Intraocular lens

Abstract

To provide an intraocular lens enabling a better visual field to be easily obtained.SOLUTION: An intraocular lens 1 comprises a disk-shaped lens portion 2. Three or more segment areas 20 having different refractive powers are formed at least in one of the front surface and rear surface of the lens portion 2. The plurality of segment areas 20 include a distant area 20A having the smallest refractive power, a close area 20B having the largest refractive power, and an intermediate area 20C having a refractive power between the refractive power of the distant area 20A and the refractive power of the close area 20B. The plurality of segment areas 20 are radially spread from the center portion of the lens portion 2 to the outside, and have different refractive powers due to different curvature radiuses.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to intraocular lenses that are inserted into the eye. [Background technology]

[0002] As an intraocular lens inserted into the eye, a multifocal intraocular lens is known that distributes and focuses incident light to a lens portion at a plurality of focal points. The multifocal intraocular lens can provide the wearer with a pseudo-accommodative power. Multifocal intraocular lenses include refractive lenses in which a plurality of regions with different refractive powers are formed in the optical portion, and diffractive lenses that utilize the diffraction phenomenon of light. The refractive multifocal intraocular lens has the advantage that there is less loss of light reaching the wearer's retina than the diffractive multifocal intraocular lens.

[0003] In conventional refractive multifocal intraocular lenses, a plurality of regions with different refractive powers are generally arranged concentrically in the lens portion. When the plurality of regions in the lens portion are arranged concentrically, if the pupil of the wearer becomes small, light passes only through the region arranged near the center among the plurality of regions arranged on the concentric circles, and light does not pass through the region arranged on the periphery, making it difficult to obtain the multifocal effect.

[0004] Therefore, in the multifocal intraocular lens described in Patent Document 1, the disk-shaped optical part is divided into multiple regions by boundaries extending from the periphery toward the geometric center, and a group of microprisms is formed in each divided region in a different pattern, thereby giving each region a different refractive power. By forming each region so that it is in contact with the optical axis of the lens part, the aim is to obtain a multifocal effect regardless of the size of the wearer's pupil. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2010-125292 A Summary of the Invention [Problem to be solved by the invention]

[0006] The multifocal intraocular lens described in Patent Document 1 has problems in that the microprism group is difficult to process and difficult to process with high precision, and the microprism group is easily damaged when inserted into the eye. Furthermore, there is also a problem in that a part of the light passing through the microprism group is scattered in an unintended direction, reducing the amount of light focused on the retina, making it difficult to obtain a good field of vision.

[0007] A typical object of the present disclosure is to provide an intraocular lens that facilitates better vision. [Means for solving the problem]

[0008] An intraocular lens provided by a typical embodiment of the present disclosure is an intraocular lens having a disk-shaped lens portion, and three or more segmental regions having different refractive powers are formed on at least one of the front and rear surfaces of the lens portion, the segmental regions including a distance region having the smallest refractive power, a near region having the largest refractive power, and an intermediate region having a refractive power between the refractive power of the distance region and the refractive power of the near region, and the segmental regions extend radially outward from a center of the lens portion and have different radii of curvature, thereby having different refractive powers.

[0009] The intraocular lens according to the present disclosure facilitates obtaining a better field of vision. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a plan view of an intraocular lens 1. [Diagram 2] FIG. 2 is a perspective view of the intraocular lens insertion instrument 100 as seen from diagonally above on the right. [Diagram 3] FIG. 2 is a perspective view of the plunger 300 as viewed from diagonally above on the right. [Figure 4]FIG. 2 is a schematic explanatory diagram showing a state in which the intraocular lens 1 has been appropriately moved and deformed. [Diagram 5] 1 is a plan view showing an example of an intraocular lens 1 in which a plurality of segmental regions 20 are formed. [Figure 6] 1 is a schematic comparison of cross sections of a distance region 20A and a near region 20B, the cross sections passing through the geometric center O of the lens portion 2 and perpendicular to the lens surface of the lens portion 2. FIG. [Figure 7] 1 is a diagram comparing MTF curves of four intraocular lenses 1 in which the refractive power and central angle of each of the distance region 20A, the near region 20B, and the intermediate region 20C are changed. [Figure 8] 1 is a diagram comparing the MTF curves of an intraocular lens 1 in which a transition portion is formed between the distance region and the near region and in which a transition portion is formed. [Figure 9] FIG. 6 is a diagram showing a line for calculating the total refractive power of the intraocular lens 1 shown in FIG. 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] <Summary> A first embodiment of an intraocular lens in the present disclosure will be described. The intraocular lens exemplified in the present disclosure includes a disk-shaped lens portion. At least one of the front and rear surfaces of the lens portion is formed with three or more segmented regions having different refractive powers. The multiple segmented regions include a distance region having the smallest refractive power, a near region having the largest refractive power, and an intermediate region having a refractive power between the refractive powers of the distance region and the near region. The multiple segmented regions extend radially outward from the center of the lens portion, and have different radii of curvature, thereby having different refractive powers.

[0012] In the intraocular lens exemplified in the present disclosure, a plurality of segmental regions with different refractive powers spread radially outward from the center of the lens portion. Therefore, unlike an intraocular lens in which a plurality of regions are arranged concentrically, even if the wearer's pupil becomes small, light can easily pass through all of the plurality of segmental regions. Furthermore, the plurality of segmental regions have different refractive powers due to their different radii of curvature. Therefore, compared to the case where a group of microprisms or the like is formed in the segmental regions, the amount of light scattered in unintended directions is reduced. As a result, light loss to the retina is less likely to occur, making it easier to obtain a better field of vision. In addition, it is easy to process with high precision, and there is a low possibility of breakage when inserted into the eye.

[0013] The multiple segmented regions may extend radially outward from one reference point in the center of the lens. In other words, the linear ends of each segmented region extending outward from the center of the lens may all pass through the same reference point. In this case, even if the wearer's pupil becomes small, the amount of light passing through each of the multiple segmented regions is more likely to be secured than when a certain region (e.g., a circular region) is separately formed in the center of the lens. As a result, the multifocal effect is more likely to be obtained regardless of the size of the wearer's pupil, and the wearer's field of vision is more likely to be improved.

[0014] The lens surface of each segmental region may be spherical or aspherical. The refractive power is approximately constant within each segmental region. In other words, when a transitional portion (described later) is provided on the lens surface, the refractive power changes within the transitional portion, whereas the refractive power is approximately constant within the segmental region.

[0015] A transitional section may be formed between the plurality of segmented regions in the lens section. The transitional section may smoothly connect the ends of the pair of segmented regions by continuously changing the radius of curvature from the end of one segmented region of a pair of adjacent segmented regions to the end of the other segmented region. If no transitional section is formed in the lens section, a step or the like may be formed at the boundary between the pair of adjacent segmented regions, and the step or the like may cause a phenomenon in which light is diffusely reflected by the step or the like and the field of view is deteriorated (e.g., a halo or glare). In contrast, by forming a transitional section between a pair of adjacent segmented regions, the effect of diffuse reflection of light due to the step or the like is less likely to occur. Furthermore, when a transitional section is formed in the lens section, the refractive power of each region in the transitional section smoothly transitions from the refractive power of one adjacent segmented region to the refractive power of the other segmented region. As a result, in addition to the refractive power of each segmented region, the lens section is also given a refractive power between the refractive powers of the segmented regions. Therefore, by forming a transition portion in the lens portion, the effect of the expanded depth of focus (EDOF) of the multifocal intraocular lens can be appropriately obtained.

[0016] Both the segmental region and the transitional portion may refract light that enters the lens portion parallel to the optical axis of the lens portion in a direction approaching 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, a better field of vision is more easily obtained. It is also possible to manufacture an intraocular lens without forming a transitional portion in the lens portion. Even in this case, a better field of vision is more easily obtained than when a group of microprisms or the like is formed in the segmental region.

[0017] The central angle of the transition portion that spreads outward from the center of the lens portion may be 5 degrees or more and 30 degrees or less. In this case, it becomes easier to appropriately obtain both the multifocal effect due to the multiple segmented regions and the focal depth extension effect.

[0018] The central angle of the transition portion may be 15 degrees or more and 20 degrees or less. In this case, the multifocal effect by the multiple segmented regions and the focal depth extension effect can be more appropriately obtained.

[0019] The central angles of the distance region, near region, and intermediate region, which extend outward from the center of the lens portion, may be the largest in the distance region and the smallest in the intermediate region. In this case, it becomes easier to appropriately obtain both distance vision by the distance region and near vision by the near region with an expanded depth of focus.

[0020] The central angle of the distance region may be 140 degrees or more, the central angle of the near region may be 90 degrees or more, and the central angle of the intermediate region may be 30 degrees or more. In this case, it becomes easier to appropriately obtain far vision by the distance region and near vision by the near region with both of the focal depths expanded.

[0021] The refractive power of the near zone may be +2.5 D or more and +4.0 D or less, and the refractive power of the intermediate zone may be +1.0 D or more and +2.5 D or less. In this case, it becomes easier to appropriately obtain both the multifocal effect of the multiple segment zones and the focal depth extension effect.

[0022] The refractive power of the near zone may be +3.0 D or more and +3.5 D or less, and the refractive power of the intermediate zone may be +1.5 D or more and +2.0 D or less. In this case, the multifocal effect and the focal depth extension effect can be more appropriately obtained.

[0023] At least one of the front and rear surfaces of the lens portion may be formed with a toric surface for correcting astigmatism of the wearer. In this case, an intraocular lens is provided that can provide both far vision and near vision as well as correct astigmatism of the wearer.

[0024] The multiple segmental regions may be formed on the front surface of the lens surface (i.e., the surface facing the front (cornea) of the eye when worn in the wearer's eye). In this case, the shape of the rear surface of the lens surface is more likely to be smooth, which makes it easier to prevent cells, etc. from getting between the rear surface of the lens surface and the posterior capsule of the eye and causing secondary cataracts. In addition, the multiple segmental regions and the toric surface may both be formed on the front surface of the lens surface. In this case, even when a toric surface is formed on the lens surface, the occurrence of secondary cataracts is more likely to be prevented. However, it is also possible to form at least one of the segmental regions and the toric surface on the rear surface of the lens surface. The surface on which the segmental regions are formed may be different from the surface on which the toric surface is formed.

[0025] A second aspect of the intraocular lens in the present disclosure will be described. The intraocular lens exemplified in the present disclosure is deformable and is inserted into the patient's eye from an insertion port at the front end through a passage inside the intraocular lens insertion device. The intraocular lens insertion device includes a pusher member and a nozzle. The pusher member pushes the intraocular lens forward by moving forward inside the passage along the pusher axis, which is the axis of the passage. The passage area of ​​the nozzle is formed to become smaller toward the front. The nozzle has an insertion port at the front end, and after folding the intraocular lens in the process of pushing the intraocular lens forward inside the passage by the pusher member, the nozzle ejects the intraocular lens from the insertion port. The intraocular lens includes a lens portion having a substantially disk shape. A cross section in any direction that passes through the geometric center of the lens portion and satisfies the condition of being perpendicular to the lens surface of the lens portion is assumed as a virtual cross section. In the intraocular lens of the present disclosure, the cross-sectional area of ​​the lens portion in the virtual cross section changes depending on the direction in which the virtual cross section is assumed. When the intraocular lens is folded by the nozzle, the cross-sectional area of ​​the lens portion in a virtual cross section (first cross section) perpendicular to the extrusion axis becomes equal to or smaller than the cross-sectional area in a virtual cross section in another direction.

[0026] When the intraocular lens of the present disclosure is extruded through the passage of the nozzle at an appropriate angle to the extrusion axis of the intraocular lens insertion tool, the maximum value of the cross-sectional area of ​​the lens portion in the direction perpendicular to the extrusion axis (i.e., the cross-sectional area of ​​the first cross section where the cross-sectional area of ​​the lens portion in the folded state is maximum) becomes small. Therefore, the intraocular lens of the present disclosure can be folded small within the passage of the nozzle.

[0027] The sum of the refractive power on a line extending from the geometric center to one outer periphery along the imaginary cross section and the refractive power on a line extending from the geometric center to the other outer periphery along the imaginary cross section is calculated for each imaginary cross section in any direction. In this case, the intraocular lens may be designed so that the sum of the refractive power on a pair of lines along the first cross section is equal to or greater than the sum of the refractive power on a pair of lines along the imaginary cross section in the other direction.

[0028] In the lens portion, the radius of curvature of the portion with the larger refractive power is smaller than the radius of curvature of the portion with the smaller refractive power. In other words, in the lens portion, the curve of the lens surface of the portion with the larger refractive power is steeper than the curve of the lens surface of the portion with the smaller refractive power. Here, since it is optically undesirable to provide a step at the geometric center of the lens portion, the thickness of the lens portion at the geometric center in the virtual cross section is made the same regardless of the direction of the assumed virtual cross section. As a result, the thickness of the lens portion side surface (edge ​​portion) at the portion with the larger refractive power (portion with the steeper curve of the lens surface) is smaller than the thickness of the lens portion side surface at the portion with the smaller refractive power (portion with the gentler curve of the lens surface). Therefore, the larger the sum of the refractive powers on the lines extending from the geometric center along the virtual cross section in both directions, the smaller the cross-sectional area of ​​the lens portion in the virtual cross section. Therefore, the intraocular lens is designed so that the sum of the refractive powers on the line along the first cross section is equal to or greater than the sum of the refractive powers on the line along the virtual cross section in the other direction, so that the cross-sectional area of ​​the lens portion in the first cross section is appropriately reduced. As a result, the intraocular lens is easily folded into a small size within the passage of the nozzle.

[0029] It is also possible to change the method of defining the configuration of the lens portion 2 in the first cross section. For example, the sum of the radius of curvature of the lens portion on a line extending from the geometric center along the virtual cross section to one outer periphery (for example, the average value of the radius of curvature on the line, etc. The same applies below) and the radius of curvature on a line extending from the geometric center along the virtual cross section to the other outer periphery is calculated for each virtual cross section in any direction. In this case, the intraocular lens may be designed so that the sum of the radius of curvature on the line along the first cross section is equal to or less than the sum of the radius of curvature on the line along the virtual cross section in the other direction. Even in this case, the cross-sectional area of ​​the lens portion in the first cross section is appropriately reduced.

[0030] Furthermore, when the intraocular lens is a toric intraocular lens that corrects the wearer's astigmatism, the lens portion has a strong meridian and a weak meridian. The strong meridian is a meridian that has a small radius of curvature and a maximum refractive power among any meridians. The weak meridian is a meridian that has a large radius of curvature and a minimum refractive power. In the case of a toric intraocular lens, the intraocular lens may be designed so that the position of the first cross section coincides with the strong meridian of the lens portion. In this case as well, the cross-sectional area of ​​the lens portion in the first cross section is appropriately reduced.

[0031] The intraocular lens may further include a pair of haptics. The pair of haptics extend outward from different positions on the side surface of the lens portion and support the lens portion inside the patient's eye. The intraocular lens may be designed such that a cross-sectional area of ​​the lens portion in a virtual cross section (second cross section) in a direction passing through the base end of each of the pair of haptics is equal to or greater than a cross-sectional area in a virtual cross section in another direction.

[0032] In order to stably support the lens part in the eye, it is desirable that the base end of each of the pair of support parts is connected to a thicker part of the side of the lens part. In addition, if the base end of the support part is connected to a thinner part of the side of the lens part, when the support part is bent during insertion of the intraocular lens into the eye, unintended deformation or damage is likely to occur in the base end of the support part and the lens part. Here, by designing the intraocular lens so that the cross-sectional area of ​​the lens part in the second cross section in the direction passing through the base end of each of the pair of support parts is equal to or greater than the cross-sectional area in the imaginary cross section in the other direction, the thickness of the part of the side of the lens part to which the base end of the pair of support parts is connected becomes large. As a result, the rigidity of the base end of the support part is ensured, so that unintended deformation or damage is unlikely to occur, and the intraocular lens is more easily installed in the eye. In addition, the deformation amount of the pair of support parts is also likely to be uniform, so that the stability of the intraocular lens during insertion into the eye is also likely to be improved.

[0033] The sum of the refractive power on a line extending from the geometric center along the virtual cross section to one outer periphery and the refractive power on a line extending from the geometric center along the virtual cross section to the other outer periphery is calculated for each virtual cross section in any direction. In this case, the intraocular lens may be designed so that the sum of the refractive power on the line along the second cross section is equal to or less than the sum of the refractive power on the line along the virtual cross section in the other direction.

[0034] As described above, the thickness of the lens part side (edge ​​part) in the part with low refractive power (part with gentle curve of the lens surface) is greater than the thickness of the lens part side in the part with high refractive power (part with steep curve of the lens surface). Therefore, by designing the intraocular lens so that the total value of the refractive power on the line along the second cross section is equal to or greater than the total value of the refractive power on the line along the imaginary cross section in the other direction, the thickness of the part of the lens part side where the base ends of the pair of support parts are connected becomes greater.

[0035] It is also possible to change the method of defining the direction of the second cross section. For example, the sum of the radius of curvature of the lens part on a line extending from the geometric center along the virtual cross section to one outer periphery (for example, the average value of the radius of curvature on the line, etc., the same applies below) and the radius of curvature on a line extending from the geometric center along the virtual cross section to the other outer periphery is calculated for each virtual cross section in any direction. In this case, the intraocular lens may be designed so that the sum of the radius of curvature on a pair of lines along the second cross section is equal to or less than the sum of the radius of curvature on a pair of lines along the virtual cross section in the other direction. Even in this case, the thickness of the part of the side surface of the lens part to which the base ends of the pair of support parts are connected becomes large.

[0036] In addition, the toric intraocular lens may be designed so that the position of the second cross section coincides with the weak meridian of the optic. In this case, the thickness of the side surface of the optic is increased at the portion where the base ends of the pair of support parts are connected.

[0037] A plurality of segmented regions may be formed on at least one of the front and rear surfaces of the lens portion. The plurality of segmented regions may extend radially outward from the center of the lens portion and have different radii of curvature, thereby having different refractive powers. The plurality of segmented regions may be arranged on the lens portion such that the cross-sectional area of ​​the lens portion in a first cross section is equal to or smaller than the cross-sectional area of ​​a virtual cross section in another direction.

[0038] In this case, unlike an intraocular lens in which multiple regions are arranged on concentric circles, even if the wearer's pupil becomes small, light passes through each of the multiple segmented regions and is focused on the retina. In addition, the multiple segmented regions have different radii of curvature and therefore different refractive powers. Therefore, compared to when a group of microprisms or the like is formed in the segmented regions, the amount of light scattered in unintended directions is reduced. As a result, there is less loss of light reaching the retina, making it easier to obtain a better field of vision. In addition, it is easy to process with high precision, and there is little possibility of breakage during insertion into the eye. Furthermore, the intraocular lens is folded small inside the nozzle passage and inserted into the eye.

[0039] 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., a toric intraocular lens, etc.) that does not have a plurality of segmental regions. In addition, both a plurality of segmental regions and a toric surface that corrects astigmatism in a wearer may be formed in the lens portion. Of the front and rear surfaces of the lens surface, the surface on which the segmental regions are formed and the surface on which the toric surface is formed may be the same surface or different surfaces.

[0040] <Embodiment> A typical embodiment of the present disclosure will be described below with reference to the drawings. An intraocular lens 1 of this embodiment is inserted into a patient's eye by an intraocular lens insertion instrument 100. In the following description, the side of the intraocular lens 1 that is inserted first into the eye by the intraocular lens insertion instrument 100 (the left side in FIG. 1 ) is referred to as the front of the intraocular lens 1.

[0041] (Schematic configuration of intraocular lens) With reference to FIG. 1, a schematic configuration of an intraocular lens 1 in this embodiment will be described. The intraocular lens 1 includes a lens portion 2 and a support portion 3. The intraocular lens 1 in this embodiment is a so-called one-piece type intraocular lens in which the lens portion 2 and the support portion 3 are integrally molded. However, at least a part of the technology exemplified in this disclosure can also be applied to a so-called three-piece type intraocular lens in which the lens portion 2 and the support portion 3 are formed of separate members. The intraocular lens 1 can be deformed. As the material of the intraocular lens 1, various soft materials can be used, such as simple substances such as BA (butyl acrylate) and HEMA (hydroxyethyl methacrylate), and composite materials of acrylic acid ester and methacrylic acid ester.

[0042] The lens portion 2 provides a predetermined refractive power to the eye of a wearer wearing the intraocular lens 1 (i.e., the patient's eye). The refractive power provided to the lens portion 2 will be described in detail later. The lens portion 2 is disc-shaped. The optical axis of the lens portion 2 illustrated in this embodiment passes through the geometric center O of the lens portion 2 and extends in a direction perpendicular to the lens surface of the lens portion 2 (up and down direction). However, the optical axis of the lens portion 2 does not have to coincide with the geometric center O of the lens portion.

[0043] The intraocular lens 1 of this embodiment includes a pair of support parts 3 (a front support part 3A and a rear support part 3B). The base ends 4 of the pair of support parts 3 (i.e., the base end part 4A of the front support part 3A and the base end part 4B of the rear support part 3B) are connected to different parts of the side surface of the outer periphery of the lens part 2 (in this embodiment, each of the diametrically opposite parts of the outer periphery of the disk-shaped lens part 2). When the intraocular lens 1 is worn in the patient's eye, the pair of support parts 3 support the lens part 2 in the patient's eye.

[0044] Although details will be described later, in this embodiment, a traveling direction D of the intraocular lens 1 is assumed beforehand when the intraocular lens 1 advances inside the passage of the nozzle 180 (see Figs. 2 and 4) of the intraocular lens insertion instrument 100. In other words, when the intraocular lens 1 advances inside the passage of the nozzle 180, the previously assumed traveling direction D of the intraocular lens 1 coincides with the extrusion axis A (see Figs. 2 and 4), which is the axis of the passage of the nozzle 180.

[0045] When the intraocular lens 1 is placed in the setting section 130 of the intraocular lens insertion instrument 100, the front support section 3A curves and extends from the side surface of the outer periphery of the lens section 2 toward the front of the intraocular lens insertion instrument 100 (see FIG. 4). In other words, the front support section 3A has a loop shape curved in the circumferential direction, and the tip of the front support section 3A is a free end. When the intraocular lens 1 is placed in the setting section 130 of the intraocular lens insertion instrument 100, the rear support section 3B curves and extends from the outer periphery of the lens section 2 toward the rear of the intraocular lens insertion instrument 100 (see FIG. 4). In other words, the rear support section 3B has a loop shape curved in the circumferential direction, and the tip of the rear support section 3B is also a free end.

[0046] (Intraocular lens insertion device) The intraocular lens insertion instrument 100 will be described. In the following description, the direction of the nozzle 180 side of the main body 101 in the intraocular lens insertion instrument 100 (the lower left side of the paper in FIG. 2) will be referred to as the front of the intraocular lens insertion instrument 100, and the direction of the pressing part 370 of the plunger 300 (the upper right side of the paper in FIG. 2) will be referred to as the rear of the intraocular lens insertion instrument 100. Furthermore, the upper side of the paper in FIG. 2 will be referred to as the upper side of the intraocular lens insertion instrument 100, the lower side of the paper in FIG. 2 will be referred to as the lower side of the intraocular lens insertion instrument 100, the lower right side of the paper in FIG. 2 will be referred to as the right side of the intraocular lens insertion instrument 100, and the upper left side of the paper in FIG. 2 will be referred to as the left side of the intraocular lens insertion instrument 100.

[0047] First, the overall configuration of the intraocular lens insertion instrument 100 of this embodiment will be described with reference to Fig. 2. As described above, the intraocular lens insertion instrument 100 is used to insert the deformable intraocular lens 1 into the eye. The intraocular lens insertion instrument 100 includes a main body 101 and a plunger 300. The main body 101 is substantially cylindrical, and the intraocular lens 1 is inserted into the eye through a passage inside the main body 101. The plunger 300 is rod-shaped, and can move in the front-rear direction through the passage inside the main body 101. The plunger 300 moves forward along an extrusion axis (axis of the passage) A to push out the intraocular lens 1 loaded inside the main body 101.

[0048] The main body 101 and the plunger 300 of this embodiment are made of a resin material. The intraocular lens insertion instrument 100 may be formed by molding, cutting by scraping out resin, or the like. By forming the intraocular lens insertion instrument 100 from a resin material, a user can easily dispose of the intraocular lens insertion instrument 100 after use.

[0049] In this embodiment, a lubricating coating is applied to the inner wall of the main body 101 in order to smoothly insert the adhesive soft intraocular lens 1 into the eye. Moreover, the intraocular lens insertion device 100 of this embodiment is formed to be colorless transparent or colorless translucent. Therefore, the user can easily visually check the deformation state of the intraocular lens 1 filled inside the intraocular lens insertion device 100 from the outside of the intraocular lens insertion device 100.

[0050] The main body 101 will be described with reference to Fig. 2. The main body 101 includes a tubular main body portion 110, an installation portion 130, and a nozzle (insertion portion) 180.

[0051] The main body tube 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. A protruding portion 111 to be gripped by a user is formed on the outer periphery of the main body tube portion 110 slightly forward of the rear end.

[0052] The installation section 130 is connected to the front end side of the main body tube section 110. The intraocular lens 1 is installed (loaded) in the installation section 130. In detail, the installation section 130 includes a holding section 160 and a setting section 170. The holding section 160 holds the intraocular lens 1 when the intraocular lens insertion device 100 is in a stored state. The setting section 170 is provided so as to be rotatable about the axis of the tip section. When the setting section 170 is rotated, the intraocular lens 1 held in the holding section 160 moves to a standby position where it can be pushed out by the plunger 300 and is positioned there.

[0053] The nozzle 180 is connected to the front end side of the installation part 130. The passage area in the nozzle 180 becomes smaller toward the front in order to deform the intraocular lens 1 into a smaller size in the process of pushing the intraocular lens 1 forward. In other words, a tapered internal space is formed in the nozzle 180. A cylindrical insertion part 182 with an obliquely cut tip is provided at the front end of the nozzle 180. The insertion part 182 is inserted into the eye. At the front end of the insertion part 182, an insertion port 183 is formed as an opening for discharging the intraocular lens 1 forward from the internal passage. The internal passage of the main body part 101 penetrates from the rear end of the main body tube part 110 to the insertion port 183 at the front end of the nozzle 180.

[0054] 3, a schematic configuration of the plunger 300 will be described. The plunger 300 of this embodiment includes a pusher member 310, a shaft base portion 350, and a pressing portion 370.

[0055] The pressing portion 370 is formed at the rear end of the plunger 300. The pressing portion 370 is a plate-shaped member extending in a direction perpendicular to the extrusion axis A (see FIG. 2). The pressing portion 370 comes into contact with the user's finger when the user pushes the plunger 300 forward.

[0056] The shaft base 350 is a rod-shaped member extending forward from the front end side of the pressing part 370. In this embodiment, the shaft base 350 is formed so that the cross section perpendicular to the extrusion axis A has a substantially H-shape. By inserting the shaft base 350 into the main body tube part 110, the cross section perpendicular to the extrusion axis A has a substantially rectangular shape, the circumferential rotation of the extrusion axis A of the plunger 300 relative to the main body part 101 is suppressed. When the plunger 300 moves forward and reaches a position where the insertion of the intraocular lens 1 into the eye is completed, the inclined surface at the lower front end of the shaft base 350 comes into contact with an inclined surface formed at a predetermined position of the main body part 101. As a result, the front end of the plunger 300 is prevented from excessively protruding from the insertion port 183 (see FIG. 2).

[0057] The pushing member 310 is a rod-shaped member, and extends forward from the front end of the shaft base 350 along the axial direction of the pushing axis A. The pushing member 310 is formed so that the cross section perpendicular to the pushing axis A has a substantially circular shape. The pushing member 310 has a thickness that allows it to pass through the insertion opening 183 of the main body 101. The pushing member 310 moves forward along the pushing axis A within the passage of the main body 101, pushing the intraocular lens 1 forward while folding it small, and discharging it from the insertion opening 183 into the eye.

[0058] With reference to Fig. 4, the movement and deformation state of the intraocular lens 1 when the intraocular lens 1 is inserted into the eye by the intraocular lens insertion instrument 10 of this embodiment will be described. First, the operator rotates the setting unit 170 (see Fig. 2) to move the intraocular lens 1 held by the holding unit 160 (see Fig. 2) of the installation unit 130 to a standby position where it can be pushed out by the plunger 300. Here, as shown in Fig. 4(a), the base end 4B of the rear support part 3B of the intraocular lens 1 held by the holding unit 160 is shifted to the left or right with respect to the push-out axis A.

[0059] Next, the operator injects a lubricant (viscoelastic material) into the installation portion 130 using a syringe or the like, and starts the forward movement of the plunger 300. As a result, as shown in FIG. 4(a), the pushing member 310 comes into contact with the rear support portion 3B of the intraocular lens 1.

[0060] When the plunger 300 is further pushed forward, the rear support part 3B is moved (bent) by the pushing member 310 in a direction approaching the lens part 2, as shown in Fig. 4(b). As a result, the rear support part 3B is deformed and moved upward above the lens part 2, and the tip of the rear support part 3B faces forward. The state shown in Fig. 4(b) is sometimes referred to as a state in which the rear support part 3B has been tacked.

[0061] When the plunger 300 is further pushed forward, the pushing member 310 comes into contact with the lens portion 2, and the entire intraocular lens 1 moves forward. As shown in FIG. 4(c), when the intraocular lens 1 reaches the nozzle 180, the front support portion 3A comes into contact with the tapered inner wall of the nozzle 180. As a result, the front support portion 3A deforms and moves upward on the lens portion 2, and the tip of the front support portion 3A faces backward. That is, tucking of the front support portion 3A is performed. Furthermore, as the front support portion 3A comes into contact with the tapered inner wall of the nozzle 180, the previously assumed traveling direction D of the intraocular lens 1 (see FIG. 1) approximately coincides with the pushing axis A of the intraocular lens insertion device 100.

[0062] As the plunger 300 is further pushed forward, the lens portion 2 of the intraocular lens 1 also comes into contact with the tapered inner wall of the nozzle 180. As a result, as shown in FIG. 4(d), the lens portion 2 of the intraocular lens 1 is folded into a small size.

[0063] As shown in Fig. 4(e), the intraocular lens 1 is folded smaller as it is pushed forward. Since the passage area of ​​the nozzle 180 becomes narrower toward the front, the load on the intraocular lens 1 may gradually increase. However, the intraocular lens 1 of this embodiment is designed to be more easily folded smaller by the nozzle 180. The details will be described later.

[0064] (Lens segment area) The segment regions 20 formed in the lens portion 2 of the intraocular lens 1 of this embodiment will be described. As shown in Fig. 5, in the intraocular lens 1 of this embodiment, three or more segment regions 20 (20A, 20B, 20C) are formed on at least one of the front surface and the rear surface of the disk-shaped lens portion 2.

[0065] The multiple segmental regions 20 have different refractive powers. In detail, the lens unit 2 of this embodiment is formed with a distance region 20A, a near region 20B, and an intermediate region 20C. The distance region 20A has the smallest refractive power among the multiple segmental regions 20. The near region 20B has the largest refractive power among the multiple segmental 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, the light passing through the distance region 20A, the near region 20B, and the intermediate region 20C in the lens unit 2 is focused on the wearer's retina, thereby obtaining a multifocal effect. In addition, in the present disclosure, each segmental region 20 is an area having approximately the same refractive power regardless of the part within the area.

[0066] When the lens portion 2 is viewed from a direction perpendicular to the lens surface, the multiple segmented regions 20 spread radially outward from the center of the lens portion 2. That is, each segmented region 20 is segmented by a boundary line that extends linearly from one point in the center of the lens portion 2 outward. Therefore, unlike an intraocular lens in which multiple regions are arranged concentrically, even if the wearer's pupil becomes small, light can easily pass through all of the multiple segmented regions 20. As a result, the multifocal effect can be easily obtained regardless of the size of the wearer's pupil. The boundary line of the segmented region 20 is not limited to a straight line, and may be a curve, or may be bent.

[0067] In detail, in the intraocular lens 1 of this embodiment, the lens portion 2 radially spreads outward from one reference point (in this embodiment, the geometric center O of the lens portion 2). That is, in each of the segmented regions 20, the linear boundary lines (ends) extending outward from the center of the lens portion 2 all pass through the same reference point. Therefore, even if the pupil of the wearer becomes small, the amount of light passing through each of the segmented regions 20 is more easily ensured than when a certain region (e.g., a circular region, etc.) is separately formed in the center of the lens portion 2. As a result, the multifocal effect is more easily obtained regardless of the size of the wearer's pupil, and the field of vision of the wearer is more easily improved. However, it is also possible to provide a certain region in the center of the lens portion 2. Even in this case, the multifocal effect is more easily obtained regardless of the size of the wearer's pupil than when a plurality of regions are arranged concentrically.

[0068] 6 is a schematic comparison of cross-sectional views of the distance region 20A and the near region 20B, which are cross-sectional views passing through the geometric center O of the lens portion 2 and perpendicular to the lens surface of the lens portion 2. As shown in FIG. 6, the multiple segment regions 20 formed in the intraocular lens 1 of this embodiment have different radii of curvature, and thus have different refractive powers. The lens surface of each segment region 20 may be spherical or aspheric. When the lens surface is aspheric, the term "radius of curvature" in the present disclosure may be interpreted as the radius of curvature of a sphere approximating the aspheric lens surface.

[0069] In the example shown in FIG. 6, the radius of curvature of the distance region 20A, which has a small refractive power, is larger than the radius of curvature of the near region 20B, which has a large refractive power. In other words, the curve of the lens surface of the distance region 20A, which has a small refractive power, is gentler than the curve of the lens surface of the near region 20B, which has a large refractive power. By changing 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 unintended directions is reduced compared to the case where the refractive power is changed by forming different micro prism groups or the like in each segmented region 20. As a result, the loss of light reaching the retina is less likely to occur, making it easier to obtain a better field of view. In addition, the intraocular lens 1 of this embodiment is easy to process with high precision, and is less likely to be damaged when inserted into the eye.

[0070] 6, 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 the portion with the greater refractive power (portion with a steeper curve of the lens surface) is smaller than the thickness of the side surface of the lens portion 2 at the portion with the smaller refractive power (portion with a gentler curve of the lens surface).

[0071] 5, when the lens portion 2 is viewed in a direction perpendicular to the lens surface, transition portions 21 (21A, 21B, 21C) are formed between a plurality of segment regions 20 in the lens portion 2. Each transition portion 21 smoothly connects the ends of the pair of segment regions 20 by continuously changing the radius of curvature from the end of one segment region 20 of a pair of adjacent segment regions 20 through the transition portion 21 to the end of the other segment region 20.

[0072] In the example shown in FIG. 5, the refractive power of the far region 20A is 0D, the refractive power of the near region 20B is +3.25D, and the refractive power of the intermediate region 20C is +2.0D. Therefore, in the transitional portion 21A formed between the far region 20A and the near region 20B, the refractive power changes smoothly from 0D to +3.25D as it approaches the end of the near region 20B side from the end of the far region 20A side. In the transitional portion 21B formed between the near region 20B and the intermediate region 20C, the refractive power changes smoothly from +3.25D to +2.0D as it approaches the end of the intermediate region 20C side from the end of the near region 20B side. In the transitional portion 21C formed between the intermediate region 20C and the far region 20A, the refractive power changes smoothly from +2.0D to 0D as it approaches the end of the far region 20A side from the end of the intermediate region 20C side.

[0073] If the transition portion 21 is not formed in the lens portion 2, a step or the like may occur at the boundary between a pair of adjacent segment regions 20, and the step or the like may cause a phenomenon in which light is diffusely reflected and the field of view is deteriorated (for example, a halo or glare). In contrast, by forming the transition portion 21 between a pair of adjacent segment regions 20, the effect of diffuse reflection of light due to the step or the like is less likely to occur. Furthermore, if the transition portion 21 is formed in the lens portion 2, the refractive power of each region in the transition portion 21 smoothly transitions from the refractive power of one adjacent segment region 20 to the refractive power of the other segment region 20. As a result, in addition to the refractive power of each segment region 20, the lens portion 2 is also given a refractive power between the refractive powers of the segment regions 20. Therefore, by forming the transition portion 21 in the lens portion 2, the effect of the expanded depth of focus (EDOF) of the multifocal intraocular lens can be appropriately obtained.

[0074] In the intraocular lens 1 of this embodiment, both the segmental region 20 and the transitional region 21 refract the light that enters the lens portion 2 parallel to the optical axis of the lens portion 2 in a direction approaching the optical axis. As a result, the amount of light that passes through the lens portion 2 and is lost without reaching the retina is reduced. Therefore, a better field of vision is easily obtained.

[0075] The central angle of each transition portion 21 that spreads outward from the center of the lens portion 2 (in this embodiment, the geometric center O, which is the reference point) is designed to be 5 degrees or more and 30 degrees or less. In this case, it is easier to appropriately obtain both the multifocal effect of the multiple segment regions 20 and the focal depth extension effect. It is more preferable that the central angle of each transition portion 21 is designed to be 15 degrees or more and 20 degrees or less. As an example, the central angles of the three transition portions 21 formed in the intraocular lens 1 illustrated in FIG. 5 are all designed to be 20 degrees. However, it goes without saying that when multiple transition portions 21 are formed in the lens portion 2, the central angles of each transition portion 21 do not have to be the same.

[0076] The central angles of the distance region 20A, the near region 20B, and the intermediate region 20C, which spread outward from the center of the lens portion 2, are designed so that the central angle CA of the distance region 20A is the largest and the central angle CC of the intermediate region 20CC is the smallest. In this case, it becomes easier to appropriately obtain both distance vision by the distance region 20A and near vision by the near region 20B with an expanded depth of focus.

[0077] In detail, the central angle CA of the distance region 20A is designed to be 140 degrees or more, the central angle CB of the near region 20B is designed to be 90 degrees or more, and the central angle CC of the intermediate region 20C is designed to be 30 degrees or more. In this case, it becomes easier to appropriately obtain far vision by the distance region 20A and near vision by the near region 20B with the focal depth expanded. As an example, in the intraocular lens 1 illustrated in FIG. 5, the central angle CA of the distance region 20A is designed to be 150 degrees, the central angle CB of the near region 20B is designed to be 100 degrees, and the central angle CC of the intermediate region 20C is designed to be 50 degrees.

[0078] In the intraocular lens 1 of this embodiment, the refractive power of the near region 20B is designed to be +2.5D or more and +4.0D or less, and the refractive power of the intermediate region 20C is designed to be +1.0D or more and +2.5D or less. In this case, it is easy to appropriately obtain both the multifocal effect and the focal depth extension effect due to the multiple segment regions 20. It is more preferable that the refractive power of the near region 20B is designed to be +3.0D or more and +3.5D or less, and the refractive power of the intermediate region 20C is designed to be +1.5D or more and +2.0D or less. As an example, in the intraocular lens 1 illustrated in FIG. 5, the refractive power of the far region 20A is designed to be 0D, the refractive power of the near region 20B is designed to be +3.25D, and the refractive power of the intermediate region 20C is designed to be +2.0D.

[0079] It is also possible to form a toric surface that corrects the astigmatism of the wearer on at least one of the front and rear surfaces of the lens part 2. In this case, an intraocular lens 1 that can obtain both far vision and near vision and can also correct the astigmatism of the wearer is provided. The plurality of segmental regions 20 may be formed on the front surface of the lens surface (i.e., the surface that faces the front side (cornea side) of the eye when worn in the eye of the wearer). In this case, the shape of the rear surface of the lens surface is likely to be smooth, so that it is easy to prevent cells and the like from entering between the rear surface of the lens surface and the posterior capsule of the eye and causing secondary cataracts. In addition, the plurality of segmental regions 20 and the toric surface may be formed on the front surface of the lens surface. In this case, even when a toric surface is formed on the lens surface, it is easy to prevent the occurrence of secondary cataracts. However, it is also possible to form at least one of the segmental regions 20 and the toric surface on the rear surface of the lens surface. The surface on which the segmental regions 20 are formed and the surface on which the toric surface is formed may be different.

[0080] With reference to Fig. 7, the characteristics of MTF when the refractive power and the central angle of each of the far vision area 20A, the near vision area 20B, and the intermediate vision area 20C are changed will be described. MTF (Modulation Transfer Function) is an index that indicates contrast. The graph in Fig. 7 shows an MTF curve at a spatial frequency of 50 lp / mm, with the horizontal axis representing the amount of defocus (amount of focus deviation, degree deviation) and the vertical axis representing MTF.

[0081] In the four intraocular lenses 1 of A, B, C, and D whose MTF curves are shown in Fig. 7, the refractive power and central angle of each of the distance region 20A, near region 20B, and intermediate region 20C are changed within the range of the above-mentioned desirable conditions. In detail, in the intraocular lens 1 of A, the central angle of the distance region 20A is 180 degrees, the refractive power is 0D, the central angle of the near region 20B is 120 degrees, the refractive power is +3.5D, and the central angle of the intermediate region 20C is 60 degrees, the refractive power is +1.75D. In the intraocular lens 1 of B, the central angle of the distance region 20A is 180 degrees, the refractive power is 0D, the central angle of the near region 20B is 120 degrees, the refractive power is +3.25D, and the central angle of the intermediate region 20C is 60 degrees, the refractive power is +1.75D. In the intraocular lens 1 of C, the central angle of the distance region 20A is 180 degrees, the refractive power is 0D, the central angle of the near region 20B is 120 degrees, the refractive power is +3.25D, and the central angle of the intermediate region 20C is 60 degrees, and the refractive power is +2.0D. In the intraocular lens 1 of D, the central angle of the distance region 20A is 170 degrees, the refractive power is 0D, the central angle of the near region 20B is 120 degrees, the refractive power is +3.25D, and the central angle of the intermediate region 20C is 70 degrees, and the refractive power is +2.0D. In the four intraocular lenses 1 of A, B, C, and D whose MTF curves are shown in Figure 7, a transition portion with a central angle of 5 degrees is actually provided between each region.

[0082] As shown in FIG. 7, in each of the four intraocular lenses 1 A, B, C, and D, the MTF has a maximum value near the defocus amount 0D corresponding to far vision, and also has a maximum value in the range of defocus amounts -1.5D to -2.5D corresponding to near vision. Furthermore, in each intraocular lens 1, the focal depth is appropriately expanded for both far vision and near vision. From the above results, it can be seen that by setting the refractive power and central angle of each of the far vision region 20A, the near vision region 20B, and the intermediate vision region 20C within the range of the above-mentioned desirable conditions, it is easy to appropriately obtain both far vision and near vision with the focal depth expanded. It can also be seen that the MTF characteristics of the intraocular lens 1 can be adjusted by appropriately adjusting the refractive power and central angle of each of the far vision region 20A, the near vision region 20B, and the intermediate vision region 20C.

[0083] The MTF characteristics when a transition area is formed and when a transition area is not formed between the distance area and the near area will be described with reference to Fig. 8. In the graph of Fig. 8, as in the graph of Fig. 7, the horizontal axis represents the amount of defocus (amount of focus deviation, deviation in power) and the vertical axis represents the MTF, and the MTF curve is shown at a spatial frequency of 50 lp / mm.

[0084] FIG. 8 shows the MTF curve of an intraocular lens without a transition between the distance and near regions, and with a transition between the distance and near regions. In detail, the intraocular lens without a transition has a central angle of 180 degrees and a refractive power of 0D in the distance region, and a central angle of 180 degrees and a refractive power of +3.0D in the near region. The intraocular lens with a transition has a central angle of 90 degrees and a refractive power of 0D in the distance region, and a central angle of 90 degrees and a refractive power of +3.0D in the near region. The intraocular lens with a transition has two transitions between the distance and near regions, each with a central angle of 90 degrees.

[0085] As shown in Figure 8, in the intraocular lens with a "transitional section", the MTF maximum value corresponding to distance vision and the MTF maximum value corresponding to near vision are closer to each other than in the intraocular lens without a transitional section. In addition, the intraocular lens with a "transitional section" has an improved effect of expanding the depth of focus compared to the intraocular lens without a transitional section. As described above, it can be seen that by forming a transitional section in the lens section of the intraocular lens, the effect of the extended depth of focus (EDOF) of the multifocal intraocular lens can be appropriately obtained.

[0086] (Cross-sectional area of ​​lens part) The cross-sectional area of ​​the lens portion 2 of the intraocular lens 1 of this embodiment will be described. As described with reference to FIG. 4, the intraocular lens of this embodiment is inserted into the patient's eye by the intraocular lens insertion instrument 100. In detail, the intraocular lens 1 is moved forward along the extrusion axis A in the passage of the intraocular lens insertion instrument 100 by the pushing member 310. When the intraocular lens 1 reaches the nozzle 180, the front support part 3A comes into contact with the inner wall of the nozzle 180, which is tapered (i.e., the passage area becomes smaller toward the front), and the previously assumed traveling direction D of the intraocular lens 1 (see FIG. 1 and FIG. 4) is approximately aligned with the extrusion axis A of the intraocular lens insertion instrument 100. Thereafter, the lens portion 2 of the intraocular lens 1 comes into contact with the inner wall of the nozzle 180, which is tapered, and is folded small.

[0087] As shown in Fig. 5, a virtual cross section is assumed in any direction that passes through the geometric center O of the lenticular portion 2 and is perpendicular to the lens surface of the lenticular portion 2. The first cross section S1 and the second cross section S2 shown in Fig. 5 are examples of multiple assumed virtual cross sections. As described above, in the intraocular lens 1 of this embodiment, the cross-sectional area of ​​the lenticular portion 2 in the virtual cross section changes depending on the direction in which the virtual cross section is assumed.

[0088] When the intraocular lens 1 is folded by the nozzle 180 of the intraocular lens insertion instrument 100, a virtual cross section in a direction perpendicular to the extrusion axis A (see Figs. 2 and 4) of the intraocular lens insertion instrument 100 is defined as a first cross section S1. As described above, when the intraocular lens 1 reaches the nozzle 180, the pre-assumed traveling direction D of the intraocular lens 1 coincides with the extrusion axis A. Therefore, the first cross section S1 can also be expressed as a virtual cross section perpendicular to the pre-assumed traveling 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 cross section S1 is equal to or smaller than the cross-sectional area in the virtual cross section in the other direction. Therefore, when the intraocular lens 1 is extruded through the passage of the nozzle 180 at an appropriate angle to the extrusion axis A, the maximum value of the cross-sectional area of ​​the lens portion 2 in the direction perpendicular to the extrusion axis A (i.e., the cross-sectional area in the first cross section S1 where the cross-sectional area of ​​the lens portion 2 in the folded state is maximum) becomes small. Therefore, the intraocular lens 1 of this embodiment can be folded compactly within the passage of the nozzle 180.

[0089] The relationship between the first cross section S1 and the configuration of the lens unit 2 will be further described. As described with reference to FIG. 6, in the lens unit 2, the radius of curvature of the portion with the greater refractive power is smaller than the radius of curvature of the portion with the less refractive power. In other words, in the lens unit 2, the curve of the lens surface of the portion with the greater refractive power is steeper than the curve of the lens surface of the portion with the less refractive power. Here, since it is optically undesirable to provide a step at the geometric center O of the lens unit 2, the thickness of the lens unit at the geometric center O in the virtual cross section is made the same regardless of the direction of the assumed virtual cross section (see FIG. 6). As a result, the thickness of the side surface (edge ​​portion) of the lens unit 2 at the portion with the greater refractive power (portion with the steeper curve of the lens surface) is smaller than the thickness of the side surface of the lens unit 2 at the portion with the less refractive power (portion with the gentler curve of the lens surface). In other words, in the lens unit 2, the thickness becomes smaller as the portion with the greater refractive power becomes larger.

[0090] Here, in the lens part 2, the sum of the refractive power on the line extending from the geometric center O along the virtual cross section to one outer periphery and the refractive power on the line extending from the geometric center O along the same virtual plane to the other outer periphery is calculated for the virtual cross section in any direction. For example, in the example shown in Fig. 9, the sum of the refractive power of the line LX1 extending from the geometric center O along the first cross section S1 to one outer periphery (refractive power 0D of the distance area 20A shown in Fig. 5) and the refractive power of the line LY1 extending from the geometric center O along the first cross section S1 to the other outer periphery (refractive power +3.25D of the near area 20B shown in Fig. 5) is +3.25D.

[0091] In the intraocular lens 1 of this embodiment, the lens portion 2 is designed so that the sum of the refractive powers on two lines LX1, LY1 along the first cross section S1 is equal to or greater than the sum of the refractive powers on two lines along imaginary cross sections in other directions. Therefore, the thickness of the lens portion 2 decreases as the refractive power increases, and the cross-sectional area of ​​the lens portion 2 in the first cross section S1 is equal to or smaller than the cross-sectional area of ​​the lens portion 2 in imaginary cross sections in other directions. As a result, the cross-sectional area of ​​the lens portion 2 in the first cross section S1 is appropriately reduced, and the intraocular lens 1 is easily folded small within the passage of the nozzle 180.

[0092] The method of defining the configuration of the lens portion 2 in the first cross section S1 may be changed. For example, the sum of the radius of curvature of the lens portion 2 on a line extending from the geometric center O along the virtual cross section to one outer periphery (for example, the average value of the radius of curvature on the line, etc., the same applies below) and the radius of curvature on a line extending from the geometric center O along the same virtual cross section to the other outer periphery is calculated for each virtual cross section in any direction. In this case, the intraocular lens 1 may be designed so that the sum of the radius of curvature on two lines LX1 and LY1 along the first cross section S1 is equal to or smaller than the sum of the radius of curvature on two lines along the virtual cross section in the other direction. Even in this case, the cross-sectional area of ​​the lens portion 2 in the first cross section S1 is appropriately reduced.

[0093] The relationship between the base ends 4 (4A, 4B) of the support parts 3 (3A, 3B) and the lens part 2 will be described. As shown in Figs. 1, 5, and 9, the intraocular lens 1 of this embodiment includes a pair of support parts 3 (3A, 3B). The pair of support parts 3 extend outward from different positions on the side (edge) of the lens part 2. It is desirable that the base ends 4 of each of the pair of support parts 3 are connected to a thicker part of the side of the lens part 2 in order to stably support the lens part 2 inside the eye. Furthermore, if the base ends 4 of the support parts 3 are connected to a thinner part of the side of the lens part 2, unintended deformation or damage is likely to occur in the lens part 2 when the support parts 3 are bent during insertion of the intraocular lens 1 into the eye.

[0094] Here, as shown in Fig. 5 and Fig. 9, a virtual section in a direction passing through each of the base ends 4 of the pair of support parts 3 is defined as a second section S2. In the intraocular lens 1 of this embodiment, the cross-sectional area of ​​the lens part 2 in the second section is equal to or larger than the cross-sectional area in the virtual section in the other direction. As a result, the thickness of the part of the side surface of the lens part 2 to which the base ends 4 of the pair of support parts 3 are connected is increased. Therefore, the rigidity of the base ends 4 of the support parts 3 is ensured, so that unintended deformation or breakage is less likely to occur, and the intraocular lens 1 is more easily installed in the eye. In addition, the deformation amount of the pair of support parts 3 is more easily uniform, so that the stability of the intraocular lens 1 when inserted into the eye is also more easily improved.

[0095] The relationship between the second cross section S2 and the configuration of the lens portion 2 will be further described. In the example shown in FIG. 9, the sum of the refractive power of the line LX2 extending from the geometric center O along the second cross section S2 to one outer periphery (refractive power 0D of the distance area 20A shown in FIG. 5) and the refractive power of the line LY2 extending from the geometric center O along the second cross section S2 to the other outer periphery (refractive power +2.0D of the intermediate area 20C shown in FIG. 5) is +2.0D. In the intraocular lens 1 of this embodiment, the lens portion 2 is designed so that the sum of the refractive powers on the two lines LX2, LY2 (see FIG. 9) along the second cross section S2 is equal to or less than the sum of the refractive powers on the two lines along the virtual cross section in the other direction. Therefore, the thickness of the lens portion 2 increases as the refractive power decreases, so that the cross-sectional area of ​​the lens portion 2 in the second cross section S2 is equal to or greater than the cross-sectional area of ​​the lens portion 2 in the virtual cross section in the other direction. As a result, the thickness of the portion of the side surface of the lens portion 2 to which the base ends 4 of the pair of support portions 3 are connected becomes large.

[0096] The method of defining the configuration of the lens portion 2 in the second cross section S2 may be changed. For example, the intraocular lens 1 may be designed so that the sum of the radii of curvature on two lines LX2, LY2 along the second cross section S2 is equal to or greater than the sum of the radii of curvature on two lines along a virtual cross section in another direction. Even in this case, the thickness of the portion of the side surface of the lens portion 2 to which the base ends 4 of the pair of support portions 3 are connected becomes large.

[0097] As shown in FIG. 5, the lens portion of the intraocular lens 1 of this embodiment has a plurality of segment regions 20 (20A, 20B, 20C) formed on at least one of the front surface and the rear surface. The plurality of segment regions 20 spread radially outward from the center of the lens portion 2, and have different radii of curvature, thereby having different refractive powers. In the intraocular lens 1 of this embodiment, the plurality of segment regions 20 (in the example shown in FIG. 5, the plurality of segment regions 20 and the transition portion 21) are arranged in the lens portion 2 so that the cross-sectional area of ​​the lens portion 2 in the first cross section S1 is equal to or smaller than the cross-sectional area in the imaginary cross section in the other direction. In addition, the plurality of segment regions 20 (in the example shown in FIG. 5, the plurality of segment regions 20 and the transition portion 21) are arranged in the lens portion 2 so that the cross-sectional area of ​​the lens portion 2 in the second cross section S2 is equal to or larger than the cross-sectional area in the imaginary cross section in the other direction. Therefore, unlike an intraocular lens in which multiple regions are arranged on concentric circles, even if the wearer's pupil becomes small, light passes through each of the multiple segmented regions 20 and is focused on the retina. In addition, the multiple segmented regions 20 have different radii of curvature and therefore different refractive powers. Therefore, compared to a case in which a group of microprisms or the like is formed in the segmented regions, the amount of light scattered in unintended directions is reduced. As a result, loss of light reaching the retina is less likely to occur, making it easier to obtain a better field of vision. Furthermore, the intraocular lens 1 is folded small in the passage of the nozzle and inserted into the eye.

[0098] The techniques disclosed in the above embodiments are merely examples. Therefore, it is possible to change the techniques exemplified in the above embodiments. First, it is possible to adopt only a part of the techniques exemplified in the above embodiments to the intraocular lens. For example, it is possible to adopt only a technique for forming three or more segmented regions 20 having different radii of curvature in the lens portion 2 without adopting a technique for reducing the cross-sectional area of ​​the lens portion 2 in the first cross section S1. In this case, the intraocular lens may be inserted into the eye without using the intraocular lens insertion instrument 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 that has a support portion, the number and shape of the support portion are not limited to those exemplified in the above embodiments.

[0099] It is also possible to adopt only the technique of reducing the cross-sectional area of ​​the lens portion 2 at the first cross section S1 without adopting the technique of forming three or more segment regions 20 in the lens portion 2. For example, the technique of reducing the cross-sectional area of ​​the lens portion 2 at the first cross section S1 can be adopted in a toric intraocular lens that corrects the astigmatism of a wearer. In this case, the toric intraocular lens may be designed so that the position of the first cross section coincides with the steepest meridian of the lens portion. In this case as well, the cross-sectional area of ​​the lens portion at the first cross section is appropriately reduced.

[0100] Furthermore, in the above embodiment, the front support part 3A of the intraocular lens 1 comes into contact with the tapered inner wall of the nozzle 180, so that the pre-determined traveling direction D of the intraocular lens 1 approximately coincides with the extrusion axis A of the intraocular lens insertion instrument 100. However, it is also possible to change the method of approximately aligning the traveling direction of the intraocular lens 1 with the extrusion axis A of the intraocular lens insertion instrument 100. For example, a guide or the like for approximately aligning the traveling direction D of the intraocular lens 1 with the extrusion axis A may be provided separately. [Explanation of symbols]

[0101] 1. Intraocular Lenses 2 Lens section 3 Support part 4 Proximal end 20 segment areas 20A distance area 20B Near field 20C intermediate area 21 (21A, 21B, 21C) Transition section 100 Intraocular lens insertion device 180 Nozzle 183 Insertion port A Extrusion shaft D Direction of travel O geometric center S1 1st section S2 2nd cross section

Claims

1. An intraocular lens having a disc-shaped lens portion, Three or more segmented regions having different refractive powers are formed on at least one of the front and rear surfaces of the lens portion, The plurality of segmental regions include: a distance area with the smallest refractive power; The near area has the greatest refractive power, an intermediate area having a refractive power between the refractive power of the distance area and the refractive power of the near area; Including, An intraocular lens characterized in that the multiple segmental regions extend radially outward from the center of the lens portion and have different radii of curvature, thereby having different refractive powers.

2. 10. The intraocular lens of claim 1, An intraocular lens characterized in that between the multiple segmental regions in the lens portion, a transition portion is formed that smoothly connects the ends of the pair of segmental regions, with the radius of curvature changing continuously from the end of one of the segmental regions of a pair of adjacent segmental regions to the end of the other segmental region.

3. The intraocular lens according to claim 2, An intraocular lens characterized in that both the segmental region and the transitional portion refract light that enters the lens portion parallel to the optical axis of the lens portion in a direction approaching the optical axis.

4. 10. The intraocular lens of claim 1, An intraocular lens characterized in that the central angles of the distance region, the near region, and the intermediate region, which extend outward from the central portion of the lens portion, are such that the central angle of the distance region is the largest and the central angle of the intermediate region is the smallest.

5. 10. The intraocular lens of claim 1, the refractive power of the near vision area is equal to or greater than +2.5D and equal to or less than +4.0D, An intraocular lens characterized in that the refractive power of the intermediate region is +1.0D or more and +2.5D or less.

6. 10. The intraocular lens of claim 1, An intraocular lens characterized in that a toric surface for correcting the wearer's astigmatism is formed on at least one of the front and rear surfaces of the lens portion.

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