Intraocular lens

Abstract

An intraocular lens (1) is provided with a disc-shaped lens section (2). Three or more segment regions (20) having different refractive powers are formed on at least one of the front surface and the rear surface of the lens section (2). The plurality of segment regions (20) include a far region (20A) having the smallest refractive power, a near region (20B) having the largest refractive power, and an intermediate region (20C) having a refractive power between the refractive power of the far region (20A) and the refractive power of the near region (20B). The plurality of segment regions (20) extend radially outward from the center of the lens section (2).

Description

Technical Field

[0001] The present disclosure relates to an intraocular lens implanted into an eye. Background Art

[0002] As an intraocular lens implanted into an eye, a multifocal intraocular lens that separately converges incident light incident on a lens portion to a plurality of focal points is known. When a multifocal intraocular lens is adopted, virtual accommodation power can be given to a wearer. Among multifocal intraocular lenses, there are refractive lenses in which a plurality of regions having different refractive powers are formed in an optical portion and diffractive lenses that utilize the diffraction phenomenon of light. Compared with diffractive multifocal intraocular lenses, refractive multifocal intraocular lenses have the advantage that the loss of light reaching the retina of the wearer is less.

[0003] As described in Patent Document 1, in a conventional refractive multifocal intraocular lens, in the lens portion, a plurality of regions having different refractive powers are usually provided in a concentric circle shape. When the plurality of regions in the lens portion are arranged in a concentric circle shape, when the pupil of the wearer becomes small, light only passes through the region arranged near the center portion among the plurality of regions arranged on the concentric circle, and light does not pass through the region arranged in the peripheral portion, so it is difficult to obtain a multifocal effect.

[0004] In the multifocal intraocular lens described in Patent Document 2, a disk-shaped optical portion is divided into a plurality of regions by a boundary line extending from the periphery toward the geometric center, and a micro prism group is formed in each of the divided regions with different patterns, thereby giving different refractive powers to each region.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2010-82290

[0008] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2010-125292 Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] Explain the first aspect of the present invention. The multifocal intraocular lens described in Patent Document 2 also has the following problems: It is difficult to process the micro prism group, and it is not only difficult to process with high precision, but also the micro prism group is easily damaged when implanted into the eye. And there is also the following problem: A part of the light passing through the micro prism group is scattered in an undesired direction, and the amount of light converging on the retina is reduced, so it is difficult to obtain a good visual field.

[0011] Describe a second aspect of the present invention. As described in Patent Document 1, in an intraocular lens in which a plurality of regions of a lens portion are arranged in concentric circles, when the pupil of a wearer becomes small, light only passes through a region arranged near the center portion among the plurality of regions arranged in concentric circles. As a result, light does not pass through the region arranged in the peripheral portion, and thus it is difficult to obtain a multifocal effect. Therefore, in the intraocular lens described in Patent Document 1, the wearer sometimes cannot obtain a good visual field based on multifocality. In addition, in Patent Document 2, it is also difficult to say that sufficient research has been conducted to provide a good visual field based on multifocality to the wearer. That is, in the conventional intraocular lens, it is difficult to appropriately provide a good visual field based on multifocality to the wearer regardless of the size of the wearer's pupil.

[0012] A typical object of the present disclosure is to provide an intraocular lens that can easily obtain a better visual field.

[0013] The intraocular lens provided by a typical embodiment in the present disclosure includes a disc-shaped lens portion, wherein at least one of the front surface and the rear surface of the lens portion is formed with three or more segmented regions having different refractive powers. The plurality of segmented regions include a distance vision region with the smallest refractive power, a near vision region with the largest refractive power, and an intermediate region having a refractive power between the refractive power of the distance vision region and the refractive power of the near vision region, and the plurality of segmented regions radially extend outward from the central portion of the lens portion.

[0014] By using the intraocular lens of the present disclosure, it is easy to obtain a better visual field.

[0015] Describe a first form of the intraocular lens in the present disclosure. The intraocular lens exemplified in the present disclosure includes a disc-shaped lens portion. At least one of the front surface and the rear surface of the lens portion is formed with three or more segmented regions having different refractive powers. The plurality of segmented regions include a distance vision region with the smallest refractive power, a near vision region with the largest refractive power, and an intermediate region having a refractive power between the refractive power of the distance vision region and the refractive power of the near vision region. The plurality of segmented regions radially extend outward from the central portion of the lens portion.

[0016] In the intraocular lens exemplified in the present disclosure, the plurality of segmented regions having different refractive powers radially extend outward from the central portion of the lens portion. Therefore, different from the intraocular lens in which a plurality of regions are arranged in concentric circles, even when the pupil of the wearer becomes small, light easily passes through all the plurality of segmented regions.

[0017] Alternatively, the multiple segmented regions may have different refractive powers due to their different radii of curvature. In this case, the amount of light scattered in undesirable directions is reduced compared to a case where microprisms are formed in the segmented regions. As a result, light reaching the retina is less likely to be lost, making it easier to obtain a better visual field. Furthermore, the device can be easily processed with high precision, and the possibility of damage during implantation in the eye is also reduced.

[0018] Alternatively, multiple segmented areas may extend radially outward from a single reference point in the center of the lens portion. That is, all of the linear ends of the segmented areas extending outward from the center of the lens portion may pass through the same reference point. In this case, even if the wearer's pupil becomes smaller, it is easier to ensure the amount of light passing through each of the multiple segmented areas, compared to a case where a certain area (e.g., a circular area) is formed in the center of the lens portion. As a result, regardless of the size of the wearer's pupil, a multifocal effect is easily obtained, and thus the wearer's field of vision is easily improved.

[0019] Furthermore, the lens surface of each segmented region can be either spherical or aspherical. Furthermore, the refractive power is substantially constant within each segmented region. Specifically, when a transition portion (described later) is provided on the lens surface, the refractive power varies within the transition portion, whereas the refractive power remains substantially constant within the segmented region.

[0020] Alternatively, a transition portion may be formed between the plurality of segmented regions of the lens portion. Alternatively, the transition portion may smoothly connect the ends of a pair of segmented regions to each other by continuously changing the radius of curvature from the end of one segmented region to the end of the other segmented region in a pair of adjacent segmented regions. In the case where the lens portion is not formed with a transition portion, steps or the like may sometimes be generated at the boundary between a pair of adjacent segmented regions. Therefore, sometimes a phenomenon may occur where light is diffusely reflected due to the steps or the like, thereby causing a deterioration in the field of vision (e.g., halo or glare). In contrast, by forming a transition portion between a pair of adjacent segmented regions, the effect of diffuse reflection of light caused by steps or the like is less likely to occur. Furthermore, in the case where the lens portion is formed with a transition portion, the refractive power of each region within the transition portion smoothly transitions from the refractive power of an adjacent segmented region to the refractive power of the other segmented region. As a result, in addition to the refractive power given to each segmented region, the lens portion is also given a refractive power between the refractive powers of the segmented regions. Therefore, by forming the transition portion in the lens portion, the effect of the expanded depth of focus (EDOF) of the multifocal intraocular lens can be appropriately obtained.

[0021] Alternatively, both the segmented region and the transition portion refract light incident on the lens portion parallel to the optical axis of the lens portion in a direction closer to the optical axis. In this case, the amount of light that passes through the lens portion and is lost without reaching the retina is reduced. Therefore, it is easier to obtain a better visual field. In addition, it is also possible to manufacture an intraocular lens without forming a transition portion in the lens portion. Even in this case, a good visual field is more easily obtained than in the case of forming a micro prism group or the like in the segmented region.

[0022] Alternatively, the central angle of the transition portion extending outward from the central portion of the lens portion is 5 degrees or more and 30 degrees or less. In this case, it is easy to appropriately obtain both the multi-focal effect based on multiple segmented regions and the depth-of-focus extension effect at the same time.

[0023] In addition, the central angle of the transition portion may be 15 degrees or more and 20 degrees or less. In this case, it is easier to appropriately obtain both the multi-focal effect based on multiple segmented regions and the depth-of-focus extension effect.

[0024] Alternatively, among the central angles of the distance vision region, near vision region, and intermediate region that extend outward from the central portion of the lens portion, the central angle of the distance vision region is the largest, and the central angle of the intermediate region is the smallest. In this case, it is easy to appropriately obtain both the distance vision based on the distance vision region and the near vision based on the near vision region while the depth of focus is expanded.

[0025] Alternatively, the central angle of the distance vision region is 140 degrees or more, the central angle of the near vision region is 90 degrees or more, and the central angle of the intermediate region is 30 degrees or more. In this case, it is easy to appropriately obtain both the distance vision based on the distance vision region and the near vision based on the near vision region while the depth of focus is expanded.

[0026] Alternatively, the refractive power of the near vision region is +2.5 D or more and +4.0 D or less, and the refractive power of the intermediate region is +1.0 D or more and +2.5 D or less. In this case, it is easy to appropriately obtain both the multi-focal effect based on multiple segmented regions and the depth-of-focus extension effect at the same time.

[0027] In addition, the refractive power of the near vision region may be +3.0 D or more and +3.5 D or less, and the refractive power of the intermediate region may be +1.5 D or more and +2.0 D or less. In this case, it is easier to appropriately obtain the multi-focal effect and the depth-of-focus extension effect.

[0028] Alternatively, a toric surface for correcting the astigmatism of the wearer is formed on at least one of the front surface and the rear surface of the lens portion. In this case, it is possible to provide an intraocular lens that can not only obtain distance vision and near vision at the same time, but also correct the astigmatism of the wearer.

[0029] Furthermore, a plurality of segmented regions may be formed on the front surface of the lens surface (i.e., the surface facing the front side of the eye (cornea side) when worn in the wearer's eye). In this case, the shape of the rear surface of the lens surface tends to become smooth, thereby easily suppressing the intrusion of cells and the like between the rear surface of the lens surface and the posterior capsule of the eye to cause posterior cataracts. In addition, a plurality of segmented regions and a complex curved surface may be simultaneously formed on the front surface of the lens surface. In this case, even when a complex curved surface is formed on the lens surface, the occurrence of posterior cataracts is easily suppressed. However, at least one of the segmented regions and the complex curved surface may also be formed on the rear surface of the lens surface. The surface forming the segmented regions and the surface forming the complex curved surface may also be different.

[0030] Alternatively, the MTF curve of the intraocular lens at a spatial frequency of 50 lp / mm may have a maximum for distance, a maximum for near, and an intermediate maximum. The maximum for distance is the maximum value within the range that provides the wearer with a distant visual field. The maximum for near is the maximum value within the range that provides the wearer with a near visual field. The intermediate maximum is the maximum value within the range between the maximum for distance and the maximum for near. The maximum for distance, the maximum for near, and the intermediate maximum may each be 0.10 or greater.

[0031] In the intraocular lens exemplified in this disclosure, multiple segmented regions with varying refractive powers extend radially outward from the center of the lens portion. Therefore, unlike intraocular lenses in which multiple regions are arranged concentrically, light easily passes through all of the multiple segmented regions, even when the wearer's pupil is small. Furthermore, in the MTF curve at a spatial frequency of 50 lp / mm, if the MTF values for the distance maximum, near maximum, and intermediate maximum are each 0.10 or greater, excellent visual field is easily achieved not only at far distances but also at near and intermediate distances, regardless of pupil size.

[0032] Alternatively, in the MTF curve at a spatial frequency of 50 lp / mm, the difference between the MTF value of the smaller of the near maximum and the intermediate maximum and the minimum value between the near maximum and the intermediate maximum may be 0.10 or less. In this case, the distance between the near distance and the intermediate distance is less likely to include a reduced visual field. In other words, a generally good visual field is easily obtained from the near distance to the intermediate distance. Therefore, regardless of pupil size, a good visual field is easily obtained not only at far distances but also at near and intermediate distances.

[0033] Furthermore, in the MTF curve at a spatial frequency of 50 lp / mm, the difference between the MTF value of the smaller of the near maximum and the intermediate maximum and the minimum value between the near maximum and the intermediate maximum may be 0.08 or less. More preferably, the difference between the MTF value of the smaller of the near maximum and the intermediate maximum and the minimum value between the near maximum and the intermediate maximum may be 0.05 or less. In this case, a better field of view from near to intermediate distances can be obtained more easily.

[0034] The MTF curve may have a maximum value for near use greater than a maximum value for intermediate use. In this case, the contrast at the near distance, where visual recognition is more frequent, becomes higher, making it easier to obtain a better field of view.

[0035] However, the near maximum value can also be set to below the intermediate maximum value. Even in this case, no matter how big the pupil is, good visual field can be obtained at far, near and intermediate distances.

[0036] In the MTF curve at a spatial frequency of 50 lp / mm, the difference between the near maximum and the intermediate maximum can be 0.05 or less. In this case, a good field of view is easily achieved at both near and intermediate distances. Therefore, regardless of pupil size, a good field of view is easily achieved not only at far distances but also at near and intermediate distances.

[0037] Alternatively, when the refractive power of the near zone is set to S and the refractive power of the intermediate zone is set to M, the conditions of S ≥ +2.75D and M < S ≤ (M + 1.4D) can be simultaneously satisfied. In other words, the difference between the refractive power S of the near zone and the refractive power M of the intermediate zone can be 1.4D or less. The inventors of the present invention conducted repeated trial and error and simulations and discovered that by reducing the difference between the refractive power S of the near zone and the refractive power M of the intermediate zone to 1.4D or less, compared to a difference greater than 1.4D, not only does the intermediate maximum in the MTF curve increase, but the overall MTF value increases from intermediate to near distances. Therefore, by designing an intraocular lens to satisfy the conditions of S ≥ +2.75D and M < S ≤ (M + 1.4D), it is easier to achieve a better visual field not only at far distances but also at near and intermediate distances, regardless of pupil size.

[0038] Alternatively, the intraocular lens may simultaneously satisfy the conditions of S ≥ +2.75D and M < S ≤ (M + 1.35D). In other words, the difference between the refractive power S in the near zone and the refractive power M in the intermediate zone may be 1.35D or less. In this case, the effect of increasing the intermediate maximum value in the MTF curve and the overall increase in MTF values from intermediate to near distances can be further achieved.

[0039] Alternatively, when the refractive power of the near-using region is set to S and the refractive power of the intermediate region is set to M, the conditions of S≥+2.75D and (M + 1.1D)≤S≤(M + 1.4D) are satisfied simultaneously. As described above, by making the difference between the refractive power S of the near-using region and the refractive power M of the intermediate region approach below 1.4D, a useful synergistic effect can be obtained. On the other hand, if the refractive power S of the near-using region is made too close to the refractive power M of the intermediate region, the effect of the multifocal intraocular lens for obtaining good visions at distant, near, and intermediate distances is reduced. Therefore, by designing the intraocular lens in such a way that the conditions of S≥+2.75D and (M + 1.1D)≤S≤(M + 1.4D) are satisfied simultaneously, regardless of the size of the pupil, not only at a distant point, but also the visions at near and intermediate distances can be obtained more favorably through the multifocal effect.

[0040] In addition, the difference between the refractive power S of the near-using region and the refractive power M of the intermediate region may also be 1.15D or more. In this case, not only at a distant point, but also the visions at near and intermediate distances can be obtained more favorably through the multifocal effect.

[0041] In addition, it is also possible to design the intraocular lens in such a way that the conditions of S≥+2.75D and M<S≤(M + 1.4D) are satisfied regardless of whether the above-mentioned MTF value conditions are met. Even in this case, since the intraocular lens is designed in such a way that the conditions of S≥+2.75D and M<S≤(M + 1.4D) are satisfied, regardless of the size of the pupil, not only at a distant point, but also the visions at near and intermediate distances can be obtained more favorably.

[0042] Describe the second form of the intraocular lens in the present disclosure. The intraocular lens exemplified in the present disclosure can be deformed and implanted into the eye of a patient through the implantation port at the front end via the internal passage of the intraocular lens implantation device. The intraocular lens implantation device includes a pushing member and a mouth portion. By moving the pushing member forward in the passage along the pushing axis that is the axis of the passage, the intraocular lens is pushed forward. The passage area of the mouth portion is formed to be smaller toward the front. The mouth portion has an implantation port at the front end, folds the intraocular lens during the process of pushing the intraocular lens forward in the passage by the pushing member, and then discharges the intraocular lens from the implantation port. The intraocular lens includes a lens portion having a substantially disc shape. Any direction of the cross-section that satisfies the condition of passing through the geometric center of the lens portion and being perpendicular to the lens surface of the lens portion is assumed to be a hypothetical cross-section. In the intraocular lens of the present disclosure, the cross-sectional area of the lens portion in the hypothetical cross-section varies according to the assumed direction of the hypothetical cross-section. The cross-sectional area of the lens portion in the hypothetical cross-section (the first cross-section) in the direction perpendicular to the pushing axis when the intraocular lens is folded by the mouth portion is less than or equal to the cross-sectional areas in the hypothetical cross-sections in other directions.

[0043] When the intraocular lens in the present disclosure is pushed out in the passage of the mouth at an appropriate angle with respect to the pushing axis of the intraocular lens implantation device, the maximum value of the cross-sectional area of the lens portion in the direction perpendicular to the pushing axis (i.e., the cross-sectional area in the first cross-section when the cross-sectional area of the folded lens portion reaches the maximum) becomes smaller. Therefore, the intraocular lens of the present disclosure can be folded smaller in the passage of the mouth.

[0044] For an imaginary cross-section in any direction, calculate the sum of the refractive powers of the lines extending from the geometric center along the imaginary cross-section to the outer periphery on one side and the refractive powers of the lines extending from the geometric center along the imaginary plane to the outer periphery on the other side. In this case, it is also possible that the intraocular lens is designed such that the sum of the refractive powers of the pair of lines along the first cross-section is greater than or equal to the sum of the refractive powers of the pair of lines of the imaginary cross-sections in other directions.

[0045] In the lens portion, the radius of curvature of the portion with a larger refractive power is smaller than the radius of curvature of the portion with a smaller refractive power. In other words, in the lens portion, the curve of the lens surface of the portion with a larger refractive power is steeper than the curve of the lens surface of the portion with a smaller refractive power. Here, it is not optically desirable to provide a step at the geometric center of the lens portion. Therefore, regardless of the direction of the imaginary cross-section assumed, the thickness of the lens portion at the geometric center in the imaginary cross-section is the same. As a result, the thickness of the side surface (edge portion) of the lens portion at the portion with a larger refractive power (the portion where the curve of the lens surface is steep) is smaller than the thickness of the side surface of the lens portion at the portion with a smaller refractive power (the portion where the curve of the lens surface is gentle). Therefore, the larger the sum of the refractive powers of the lines extending from the geometric center along the imaginary cross-section in two directions, the smaller the cross-sectional area of the lens portion in the imaginary cross-section. Therefore, by designing the intraocular lens such that the sum of the refractive powers of the lines along the first cross-section is greater than or equal to the sum of the refractive powers of the lines of the imaginary cross-sections in other directions, the cross-sectional area of the lens portion in the first cross-section is appropriately reduced. As a result, the intraocular lens can be easily folded smaller in the passage of the mouth.

[0046] In addition, the method of defining the structure of the lens portion 2 in the first cross-section can also be changed. For example, for an imaginary cross-section in any direction, calculate the sum of the radius of curvature of the lens portion (for example, the average value of the radius of curvature of the line, etc. The same applies hereinafter) of the line extending from the geometric center along the imaginary cross-section to the outer periphery on one side and the radius of curvature of the line extending from the geometric center along the imaginary cross-section to the outer periphery on the other side. In this case, the intraocular lens can be designed such that the sum of the radii of curvature of the lines along the first cross-section is less than or equal to the sum of the radii of curvature of the lines of the imaginary cross-sections in other directions. Even in this case, the cross-sectional area of the lens portion in the first cross-section is appropriately reduced.

[0047] Furthermore, if the intraocular lens is a toric intraocular lens designed to correct the wearer's astigmatism, the lens portion has a steep meridian and a flat meridian. The steep meridian is the meridian with the smallest radius of curvature and the highest refractive power among any meridians. Meanwhile, the flat meridian is the meridian with the largest radius of curvature and the lowest refractive power. In a toric intraocular lens, the lens can be designed so that the position of the first cross section coincides with the steep meridian of the lens portion. In this case, the cross-sectional area of the lens portion in the first cross section is also appropriately reduced.

[0048] The intraocular lens may further include a pair of support portions. The pair of support portions extend outward from different locations on the side of the lens portion and support the lens portion within the patient's eye. The intraocular lens may be designed so that the cross-sectional area of the lens portion in a virtual cross-section (second cross-section) passing through the proximal ends of each of the pair of support portions is greater than the cross-sectional area in virtual cross-sections in other directions.

[0049] To stably support the lens portion within the eye, it is desirable that the base ends of each of the pair of support portions be connected to a thicker portion of the side surface of the lens portion. However, if the base ends of the support portions are connected to a thinner portion of the side surface of the lens portion, undesirable deformation or damage may easily occur at the base ends of the support portions and the lens portion when the support portions bend during implantation. Therefore, by designing the intraocular lens so that the cross-sectional area of the lens portion in the second section passing through the base ends of each of the pair of support portions is greater than the cross-sectional area in imaginary sections in other directions, the thickness of the side surface of the lens portion connecting the base ends of the pair of support portions is increased. As a result, the rigidity of the base ends of the support portions is ensured, making it less likely to cause undesirable deformation or damage, and further facilitating proper placement of the intraocular lens within the eye. Furthermore, since the deformation of the pair of support portions is more even, the stability of the intraocular lens during implantation is also improved.

[0050] For any imaginary cross section in each direction, the sum of the refractive power along a line extending from the geometric center along the imaginary cross section toward the periphery on one side and the refractive power along a line extending from the geometric center along the imaginary plane toward the periphery on the other side is calculated. In this case, the intraocular lens can be designed so that the sum of the refractive power along the line along the second cross section is less than the sum of the refractive power along the lines along the imaginary cross sections in the other directions.

[0051] As described above, the thickness of the side surface (edge portion) of the lens part at the portion with a smaller refractive power (the portion where the curve of the lens surface is gentle) is greater than the thickness of the side surface of the lens part at the portion with a greater refractive power (the portion where the curve of the lens surface is steep). Therefore, by designing the intraocular lens such that the total refractive power along the line of the second cross-section is greater than or equal to the total refractive power along the line of the imaginary cross-section in other directions, the thickness of the portion connecting the base ends of the pair of supporting parts in the side surface of the lens part becomes larger.

[0052] In addition, the method of defining the direction of the second cross-section can also be changed. For example, for the imaginary cross-section in any direction, calculate the sum of the radius of curvature of the lens part along the line extending from the geometric center to the outer periphery on one side along the imaginary cross-section (for example, the average value of the radius of curvature on the line, etc. The same applies hereinafter) and the radius of curvature along the line extending from the geometric center to the outer periphery on the other side along the imaginary cross-section. In this case, the intraocular lens can be designed such that the sum of the radii of curvature along the pair of lines of the second cross-section is less than or equal to the sum of the radii of curvature along the pair of lines of the imaginary cross-section in other directions. Even in this case, the thickness of the portion connecting the base ends of the pair of supporting parts in the side surface of the lens part becomes larger.

[0053] Furthermore, in the toric intraocular lens, the intraocular lens can be designed such that the position of the second cross-section coincides with the flat meridian of the lens part. In this case, the thickness of the portion connecting the base ends of the pair of supporting parts in the side surface of the lens part also becomes larger.

[0054] It is also possible that a plurality of segmented regions are formed on at least one of the front surface and the rear surface of the lens part. It is also possible that the plurality of segmented regions radiate outward from the central part of the lens part and have different refractive powers due to different radii of curvature. The plurality of segmented regions can also be arranged in the lens part such that the cross-sectional area of the lens part in the first cross-section is less than or equal to the cross-sectional area in the imaginary cross-section in other directions.

[0055] In this case, different from the intraocular lens in which a plurality of regions are arranged on concentric circles, even when the pupil of the wearer becomes smaller, light passes through each of the plurality of segmented regions and converges on the retina. In addition, the plurality of segmented regions have different refractive powers due to different radii of curvature. Therefore, compared with the case where a micro prism group or the like is formed in the segmented region, the amount of light scattered in an undesired direction is reduced. As a result, it is not easy to cause loss of light reaching the retina, and it is easy to obtain a better visual field. In addition, it is easy to process with high precision, and the possibility of breakage during implantation into the eye is also low. And the intraocular lens is folded smaller in the passage of the mouth and implanted into the eye.

[0056] However, as described above, the technology exemplified in the second aspect of the present disclosure can also be applied to an intraocular lens (e.g., an aspheric intraocular lens, etc.) in which a plurality of segmented regions are not formed. Additionally, both a plurality of segmented regions and an aspheric surface for correcting the astigmatism of the wearer can be formed in the lens portion. Further, the surface on which the segmented region is formed and the surface on which the aspheric surface is formed among the front surface and the rear surface of the lens surface can be the same surface or different surfaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 is a top view of the intraocular lens 1.

[0058] Figure 2 is a perspective view of the intraocular lens implantation device 100 observed from the upper right obliquely.

[0059] Figure 3 is a perspective view of the plunger 300 observed from the upper right obliquely.

[0060] Figure 4 is a schematic explanatory view showing a state in which the intraocular lens 1 is appropriately moved and deformed.

[0061] Figure 5 is a top view showing an example of the intraocular lens 1 in which a plurality of segmented regions 20 are formed.

[0062] Figure 6 is a diagram of a cross-sectional view schematically comparing a cross-section passing through the geometric center O of the lens portion 2 and perpendicular to the lens surface of the lens portion 2 for the distance vision region 20A and the near vision region 20B.

[0063] Figure 7 is a diagram comparing the MTF curves of four intraocular lenses 1 in which the refractive powers and central angles of the distance vision region 20A, the near vision region 20B, and the intermediate region 20C are changed.

[0064] Figure 8 is a diagram comparing the MTF curves of three intraocular lenses in which the refractive powers of the distance vision region 20A, the near vision region 20B, and the intermediate region 20C are changed.

[0065] Figure 9 is a diagram comparing the MTF curves of the intraocular lens 1 in the case where no transition portion is formed between the distance vision region and the near vision region and the case where a transition portion is formed.

[0066] Figure 10 is in Figure 5 the intraocular lens 1 shown shows a line for calculating the total value of the refractive power. DETAILED DESCRIPTION OF THE INVENTION

[0067] Hereinafter, typical embodiments in the present disclosure will be described with reference to the accompanying drawings. The intraocular lens 1 of this embodiment is implanted into the eye of a patient through an intraocular lens implantation device 100. In the following description, the direction (the left side of Figure 1 ) in which the intraocular lens 1 is first implanted into the eye through the intraocular lens implantation device 100 is defined as the front of the intraocular lens 1.

[0068] (Schematic structure of the intraocular lens)

[0069] Refer to Figure 1 to describe the schematic structure of the intraocular lens 1 in this embodiment. The intraocular lens 1 includes a lens portion 2 and a support portion 3. The intraocular lens 1 of this embodiment is a so-called one-piece intraocular lens in which the lens portion 2 and the support portion 3 are integrally formed. However, at least a part of the technology exemplified in the present disclosure can also be applied to a so-called three-piece intraocular lens in which the lens portion 2 and the support portion 3 are formed of independent members. The intraocular lens 1 can be deformed. For the material of the intraocular lens 1, various soft materials such as monomers such as BA (butyl acrylate) and HEMA (2-hydroxyethyl methacrylate), and composite materials of acrylate and methacrylate can be used, for example.

[0070] The lens portion 2 provides a prescribed refractive power to the eye of the wearer who wears the intraocular lens 1 (that is, the patient's eye). The details of the refractive power given to the lens portion 2 will be described later. The shape of the lens portion 2 is a disc shape. In the example of this embodiment, the optical axis of the lens portion 2 passes through the geometric center O of the lens portion 2 and extends in a direction (vertical direction) perpendicular to the lens surface of the lens portion 2. However, the optical axis of the lens portion 2 may not coincide with the geometric center O of the lens.

[0071] The intraocular lens 1 of this embodiment includes a pair of support portions 3 (front support portion 3A and rear support portion 3B). The base ends 4 of the pair of support portions 3 (that is, the base end 4A of the front support portion 3A and the base end 4B of the rear support portion 3B) are connected to different portions of the side surface of the outer peripheral portion of the lens portion 2 (in this embodiment, the opposite portions in the outer peripheral portion of the disc-shaped lens portion 2). When the intraocular lens 1 is worn in the eye of a patient, the pair of support portions 3 support the lens portion 2 in the eye of the patient.

[0072] In this embodiment, the traveling direction D of the intraocular lens 1 when it travels in the passage of the mouth portion 180 of the intraocular lens implantation device 100 (refer to Figure 2 and Figure 4 ) is presupposed, and the details will be described later. That is, when the intraocular lens 1 travels in the passage of the mouth portion 180, the presupposed traveling direction D of the intraocular lens 1 and the ejection axis A (refer to Figure 2 and Figure 4)Consistent.

[0073] In a state where the intraocular lens 1 is disposed in the setting portion 130 of the intraocular lens implantation instrument 100, the front support portion 3A bends and extends forward from the side surface of the outer peripheral portion of the lens portion 2 toward the intraocular lens implantation instrument 100 (see Figure 4 ). That is, the front support portion 3A has an annular shape that bends in the circumferential direction, and the tip portion of the front support portion 3A is a free end. In a state where the intraocular lens 1 is disposed in the setting portion 130 of the intraocular lens implantation instrument 100, the rear support portion 3B bends and extends rearward from the outer peripheral portion of the lens portion 2 toward the intraocular lens implantation instrument 100 (see Figure 4 ). That is, the rear support portion 3B has an annular shape that bends in the circumferential direction, and the tip portion of the rear support portion 3B is also a free end.

[0074] (Intraocular lens implantation instrument)

[0075] Describe the intraocular lens implantation instrument 100. In the following description, the direction on the side of the mouth portion 180 of the main body portion 101 in the intraocular lens implantation instrument 100 ( Figure 2 the lower left side of the paper surface) is set as the front of the intraocular lens implantation instrument 100, and the direction of the pressing portion 370 of the plunger 300 ( Figure 2 the upper right side of the paper surface) is set as the rear of the intraocular lens implantation instrument 100. In addition, Figure 2 the upper side of the paper surface is set as the upper side of the intraocular lens implantation instrument 100, Figure 2 the lower side of the paper surface is set as the lower side of the intraocular lens implantation instrument 100, Figure 2 the lower right side of the paper surface is set as the right side of the intraocular lens implantation instrument 100, Figure 2 the upper left side of the paper surface is set as the left side of the intraocular lens implantation instrument 100.

[0076] First, with reference to Figure 2 , describe the overall structure of the intraocular lens implantation instrument 100 of the present embodiment. As described above, the intraocular lens implantation instrument 100 is used to implant the deformable intraocular lens 1 into the eye. The intraocular lens implantation instrument 100 includes a main body portion 101 and a plunger 300. The main body portion 101 is substantially cylindrical, and the intraocular lens 1 is implanted into the eye through a passage inside the main body portion 101. The plunger 300 is rod-shaped and can move in the forward and backward directions in the passage inside the main body portion 101. The plunger 300 moves forward along the ejection axis (axis of the passage) A, thereby ejecting the intraocular lens 1 loaded inside the main body portion 101.

[0077] The main body portion 101 and the plunger 300 of this embodiment are formed of a resin material. The intraocular lens implanting device 100 can also be formed by molding, cutting based on resin cutting, etc. By forming the intraocular lens implanting device 100 of a resin material, the user can easily discard the used intraocular lens implanting device 100.

[0078] In this embodiment, in order to smoothly implant the soft intraocular lens 1 having adhesiveness into the eye, a lubricating coating treatment is performed on the inner wall of the main body portion 101. In addition, the intraocular lens implanting device 100 of this embodiment is formed to be colorless and transparent or colorless and translucent. Thus, the user can easily visually recognize the deformed state, etc. of the intraocular lens 1 filled inside the intraocular lens implanting device 100 from the outside of the intraocular lens implanting device 100.

[0079] Refer to Figure 2 , and the main body portion 101 will be described. The main body portion 101 includes a main body cylinder portion 110, a setting portion 130, and a mouth portion (implanting portion) 180.

[0080] The main body cylinder portion 110 is formed in a cylindrical shape extending in the front-rear direction and is located on the rear end side (base end side) of the main body portion 101. On the outer periphery of the main body cylinder portion 110 slightly forward of the rear end, a protruding portion 111 for the user to hold is formed.

[0081] The setting portion 130 is connected to the front end side of the main body cylinder portion 110. The intraocular lens 1 is set (loaded) in the setting portion 130. Specifically, the setting portion 130 includes a holding portion 160 and a placing portion 170. The holding portion 160 holds the intraocular lens 1 when the intraocular lens implanting device 100 is in a storage state. The placing portion 170 is set to be rotatable about the axis of the tip portion. When the placing portion 170 rotates, the intraocular lens 1 held by the holding portion 160 moves to a standby position where it can be pushed out by the plunger 300 and is positioned.

[0082] The mouth portion 180 is connected to the front end side of the setting portion 130. In order to make the intraocular lens 1 less deformed during the process of pushing the intraocular lens 1 forward, the passage area inside the mouth portion 180 becomes smaller toward the front. That is, an internal space with a tapered tip is formed in the mouth portion 180. At the front end of the mouth portion 180, a cylindrical implanting portion 182 with a slanted cut tip is provided. The implanting portion 182 is inserted into the eye. At the front end of the implanting portion 182, an opening, that is, an implantation port 183, for discharging the intraocular lens 1 from the internal passage to the front is formed. The passage inside the main body portion 101 penetrates from the rear end of the main body cylinder portion 110 to the implantation port 183 at the front end of the mouth portion 180.

[0083] Refer to Figure 3, illustrate the schematic structure of the plunger 300. The plunger 300 of this embodiment includes a pushing member 310, a shaft base portion 350, and a pressing portion 370.

[0084] The pressing portion 370 is formed at the rear end of the plunger 300. The pressing portion 370 is a plate-like member extending in a direction orthogonal to the pushing axis A (refer to Figure 2 ). When the user pushes the plunger 300 forward, the user's finger contacts the pressing portion 370.

[0085] The shaft base portion 350 is a rod-like member extending forward from the front end side of the pressing portion 370. In this embodiment, the shaft base portion 350 is formed in a shape with a substantially H-shaped cross-section orthogonal to the pushing axis A. By inserting the shaft base portion 350 into the main body cylinder portion 110 having a substantially rectangular cross-section orthogonal to the pushing axis A, rotation of the plunger 300 relative to the main body portion 101 in the circumferential direction of the pushing axis A is suppressed. When the plunger 300 moves forward and reaches the position where the implantation of the intraocular lens 1 into the eye is completed, the inclined surface at the lower front end of the shaft base portion 350 contacts the inclined surface formed at a specified portion of the main body portion 101. As a result, the front end of the plunger 300 is prevented from protruding excessively from the implantation port 183 (refer to Figure 2 ).

[0086] The pushing member 310 is a rod-like member extending forward from the front end of the shaft base portion 350 along the axial direction of the pushing axis A. The pushing member 310 is formed in a shape with a substantially circular cross-section orthogonal to the pushing axis A. In addition, the thickness of the pushing member 310 is such that it can pass through the thickness of the implantation port 183 of the main body portion 101. The pushing member 310 moves forward along the pushing axis A within the passage of the main body portion 101, thereby pushing the intraocular lens 1 forward while folding it smaller and discharging it into the eye from the implantation port 183.

[0087] Refer to Figure 4 , and illustrate the state of movement and deformation of the intraocular lens 1 when implanting the intraocular lens 1 into the eye using the intraocular lens implantation instrument 10 of this embodiment. First, the operator rotates the placement portion 170 (refer to Figure 2 ), thereby moving the intraocular lens 1 held by the holding portion 160 of the setting portion 130 (refer to Figure 2 ) to the standby position where it can be pushed out by the plunger 300. Here, as shown in (a) of Figure 4 , the base end portion 4B of the rear support portion 3B in the intraocular lens 1 held by the holding portion 160 is offset in either the left or right direction with respect to the pushing axis A.

[0088] Next, the operator injects a lubricant (viscoelastic substance) into the setting portion 130 using an injector or the like, and starts moving the plunger 300 forward. As a result, asFigure 4 As shown in FIG. 1 ( a ), the pushing member 310 is in contact with the rear support portion 3B of the intraocular lens 1 .

[0089] If the plunger 300 is pushed further forward, Figure 4 As shown in (b), the rear support portion 3B moves (bends) toward the direction close to the lens portion 2 due to the pushing member 310. As a result, the rear support portion 3B deforms and moves toward the upper side of the lens portion 2, and the top end of the rear support portion 3B faces forward. Figure 4 The state shown in (b) is a state where the rear support portion 3B is folded (tucking).

[0090] When the plunger 300 is pushed further forward, the pushing member 310 comes into contact with the lens portion 2, and the intraocular lens 1 as a whole moves forward. Figure 4 As shown in (c), when the intraocular lens 1 reaches the mouth 180, the front support portion 3A contacts the inner wall of the tapered mouth 180. As a result, the front support portion 3A deforms and moves upward from the lens portion 2, with the tip of the front support portion 3A facing backward. In other words, the front support portion 3A is folded. In addition, the front support portion 3A contacts the inner wall of the tapered mouth 180, thereby preventing the previously assumed travel direction D of the intraocular lens 1 (see FIG. 1 ). Figure 1 ) is roughly consistent with the pushing axis A of the intraocular lens implantation device 100.

[0091] When the plunger 300 is pushed further forward, the lens portion 2 of the intraocular lens 1 also comes into contact with the inner wall of the tapered mouth portion 180. As a result, Figure 4 As shown in (d), the lens portion 2 of the intraocular lens 1 is folded smaller.

[0092] like Figure 4 As shown in (e), the intraocular lens 1 is folded smaller as it is pushed forward. Since the passage area of the nozzle 180 narrows toward the front, the load applied to the intraocular lens 1 can gradually increase. However, the intraocular lens 1 of this embodiment is designed to facilitate folding into a smaller size by the nozzle 180. This will be described in detail later.

[0093] (Segmented area of the lens part)

[0094] The segmented regions 20 formed in the lens portion 2 of the intraocular lens 1 of this embodiment will be described. Figure 5 As shown, in the intraocular lens 1 of the present embodiment, three or more segmented regions 20 ( 20A, 20B, 20C) are formed on at least one of the front surface and the back surface of the disc-shaped lens portion 2 .

[0095] The plurality of segmented regions 20 have mutually different refractive powers. Specifically, a distance region 20A, a near region 20B, and an intermediate region 20C are formed in the lens portion 2 of the present embodiment. The distance region 20A has the smallest refractive power among the plurality of segmented regions 20. The near region 20B has the largest refractive power among the plurality of segmented regions 20. The intermediate region 20C has a refractive power between the refractive power of the distance region 20A and the refractive power of the near region 20B. Therefore, by converging the light that has passed through the distance region 20A, the near region 20B, and the intermediate region 20C in the lens portion 2 on the wearer's retina, a multifocal effect is obtained. In addition, in the present disclosure, each segmented region 20 is set as a region having approximately the same refractive power regardless of the location within the region.

[0096] When the lens portion 2 is viewed perpendicular to the lens surface, the multiple segmented regions 20 extend radially outward from the center of the lens portion 2. That is, each segmented region 20 is segmented by a boundary line extending linearly outward from a single point in the center of the lens portion 2. Therefore, unlike intraocular lenses in which multiple regions are arranged concentrically, light easily passes through all of the multiple segmented regions 20 even when the wearer's pupil is small. As a result, a multifocal effect is easily achieved regardless of the size of the wearer's pupil. Furthermore, the boundary line between the segmented regions 20 is not limited to a straight line and can be a curve or even a bend.

[0097] Specifically, in the intraocular lens 1 of this embodiment, the lens portion 2 radially expands outward from a single reference point in the center (in this embodiment, the geometric center O of the lens portion 2). That is, all linear boundaries (ends) extending outward from the center of the lens portion 2 in each segmented region 20 pass through the same reference point. Therefore, even if the wearer's pupil is small, it is easier to ensure the amount of light that passes through each of the multiple segmented regions 20, compared to a case where a separate, fixed region (e.g., a circular region) is formed in the center of the lens portion 2. As a result, a multifocal effect is easily achieved regardless of the wearer's pupil size, and the wearer's field of vision is easily improved. However, it is also possible to provide a fixed region in the center of the lens portion 2. Even in this case, a multifocal effect is easily achieved regardless of the wearer's pupil size, compared to a case where multiple regions are arranged concentrically.

[0098] Figure 6 2 is a diagram schematically comparing a cross-sectional view of a section passing through the geometric center O of the lens portion 2 and perpendicular to the lens surface of the lens portion 2 with respect to the distance zone 20A and the near zone 20B. Figure 6As shown, the multiple segmented regions 20 formed in the intraocular lens 1 of this embodiment have different refractive powers due to their different radii of curvature. Furthermore, the lens surfaces of each segmented region 20 can be either spherical or aspherical. In the case of an aspherical lens surface, the term "radius of curvature" in the present invention can also be interpreted as the radius of curvature of a spherical surface that approximates the aspherical lens surface.

[0099] exist Figure 6 In the example shown, the radius of curvature of the distance zone 20A, which has a lower refractive power, is larger than the radius of curvature of the near zone 20B, which has a higher refractive power. In other words, the curve of the lens surface of the distance zone 20A, which has a lower refractive power, is gentler than the curve of the lens surface of the near zone 20B, which has a higher refractive power. By varying the radius of curvature of each of the multiple segmented regions 20 to change the refractive power of each segmented region 20, the amount of light scattered in undesired directions is reduced compared to a method of varying the refractive power by forming different microprism groups in each segmented region 20. As a result, light reaching the retina is less likely to be lost, facilitating a better visual field. Furthermore, the intraocular lens 1 of this embodiment can be easily processed with high precision and is less likely to break during implantation.

[0100] In addition, if Figure 6 As shown, no step or the like is provided at the geometric center O of the lens portion 2. Therefore, the thickness of the side surface (edge portion) of the lens portion 2 at a portion with a larger refractive power (a portion where the curve of the lens surface is steep) is smaller than the thickness of the side surface of the lens portion 2 at a portion with a smaller refractive power (a portion where the curve of the lens surface is gentle).

[0101] like Figure 5 As shown, when the lens portion 2 is viewed from a direction perpendicular to the lens surface, transition portions 21 (21A, 21B, 21C) are formed between the plurality of segmented regions 20 in the lens portion 2. The curvature radius of each transition portion 21 continuously changes from the end of one segmented region 20 to the end of the other segmented region 20 in a pair of adjacent segmented regions 20 across the transition portion 21, thereby smoothly connecting the ends of the pair of segmented regions 20.

[0102] exist Figure 5In the example shown, the refractive power of the distance vision area 20A is 0D, the refractive power of the near vision area 20B is +3.25D, and the refractive power of the intermediate area 20C is +2.0D. Thus, in the transition part 21A formed between the distance vision area 20A and the near vision area 20B, as approaching the end on the near vision area 20B side from the end on the distance vision area 20A side, the refractive power smoothly changes from 0D to +3.25D. In the transition part 21B formed between the near vision area 20B and the intermediate area 20C, as approaching the end on the intermediate area 20C side from the end on the near vision area 20B side, the refractive power smoothly changes from +3.25D to +2.0D. In the transition part 21C formed between the intermediate area 20C and the distance vision area 20A, as approaching the end on the distance vision area 20A side from the end on the intermediate area 20C side, the refractive power smoothly changes from +2.0D to 0D.

[0103] In the case where the transition part 21 is not formed in the lens part 2, steps or the like may be generated at the boundary between a pair of adjacent segmented areas 20, and thus, a phenomenon such as light being diffusely reflected due to the steps or the like and the visual field deteriorating (such as halos or glare) may also occur. In contrast, by forming the transition part 21 between a pair of adjacent segmented areas 20, the influence of diffuse reflection of light caused by steps or the like is less likely to occur. And, in the case where the transition part 21 is formed in the lens part 2, the refractive power of each area in the transition part 21 smoothly transitions from the refractive power of one adjacent segmented area 20 to the refractive power of the other segmented area 20. As a result, for the lens part 2, in addition to the refractive power given to each segmented area 20, the refractive power between the refractive powers of each segmented area 20 is also given. Therefore, by forming the transition part 21 in the lens part 2, the effect of expanding the depth of focus (EDOF: Expanded Depth of Focus) of the multifocal intraocular lens can also be appropriately obtained.

[0104] In the intraocular lens 1 of the present embodiment, both the segmented area 20 and the transition part 21 refract the light incident on the lens part 2 parallel to the optical axis of the lens part 2 in a direction approaching the optical axis. As a result, the amount of light that is not incident on the retina and is lost in the light passing through the lens part 2 is reduced. Therefore, it is easy to obtain a better visual field.

[0105] The central angle of each transition part 21 extending outward from the central part of the lens part 2 (the geometric center O as the reference point in the present embodiment) is designed to be 5 degrees or more and 30 degrees or less. In this case, it is easy to appropriately obtain both the multifocal effect based on the plurality of segmented areas 20 and the depth of focus expansion effect at the same time. In addition, the central angle of each transition part 21 is more desirably designed to be 15 degrees or more and 20 degrees or less. As an example, in Figure 5The central angles of the three transition portions 21 formed in the illustrated intraocular lens 1 are all designed to be 20 degrees. However, when a plurality of transition portions 21 are formed in the lens portion 2, the central angles of the transition portions 21 may naturally be different.

[0106] The center angles of the distance zone 20A, near zone 20B, and intermediate zone 20C, which extend outward from the center of the lens portion 2, are designed so that the center angle CA of the distance zone 20A is the largest and the center angle CC of the intermediate zone 20CC is the smallest. In this case, it is easy to simultaneously achieve appropriate distance vision using the distance zone 20A and near vision using the near zone 20B while maintaining an extended depth of focus.

[0107] Specifically, the central angle CA of the distance zone 20A is designed to be greater than 140 degrees, the central angle CB of the near zone 20B is designed to be greater than 90 degrees, and the central angle CC of the intermediate zone 20C is designed to be greater than 30 degrees. In this case, it is easy to appropriately obtain both the far vision based on the distance zone 20A and the near vision based on the near zone 20B while the depth of focus is expanded. For example, in Figure 5 In the illustrated intraocular lens 1 , the central angle CA of the distance zone 20A is designed to be 150 degrees, the central angle CB of the near zone 20B is designed to be 100 degrees, and the central angle CC of the intermediate zone 20C is designed to be 50 degrees.

[0108] In the intraocular lens 1 of this embodiment, the refractive power of the near zone 20B is designed to be between +2.5D and +4.0D, and the refractive power of the intermediate zone 20C is designed to be between +1.0D and +2.5D. In this case, it is easy to simultaneously and appropriately obtain the multifocal effect and the extended depth of focus effect based on the plurality of segmented zones 20. Furthermore, it is more desirable that the refractive power of the near zone 20B is designed to be between +3.0D and +3.5D, and the refractive power of the intermediate zone 20C is designed to be between +1.5D and +2.0D. As an example, in Figure 5 In the illustrated intraocular lens 1 , the refractive power of the distance zone 20A is designed to be 0D, the refractive power of the near zone 20B is designed to be +3.25D, and the refractive power of the intermediate zone 20C is designed to be +2.0D.

[0109] It is also possible to form an aspherical surface for correcting the astigmatism of the wearer on at least one of the front surface and the rear surface of the lens unit 2. In this case, an intraocular lens 1 is provided that can not only obtain both distant vision and near vision at the same time, but also correct the astigmatism of the wearer. In addition, a plurality of segmented regions 20 may be formed on the front surface of the lens surface (i.e., the surface facing the front side (corneal side) of the eye when worn in the wearer's eye). In this case, the shape of the rear surface of the lens surface is likely to become smooth, so it is easy to suppress cells and the like from entering between the rear surface of the lens surface and the posterior capsule of the eye and causing posterior capsular opacification. In addition, a plurality of segmented regions 20 and an aspherical surface may be formed on the front surface of the lens surface at the same time. In this case, even when an aspherical surface is formed on the lens surface, it is easy to suppress the occurrence of posterior capsular opacification. However, at least one of the segmented region 20 and the aspherical surface can also be formed on the rear surface of the lens surface. The surface forming the segmented region 20 and the surface forming the aspherical surface may be different.

[0110] Refer to Figure 7 and , and explain the MTF characteristics in the case where at least one of the refractive powers and central angles of the distance vision region 20A, the near vision region 20B, and the intermediate region 20C is changed. MTF (Modulation Transfer Function) is an index indicating contrast. In the Figure 8 and Figure 7 charts, MTF curves at a spatial frequency of 50 lp / mm with the defocus amount (the amount of focus deviation, degree deviation) as the horizontal axis and the MTF as the vertical axis are shown. In addition, in the present embodiment, the MTF curve is shown in the case where the analysis direction of the light intensity passing through the lens unit 2 of the intraocular lens 1 is set parallel to the straight line X that bisects the central angle of the distance vision region 20F in order to obtain the MTF.

[0111] In Figure 8Among the four intraocular lenses 1 of A, B, C, and D shown by the MTF curve, the refractive power and the central angle of each of the distance vision region 20A, the near vision region 20B, and the intermediate region 20C are changed within the range of the above-mentioned desired conditions. Specifically, in the intraocular lens 1 of A, the central angle of the distance vision region 20A is set to 180 degrees, the refractive power is set to 0D, the central angle of the near vision region 20B is set to 120 degrees, the refractive power is set to +3.5D, the central angle of the intermediate region 20C is set to 60 degrees, and the refractive power is set to +1.75D. In the intraocular lens 1 of B, the central angle of the distance vision region 20A is set to 180 degrees, the refractive power is set to 0D, the central angle of the near vision region 20B is set to 120 degrees, the refractive power is set to +3.25D, the central angle of the intermediate region 20C is set to 60 degrees, and the refractive power is set to +1.75D. In the intraocular lens 1 of C, the central angle of the distance vision region 20A is set to 180 degrees, the refractive power is set to 0D, the central angle of the near vision region 20B is set to 120 degrees, the refractive power is set to +3.25D, the central angle of the intermediate region 20C is set to 60 degrees, and the refractive power is set to +2.0D. In the intraocular lens 1 of D, the central angle of the distance vision region 20A is set to 170 degrees, the refractive power is set to 0D, the central angle of the near vision region 20B is set to 120 degrees, the refractive power is set to +3.25D, the central angle of the intermediate region 20C is set to 70 degrees, and the refractive power is set to +2.0D. In Figure 7 Among the four intraocular lenses 1 of A, B, C, and D shown by the MTF curve, actually, a transition portion with a central angle of 5 degrees is provided between the respective regions.

[0112] As Figure 7 shown, in any of the four intraocular lenses 1 of A, B, C, and D, the MTF has a maximum value near the defocus amount of 0D corresponding to the distance vision, and also has a maximum value within the range of the defocus amount of -1.5D to -2.5D corresponding to the near vision. And, in any intraocular lens 1, the depth of focus of the distance vision and the near vision are each appropriately enlarged. From the above results, it can be seen that by setting the refractive power and the central angle of each of the distance vision region 20A, the near vision region 20B, and the intermediate region 20C within the range of the above-mentioned desired conditions, it is easy to appropriately obtain the distance vision and the near vision simultaneously in a state where the depth of focus is enlarged. In addition, it is known that by appropriately adjusting the refractive power and the central angle of each of the distance vision region 20A, the near vision region 20B, and the intermediate region 20C, the characteristics of the MTF of the intraocular lens 1 can be adjusted.

[0113] In Figure 7In the three intraocular lenses 1 (A, B, and C) shown in the MTF curves, the central angles of the distance zone 20A, near zone 20B, and intermediate zone 20C are aligned, and only the refractive power of each zone is changed. Specifically, in intraocular lens 1 A, the central angle of the distance zone 20A is set to 170 degrees and the refractive power is set to 0D; the central angle of the near zone 20B is set to 120 degrees and the refractive power is set to +3.50D; and the central angle of the intermediate zone 20C is set to 70 degrees and the refractive power is set to +2.00D. Intraocular lens 1 A is merely shown as a comparative example, and details will be described later. Intraocular lens 1 B, the central angle of the distance zone 20A is set to 170 degrees and the refractive power is set to 0D; the central angle of the near zone 20B is set to 120 degrees and the refractive power is set to +3.25D; and the central angle of the intermediate zone 20C is set to 70 degrees and the refractive power is set to +2.00D. In the intraocular lens 1 of C, the central angle of the distance zone 20A is set to 170 degrees and the refractive power is set to 0D, the central angle of the near zone 20B is set to 120 degrees and the refractive power is set to +3.00D, and the central angle of the intermediate zone 20C is set to 70 degrees and the refractive power is set to +2.0D. Figure 8 In the three intraocular lenses 1, A, B, and C, shown in the MTF curves, transition portions with a central angle of 20 degrees are actually provided between the respective zones. Therefore, excluding the angles of the transition portions, the central angle of the distance zone 20A of the three intraocular lenses 1, A, B, and C, is 150 degrees, the central angle of the near zone 20B is 100 degrees, and the central angle of the intermediate zone 20C is 50 degrees.

[0114] In the intraocular lenses 1 of B and C, the refractive power of each area is designed so that three maximum values (the maximum value for far use, the maximum value for near use, and the intermediate maximum value) of the MTF value of 0.10 or more appear in the MTF curve when the spatial frequency is 50lp / mm. The maximum value for far use is the maximum value within the range of the defocus amount that provides the wearer with a distant visual field (in the present embodiment, the range of the defocus amount is -1.0D to 1.0D). The maximum value for near use is the maximum value within the range of the defocus amount that provides the wearer with a distant visual field (in the present embodiment, the range of the defocus amount is a negative value compared to the maximum value for far use). The intermediate maximum value is the maximum value of the defocus amount within the range between the maximum value for far use and the maximum value for near use. In addition, Figure 8 The illustrated MTF curve is based on the cornea, and the closer the distance to the wearer's field of view is, the more negative the value becomes. However, in an MTF curve based on the surface of the intraocular lens 1, the closer the distance to the wearer's field of view is, the more positive the value becomes.

[0115] As described above, in the intraocular lens 1 of the present embodiment, a plurality of segmented regions (distant vision region 20A, near vision region 20B, and intermediate region 20C) having different refractive powers radially extend outward from the central portion of the lens portion. Therefore, unlike an intraocular lens in which a plurality of regions are arranged in concentric circles, even when the pupil of the wearer becomes smaller, light can easily pass through all the plurality of segmented regions. Further, by designing the intraocular lens 1 as exemplified in B and C such that there are three maxima (distant vision maximum, near vision maximum, and intermediate maximum) where the MTF value is 0.10 or more, unlike the intraocular lens A as a comparative example, in addition to distant and near distances, a good visual field can be easily obtained for an intermediate distance between the distant and near distances. That is, according to the intraocular lens 1 exemplified in B and C, regardless of the size of the pupil, a good visual field can be easily obtained not only for distant objects but also for near objects and the intermediate distance therebetween.

[0116] As Figure 8 shown, in the intraocular lens 1 of B and C, in the MTF curve at a spatial frequency of 50 lp / mm, the difference between the MTF value of the smaller one of the near vision maximum and the intermediate maximum and the minimum value existing between the near vision maximum and the intermediate maximum is designed to be 0.10 or less. Specifically, in the intraocular lens of B, the difference between the MTF value (about 0.21) of the smaller one of the near vision maximum and the intermediate maximum (the intermediate maximum in the intraocular lens 1 of B) and the minimum value (about 0.18) existing between the near vision maximum and the intermediate maximum is about 0.03 (≤0.10). In the intraocular lens of C, the difference between the MTF value (about 0.21) of the smaller one of the near vision maximum and the intermediate maximum (the near vision maximum in the intraocular lens 1 of C) and the minimum value (about 0.15) existing between the near vision maximum and the intermediate maximum is about 0.06 (≤0.10). In these cases, a distance with a deteriorated visual field is not likely to be included between the near vision distance and the intermediate distance. In other words, in the range from the near distance to the intermediate distance, a good visual field can be easily obtained as a whole. Therefore, regardless of the size of the pupil, a good visual field can be easily obtained not only for distant objects but also for near objects and the intermediate distance therebetween to an even greater extent.

[0117] Specifically, in the intraocular lens 1 of B and C, in the MTF curve at a spatial frequency of 50 lp / mm, the difference between the MTF value of the smaller one of the near vision maximum and the intermediate maximum and the minimum value existing between the near vision maximum and the intermediate maximum is designed to be 0.08 or less. In this case, a good visual field can be more easily obtained in the range from the near distance to the intermediate distance.

[0118] More specifically, in the intraocular lens 1 of type B, the difference between the MTF value of the smaller of the near maximum and the intermediate maximum in the MTF curve at a spatial frequency of 50 lp / mm and the minimum value between the near maximum and the intermediate maximum is designed to be 0.05 or less. In this case, it is easier to obtain a better visual field from near to intermediate distances.

[0119] like Figure 8 As shown, in the intraocular lens 1 of B, the refractive power and other characteristics of each region are designed so that the near maximum value is greater than the intermediate maximum value in the MTF curve at a spatial frequency of 50 lp / mm. By satisfying the condition that the near maximum value is greater than the intermediate maximum value, the contrast at the near distance, where visual recognition is more frequent, is increased. As a result, a better visual field is easily achieved.

[0120] like Figure 8 As shown, in intraocular lenses 1 of type B and C, the refractive power of each region is designed so that the difference between the near maximum and the intermediate maximum in the MTF curve at a spatial frequency of 50 lp / mm is 0.05 or less. Specifically, in intraocular lens 1 of type B, the difference between the near maximum and the intermediate maximum is approximately 0.02 (≤ 0.05). In intraocular lens 1 of type C, the difference between the near maximum and the intermediate maximum is approximately 0.03 (≤ 0.05). These conditions facilitate obtaining a good visual field at both near and intermediate distances. Consequently, regardless of pupil size, a better visual field is easily obtained not only at far distances but also at near and intermediate distances.

[0121] The inventors of the present invention conducted repeated trial and error and simulations, and as a result, discovered that by reducing the difference between the refractive power S of the near zone 20B and the refractive power M of the intermediate zone 20C to less than 1.4D, in addition to an increase in the intermediate maximum value in the MTF curve, a synergistic effect can be achieved in which the MTF value increases as a whole in the range from the intermediate distance to the near distance, as compared to the case where the difference is greater than 1.4D.

[0122] In fact, if Figure 8As shown, in the intraocular lens of A as a comparative example, the difference between the refractive power S of the near vision region 20B and the refractive power M of the intermediate region 20C is 1.4D (> 1.5D). In the intraocular lens of A, the MTF value at the intermediate distance is insufficient, and the MTF value is also insufficient as a whole in the range from the intermediate distance to the near distance. In contrast, in the intraocular lenses 1 of B and C, the difference between the refractive power S of the near vision region 20B and the refractive power M of the intermediate region 20C is less than 1.4D. Specifically, in the intraocular lens 1 of B, the difference between the refractive power S of the near vision region 20B and the refractive power M of the intermediate region 20C is 1.25D (≤ 1.4D). In the intraocular lens 1 of C, the difference between the refractive power S of the near vision region 20B and the refractive power M of the intermediate region 20C is 1.00D (≤ 1.4D). It can be seen that in the intraocular lenses 1 of B and C, compared with the intraocular lens of A, in addition to the rise of the intermediate maximum value in the MTF curve, a synergistic effect of the overall rise of the MTF value in the range from the intermediate distance to the near distance is also produced. In other words, in the intraocular lenses 1 of B and C, when the refractive power of the near vision region is set as S and the refractive power of the intermediate region is set as M, by simultaneously satisfying the conditions of S ≥ +2.75D and M < S ≤ (M + 1.4D), regardless of the size of the pupil, not only at a distance, but also the fields of view at the near and intermediate distances can be easily and well obtained.

[0123] In addition, as in the intraocular lenses 1 of B and C, the conditions of S ≥ +2.75D and M < S ≤ (M + 1.35D) can also be simultaneously satisfied. That is, the difference between the refractive power S of the near vision region and the refractive power M of the intermediate region can be 1.35D or less. In this case, it is easy to further obtain the effect of the rise of the intermediate maximum value in the MTF curve and the effect of the overall rise of the MTF value in the range from the intermediate distance to the near distance.

[0124] In addition, in the intraocular lens 1 of B, when the refractive power of the near vision region is set as S and the refractive power of the intermediate region is set as M, the conditions of S ≥ +2.75D and (M + 1.1D) ≤ S ≤ (M + 1.4D) are simultaneously satisfied. As described above, by making the difference between the refractive power S of the near vision region and the refractive power M of the intermediate region approach below 1.4D, a useful synergistic effect can be obtained. On the other hand, if the refractive power S of the near vision region and the refractive power M of the intermediate region are too close, the effect of the multifocal intraocular lens for well obtaining the fields of view at a distance, near, and intermediate distances is reduced. Therefore, by designing the intraocular lens 1 in such a way that the conditions of S ≥ +2.75D and (M + 1.1D) ≤ S ≤ (M + 1.4D) are simultaneously satisfied, regardless of the size of the pupil, not only at a distance, but also the fields of view at the near and intermediate distances can be further easily and well obtained by the multifocal effect. As described above, the value of "1.4D" in the above conditions can also be set as "1.35D".

[0125] Furthermore, the difference between the refractive power S of the near area and the refractive power M of the intermediate area may be greater than 1.15 D. In this case, it is easy to obtain a better visual field not only at far distances but also at near and intermediate distances due to the multifocal effect.

[0126] Reference Figure 8 , the MTF characteristics are described for the case where no transition portion is formed between the distance area and the near area and the case where a transition portion is formed. Figure 9 In the chart, Figure 9 and Figure 7 Similarly, the graph of shows an MTF curve when the spatial frequency is 50 lp / mm, with the defocus amount (amount of focus deviation, power deviation) as the horizontal axis and the MTF as the vertical axis.

[0127] exist Figure 8 , shows the MTF curves of an intraocular lens with no transition zone, i.e., no distance zone and near zone, and an intraocular lens with a transition zone, i.e., a lens with a transition zone. Specifically, in the intraocular lens with no transition zone, the center angle of the distance zone is set to 180 degrees, the refractive power is set to 0 D, and the center angle of the near zone is set to 180 degrees, the refractive power is set to +3.0 D. In the intraocular lens with a transition zone, the center angle of the distance zone is set to 90 degrees, the refractive power is set to 0 D, and the center angle of the near zone is set to 90 degrees, the refractive power is set to +3.0 D. Furthermore, in the intraocular lens with a transition zone, two transition zones with center angles of 90 degrees are formed between the distance zone and the near zone.

[0128] like Figure 9 As shown, in the intraocular lens with a transition portion, the maximum values of the MTF corresponding to distance vision and the maximum values of the MTF corresponding to near vision are closer to each other than in the intraocular lens without a transition portion. Furthermore, the intraocular lens with a transition portion exhibits a greater effect of extending the depth of focus than in the intraocular lens without a transition portion. As described above, it is clear that forming a transition portion in the lens portion of the intraocular lens can appropriately achieve the extended depth of focus (EDOF) effect of the multifocal intraocular lens.

[0129] (Cross-sectional area of lens)

[0130] The cross-sectional area of the lens portion 2 of the intraocular lens 1 of this embodiment will be described. Figure 9As described above, the intraocular lens of this embodiment is implanted into the patient's eye using the intraocular lens implantation device 100. Specifically, the intraocular lens 1 is moved forward along the ejection axis A within the passage of the intraocular lens implantation device 100 using the ejection member 310. When the intraocular lens 1 reaches the mouth 180, the front support portion 3A contacts the inner wall of the mouth 180, which is tapered (i.e., the passage area decreases as it moves forward), thereby changing the pre-determined travel direction D of the intraocular lens 1 (see FIG. 1 ). Figure 4 and Figure 1 ) is substantially consistent with the push-out axis A of the intraocular lens implantation device 100. Thereafter, the lens portion 2 of the intraocular lens 1 is folded smaller by contacting the inner wall of the tapered mouth portion 180.

[0131] like Figure 4 As shown in FIG. 1 , a virtual cross section in an arbitrary direction that satisfies the conditions of passing through the geometric center O of the lens portion 2 and being perpendicular to the lens surface of the lens portion 2 is assumed. Figure 5 As described above, in the intraocular lens 1 of this embodiment, the cross-sectional area of the lens portion 2 in the virtual cross section changes depending on the assumed direction of the virtual cross section.

[0132] When the intraocular lens 1 is folded by the mouth portion 180 of the intraocular lens implantation device 100, the ejection axis A (refer to Figure 5 and Figure 2 ) is referred to as the first section S1. As described above, when the intraocular lens 1 reaches the mouth 180, the pre-conceptual travel direction D of the intraocular lens 1 coincides with the push-out axis A. Therefore, the first section S1 can also be expressed as a pre-conceptual section perpendicular to the pre-conceptual travel direction D of the intraocular lens 1. In the intraocular lens 1 of this embodiment, the cross-sectional area of the lens portion 2 in the first section S1 is smaller than the cross-sectional area of the pre-conceptual sections in other directions. Therefore, when the intraocular lens 1 is pushed out into the passage of the mouth 180 at an appropriate angle relative to the push-out axis A, the maximum cross-sectional area of the lens portion 2 in the direction perpendicular to the push-out axis A (i.e., the cross-sectional area in the first section S1 at which the cross-sectional area of the lens portion 2 in the folded state reaches its maximum) becomes smaller. Consequently, the intraocular lens 1 of this embodiment can be folded compactly within the passage of the mouth 180.

[0133] The relationship between the first cross section S1 and the structure of the lens portion 2 will be further described. Figure 4As explained above, in the lens portion 2, the radius of curvature of the portion with greater refractive power is smaller than the radius of curvature of the portion with less refractive power. In other words, in the lens portion 2, the curve of the lens surface of the portion with greater refractive power is steeper than the curve of the lens surface of the portion with less refractive power. Here, it is optically undesirable to provide a step at the geometric center O of the lens portion 2, so the thickness of the lens portion at the geometric center O in the imaginary cross section is made uniform regardless of the direction of the imaginary cross section (see Figure 6 As a result, the thickness of the side surface (edge portion) of the lens portion 2 at a portion with greater refractive power (a portion where the curve of the lens surface is steep) is smaller than the thickness of the side surface of the lens portion 2 at a portion with less refractive power (a portion where the curve of the lens surface is gentle). In other words, the thickness of the lens portion 2 decreases as the refractive power increases.

[0134] Here, for an imaginary cross section in any direction in the lens portion 2, the total value of the refractive power on a line extending from the geometric center O along the imaginary cross section to the periphery on one side and the refractive power on a line extending from the geometric center O along the same imaginary plane to the periphery on the other side is calculated. Figure 6 In the example shown, the refractive power of the line LX1 extending from the geometric center O to the outer periphery of one side along the first section S1 is ( Figure 9 The refractive power OD of the distance vision area 20A shown in FIG. 1 and the refractive power of the line LY1 extending from the geometric center O along the first section S1 to the other side of the periphery ( Figure 5 The total value of the refractive power of the near zone 20B shown is +3.25D).

[0135] In the intraocular lens 1 of this embodiment, the lens portion 2 is designed so that the sum of the refractive powers along the two lines LX1 and LY1 along the first section S1 is greater than the sum of the refractive powers along the two lines along virtual sections in other directions. Therefore, the thickness of the lens portion 2 decreases as the refractive power increases. Consequently, the cross-sectional area of the lens portion 2 in the first section S1 is smaller than the cross-sectional area of the lens portion 2 in virtual sections in other directions. As a result, the cross-sectional area of the lens portion 2 in the first section S1 is appropriately reduced, making it easier for the intraocular lens 1 to be folded compactly within the passageway of the mouth portion 180.

[0136] In addition, the method of specifying the structure of the lens portion 2 in the first cross-section S1 can also be changed. For example, for an imaginary cross-section in any direction, the radius of curvature of the lens portion 2 on a line extending from the geometric center O along the imaginary cross-section to the outer periphery on one side (for example, the average value of the radius of curvature on the line, and the same applies hereinafter) and the radius of curvature of the lens portion 2 on a line extending from the geometric center O along the same imaginary cross-section to the outer periphery on the other side are calculated. In this case, the intraocular lens 1 can be designed such that the sum of the radii of curvature on two lines LX1 and LY1 along the first cross-section S1 is less than or equal to the sum of the radii of curvature on two lines in an imaginary cross-section in other directions. Even in this case, the cross-sectional area of the lens portion 2 in the first cross-section S1 is appropriately reduced.

[0137] Describe the relationship between the base ends 4 (4A, 4B) of the support portions 3 (3A, 3B) and the lens portion 2. As Figure 5 , Figure 1 , Figure 5 shown, the intraocular lens 1 of the present embodiment includes a pair of support portions 3 (3A, 3B). The pair of support portions 3 extend outward from different portions of the side surface (edge portion) of the lens portion 2. In order to stably support the lens portion 2 in the eye, it is preferable that the base ends 4 of the pair of support portions 3 are connected to the portion of the side surface of the lens portion 2 having a larger thickness. In addition, when the base end 4 of the support portion 3 is connected to the portion of the side surface of the lens portion 2 having a smaller thickness, when the support portion 3 is bent when the intraocular lens 1 is implanted into the eye, undesired deformation or breakage is likely to occur in the lens portion 2.

[0138] Here, as Figure 10 and Figure 5 shown, an imaginary cross-section in the direction passing through the base ends 4 of the pair of support portions 3 is defined as the second cross-section S2. In the intraocular lens 1 of the present embodiment, the cross-sectional area of the lens portion 2 in the second cross-section is greater than or equal to the cross-sectional area in an imaginary cross-section in other directions. As a result, the thickness of the portion of the side surface of the lens portion 2 connecting the base ends 4 of the pair of support portions 3 becomes larger. Therefore, the rigidity of the base ends 4 of the support portions 3 is ensured, and thus undesired deformation or breakage is less likely to occur, and the intraocular lens 1 can be more easily and appropriately disposed in the eye. In addition, since the amount of deformation of the pair of support portions 3 is also likely to be equal, the stability when the intraocular lens 1 is implanted into the eye is also likely to be improved.

[0139] Further describe the relationship between the second cross-section S2 and the structure of the lens portion 2. In the example shown in Figure 10 , the refractive power of the line LX2 extending from the geometric center O along the second cross-section S2 to the outer periphery on one side (the refractive power of the distance vision region 20A shown in Figure 10 ) and the refractive power of the line LY2 extending from the geometric center O along the second cross-section S2 to the outer periphery on the other side ( Figure 5The total refractive power of the intermediate region 20C shown is +2.0 D) is +2.0 D. In the intraocular lens 1 of this embodiment, the lens portion 2 is designed to be along the two lines LX2 and LY2 of the second cross section S2 (see Figure 5 ) is less than the sum of the refractive powers along two lines of imaginary cross-sections along other directions. Therefore, in the lens portion 2, the thickness increases as the area with lower refractive power increases. Therefore, the cross-sectional area of the lens portion 2 in the second cross-sectional area S2 is greater than the cross-sectional area of the lens portion 2 in imaginary cross-sections along other directions. As a result, the thickness of the side surface of the lens portion 2 connecting the base end portions 4 of the pair of support portions 3 increases.

[0140] Furthermore, the method for specifying the structure of the lens portion 2 in the second cross-section S2 may be modified. For example, the intraocular lens 1 may be designed so that the sum of the radii of curvature along the two lines LX2 and LY2 along the second cross-section S2 is greater than the sum of the radii of curvature along two lines of an imaginary cross-section along another direction. Even in this case, the thickness of the side surface of the lens portion 2 connecting the base end portions 4 of the pair of support portions 3 increases.

[0141] like Figure 10 As shown in FIG. 1 , in the lens portion of the intraocular lens 1 of this embodiment, a plurality of segmented regions 20 (20A, 20B, 20C) are formed on at least one of the front and back surfaces. The plurality of segmented regions 20 extend radially outward from the center of the lens portion 2 and have different refractive powers due to their different curvature radii. In the intraocular lens 1 of this embodiment, the plurality of segmented regions 20 (in Figure 5 In the example shown, the plurality of segmented regions 20 and transitional portions 21 are arranged in the lens portion 2 in such a manner that the cross-sectional area of the lens portion 2 in the first cross-section S1 is less than the cross-sectional area in the imaginary cross-section in other directions. Figure 5 Figure 5 In the example shown, multiple segmented regions 20 and transitional regions 21 are arranged within the lens portion 2 such that the cross-sectional area of the lens portion 2 in the second section S2 is greater than the cross-sectional area in imaginary cross-sections in other directions. Therefore, unlike intraocular lenses in which multiple regions are arranged concentrically, light passes through each of the multiple segmented regions 20 and converges on the retina even when the wearer's pupil is small. Furthermore, the multiple segmented regions 20 have different refractive powers due to their varying radii of curvature. Consequently, the amount of light scattered in undesirable directions is reduced compared to situations where microprisms are formed within the segmented regions. As a result, light reaching the retina is less likely to be lost, facilitating a better visual field. Furthermore, the intraocular lens 1 is folded compactly within the passageway of the mouth for implantation into the eye.

[0142] The technology disclosed in the above-described embodiment is merely an example. Therefore, the technology exemplified in the above-described embodiment can also be changed. First, the intraocular lens can also adopt only a part of the multiple technologies exemplified in the above-described embodiment. For example, it may be that the technology of reducing the cross-sectional area of the lens portion 2 in the first cross-section S1 is not adopted, and only the technology of forming three or more segmented regions 20 having different radii of curvature in the lens portion 2 is adopted. In this case, the intraocular lens can also be implanted into the eye without using the intraocular lens implantation device 100. In addition, three or more segmented regions may be formed in an intraocular lens that does not have a support portion. Even when three or more segmented regions are formed in an intraocular lens having a support portion, the number and shape of the support portions are not limited to those exemplified in the above-described embodiment.

[0143] In addition, it may be that the technology of forming three or more segmented regions 20 in the lens portion 2 is not adopted, and only the technology of reducing the cross-sectional area of the lens portion 2 in the first cross-section S1 is adopted. For example, the technology of reducing the cross-sectional area of the lens portion 2 in the first cross-section S1 can also be used for an aspheric intraocular lens for correcting the astigmatism of the wearer. In this case, in the aspheric intraocular lens, the intraocular lens can be designed such that the position of the first cross-section coincides with the steep meridian of the lens portion. In this case, the cross-sectional area of the lens portion in the first cross-section also appropriately becomes smaller.

[0144] In addition, in the above-described embodiment, by bringing the front support portion 3A of the intraocular lens 1 into contact with the inner wall of the tip-thin mouth portion 180, the assumed traveling direction D of the intraocular lens 1 substantially coincides with the pushing axis A of the intraocular lens implantation device 100. However, the method of making the traveling direction of the intraocular lens 1 substantially coincide with the pushing axis A of the intraocular lens implantation device 100 can also be changed. For example, a guide member or the like for making the traveling direction D of the intraocular lens 1 substantially coincide with the pushing axis A may be additionally provided.

[0145] In addition, it may be that the intraocular lens 1 having multiple segmented regions is designed in such a way that the conditions of S≥+2.75D and M<S≤(M + 1.4D) are satisfied regardless of whether the conditions of the MTF value exemplified in the above-described embodiment are satisfied. Even in this case, since the intraocular lens 1 is designed in such a way that the conditions of S≥+2.75D and M<S≤(M + 1.4D) are satisfied, regardless of the size of the pupil, not only at a distance, but also at near and intermediate distances, it is easier to obtain a better view.

Claims

1. An intraocular lens having a lens portion in a disc shape, characterized in that on at least one of the front surface and the rear surface of the lens portion, there are formed three or more segmented regions having different refractive powers from each other, a plurality of the segmented regions include a distance vision region with the lowest refractive power, a near vision region with the highest refractive power, and an intermediate region having a refractive power between the refractive power of the distance vision region and the refractive power of the near vision region, and the plurality of the segmented regions radially extend from the central portion of the lens portion toward the outside.

2. The intraocular lens according to claim 1, characterized in that the plurality of the segmented regions have different refractive powers due to different radii of curvature.

3. The intraocular lens according to claim 1 or 2, characterized in that a transition portion is formed between the plurality of the segmented regions of the lens portion, and the transition portion smoothly connects the ends of the pair of segmented regions by continuously changing the radius of curvature from the end of one of the pair of adjacent segmented regions to the end of the other segmented region.

4. The intraocular lens according to claim 3, characterized in that both the segmented region and the transition portion refract the light incident on the lens portion parallel to the optical axis of the lens portion toward a direction closer to the optical axis.

5. The intraocular lens according to claim 3 or 4, characterized in that the central angle of the transition portion extending from the central portion of the lens portion toward the outside is 5 degrees or more and 30 degrees or less.

6. The intraocular lens according to any one of claims 1 to 5, characterized in that among the central angles of the distance vision region, the near vision region, and the intermediate region extending from the central portion of the lens portion toward the outside, the central angle of the distance vision region is the largest, and the central angle of the intermediate region is the smallest.

7. The intraocular lens according to claim 6, characterized in that the central angle of the distance vision region is 140 degrees or more, the central angle of the near vision region is 90 degrees or more, the central angle of the intermediate region is 30 degrees or more.

8. The intraocular lens according to any one of claims 1 to 7, characterized in that the refractive power of the near vision region is +2.5 D or more and +4.0 D or less, the refractive power of the intermediate region is +1.0 D or more and +2.5 D or less.

9. The intraocular lens according to any one of claims 1 to 8, characterized in that a toric surface for correcting the astigmatism of the wearer is formed on at least one of the front surface and the rear surface of the lens portion.

10. The intraocular lens according to any one of claims 1 to 9, characterized in that the MTF curve at a spatial frequency of 50 lp / mm has an intermediate maximum value as a maximum value within the range between the distance vision maximum value and the near vision maximum value, the distance vision maximum value, the near vision maximum value, and the intermediate maximum value are each 0.10 or more.

11. The intraocular lens according to claim 10, characterized in that In the MTF curve at a spatial frequency of 50 lp / mm, the difference between the MTF value of the smaller one of the near maximum value and the intermediate maximum value and the minimum value existing between the near maximum value and the intermediate maximum value is 0.10 or less.

12. The intraocular lens according to claim 10 or 11, wherein in the MTF curve, the near maximum value is greater than the intermediate maximum value.

13. The intraocular lens according to any one of claims 10 to 12, wherein in the MTF curve at a spatial frequency of 50 lp / mm, the difference between the near maximum value and the intermediate maximum value is 0.05 or less.

14. The intraocular lens according to any one of claims 10 to 13, wherein when the refractive power of the near region is set to S and the refractive power of the intermediate region is set to M, the conditions of S≥+2.75D and M<S≤(M + 1.4D) are satisfied simultaneously.

15. The intraocular lens according to claims 10 to 13, wherein when the refractive power of the near region is set to S and the refractive power of the intermediate region is set to M, the conditions of S≥+2.75D and (M + 1.1D)≤S≤(M + 1.4D) are satisfied simultaneously.

16. The intraocular lens according to any one of claims 1 to 9, wherein when the refractive power of the near region is set to S and the refractive power of the intermediate region is set to M, the conditions of S≥+2.75D and M<S≤(M + 1.4D) are satisfied simultaneously.

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