A progressive multifocal ophthalmic lens

Abstract

The present invention relates to a progressive multifocal ophthalmic lens and a method for providing the lens to a subject. The addition power of the progressive multifocal ophthalmic lens of the present invention is independent of the progressive multifocal path, which provides doctors with greater fitting freedom, thereby providing subjects with an ophthalmic lens that better meets their characteristics and needs.

Description

Technical Field

[0001] The present disclosure relates to the technical field of ophthalmic lenses, and more particularly, to a high-dimensional progressive multifocal ophthalmic lens. Background Art

[0002] Myopia is a common vision problem, and traditional framed glasses are the standard tool for correcting myopia. However, when it comes to myopia control, wearing ordinary framed glasses can lead to a rapid annual increase in myopia. It has been proposed that the progression of myopic refractive error can be controlled by positioning the focal point in front of the retina. Specifically, through lens design, the Petzval surface, the curved surface formed by the image point, is tangent to the retina in the macula and located inward of the retina in the paracentral region, resulting in peripheral myopic defocus.

[0003] In the process of myopia prevention and control, in order to achieve peripheral myopia defocus, multifocal lenses need to be used. Some multifocal designs in the existing technology use annular refractive multifocal technology or diffraction multifocal technology. Such technical solutions will cause sudden changes in optical power or lens surface morphology, resulting in scattering or diffraction in the mutation area. However, scattering may cause diffuse light to illuminate the macular area, producing halos, light spots, and reducing contrast sensitivity. Diffraction multifocals can usually only use the first few levels of diffracted light, and part of the light energy cannot be transmitted to the retina, resulting in a decrease in energy utilization, which is also manifested as reduced contrast sensitivity. The continuous multifocal design can avoid these problems.

[0004] In the prior art, progressive addition lenses typically use standard conic sections to describe the surface morphology, controlled by the e-value. However, this coupling of the addition power and the progressive multifocal path is achieved. For example, once the two ends of the focal power curve are determined, such as -0.25D at 0mm and -3D at 2.75mm, there is only one progressive multifocal configuration, or in other words, the addition power and the progressive multifocal path are coupled.

[0005] When controlling myopia, doctors may need to adjust the intensity of myopic defocus and imaging quality according to the patient's progression rate. The coupled light addition and progressive multifocal path provide little freedom and cannot fully meet the doctor's needs. Summary of the Invention

[0006] The present invention provides a progressive multifocal ophthalmic lens, wherein the lens comprises a progressive multifocal zone in its optical zone, wherein the progressive multifocal zone has an optical center and a radius r B , wherein, in the optical zone, the optical power P(r) at a distance r mm from the optical center is:

[0007]

[0008] Among them, A is the additional focal length, L is the gradient coefficient, PC is the optical power of the optical center, and

[0009] When the sign before A is positive, P C =Prescription power P0;

[0010] When the sign before A is negative, P C =P0+A.

[0011] In some embodiments, A is selected from +0.25D to +10.00D.

[0012] In some embodiments, L is selected from 0.1 to 10.

[0013] In some embodiments, when r>r B When P(r)=P(r B ).

[0014] In some embodiments, the optical center does not coincide with the geometric center of the lens.

[0015] In some embodiments, the optical center is located 0.1 to 1 mm nasally to the geometric center.

[0016] In some embodiments, the gradient multi-focal zone includes two or more fan-shaped partitions sharing a central vertex, wherein each fan-shaped partition has the same A value and P value. C value, and at least one sector-shaped partition has a different L value.

[0017] In some embodiments, the progressive multi-focal zone includes four sector-shaped partitions.

[0018] In some embodiments, the lens is provided with a structure for increasing the rotational stability of the lens.

[0019] In some embodiments, the lens is a contact lens, a scleral lens, a spectacle lens, an intraocular lens, or a corneal inlay.

[0020] In some embodiments, the lenses are used to prevent and / or slow the progression of myopia.

[0021] The present invention also provides a method for providing an ophthalmic lens to a subject, preferably a myopic patient or a person susceptible to myopia. The ophthalmic lens comprises a progressive multifocal zone in its optical zone, the progressive multifocal zone having an optical center and a radius r B , the method comprising:

[0022] (1) selecting an add power A value and a gradient factor L for at least one eye of the subject;

[0023] (2) Determining the optical power curve of the ophthalmic lens for the at least one eye according to formula (1):

[0024]

[0025] Where P(r) is the focal length at a distance of r mm from the optical center, A is the additional focal length, L is the gradient coefficient, and P C is the optical power of the optical center, and

[0026] When the sign before A is positive, P C =Prescription power P0;

[0027] When the sign before A is negative, P C =P0+A.

[0028] In some embodiments, the selection in step (1) is based on: the age of the subject, the ratio of the subject's near vision time to the distance vision time, the rate of myopia progression of at least one eye, retinal topography, residual accommodation power, or any combination thereof.

[0029] In some embodiments, the method of the present invention further comprises dividing the progressive multifocal area of ​​the ophthalmic lens into two or more sector-shaped partitions having a common central vertex according to the retinal topography or refractive topography of the at least one eye of the subject, wherein each sector-shaped partition has the same A value and P value. C value, and at least one sector-shaped partition has a different L value. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 shows the optical power curves when the sign before A is positive and negative according to an embodiment of the present invention, wherein r B =2.75mm, L=0.5, P0=-3D, A=0.75D;

[0031] Figure 2 The optical power curves under different L values ​​according to one embodiment of the present invention are shown, wherein the sign before A is positive, r B =2.75mm, P0=-3D, A=0.75D;

[0032] Figure 3 The optical power curves under different A values ​​according to one embodiment of the present invention are shown, wherein the sign before A is positive, r B =2.75mm, P0=-3D, L=0.5;

[0033] Figures 4A to 4CThe different spherical power curves ( Figure 4A )、Field Curve( Figure 4B ) and MTF curves ( Figure 4C );

[0034] Figures 5A to 5C The different spherical power curves ( Figure 5A )、Field Curve( Figure 5B ) and MTF curves ( Figure 5C ). DETAILED DESCRIPTION

[0035] Exemplary embodiments of the present invention will be described below with reference to the accompanying drawings. Unless otherwise defined, all technical and / or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0036] The present invention provides a progressive multifocal ophthalmic lens. The ophthalmic lens can be a progressive multifocal lens for preventing the occurrence of myopia and controlling the progression of myopia, or a progressive multifocal lens for presbyopia and hyperopia. The lens includes a progressive multifocal area in its optical zone, the progressive multifocal area having an optical center and a radius r B , wherein, in the optical zone, the optical power P(r) at a distance r mm from the optical center is:

[0037]

[0038] Among them, A is the additional focal length, L is the gradient coefficient, P C is the optical power of the optical center, and

[0039] When the sign before A is positive, P C = Prescription power P0; that is, the power of the optical center of the lens is the prescription power. In this case, the lens is basically a CD (center-for-distance) lens (see Figure 1 solid line).

[0040] When the sign before A is negative, P C =P0+A, the focal power of the optical center of the lens has additional focal power, at this time, the lens is basically a CN (center-for-near) lens (see Figure 1 middle dashed line).

[0041] By decoupling the addition power from the progressive multifocal path, the present invention enables doctors to adjust the lens prescription according to the patient's condition (such as the degree of myopia, tolerance, rate of myopia progression, etc.). The present invention can also adjust the lens according to the patient's retinal topography / refractive topography (some patients may experience local retinal deformation, such as patients with posterior scleral staphyloma), giving doctors more freedom in fitting, thereby providing subjects with ophthalmic lenses that better suit their characteristics and needs.

[0042] In the method of the present invention, L describes the gradual multi-focal path. When the sign before A is positive, it is a concave curve when L>1, a convex curve when L<1, and a straight line when L=1 ( Figure 2 ). L can be any value selected from 0.1 to 10, such as 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10. The greater the difference between L and 1, the greater the rate of change of the optical power in certain areas (when L>1, it is the peripheral area; when L<1, it is the central area), that is, the local optical power curve will be steeper. A steeper optical power curve causes a sudden and large change in optical power, which may cause more scattered light, thereby reducing imaging quality. Therefore, in a preferred case, L is any value selected from 0.5 to 2, such as 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9 or 2.

[0043] In all cases of the present invention, the additional power A itself is a positive value. According to different application scenarios, the additional power A can be any value selected from +0.25D to +10.00D, preferably +0.50D to +9.00D, +0.75D to +8.00D, +1.00D to +7.00D, +1.25D to +6.00D, +1.50D to +5.00D, or +2.00D to +4.00D, for example, +0.25D, +0.50D, +0.75D, +1.00D, +1.25D, +1.50D, +1.75D, +2.00D, +2.25D, +2.50D, +2.75D , +3.00D, +3.25D, +3.50D, +3.75D, +4.00D, +4.25D, +4.50D, +4.75D, +5.00D, +5.25D, +5.50D, +5.75D, +6.00D, +6.25D, +6.50D, +6.75D, +7.00D, +7.25D, +7.50D, +7.75D, +8.00D, +8.25D, +8.50D, +8.75D, +9.00D, +9.25D, +9.50D, +9.75D, or +10.00D. The larger the A value, the larger the range of optical power variation of the progressive multifocal zone (see Figure 3 ).

[0044] In the case of using for preventing the occurrence of myopia and controlling the progression of myopia, the A value is preferably +1.00D to +5.00D, more preferably +2.00D to +4.00D.

[0045] Studies on simulated eyes found that different combinations of A and L can produce different myopia control effects and visual qualities.

[0046] Specifically, as described by Liou et al. (Hwey-Lan Liou and Noel A. Brennan, "Anatomically accurate, finite model eye for optical modeling," J. Opt. Soc. Am. A 14, 1684-1695 (1997)), the Liou & Brennan model eye was established in Optic Studio Zemax, and the eye was simulated according to the The optical focal length is adjusted by adding the corresponding optical surface to simulate the corresponding contact eye.

[0047] The optical power changes under different A and L combinations are obtained by calculation ( Figure 4A and Figure 5A ), where the horizontal axis represents the distance from the center of the lens and the vertical axis represents the spherical focal length. Figure 4A and5A As shown in the figure, the larger the A is, the higher the addition power is; the larger the L is, the smoother the change in focal power is. The field curvature under different combinations of A and L is also obtained by calculation ( Figure 4B and Figure 5B ) and MTF curves ( Figure 4C and Figure 5C The degree to which the field curvature shifts toward negative values ​​represents the degree of myopic defocus. The low-frequency portion of the MTF reflects the transmission of object outlines; the mid-frequency portion reflects the transmission of optical layers; and the high-frequency portion reflects the transmission of object details. The results shown in the figure are summarized in Table 1.

[0048] Table 1 Effects of A and L on myopic defocus and visual quality in different lens designs

[0049]

[0050] This shows that A and L have different effects in central distance lenses and central near lenses. When used for myopia prevention and control, doctors can choose different combinations of A and L based on factors such as the patient's myopia progression rate and accommodation lag, as well as the lens type, to provide stronger myopia control or better visual acuity and adjust lens dispensing parameters.

[0051] In the area outside the gradient multi-focal area, that is, when r>r B When the optical power is preferably a constant value, that is, P(r)=P(r B In some embodiments, the entire optical zone of the lens is a progressive multifocal zone, i.e., B Equal to the radius of the optical zone of the lens. B It can be any value selected from 0.5 to 3.5 mm, such as 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4 mm. Those skilled in the art can select a suitable size of the progressive multifocal area, but for myopia prevention and control, it is preferred that r B In the range of 2.5 to 3.5 mm, thereby providing the required myopic defocus effect over more area of ​​the retina.

[0052] In some embodiments of the present invention, the optical center of the progressive multifocal zone does not coincide with the geometric center of the lens. This is because the visual axis and optical axis of the human eye do not coincide, resulting in an angle, known as the Kappa angle. Therefore, the physician can select the optical center of the lens based on the patient's Kappa angle. For example, the optical center can be 0.1 to 1 mm nasally to the geometric center, such as 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or 0.9 mm, preferably 0.5 mm.

[0053] The lens design of the present invention also allows the progressive multifocal area to be divided into 2 or more (e.g., 3, 4, 5, 6, 7, 8) sectoral areas sharing a central vertex, wherein each sectoral area has the same A value and P value. C value, and at least one of the sector-shaped partitions has a different L value. Existing literature shows that on both sides of the fovea, the morphology of the nasal and temporal sides of the human eye's retina is not completely symmetrical. Therefore, axisymmetric contact lenses or frame glasses may produce different myopic defocus on the nasal and temporal sides of the retina, thereby causing asymmetry in the emmetropization process on both sides of the retina, and may cause local axial length growth. The method of the present invention enables doctors to make adjustments based on the fundus conditions of different subjects, so that the optical power curve of the lens is different in different areas. For example, the lens can be divided into four partitions: upper, lower, nasal, and temporal, and the gradient path of each partition can be different, that is, L is different. It is preferably divided into 2 to 4 partitions.

[0054] The doctor can change the gradient coefficient of each partition according to the subject's retinal topography or refractive topography, and select the combination of A and L according to the patient's myopia progression process.

[0055] After determining the optical power curve, conventional methods in the art are used, for example, the sagittal heights of the front and back surfaces of the lens are calculated from the optical power curve, and then the lens is processed on a CNC machine tool to produce the desired lens.

[0056] The progressive multifocal ophthalmic lens of the present invention is selected from a corneal contact lens, a scleral lens, a spectacle lens, an intraocular lens or a corneal inlay, and is provided, if necessary, with a structure for increasing the rotational stability of the lens. This is because, in the case of an asymmetric optical zone of the lens, it must be effectively maintained in a specific orientation. In particular, in the case of contact lenses, they tend to rotate on the eye due to the forces exerted on the contact lens by the eyelids during blinking, as well as the movement of the eyelids and the tear film. Maintaining the orientation of the contact lens on the eye is usually achieved by changing the mechanical properties of the contact lens. Known methods include: prismatic weighting (including decentering or tilting the front surface of the contact lens relative to the back surface), thickening the periphery of the lower contact lens, forming depressions or protrusions on the contact lens surface, and truncating the edge of the contact lens.

[0057] The present invention also provides a method for providing an ophthalmic lens to a subject, in particular a myopic patient or a person susceptible to myopia, wherein the ophthalmic lens comprises a progressive multifocal zone in its optical zone, wherein the progressive multifocal zone has an optical center and a radius r B , the method comprising:

[0058] (1) selecting an add power A value and a gradient factor L for at least one eye of the subject;

[0059] (2) Determining the optical power curve of the ophthalmic lens for the at least one eye according to formula (1):

[0060]

[0061] Where P(r) is the focal length at a distance of r mm from the optical center, A is the additional focal length, L is the gradient coefficient, and P C is the optical power of the optical center, and

[0062] When the sign before A is positive, P C =Prescription power P0;

[0063] When the sign before A is negative, P C =P0+A.

[0064] The selection in step (1) is based on: the age of the subject, the ratio of the subject's near vision time to the distance vision time, the myopia progression rate of at least one eye, the retinal topography, the residual accommodation power or any combination thereof.

[0065] As an example, for a myopic patient named A, since he usually writes his homework at a position of 33cm, the starting A value can be selected as 100cm / 33cm=3D (i.e. A=1 / near visual distance), and the doctor / optometrist will then make adjustments around this value based on factors such as the patient's tolerance and accommodation lag. For presbyopic patients, A=1 / near visual distance-the patient's residual accommodation power, so the additional optical power A is determined by the patient's residual accommodation power. The greater the residual accommodation power, the smaller the required light addition. For example, a presbyopic patient named B usually uses a mobile phone at a position of 33cm and has an accommodation power of 1D, then the starting A value can be selected as 100cm / 33cm-1D=2D, and the doctor / optometrist will then make adjustments around this value based on the patient's tolerance.

[0066] L can be determined based on the ratio of the time spent near and far vision in the subject's daily life. For example, if L=2 is used as the starting point, for a central near vision design, the larger L is, the stronger the myopia control effect is. Therefore, L is positively correlated with the near vision time / far vision time. When the near vision time is prolonged, L increases, providing strong control. You can first select L=2*near vision time / far vision time, and then adjust it according to the patient's tolerance. For a central far vision design, the smaller L is, the stronger the myopia control effect is. Therefore, L is positively correlated with the far vision time / near vision time. When the near vision time is prolonged, L decreases, providing strong control. You can first select L=2*far vision time / near vision time, and then adjust it according to the patient's tolerance.

[0067] For myopic patients, strong control is selected when the rate of myopia progression is greater than the average annual rate for patients of the same age. For younger subjects (e.g., 8-12 years old), strong control can also be adopted because their myopia progression is generally faster. When the rate of myopia progression is approximately equal to the average annual rate for patients of the same age, medium control is selected. When the rate of myopia progression is less than the average annual rate for patients of the same age, weak control is selected. If the rate of myopia progression increases after wearing weak control lenses for a period of time, such as one month, the patient can return to strong control lenses.

[0068] Examples of parameter selection for different control intensities are shown in Table 2. It should be understood that these are only examples, and doctors will use various parameters in combination based on their experience and the actual conditions of their patients to achieve personalized treatment.

[0069] Table 2 Example parameter selection

[0070]

[0071] Those skilled in the art will appreciate that the invention described herein is subject to variations and modifications beyond those specifically described. The present invention is not limited to the specific configurations described and illustrated herein, but encompasses all such variations and modifications within its spirit and scope. Those skilled in the art may combine any two or more of the features, structures, or parts presented herein, individually or collectively, without departing from the spirit and scope of the present invention.

Claims

1. A progressive multifocal ophthalmic lens, comprising a progressive multifocal zone in its optical zone, the progressive multifocal zone having an optical center and a radius r B ,in, In the optical zone, the optical power P(r) at a distance r mm from the optical center is: Among them, A is the additional focal length, L is the gradient coefficient, P C is the optical power of the optical center, and When the sign before A is positive, P C =Prescription power P0; When the sign before A is negative, P C =P0+A.

2. The progressive multifocal ophthalmic lens according to claim 1, characterized in that: A is selected from +0.25D to +10.00D; and / or L is selected from 0.1 to 10.

3. The progressive multifocal ophthalmic lens according to claim 1 or 2, characterized in that: When r>r B When P(r)=P(r B ).

4. The progressive multifocal ophthalmic lens according to claim 1 or 2, characterized in that: The optical center does not coincide with the geometric center of the lens.

5. The progressive multifocal ophthalmic lens according to claim 4, characterized in that: The optical center is located 0.1 to 1 mm on the nasal side of the geometric center.

6. The progressive multifocal ophthalmic lens according to claim 1 or 2, characterized in that: The gradient multi-focal area includes two or more fan-shaped partitions having a common central vertex, wherein each fan-shaped partition has the same A value and P C value, and at least one sector-shaped partition has a different L value.

7. The progressive multifocal ophthalmic lens according to claim 6, characterized in that: The gradual multi-focus area includes four fan-shaped partitions.

8. The progressive multifocal ophthalmic lens according to claim 1 or 2, characterized in that: The lens is provided with a structure for increasing the rotation stability of the lens.

9. The progressive multifocal ophthalmic lens according to claim 1 or 2, characterized in that: The lens is a corneal contact lens, a scleral lens, a spectacle lens, an intraocular lens or a corneal inlay.

10. A method for providing an ophthalmic lens to a subject, the ophthalmic lens comprising a progressive multifocal zone in an optical zone thereof, the progressive multifocal zone having an optical center and a radius r B , the method comprising: (1) selecting an add power A value and a gradient coefficient L for at least one eye of the subject; (2) determining the optical power curve of the ophthalmic lens for the at least one eye according to formula (I): Where P(r) is the focal power at a distance of r mm from the optical center, A is the additional focal power, L is the gradient coefficient, and P C is the optical power of the optical center, and When the sign before A is positive, P C =Prescription power P0; When the sign before A is negative, P C =P0+A.

11. The method according to claim 10, wherein the selection in step (1) is based on: the age of the subject, the ratio of the subject's near vision time to the distance vision time, the rate of myopia progression of at least one eye, retinal topography, residual accommodation power or any combination thereof.

12. The method according to claim 10 or 11, further comprising dividing the progressive multifocal area of ​​the ophthalmic lens into two or more sector-shaped partitions having a common central vertex according to the retinal topography or refractive topography of the at least one eye of the subject, wherein each sector-shaped partition has the same A value and P value. C value, and at least one sector-shaped partition has a different L value.

13. The method according to claim 10 or 11, wherein: The subject is a myopic patient or a myopia-susceptible population.

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