Optical device with desensitizing rotation angle alignment for astigmatism correction

Abstract

The present invention provides an ophthalmic lens, which includes a main body having a complex surface and a spherical surface opposite to the complex surface, the main body including an eyelid stabilization design structure with a thickness of less than 200 μm, wherein the spherical surface is configured to present a spherical optical power of the lens, wherein the complex surface is configured to present a cylindrical optical power of the lens, and the cylindrical optical power of the lens does not fully correct the cylindrical optical power of the eye caused by astigmatism; and wherein the spherical optical power of the lens is configured so that the smallest circle of the ophthalmic lens is located on or near the retina of the wearer's eye at a target alignment angle.

Description

Background Art 1. Technical Field

[0002] The present disclosure relates to ophthalmic devices such as wearable lenses, including contact lenses, scleral lenses, RGP lenses, implantable lenses, including inlays and onlays, and any other type of device including optical components, and more particularly, to ophthalmic devices with desensitizing rotational angle alignment for astigmatism correction and methods for use with the same.

[0003] 2. Discussion of related fields

[0004] Astigmatism is a refractive error in which the eye does not focus light symmetrically on the retina and significantly reduces the quality of the patient's retinal image, thereby reducing the quality of their perceived vision. Symptoms may depend on the degree of astigmatism. In addition to asymmetrical blurring of the image, higher degrees of astigmatism may also cause symptoms such as squinting, eye strain, fatigue, or even headaches. Eye astigmatism can be caused by asymmetry about the optical axis of both the cornea and the lens. Currently, contact lenses with cylindrical power are used to correct astigmatism.

[0005] By its very nature, the correction of astigmatism requires non-rotationally symmetric optical elements. Specifically, the degree to which the eye's astigmatism can be corrected is a function of the angular alignment between the azimuthal orientation of the eye's aberrations and the orientation of the corrective lens, among other things.

[0006] Therefore, improvement is needed. Summary of the invention

[0007] The present disclosure relates to ophthalmic lenses and methods that are less sensitive to the angular alignment between the azimuthal orientation of the eye's aberrations and the orientation of the corrective lens than conventional "toric" products. For example, the ophthalmic lenses and methods may include properties that make the function of an astigmatism-correcting contact lens insensitive to its angular position on the eye.

[0008] An ophthalmic lens may include a body having a complex surface and a spherical surface opposite the complex surface, the body including an eyelid stabilizing design structure having a thickness of less than 200 μm (e.g., a thickness difference of less than 200 μm), wherein the spherical surface is configured to present a spherical optical power of the lens, wherein the complex surface is configured to present a cylindrical optical power of the lens, which does not fully correct the cylindrical optical power of the eye due to astigmatism; and wherein the spherical optical power of the lens is configured so that the smallest circle of the ophthalmic lens is located on or near the retina of the wearer's eye at a target alignment angle.

[0009] An ophthalmic lens may include a body having a toric surface and a spherical surface opposite the toric surface, wherein the spherical surface is configured to present a spherical power of the lens, wherein the toric surface is configured to present a cylindrical power of the lens and a target cylindrical power, the cylindrical power of the lens being based at least on a direction of astigmatism of an eye of a wearer, the target cylindrical power resulting in substantially complete cylindrical correction, wherein the cylindrical power is less than the target cylindrical power, and wherein the spherical power of the lens is configured such that a smallest circle of the ophthalmic lens is located on or near a retina of an eye of the wearer at a target alignment angle.

[0010] An ophthalmic lens may include a body having a complex surface and a spherical surface opposite the complex surface, wherein the spherical surface is configured to present a spherical optical power of the lens, wherein the complex surface is configured to present a cylindrical optical power of the lens, which does not fully correct the cylindrical optical power of the eye due to astigmatism; and wherein the spherical optical power of the lens is configured so that the smallest circle of the ophthalmic lens is located on or near the retina of the wearer's eye. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The foregoing and other features and advantages of the disclosure will be apparent from the following more particular description of preferred embodiments of the disclosure, as illustrated in the accompanying drawings.

[0012] Figure 1 is a schematic diagram of an exemplary eye and ray diagram, showing that when the entire system has a certain degree of astigmatism, the smallest circle is the desired imaging position.

[0013] FIG. 2A to FIG. 2C is a graph comparing the JND change of a conventional toric lens to the JND change of a lens with an angle desensitization design according to aspects of the present disclosure.

[0014] FIG. 3A to FIG. 3C is a graph of on-eye visual function for three lenses (a conventional toric lens; a novel exemplary toric lens of the present disclosure; and a conventional spherical lens) for a patient with Rx = -3D and cyl = -1.25D.

[0015] FIG. 4A to FIG. 4B Graphs of spherical aberration (SPHA) for a toric eye over a range of spherical powers (-12 to +8D) are shown along both the toric meridian (A) and the non-toric / spherical meridian (B). As shown, multiple SPHAs are plotted for patients with -1, -2, and -3 cylindrical powers along the toric meridian (4A).

[0016] Figure 5 The front surface sag distribution after subtracting the best fit sphere is shown. The arrow indicates the ESD region. DETAILED DESCRIPTION

[0017] introduce :

[0018] An ophthalmic device such as a toric soft contact lens may include a back surface that includes a cylindrical correction in the direction of astigmatism. If the cylindrical direction of the lens is aligned with the eye cylindrical power direction, effective wavefront aberration correction is achieved and the patient can experience the desired retinal image quality. However, on the patient's eye, lens rotation and decentration often occur, for example due to factors such as blinking. Lens rotational misalignment can introduce a significant amount of residual cylindrical power. As shown in the following formula, the residual cylindrical power is proportional to the SIN function of the misalignment angle. For example, in the case of an angular misalignment of 30 degrees, the residual cylindrical power is equal to the original eye cylindrical power, so correction for it may not be required.

[0019] R=2Csin(θ)

[0020] Therefore, the rotation desensitization optical design according to various aspects of the present disclosure not only provides better lens correction, but also provides potential mechanical freedom to improve lens comfort. Currently, lens orientation stability is controlled, for example, by an eyelid stabilization design (ESD) structure (e.g., ballast) or an advanced stabilization design (ASD). Generally, better lens rotation stability lenses mean that a larger thickness difference (TD, along the azimuth at the lens peripheral zone) is required (e.g., 330μm-390μm). TD or ESD thickness can be defined as the front sag difference between the maximum sag value point and the minimum sag value point at the same radial position along the azimuth direction. A larger TD structure can reduce the lens comfort performance. According to the present disclosure, using a desensitization optical device allows better lens rotation tolerance, and therefore TD can be further reduced (e.g., 200μm-300μm or <200μm ESD thickness). When TD is reduced, a lens with improved comfort can be achieved.

[0021] Optical lens design, visual simulation and its application :

[0022] Figure 1 The basic theory behind the design of a desensitizing rotation angle lens is shown. For an ocular system with cylindrical power, there are two line foci along the optical propagation path due to the astigmatic wavefront aberration. To achieve the desired visual correction function, all cylindrical power in the system may be fully corrected. However, if the cylindrical power is only partially corrected (e.g., not fully corrected), the spherical power may be adjusted so that the smallest circle is on or near the surface of the patient's retina, thereby achieving / maintaining the desired or target visual function.

[0023] Visual fluctuations were also compared with conventional toric lenses using just noticeable differences (JNDs) as a measure of visual function, such as FIG. 2A to FIG. 2BAs shown. Clearly, the spherical lens does not produce a change in JND in response to lens rotational misalignment. However, as shown, the lens designed according to the present disclosure has better stability than a conventional toric lens, at least due to its angle-desensitizing optical design.

[0024] FIG. 3A to FIG. 3B A comparison of the change in visual acuity in response to lens rotational misalignment of a conventional toric lens, a toric lens design with rotational desensitization optics according to various aspects of the present disclosure, and a conventional equivalent spherical lens is shown. As shown, the x-axis is the lens rotational misalignment angle, and the y-axis is the patient's visual acuity (-10Log(MAR)). Visual acuity was simulated at far, middle (1D) and near (2D) positions with modeled Rx=-3D and Cyl=-1.25D patients. In the absence of rotational misalignment, the exemplary lens of the present disclosure performs 3 letters worse than a conventional toric lens, but performs about 1 line better than a spherical lens. However, in the case of rotational misalignment, the beneficial effects of the design lens according to the present disclosure perform better than conventional toric lenses. Compared with conventional toric lenses, once the misalignment angle is greater than about 20 degrees, the design lens according to the present disclosure has better VA function. In addition, the exemplary lens of the present disclosure achieves this function while reducing the lens thickness and improving comfort. For example, a lens according to the present disclosure may include an ESD structure having a thickness of less than 200 μm. Figure 5 The front surface sag distribution after subtracting the best fit sphere is shown. Arrows indicate exemplary ESD regions.

[0025] It is also important to know that angular tolerance is adjustable, depending on the amount of toricity that is partially corrected or uncorrected by the soft contact lens. Generally, the less toricity a lens handles, the better angular deviation tolerance the lens will exhibit. However, at the same time, the lens will lose a higher peak function (the visual correction function in the absence of any rotational misalignment).

[0026] Managing the misalignment of the lens with the ESD may also have a trade-off effect. For example, the smaller the ESD (e.g., the lens thickness due to the ESD), the higher the likelihood of lens misalignment due to orientation changes. Therefore, lenses according to various aspects of the present disclosure can use thinner ESD structures and / or reduced overall thickness differences to provide design freedom with astigmatism correction. The lenses of the present disclosure can be optimized based on the orientation of the cylindrical correction and the direction of the astigmatism. For example, the lens can be configured for corrective cylindrical alignment, or can be configured based on the alignment / misalignment angle relative to an axis parallel to the direction of the astigmatism. The alignment angle can be, for example, between 0 degrees and 30 degrees, between 10 degrees and 30 degrees, or between 20 degrees and 30 degrees. Other ranges or endpoint values ​​can be used. The alignment angle when configuring the lens can be, for example, at least 20 degrees. Other threshold angles for optimization can be used.

[0027] Less complete correction of cylindrical power and adjustment of spherical power can be used to tune the lens so that the minimum / minimum circle is located on or near the surface of the patient's retina to achieve / maintain the desired or target visual function. Less complete correction of cylindrical power and adjustment of spherical power can be used to tune the lens to minimize wavefront aberration or minimize spherical aberration at any given alignment / misalignment angle. For illustration, Figure 4 shows the spherical aberration (SPHA) of a toric eye along both the toric meridian (A) and the non-toric / spherical meridian (B) within the spherical power range (-12 to +8D). Along the toric meridian, multiple SPHAs for patients with -1, -2 and -3 cylindrical powers are plotted. Using such information, the power can be configured to minimize spherical aberration at a given alignment angle relative to an axis parallel to the direction of astigmatism.

Claims

1. An ophthalmic lens for wearing on an eye of a patient, comprising: a main body having a toric surface and a spherical surface opposite to the toric surface, wherein the spherical surface is configured to present a spherical optical power of the lens, wherein the toric surface is configured to present a lens cylindrical power that is less than a target cylindrical power that would result in substantially complete cylindrical correction for the patient; and Wherein the lens spherical power is configured such that the smallest circle of the ophthalmic lens is located on or near the retina of the eye of the patient at a target alignment angle such that the body can include an eyelid stabilizing design structure having a thickness of less than 200 μm.

2. The ophthalmic lens of claim 1, wherein the complex surface is a posterior surface of the body configured to be disposed on the eye of a patient.

3. The ophthalmic lens of claim 1, wherein the spherical surface is a posterior surface of the body configured to be disposed on the eye of a patient.

4. The ophthalmic lens of claim 1, wherein the target alignment angle is between 0 and 30 degrees measured from an axis parallel to the direction of astigmatism.

5. The ophthalmic lens of claim 1, wherein the target alignment angle is between 10 degrees and 30 degrees measured from an axis parallel to the direction of astigmatism.

6. The ophthalmic lens of claim 1, wherein the target alignment angle is between 20 and 30 degrees measured from an axis parallel to the direction of astigmatism.

7. The ophthalmic lens of claim 1, wherein the target alignment angle is at least 20 degrees measured from an axis parallel to the direction of astigmatism.

8. An ophthalmic lens for wearing on an eye of a patient, comprising: a main body having a toric surface and a spherical surface opposite to the toric surface, wherein the spherical surface is configured to present a spherical optical power of the lens, wherein the toric surface is configured to exhibit a lens cylindrical power based at least on a direction of astigmatism of the eye of the patient, and the lens cylindrical power is less than a target cylindrical power that would result in substantially full cylindrical correction, and Wherein the lens spherical power is configured such that the smallest circle of the ophthalmic lens is located on or near the retina of the eye of the patient at a target alignment angle such that the body can include an eyelid stabilizing design structure having a thickness of less than 200 μm.

9. The ophthalmic lens of claim 8, wherein the complex surface is a posterior surface of the body configured to be disposed on the eye of a patient.

10. The ophthalmic lens of claim 8, wherein the spherical surface is a posterior surface of the body configured to be disposed on the eye of a patient.

11. The ophthalmic lens of claim 8, wherein the target alignment angle is between 0 and 30 degrees measured from an axis parallel to the direction of the astigmatism.

12. The ophthalmic lens of claim 8, wherein the target alignment angle is between 10 degrees and 30 degrees measured from an axis parallel to the direction of the astigmatism.

13. The ophthalmic lens of claim 8, wherein the target alignment angle is between 20 and 30 degrees measured from an axis parallel to the direction of the astigmatism.

14. The ophthalmic lens of claim 8, wherein the target alignment angle is at least 20 degrees measured from an axis parallel to the direction of the astigmatism.

15. An ophthalmic lens for wearing on an eye of a patient, comprising: a main body having a toric surface and a spherical surface opposite to the toric surface, wherein the spherical surface is configured to present a lens spherical power that is different from a target cylindrical power that will result in substantially complete cylindrical correction for the patient, wherein the complex surface is configured to exhibit a cylindrical optical power of the lens; and Wherein the lens spherical power is configured such that the smallest circle of the ophthalmic lens is located on or near the retina of the eye of the patient at a target alignment angle, enabling the body to include an eyelid stabilizing design structure having a thickness of less than 200 μm.

16. The ophthalmic lens of claim 15, wherein the toric surface is a posterior surface of the body configured to be disposed on the eye of a patient.

17. The ophthalmic lens of claim 15, wherein the spherical surface is a posterior surface of the body configured to be disposed on the eye of a patient.

18. The ophthalmic lens of claim 15, wherein the target alignment angle is between 0 and 30 degrees measured from an axis parallel to the direction of astigmatism.

19. The ophthalmic lens of claim 15, wherein the target alignment angle is between 10 degrees and 30 degrees measured from an axis parallel to the direction of astigmatism.

20. The ophthalmic lens of claim 15, wherein the target alignment angle is between 20 and 30 degrees measured from an axis parallel to the direction of astigmatism.

21. The ophthalmic lens of claim 15, wherein the target alignment angle is at least 20 degrees measured from an axis parallel to the direction of astigmatism.

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