the BLOS value corresponding to a gradient of 6 D / mm represents the BLOS of the mean peripheral power in the presence of a relatively large gradient. For all field of view angles, BLOS is substantially unaffected by the gradient of the mean peripheral power.

[0059] Therefore, as is clear from Figures 4A to 4C, increasing the gradient of mean peripheral power is effective in increasing peripheral defocus without significantly impairing visual acuity or affecting BLOS.

[0060] Figures 5A to 5C show the effects of changes in the width (i.e., radius) of the central zone portion without periodic power deviation on visual acuity, peripheral myopic defocus, and BLOS, respectively, over a range of 0 to 2.0 mm. In each of Figures 5A to 5C, parameters other than the width of the central zone portion without periodic deviation are maintained as described in Embodiment 1.

[0061] Figure 5A is a graphical representation of visual acuity as a function of the width of the central zone portion where there is no periodic deviation in power. Normalized visual acuity as a function of the width of the central zone portion where there is no periodic deviation in power increases significantly until the width reaches approximately 0.5 mm (i.e., visual acuity is not impaired beyond approximately 0.5 mm). Figure 5A shows that when this portion has a diameter of zero (i.e., the periodic deviation begins at the optical axis of the lens), visual acuity is affected with a decrease of approximately 1.5 optotypes relative to peak visual acuity.

[0062] Figure 5B is a graphical representation of peripheral myopia defocus as a function of the width of the central zone portion where there is no periodic deviation in power, for a series of three field angles. Figure 5B shows that peripheral myopia defocus is nearly constant for all field angles, with some variation over the range of values ​​shown. Width has the greatest effect on peripheral myopia defocus for values ​​less than 0.5 mm, and the greatest effect occurs at larger field angles. Note that the unmodulated zone width does not affect peripheral myopia defocus as much as the peripheral gradient (as shown in Figure 4B). Note also that peripheral myopia defocus increases monotonically with increasing peripheral gradient, but the effect of increasing the width of the unmodulated zone is not monotonically.

[0063] Figure 5C is a graphical representation of BLOS as a function of the width of the central zone portion where there is no periodic deviation in power for a series of seven field angles. Figure 5C shows that the width of the central zone portion where there is no periodic deviation in power has no significant effect on BLOS in any of the seven field angles until the width exceeds 1 mm, after which BLOS increases significantly as a function of the increasing width of the unmodulated zone.

[0064] As is evident from Figures 5A-5C, the width of the unmodulated central zone affects visual acuity and BLOS, but does not significantly affect peripheral myopic defocus. Therefore, it is clear that in some cases, selecting an unmodulated zone width of 0.5-1.0 mm is advantageous; however, in other cases, the width outside this zone may be appropriate.

[0065] The width of the central zone portion without deviation is typically selected to achieve visual acuity; however, the width can affect wearer comfort. Additionally, adding deviation to the central region (i.e., reducing the width of the central zone portion without deviation) may increase the depth of focus, thereby addressing asthenopia due to insufficient accommodation in juvenile myopia. Furthermore, adding deviation to the central region may reduce the irritation to ocular growth caused by the presence of deviation in the central zone without affecting visual acuity.

[0066] While we have modeled the effects of three variables in the power profile, other variables in the profile (e.g., the central zone radius (the peripheral zone radius is varied along with the central zone radius to keep the lens radius constant) or the modulation frequency of the power deviation) can be modeled in a similar manner.

[0067] The lens according to the present invention can be made from, for example, a silicone hydrogel and can be manufactured using any suitable technique such as casting or turning.

[0068] Although various embodiments have been illustrated and described in detail in this specification, it will be apparent to those skilled in the art that various modifications, additions, substitutions, etc., can be made without departing from the spirit of the invention, and therefore these are considered to be within the scope of the invention as defined in the following claims.

[0069] Further embodiments of the present invention are defined by the following clauses: 1. Eye lenses having the following features: A central zone comprising a first region characterized by a substantially constant first optical power, and a second region located radially outside the first region, having positive and negative deviations of power as a function of radial position with respect to the substantially constant first optical power; and A peripheral zone located radially outside the central zone, wherein the peripheral zone has positive and negative deviations as a function of radial position with respect to the average optical power, and the average optical power increases as a function of radius from the substantially constant first optical power. 2. The substantially constant first optical power of the first region, the positive and negative deviations of the second region as a function of radius, and the positive and negative deviations of the peripheral zone constitute a power profile. The aforementioned power profile does not have discontinuities in power. The lens described in Clause 1, characterized by the above. 3. The lens according to Clause 1, characterized in that the diameter of the central zone is at least 2 mm. 4. The lens according to Clause 1, characterized in that the diameter of the central zone is at least 3 mm. 5. The lens according to Clause 1, characterized in that the central zone and the peripheral zone are rotationally symmetric. 6. The lens according to Clause 1, characterized in that the lens is a contact lens. 7. The lens according to Clause 1, characterized in that the positive and negative power deviations of at least one of the second region and the peripheral zone are periodic as a function of radius. 8. The lens according to Clause 1, characterized in that the region above the average power encompassed by the constant first power and the positive deviation differs by less than 20% from the region below the average power encompassed by the constant first power and the negative deviation. 9. The lens according to Clause 1, characterized in that the deviation amplitude with respect to the average optical power of the peripheral zone is equal to the deviation amplitude with respect to the substantially constant first power in the second region. 10. The lens according to Clause 1, characterized in that the average optical power in the peripheral zone increases linearly. 11. The lens according to Clause 1, characterized in that the positive and negative deviations in the peripheral zone have an amplitude in the range of 0.5 to 12.0 diopters. 12. The lens according to Clause 1, characterized in that the positive and negative deviations in the second region and the peripheral zone are determined by variations in surface curvature. 13. The lens according to Clause 2, characterized in that the lens is a contact lens. 14. The lens according to clause 13, characterized in that the central zone and the peripheral zone are rotationally symmetric. 15. The lens according to clause 14, characterized in that the diameter of the central zone is at least 2 mm. 16. The lens according to Clause 15, characterized in that the positive and negative power deviations of at least one of the second region and the peripheral zone are periodic as a function of radius. 17. The lens according to Clause 16, characterized in that the region above the average power encompassed by the constant first power and the positive deviation differs by less than 20% from the region below the average power encompassed by the constant first power and the negative deviation. 18. The lens according to Clause 17, characterized in that the positive and negative deviations in the peripheral zone have an amplitude in the range of 0.5 to 12.0 diopters. 19. The lens according to Clause 18, characterized in that the positive and negative deviations in the second region and the peripheral zone are determined by variations in surface curvature. 20. The lens according to Clause 19, characterized in that the average optical power in the peripheral zone increases linearly.

Claims

1. A central zone comprising a first region characterized by a substantially constant first optical power, and a second region located radially outside the first region, having positive and negative power deviations as a function of radial position with respect to the substantially constant first optical power; and A peripheral zone located radially outside the central zone, having positive and negative deviations as a function of radial position with respect to the average optical power, wherein the average optical power increases as a function of radius from the substantially constant first optical power. An ophthalmic lens characterized by having the following features.

2. The substantially constant first optical power of the first region, the positive and negative deviations of the second region as a function of radius, and the positive and negative deviations of the peripheral zone constitute a power profile. The aforementioned power profile does not have discontinuities in power. The lens according to claim 1, characterized in that...

3. The lens according to claim 1 or 2, characterized in that the diameter of the central zone is at least 2 mm.

4. The lens according to any one of claims 1 to 3, characterized in that the diameter of the central zone is at least 3 mm.

5. The lens according to any one of claims 1 to 4, characterized in that the central zone and the peripheral zone are rotationally symmetric.

6. The lens according to any one of claims 1 to 5, characterized in that the lens is a contact lens.

7. The lens according to any one of claims 1 to 6, characterized in that the positive and negative power deviations of at least one of the second region and the peripheral zone are periodic as a function of radius.

8. The lens according to any one of claims 1 to 7, characterized in that the region exceeding the average power encompassed by the constant first power and the positive deviation differs by less than 20% from the region below the average power encompassed by the constant first power and the negative deviation.

9. The lens according to any one of claims 1 to 8, characterized in that the deviation amplitude with respect to the average optical power of the peripheral zone is equal to the deviation amplitude with respect to a substantially constant first power in the second region.

10. The lens according to any one of claims 1 to 9, characterized in that the average optical power in the peripheral zone increases linearly.

11. The lens according to any one of claims 1 to 10, characterized in that the positive and negative deviations in the peripheral zone have an amplitude in the range of 0.5 to 12.0 diopters.

12. The lens according to any one of claims 1 to 11, characterized in that the positive and negative deviations in the second region and the peripheral zone are determined by variations in surface curvature.

13. The lens according to claim 2, characterized in that the lens is a contact lens.

14. The lens according to claim 13, characterized in that the central zone and the peripheral zone are rotationally symmetric.

15. The lens according to claim 14, characterized in that the diameter of the central zone is at least 2 mm.

16. The lens according to claim 15, characterized in that the positive and negative power deviations of at least one of the second region and the peripheral zone are periodic as a function of radius.

17. The lens according to claim 16, characterized in that the region exceeding the average power encompassed by the constant first power and the positive deviation differs by less than 20% from the region below the average power encompassed by the constant first power and the negative deviation.

18. The lens according to claim 17, characterized in that the positive and negative deviations in the peripheral zone have an amplitude in the range of 0.5 to 12.0 diopters.

19. The lens according to claim 18, characterized in that the positive and negative deviations in the second region and the peripheral zone are determined by variations in surface curvature.

20. The lens according to claim 19, characterized in that the average optical power in the peripheral zone increases linearly.

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