Intraocular lens

Abstract

Provided is an intraocular lens capable of suppressing the amount of light that cannot be recognized by a wearer among light that has passed through a lens portion and appropriately expanding a depth of focus. A first region is a circular region located at the centermost. For the first region, a fixed first refractive power is imparted regardless of the distance from the axis. A second region is an annular region that is located outside the first region and that is contiguous to the first region. In the second region, the refractive power increases or decreases from the first refractive power as the distance from the axis becomes farther. An outer region is an annular region located at a position farther outside than the second region. The outer region is imparted with a reference refractive power for focusing on a distant place. An MTF curve at a spatial frequency of 50 lp / mm with respect to light that has passed through a region centered on the axis of the lens portion and having a radius of 1.5 mm has one maximum value and the number of minimum values is 0 in a range of a defocus amount of -0.5 D to 0.5 D.

Description

Technical Field

[0001] This disclosure relates to an intraocular lens that is implanted into the eye. Background Technology

[0002] As intraocular lenses implanted inside the eye, there are known intraocular lenses that converge incident light incident toward the lens portion to a single focal point. Compared to intraocular lenses that converge incident light separately to multiple focal points, intraocular lenses that converge incident light to a single focal point make it easier to identify objects with high-resolution vision.

[0003] Furthermore, regarding intraocular lenses, techniques have been proposed for achieving adequate resolution even when the focal point deviates to a certain extent. For example, in the intraocular lens described in Patent Document 1, the focal depth is increased by making at least one surface of the lens portion aspherical, thereby suppressing the reduction in resolution when the focal point deviates.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2004-121433 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] The first issue will now be explained. As a result of various simulations and studies, it is known that if the method for increasing the focal depth of the intraocular lens is inappropriate, an increase in the amount of light passing through the lens and reaching the retina becomes unrecognizable to the wearer. If the amount of unrecognizable light increases, a good field of vision becomes difficult to obtain. Therefore, it is desirable to increase the focal depth of the intraocular lens using an appropriate method.

[0009] The second point will now be explained. As a result of various simulations and studies, it is known that a good field of vision is difficult to obtain if the method for increasing the focal depth of the intraocular lens is inappropriate. For example, methods to increase the focal depth by applying different refractive powers to the peripheral and central portions of the lens have been considered. However, the human pupil varies in radius from approximately 1 mm to approximately 8 mm. In methods that apply different refractive powers to the peripheral and central portions of the lens, if the wearer's pupil becomes smaller, the proportion of light passing through the peripheral region of the lens and reaching the retina decreases compared to a larger pupil. Therefore, when the pupil is smaller, it is difficult to achieve a good field of vision corresponding to the refractive power of the peripheral portion of the lens.

[0010] One of the typical objectives of this disclosure is to provide an intraocular lens capable of suppressing the amount of light in the light passing through the lens portion that is not perceptible to the wearer and appropriately increasing the depth of focus. Another typical objective of this disclosure is to provide an intraocular lens that readily provides a good field of view regardless of changes in the wearer's pupil size.

[0011] Solution for solving the problem

[0012] The intraocular lens provided in a typical embodiment of this disclosure is an intraocular lens having a lens portion, wherein a plurality of circular or annular regions are arranged concentrically around the axis of the lens portion. The plurality of regions include: a first region, which is a circular region located at the very center, the first region being given a fixed first refractive power regardless of distance from the axis; a second region, an annular region adjacent to the first region outside the first region, the second region being a region whose refractive power increases or decreases from the first refractive power as the distance from the axis increases; and an outer region, an annular region located further outward than the second region, the outer region being given a reference refractive power for focusing at a distance. The modulation transfer function curve at a spatial frequency of 50 lp / mm, relating to light passing through a region centered on the axis of the lens portion and with a radius of 1.5 mm, has a maximum value and zero minimum values ​​within a defocus range of -0.5D to 0.5D.

[0013] Alternatively, the area of ​​the second region may be within ±50% of the area of ​​the first region.

[0014] Alternatively, the area of ​​each of the first region and the second region can be 0.6 mm. 2 above.

[0015] Alternatively, the first refractive power imparted to the first region may be a strong refractive power, which is stronger than the reference refractive power. Alternatively, in the second region, the refractive power decreases from the strong refractive power in the first region as the distance from the axis increases.

[0016] Alternatively, the plurality of regions may further include: a third annular region adjacent to the second region on the outer side and endowed with the reference refractive power; a fourth annular region adjacent to the third region on the outer side; a fifth annular region adjacent to the fourth region on the outer side and endowed with the strong refractive power; and a sixth annular region adjacent to the fifth region on the outer side and on the inner side of the outer region. Alternatively, in the fourth region, the refractive power increases from the reference refractive power in the third region towards the strong refractive power in the fifth region as the distance from the axis increases. Alternatively, in the sixth region, the refractive power decreases from the strong refractive power in the fifth region towards the reference refractive power in the outer region as the distance from the axis increases.

[0017] Alternatively, at least a portion of the fourth region, the first region, the second region, and the third region may be arranged within a region centered on the axis of the lens portion and having a radius of 1.5 mm.

[0018] Alternatively, at least a portion of the third region, the first region, and the second region may be disposed within a region centered on the axis of the lens portion and having a radius of 1.0 mm.

[0019] Alternatively, at least a portion of the sixth region, the first region, the second region, the third region, the fourth region, and the fifth region may be arranged within a region centered on the axis of the lens portion and having a radius of 1.5 mm.

[0020] Alternatively, the plurality of regions may further include: a third annular region adjacent to the second region on the outside, and endowed with a third refractive power different from the first refractive power; and a fourth annular region adjacent to the third region on the outside. Alternatively, the first refractive power endowed to the first region may be the reference refractive power. Alternatively, the third refractive power endowed to the third region may be a strong refractive power stronger than the reference refractive power. Alternatively, in the second region, as the distance from the axis increases, the refractive power increases from the reference refractive power in the first region to the strong refractive power in the third region. Alternatively, the outer region may be arranged to be adjacent to the fourth region on the outside. Alternatively, in the fourth region, as the distance from the axis increases, the refractive power decreases from the strong refractive power in the third region to the reference refractive power in the outer region.

[0021] According to the first embodiment of the intraocular lens disclosed herein, it is possible to suppress the amount of light in the light passing through the lens portion that is not perceptible to the wearer, and to appropriately increase the depth of focus.

[0022] The intraocular lens provided in a typical embodiment of this disclosure is an intraocular lens in which a plurality of circular or annular regions are arranged concentrically around the lens axis, the plurality of regions including: a circular first region located at the very center and endowed with a first refractive power; an annular second region adjacent to the first region on the outer side; an annular third region adjacent to the second region on the outer side and endowed with a third refractive power different from the first refractive power; an annular fourth region adjacent to the third region on the outer side; and an outer region, which is an annular region located further outward than the fourth region, the outer region being endowed with a reference refractive power for focusing at a distance. The region of optical power, wherein in the second region, the refractive power increases or decreases from the first refractive power to the third refractive power as the distance from the axis increases; in the fourth region, the refractive power changes in the opposite direction to the change in refractive power in the second region as the distance from the axis increases; at least a portion of the fourth region, the first region, the second region, and the third region are arranged in a region with a radius of 1.5 mm centered on the axis of the lens portion; the modulation transfer function curve at a spatial frequency of 50 lp / mm related to light passing through the region with a radius of 1.5 mm centered on the axis of the lens portion has a maximum value and the number of minimum values ​​is 0 in the range of defocus amount of -0.5D to 0.5D.

[0023] Alternatively, the third refractive power applied to the third region may be the reference refractive power. Alternatively, the first refractive power applied to the first region may be a strong refractive power, stronger than the reference refractive power. Alternatively, in the second region, as the distance from the axis increases, the refractive power decreases from the strong refractive power in the first region to the reference refractive power in the third region. Alternatively, in the fourth region, as the distance from the axis increases, the refractive power increases from the reference refractive power in the third region.

[0024] Alternatively, at least a portion of the third region, the first region, and the second region may be disposed within a region centered on the axis of the lens portion and having a radius of 1.0 mm.

[0025] Alternatively, the plurality of regions may further include: a fifth annular region adjacent to the fourth region on the outer side, which is endowed with the strong refractive power; and a sixth annular region adjacent to the fifth region on the outer side and adjacent to the outer region on the inner side of the outer region. Alternatively, in the sixth region, the refractive power decreases from the strong refractive power of the fifth region towards the reference refractive power of the outer region as the distance from the axis increases.

[0026] Alternatively, at least a portion of the sixth region, the first region, the second region, the third region, the fourth region, and the fifth region may be arranged within a region centered on the axis of the lens portion and having a radius of 1.5 mm.

[0027] Alternatively, the first refractive power applied to the first region may be the reference refractive power. Alternatively, the third refractive power applied to the third region may be a strong refractive power stronger than the reference refractive power. Alternatively, in the second region, as the distance from the axis increases, the refractive power increases from the reference refractive power in the first region to the strong refractive power in the third region. Alternatively, the outer region may be arranged adjacent to the fourth region on its outer side. Alternatively, in the fourth region, as the distance from the axis increases, the refractive power decreases from the strong refractive power in the third region to the reference refractive power in the outer region.

[0028] Alternatively, at least a portion of the third region, the first region, and the second region may be disposed within a region centered on the axis of the lens portion and having a radius of 1.0 mm.

[0029] The intraocular lens according to this disclosure can appropriately expand the depth of focus and easily obtain a good field of view regardless of changes in the wearer's pupil size. Attached Figure Description

[0030] Figure 1 This is a top view of intraocular lens 1.

[0031] Figure 2 This is a schematic diagram showing the structure of the anterior surface of the lens portion 2 in the intraocular lens of the first embodiment.

[0032] Figure 3 This is a graph showing the relationship between the distance of the lens portion 2 from the axis O and the refractive power (diopter) of the lens portion 2 in the first embodiment.

[0033] Figure 4This is a chart comparing the MTF (Modulation Transfer Function) curve related to light passing through a region with a radius of 1.5 mm centered on the axis O of the lens section 2 in the first embodiment with the MTF curve related to light passing through a region with a radius of 1.0 mm centered on the axis O of the lens section 2.

[0034] Figure 5 This is a chart comparing the MTF curve of the intraocular lens 1 of the first embodiment with the MTF curve of the intraocular lens of the comparative example.

[0035] Figure 6 This is a graph showing the relationship between the distance of the lens portion 2 from the axis O in the second embodiment and the refractive power (diopter) of the lens portion. Detailed Implementation

[0036] <Summary>

[0037] In the first embodiment of the intraocular lens illustrated in this disclosure, multiple regions (one circular region and one or more annular regions) in a circular or annular shape are arranged concentrically around the axis of the lens portion. The multiple regions include a first region, a second region, and a lateral region. The first region is the circular region located at the very center. A fixed first refractive power is assigned to the first region regardless of its distance from the axis. The second region is an annular region adjacent to the first region on its outer side. In the second region, the refractive power increases or decreases from the first refractive power as the distance from the axis increases. The lateral region is an annular region located further outward than the second region. A reference refractive power for focusing at a distance is assigned to the lateral region. The MTF curve related to light passing through a region centered on the axis of the lens with a radius of 1.5 mm at a spatial frequency of 50 lp / mm has a maximum value in the range of -0.5D to 0.5D with the defocus amount as referenced to the position of maximum MTF (0D), and the number of minimum values ​​is 0.

[0038] For example, it has been considered to increase the focal depth of the intraocular lens by designing the center of the lens portion to have a stronger refractive power closer to the axis. However, in this method, very little light passes through the portion with the greatest refractive power (the portion along the axis). Consequently, the wearer cannot perceive the light passing through the axis and therefore cannot perceive the field of view corresponding to the greatest refractive power. The same problem may arise if the design is to have a weaker refractive power closer to the axis. In other words, in these methods, the light passing through the axis cannot be perceived by the wearer and is lost.

[0039] In contrast, in the intraocular lens illustrated in this disclosure, by configuring the first region, the second region, and the outer region, the necessary conditions for an intraocular lens to converge most of the incident light incident towards the lens portion to a predetermined focal point (a single focal point in the embodiment described later) are met (the condition that the MTF curve at a spatial frequency of 50 lp / mm has a maximum value in the range of -0.5D to 0.5D with the defocus amount based on the position of maximum MTF (OD) and the number of minimum values ​​is 0), and the depth of focus is expanded. Here, a fixed first refractive power is given to the first region located at the very center, regardless of the distance from the axis. Therefore, unlike the case where the refractive power decreases or increases only slightly away from the axis, the wearer can properly identify the field of view corresponding to the first refractive power. Therefore, the amount of light that the wearer cannot identify can be suppressed, and thus a good field of view is easily obtained. In addition, the wearer can also obtain a field of view corresponding to the refractive power range close to the first refractive power using the light passing through the second region. Therefore, according to the technology disclosed herein, it is possible to suppress the amount of light in the light passing through the lens portion that is not perceptible to the wearer, and to appropriately increase the depth of focus.

[0040] Furthermore, the range of defocus amount for which the aforementioned MTF curve has a maximum value and no minimum value can also be changed. For example, the MTF curve may have a maximum value and no minimum value within the range of -1.0D to 0.5D defocus amount. Alternatively, the MTF curve may have a maximum value and no minimum value within the range of -1.5D to 0.5D defocus amount. In these cases, it becomes an intraocular lens that does not easily reduce the field of view even when a greater focus deviation occurs.

[0041] Furthermore, the phrase "a region with a fixed refractive power imparted regardless of distance from the axis" is used throughout this disclosure. This phrase does not imply that the refractive power is strictly fixed within the region. In other words, slight variations in the refractive power within the region, for example, for the purpose of aberration correction, are also included within the scope of this disclosure. For example, it is acceptable as long as the percentage variation in the refractive power within the region (e.g., the ratio of the maximum to the minimum refractive power within the region) converges to within 15%, more preferably within 10%. Additionally, the reference refractive power imparted to the outer region may be varied to a certain extent within the outer region for the purpose of aberration correction, etc.

[0042] The area of ​​region 2 relative to the area of ​​region 1 can be within ±50%. That is, it can satisfy the condition "area of ​​region 2 / area of ​​region 1 ≤ 1 ± 0.5". In this case, the areas of regions 1 and 2 are sufficiently guaranteed. As a result, it is easier to obtain both the field of view corresponding to the first refractive power and the field of view corresponding to the range of refractive power close to the first refractive power more appropriately.

[0043] Furthermore, this value of ±50% can also be changed. For example, by setting the ratio of the area of ​​the second region to the area of ​​the first region to within ±30%, the areas of the first and second regions can be more appropriately ensured.

[0044] The area of ​​each of the first and second regions can be 0.6 mm. 2 That's all. In this case, the areas of both the first and second regions are sufficiently ensured. As a result, it is easier to obtain both the field of view corresponding to the first refractive power and the field of view corresponding to the range of refractive power close to the first refractive power more appropriately.

[0045] Furthermore, the areas of regions 1 and 2 can also be 0.8 mm. 2 The above, preferably 1.1mm 2 The above. In these cases, it is possible to more appropriately ensure the respective areas of Zone 1 and Zone 2.

[0046] The area of ​​the second region can be larger than or equal to the area of ​​the first region. In this case, the size of the second region can be more appropriately ensured to vary the refractive power according to the distance from the axis. Therefore, a field of view corresponding to a refractive power close to that of the first region can be obtained more appropriately. In other words, the focal depth of the intraocular lens becomes more appropriately deeper.

[0047] The first refractive power imparted to the first region can be a strong refractive power, stronger than the reference refractive power. In the second region, the refractive power can decrease from the strong refractive power of the first region as the distance from the axis increases. In an intraocular lens, aberrations are less likely to occur near the axis compared to the peripheral portion of the lens. Furthermore, the impact of aberrations on the wearer's field of vision is greater in areas with stronger refractive power. Therefore, by imparting a strong refractive power, stronger than the reference refractive power, to the first region, which is less prone to aberrations, the impact of aberrations on the wearer's field of vision is reduced compared to imparting the reference refractive power to the first region.

[0048] Multiple regions may also include regions 3, 4, 5, and 6. Region 3 is a ring-shaped region adjacent to and outside Region 2. A reference refractive power is assigned to Region 3. Region 4 is a ring-shaped region adjacent to and outside Region 3. Region 5 is a ring-shaped region adjacent to and outside Region 4. A strong refractive power is assigned to Region 5. Region 6 is a ring-shaped region adjacent to and outside Region 5, and inside the outer region. In Region 4, the refractive power increases from the reference refractive power in Region 3 towards the strong refractive power in Region 5 as the distance from the axis increases. In Region 6, the refractive power decreases from the strong refractive power in Region 5 towards the reference refractive power in the outer region as the distance from the axis increases.

[0049] In this configuration, the following regions are arranged sequentially from the inside out: a region of strong refractive power (region 1), a transition region (region 2), a region of reference refractive power (region 3), a transition region (region 4), a region of strong refractive power (region 5), a transition region (region 6), and a region of reference refractive power (outer region). That is, two regions of strong refractive power and a region of reference refractive power between these two regions are located closer to the outer region of the ring. Therefore, even if the wearer's pupil is not significantly dilated (i.e., even if the pupil is smaller than the outer region), light reaching the retina can easily pass appropriately through the regions of strong refractive power, reference refractive power, and the transition region. As a result, a proper visual field is more easily obtained regardless of changes in the wearer's pupil size. Furthermore, compared to having more than seven regions closer to the outer region, it is possible to suppress the increase in aberrations caused by increasing the number of regions. Moreover, the strong refractive power of region 1 and region 5 need not be strictly identical; details will be discussed later. In addition, the reference refractive power of the third region does not need to be strictly the same as that of the outer region.

[0050] In regions 1, 2, 3, 4, 5, and 6, the area ratio between all regions can be within ±50%. In this case, the area of ​​each of regions 1 through 6 is sufficiently ensured. As a result, even when the pupil is smaller than the outer region, it is easy to obtain an appropriate visual field corresponding to the range from the reference refractive power to the strongest refractive power. Furthermore, as mentioned above, this ±50% value can also be changed. For example, it can be changed to ±30%, etc.

[0051] The area of ​​each of the six regions can be 0.6 mm. 2The above. In this case, the areas of regions 1 through 6 are sufficiently ensured. As a result, even when the pupil is smaller than the outer region, it is easy to obtain an appropriate visual field corresponding to the range from the reference refractive power to the strong refractive power. Furthermore, as mentioned above, it is also possible to achieve a visual field of "0.6mm". 2 The value above can be changed. For example, it can be 0.6mm. 2 The above value has been changed to 0.8mm. 2 or above 1.1mm 2 above.

[0052] Furthermore, the area of ​​region 4 can be greater than or equal to the area of ​​region 3. The area of ​​region 6 can be greater than or equal to the area of ​​region 5. In these cases, a field of view corresponding to the refractive power between the reference refractive power and the strong refractive power can be obtained more appropriately. Therefore, the focal depth of the intraocular lens becomes more appropriately deeper.

[0053] Furthermore, at least a portion of the structure of the intraocular lens of the second embodiment described later can be added to the structure of the intraocular lens of the first embodiment described above. Additionally, at least a portion of the structure of the intraocular lens of the first embodiment can also be added to the structure of the intraocular lens of the second embodiment described later.

[0054] In the second embodiment of the intraocular lens illustrated in this disclosure, multiple regions (one circular region and one or more annular regions) in a circular or annular shape are arranged concentrically around the axis of the lens portion. The multiple regions include a first region, a second region, a third region, a fourth region, and a lateral region. The first region is the circular region located at the very center. A first refractive power is assigned to the first region. The second region is an annular region adjacent to the first region on the outer side. The third region is an annular region adjacent to the second region on the outer side. A third refractive power, different from the first refractive power, is assigned to the third region. The fourth region is an annular region adjacent to the third region on the outer side. The lateral region is an annular region located further outward than the fourth region. A reference refractive power for focusing at a distance is assigned to the lateral region. In the second region, the refractive power increases or decreases from the first refractive power to the third refractive power as the distance from the axis increases. In region 4, the refractive power changes in the opposite direction to the change in refractive power in region 2 as the distance from the axis increases. At least a portion of regions 1, 2, 3, and 4 are disposed within a region centered on the axis of the lens and with a radius of 1.5 mm. The MTF curve related to light passing through this region centered on the axis of the lens and with a radius of 1.5 mm, at a spatial frequency of 50 lp / mm, has a maximum value and zero minimum values ​​within a defocus range of -0.5D to 0.5D, with the position of maximum MTF (0D) as the reference.

[0055] In the intraocular lens illustrated in this disclosure, by sequentially arranging the first, second, third, and fourth regions from the center, the necessary conditions for an intraocular lens to converge most of the incident light incident on the lens portion to a predetermined focal point (a single focal point in the embodiment described later) are met (the condition that the MTF curve at a spatial frequency of 50 lp / mm has a maximum value and zero minimum values ​​in the range of -0.5D to 0.5D defocusing), and the focal depth is increased. Here, the first refractive power imparted to the first region is different from the third refractive power imparted to the third region. In addition, in the second and fourth regions, the refractive power of these two regions changes in opposite directions as the distance from the axis increases. Furthermore, at least a portion of the first, second, third, and fourth regions are arranged within a region with a radius of 1.5 mm corresponding to the radius of the human pupil in a state of partial constriction. Therefore, even when the wearer's pupil constricts to a certain extent, the light reaching the retina will pass through the first region endowed with the first refractive power, the third region endowed with the third refractive power, and the transitional regions (second and fourth regions) where the refractive power varies between the first and third refractive powers. Thus, regardless of changes in the wearer's pupil size, it is easy to obtain an appropriate visual field corresponding to the range of the first to third refractive powers.

[0056] Furthermore, the range of defocus amount for which the aforementioned MTF curve has a maximum value and no minimum value can also be changed. For example, the MTF curve may have a maximum value and no minimum value within the range of -1.0D to 0.5D defocus amount. Alternatively, the MTF curve may have a maximum value and no minimum value within the range of -1.5D to 0.5D defocus amount. In these cases, it becomes an intraocular lens that does not easily reduce the field of view even when a greater focus deviation occurs.

[0057] The third refractive power assigned to region 3 can be a reference refractive power for focusing at a distance. The first refractive power assigned to region 1 can be a strong refractive power stronger than the reference refractive power. In region 2, the refractive power can decrease from the strong refractive power in region 1 to the reference refractive power in region 3 as the distance from the axis increases. In region 4, the refractive power can increase from the reference refractive power in region 3 as the distance from the axis increases.

[0058] In intraocular lenses, aberrations are less likely to occur near the axis compared to the periphery of the lens. Furthermore, the impact of aberrations on the wearer's field of vision is greater in areas with higher refractive power. Therefore, by applying a stronger refractive power than the reference refractive power to the first region, which is less prone to aberrations, the impact of aberrations on the wearer's field of vision is reduced compared to applying the reference refractive power to the first region.

[0059] The reference refractive power assigned to the third region does not need to be exactly the same as the reference refractive power assigned to the outer region. For example, the ratio of the reference refractive power of the third region to the reference refractive power of the outer region can be within ±30% (that is, "reference refractive power of the third region / reference refractive power of the outer region ≤ 1 ± 0.3"), more preferably within ±20%. In this case, an appropriate visual field can be obtained regardless of changes in the wearer's pupil size. However, when the wearer's pupil becomes smaller to a certain extent, it is easier to obtain a distant visual field when the reference refractive power of the outer region is close to that of the third region.

[0060] At least a portion of regions 1, 2, and 3 can also be configured within a region centered on the axis of the lens and having a radius of 1.0 mm. In bright environments, the radius of a person's pupil shrinks to approximately 1.0 mm or less. When at least a portion of regions 1, 2, and 3 are configured within a region centered on the axis and having a radius of 1.0 mm, even in very bright environments, light reaching the retina will pass through each of regions 1, 2, and 3. Therefore, even when the wearer's pupil becomes very small, it is easy to obtain a suitable visual field corresponding to the range from the reference refractive power to the strongest refractive power.

[0061] Multiple regions may also include a fifth region and a sixth region. The fifth region is a ring-shaped region adjacent to the fourth region on its outer side. Strong refractive power is imparted to the fifth region. The sixth region is a ring-shaped region adjacent to the fifth region on its outer side and to the outer region on its inner side. In the sixth region, the refractive power decreases from the strong refractive power of the fifth region towards the reference refractive power of the outer region as the distance from the axis increases. In this case, the following regions are arranged sequentially from the inner side to the outer side: a region with strong refractive power (first region), a transition region (second region), a region with reference refractive power (third region), a transition region (fourth region), a region with strong refractive power (fifth region), a transition region (sixth region), and a region with reference refractive power (outer region). That is, two regions with strong refractive power and a region with reference refractive power between these two regions are arranged closer to the outer ring region than the outer ring region. Therefore, even without significant pupil dilation, light reaching the retina can easily pass appropriately through the areas of strong refractive power, the reference refractive power, and the transitional regions. As a result, a proper field of vision is more easily obtained regardless of changes in pupil size. Furthermore, compared to setting the number of regions further inward than the outer region to seven or more, it is possible to suppress the increase in aberrations caused by increasing the number of regions.

[0062] At least a portion of regions 1, 2, 3, 4, 5, and 6 can be configured within a region centered on the axis of the lens and having a radius of 1.5 mm. In this case, even when the wearer's pupil constricts to a certain extent, light reaching the retina will pass through the two regions of strong refractive power, the region of reference refractive power between these two regions, and each of the three transition regions. Therefore, regardless of changes in the wearer's pupil size, an appropriate visual field corresponding to the range from reference refractive power to strong refractive power can be easily obtained.

[0063] Furthermore, the value of the strong refractive power assigned to region 1 does not need to be exactly the same as the value of the strong refractive power assigned to region 5. For example, the ratio of the strong refractive power of region 5 to that of region 1 can be within ±30% (more preferably within ±20%). In this case, an appropriate field of vision can be obtained regardless of changes in the wearer's pupil size.

[0064] Furthermore, the refractive power assigned to region 5 can be closer to the strong refractive power assigned to region 1 than the baseline refractive power assigned to the outer regions. In this case, an appropriate field of vision can be obtained regardless of changes in the wearer's pupil size.

[0065] However, the structure of other regions can also be modified when strong refractive power is applied to region 1 and reference refractive power is applied to region 3. For example, region 5, which is between region 4 and region 6, can be omitted. In this case, a visual field corresponding to the range from reference refractive power to strong refractive power can also be obtained.

[0066] The first refractive power applied to the first region can be a reference refractive power for focusing at a distance. The third refractive power applied to the third region can be a strong refractive power stronger than the reference refractive power. In the second region, the refractive power can increase from the reference refractive power in the first region to the strong refractive power in the third region as the distance from the axis increases. The outer region can be set in a manner that is adjacent to the fourth region on the outside of the fourth region. In the fourth region, the refractive power can decrease from the strong refractive power in the third region to the reference refractive power in the outer region as the distance from the axis increases. In this case, the number of regions formed inside the outer region is as few as possible, four. The fewer the number of regions, the easier it is to suppress the amount of aberrations generated. Therefore, by setting the number of regions formed inside the outer region to four, an appropriate field of vision can be easily obtained regardless of the wearer's pupil size while suppressing the generation of aberrations.

[0067] Furthermore, the reference refractive power assigned to the first region need not be exactly the same as the reference refractive power assigned to the outer region. For example, the ratio of the reference refractive power of the first region to the reference refractive power of the outer region can be within ±30% (more preferably within ±20%).

[0068] At least a portion of regions 1, 2, and 3 can be configured within a region centered on the axis of the lens and having a radius of 1.0 mm. As described above, in bright environments, the radius of a human pupil shrinks to approximately 1.0 mm or less. When at least a portion of regions 1, 2, and 3 is configured within a region centered on the axis and having a radius of 1.0 mm, even in very bright environments, light reaching the retina will pass through each of regions 1, 2, and 3. Therefore, even when the wearer's pupil becomes very small, it is easy to obtain a suitable visual field corresponding to the range from the reference refractive power to the strongest refractive power.

[0069] <First Implementation>

[0070] (Overview Structure)

[0071] Reference Figures 1-5 The intraocular lens 1 of the first embodiment will now be described. First, refer to... Figure 1The general structure of the intraocular lens 1 will be described below. Furthermore, the general structure of the intraocular lens 1 described below is also common to the intraocular lens of the second embodiment described later. In addition, in the first and second embodiments, an intraocular lens (so-called a monofocal intraocular lens) is used as an example to illustrate how most of the incident light incident on the lens section 2 converges near a single focal point. However, any intraocular lens to which the technology of this disclosure can be applied is one that satisfies the condition that its MTF curve at a spatial frequency of 50 lp / mm has a maximum value in the range of -0.5D to 0.5D and the number of minimum values ​​is zero. Therefore, the technology of this disclosure can also be applied to various intraocular lenses other than monofocal intraocular lenses (e.g., multifocal intraocular lenses).

[0072] The intraocular lens 1 includes a lens portion (optical 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, the technology illustrated in this disclosure can also be applied to intraocular lenses other than one-piece lenses (e.g., three-piece intraocular lenses). Regarding the material of the intraocular lens 1, various soft materials can be used, such as monomers like BA (butyl acrylate) and HEMA (hydroxyethyl methacrylate), or composite materials of acrylates and methacrylates.

[0073] Lens portion 2 provides a prescribed refractive power to the patient's eye. A pair of lens surfaces (anterior and posterior surfaces) of lens portion 2 are formed as convex surfaces. For lens portion 2, there exists an axis O that passes perpendicularly to the lens surfaces and through the center of the lens portion. In this embodiment, axis O of lens portion 2 is aligned with the optical axis of lens portion 2.

[0074] In the intraocular lens 1 of this embodiment, the refractive power at each part of the lens portion 2 is adjusted by forming at least one of a pair of lens surfaces of the lens portion 2 into an aspherical shape. As an example, in this embodiment, the refractive power at each part of the lens portion 2 is adjusted by forming the anterior surface (convex surface) of the lens portion 2 into an aspherical shape. However, the posterior surface or both surfaces of the lens portion 2 may also be formed into an aspherical shape. For example, the surface opposite to the side of the anterior and posterior surfaces of the lens portion 2 that is set into an aspherical shape to achieve the refractive power configuration described later may be formed into a toric surface shape for astigmatism correction. In this case, in addition to the effects of the intraocular lens 1 described in this embodiment, an astigmatism correction effect is also provided.

[0075] The support portion 3 is used to support the lens portion 2 inside the wearer's eye (in this embodiment, inside the capsule). As an example, the intraocular lens 1 in this embodiment is provided with a pair of support portions 3. However, the number of support portions 3 is not limited to two. In this embodiment, the support portion 3 is shaped as a ring that is curved in the circumferential direction. The front end of the support portion 3 is provided as a free end.

[0076] (The area of ​​the lens)

[0077] Reference Figure 2 The details of the lens portion 2 in the intraocular lens 1 of the first embodiment will now be described. Figure 2 As shown, in the direction along axis O (in Figure 2 When viewing the lens section 2 from the front (center), multiple regions R1 to R6 and RO, which are circular or annular, are arranged concentrically around axis O on the lens section 2. As described above, in this embodiment, the front surface (convex surface) of the lens section 2 is formed into an aspherical shape, thereby providing multiple regions R1 to R6 and RO.

[0078] Region 1 R1 is the central circular region among the multiple regions. Regions 2 R2, 3 R3, 4 R4, 5 R5, 6 R6, and the outer region RO are all annular regions. Region 2 R2 is adjacent to Region 1 R1 on its outer side. Region 3 R3 is adjacent to Region 2 R2 on its outer side. Region 4 R4 is adjacent to Region 3 R3 on its outer side. Region 5 R5 is adjacent to Region 4 R4 on its outer side. Region 6 R6 is adjacent to Region 5 R5 on its outer side. The outer region RO is adjacent to Region 6 R6 on its outer side.

[0079] (Refractive power of each region)

[0080] Reference Figure 3 The refractive power of each region R1 to R6 and RO of the lens portion 2 in the first embodiment will be explained. Figure 3 In the graph shown, the horizontal axis represents the distance from axis O of lens section 2, and the vertical axis represents the refractive power (diopter) of lens section 2. In this embodiment, the refractive power imparted to lens section 2 to enable the wearer to focus on distant objects is defined as the reference refractive power. In the graph, the reference refractive power is set to "0D". The stronger the imparted refractive power, the closer the wearer's focal point will be to nearby objects.

[0081] The refractive power (first refractive power) assigned to the first region R1 is set to be stronger than the reference refractive power used for focusing at a distance (hereinafter referred to as "strong refractive power"). In detail, for the first region R1 of this embodiment, a fixed strong refractive power is assigned regardless of the distance from the axis O.

[0082] In the second region R2, the refractive power decreases from the first refractive power as the distance from axis O increases. Specifically, the refractive power in the second region R2 decreases from the strong refractive power of the first region R1 to the third refractive power (reference refractive power) imparted to the third region R3 as the distance from axis O increases. Furthermore, in this embodiment, the refractive power in the second region R2 decreases proportionally to the distance from axis O.

[0083] The refractive power (third refractive power) assigned to the third region R3 is the reference refractive power. In detail, for the third region R3 in this embodiment, a fixed reference refractive power is assigned regardless of the distance from axis O.

[0084] In region 4 R4, the refractive power increases from the third refractive power as the distance from axis O increases. Specifically, the refractive power in region 4 R4 increases from the reference refractive power of region 3 R3 towards the fifth refractive power (strong refractive power) imparted to region 5 R5 as the distance from axis O increases. Furthermore, in this embodiment, the refractive power in region 4 R4 increases proportionally to the distance from axis O.

[0085] The refractive power (5th refractive power) imparted to region 5 R5 is a strong refractive power. Specifically, in this embodiment, a fixed strong refractive power is imparted to region 5 R5 regardless of its distance from axis O. Furthermore, in this embodiment, the value of the strong refractive power imparted to region 1 R1 is the same as the value of the strong refractive power imparted to region 5 R5. However, the values ​​of the strong refractive power imparted to region 1 R1 and region 5 R5 need not be strictly identical. For example, the ratio of the strong refractive power of region 5 R5 to the strong refractive power of region 1 R1 may be within ±30% (more preferably within ±20%). In this case, an appropriate field of vision can be obtained regardless of changes in the wearer's pupil size.

[0086] In region R6, the refractive power decreases from the fifth refractive power as the distance from axis O increases. Specifically, the refractive power in region R6 decreases from the strong refractive power of region R5 towards the reference refractive power imparted to the outer region RO as the distance from axis O increases. Furthermore, in this embodiment, the refractive power in region R6 decreases proportionally to the distance from axis O.

[0087] The refractive power applied to the outer region RO is the reference refractive power. Specifically, in this embodiment, a fixed reference refractive power is applied to the outer region RO regardless of its distance from axis O. However, the reference refractive power applied to the outer region RO may vary within the region for purposes such as aberration correction. Furthermore, in this embodiment, the value of the reference refractive power applied to the third region R3 is the same as the value of the reference refractive power applied to the outer region RO. However, the values ​​of the reference refractive power applied to the third region R3 and the outer region RO need not be strictly identical. For example, the ratio of the reference refractive power of the third region R3 to the reference refractive power of the outer region RO may be within ±30% (more preferably within ±20%). In this case, an appropriate field of vision can be obtained regardless of changes in the wearer's pupil size.

[0088] Furthermore, in this embodiment, the regions among the multiple regions R1 to R6 and RO where the refractive power increases or decreases as the distance from axis O increases (that is, the second region R2, the fourth region R4, and the sixth region R6) are sometimes referred to as transition regions.

[0089] (Area of ​​each region)

[0090] In this embodiment, the area ratio between all regions—region 1 R1, region 2 R2, region 3 R3, region 4 R4, region 5 R5, and region 6 R6—is within ±50%. Specifically, in this embodiment, the lens portion 2 is designed so that the areas of regions 1 R1 to 6 R6 are identical.

[0091] Furthermore, in this embodiment, the area of ​​each of the first region R1, the second region R2, the third region R3, the fourth region R4, the fifth region R5, and the sixth region R6 is 0.6 mm. 2 That's all. In detail, in this embodiment, the area of ​​each of the first region R1 to the sixth region R6 is 1.1 mm. 2 above.

[0092] (Characteristics of MTF)

[0093] Reference Figure 4 and Figure 5 The characteristics of the MTF of the intraocular lens 1 in this embodiment will be explained. MTF (Modulation Transfer Function) is an indicator of contrast. Figure 4 and Figure 5 The chart shows the MTF curve at a spatial frequency of 50 lp / mm, with the amount of defocus (focus deviation, degree deviation) as the horizontal axis and MTF as the vertical axis.

[0094] Figure 4 This is a graph comparing the MTF curves related to light passing through a region with a radius of 1.5 mm (diameter of 3.0 mm) centered on the axis O of the lens section 2 and the MTF curves related to light passing through a region with a radius of 1.0 mm (diameter of 2.0 mm) centered on the axis O of the lens section 2 in an optical system that simulated the eye of a wearer wearing the intraocular lens 1 of the first embodiment. Figure 4 In the diagram, the MTF curve for a region with a radius of 1.5 mm (diameter of 3.0 mm) is represented by a dashed line, and the MTF curve for a region with a radius of 1.0 mm (diameter of 2.0 mm) is represented by a solid line. Furthermore, the region with a radius of 1.5 mm (diameter of 3.0 mm) centered on the axis O of the lens section 2 approximates the region through which light passes when the wearer's pupil constricts to a certain extent. Conversely, the region with a radius of 1.0 mm (diameter of 2.0 mm) centered on the axis O of the lens section 2 approximates the region through which light passes when the wearer's pupil becomes very small.

[0095] like Figure 4 As shown, in the intraocular lens 1 of the first embodiment, even when light passes through an area with a radius of 1.5 mm (a diameter of 3.0 mm) (that is, when the wearer's pupil constricts to a certain extent), the necessary condition for an intraocular lens to converge most of the incident light incident on the lens section 2 to a predetermined focal point (a single focal point in this embodiment) is met (the condition that the MTF curve at a spatial frequency of 50 lp / mm has a maximum value in the range of -0.5D to 0.5D (more specifically, -1.5D to 0.5D) with a defocus amount based on the position of the maximum MTF (0D), and the number of minimum values ​​is 0). Furthermore, the MTF value is not only high near the maximum value, but also remains high even when the defocus amount increases or decreases to a certain extent. In other words, in the intraocular lens 1 of the first embodiment, the focal depth is appropriately increased.

[0096] In addition, such as Figure 4 As shown, even when light passes through an area with a radius of 1.0 mm (a diameter of 2.0 mm) (i.e., when the wearer's pupil becomes very small), the conditions necessary for an intraocular lens to converge most of the incident light incident on the lens section 2 to a predetermined focal point (a single focal point in this embodiment) are met, and the depth of focus is also appropriately increased. Furthermore, the optimal focusing position with a radius of 1.0 mm changes by only about -0.15D compared to the optimal focusing position with a radius of 1.5 mm. Therefore, even when the wearer's pupil becomes very small, distance vision is not easily deteriorated.

[0097] Figure 5 This is a graph showing the simulation results comparing the MTF curve of the intraocular lens 1 of the first embodiment with the MTF curve of the intraocular lens of the comparative example. In the comparative example intraocular lens, the only difference from the intraocular lens 1 of the first embodiment is the magnitude of the strong refractive power imparted to the first region R1 and the fifth region R5, and the amount of change in refractive power in the second region R2, the fourth region R4, and the sixth region R6. Specifically, in the comparative example intraocular lens, a strong refractive power of approximately 2.4D is imparted to the first region R1, and a strong refractive power of approximately 2.8D is imparted to the fifth region R5. In contrast, in the intraocular lens 1 of the first embodiment, a strong refractive power of 1.3D is imparted to both the first region R1 and the fifth region R5 (see reference). Figure 3 Furthermore, the area through which the light passes is uniformly defined as a region centered on axis O with a radius of 1.5 mm (diameter of 3.0 mm).

[0098] like Figure 5 As shown, the comparative example's intraocular lens, with its significantly increased refractive power applied to regions 1 (R1) and 5 (R5) compared to the intraocular lens 1 of the first embodiment, forms a distance focal point and a near focal point. In other words, the comparative example's intraocular lens exhibits the characteristics of a multifocal intraocular lens, failing to converge most of the incident light incident onto the lens section 2 to the vicinity of a single focal point. In contrast, in the intraocular lens 1 of the first embodiment, by appropriately adjusting the values ​​of the refractive power applied to regions 1 (R1) and 5 (R5), the focal depth is appropriately increased while maintaining the function of converging most of the incident light incident onto the lens section 2 to the vicinity of a single focal point. Furthermore, the peak appearing between the distance and near focal points in the comparative example's graph is not an intermediate focal point, but rather a peak resulting from a phenomenon known as pseudo-resolution.

[0099] (Suppression of light loss)

[0100] like Figure 3 As shown, a fixed first refractive power (strong refractive power in this embodiment) is imparted to the first region R1 regardless of the distance from axis O. Therefore, unlike cases where the refractive power decreases or increases with only a slight movement away from axis O, the wearer can appropriately identify the field of view corresponding to the first refractive power. Thus, the amount of light that the wearer cannot identify can be suppressed, and a good field of view is easily obtained. In addition, the wearer can also obtain a field of view corresponding to a refractive power range close to the first refractive power using the light passing through the second region R2. Therefore, according to the technology of this disclosure, the amount of light in the light passing through the lens section 2 that the wearer cannot identify can be suppressed, and the depth of focus can be appropriately increased.

[0101] The area of ​​the second region R2 is within ±50% of the area of ​​the first region R1. This ensures that the areas of both the first region R1 and the second region R2 are adequately measured. Furthermore, in the first embodiment, the areas of both the first region R1 and the second region R2 are set to 0.6 mm. 2 In this way, the areas of region 1 R1 and region 2 R2 are adequately ensured. Therefore, it is easier to obtain both the field of view corresponding to the first refractive power and the field of view corresponding to the range of refractive power close to the first refractive power more appropriately.

[0102] The area of ​​the second region R2 is larger than or equal to the area of ​​the first region R1 (in this embodiment, the area of ​​the first region R1 is the same as the area of ​​the second region R2). As a result, the size of the second region R2, which varies with the distance from axis O, is appropriately ensured. Therefore, a field of view corresponding to a refractive power close to that of the first refractive power can be obtained more appropriately. In other words, the focal depth of the intraocular lens 1 is more appropriately increased.

[0103] like Figure 3 As shown, in the intraocular lens 1 of the first embodiment, a strong refractive power is imparted to the first region R1. Furthermore, in the second region R2, the refractive power decreases from the strong refractive power of the first region R1 as the distance from axis O increases. In the intraocular lens, aberrations are less likely to occur near axis O compared to the peripheral portion of the lens portion 2. Additionally, the impact of aberrations on the wearer's field of vision is greater in areas with stronger refractive power. Therefore, by imparting a stronger refractive power than the reference refractive power to the first region R1, which is less prone to aberrations, the impact of aberrations on the wearer's field of vision is reduced compared to the case where the first region R1 is only given the reference refractive power.

[0104] like Figure 2 and Figure 3As shown, in the first embodiment, the following regions are arranged sequentially from the inside to the outside: a region with strong refractive power (first region R1), a transition region (second region R2), a region with reference refractive power (third region R3), a transition region (fourth region R4), a region with strong refractive power (fifth region R5), a transition region (sixth region R6), and a region with reference refractive power (outer region RO). That is, two regions with strong refractive power and a region with reference refractive power between these two regions are arranged closer to the outer region RO than the annular outer region. Therefore, even when the pupil is smaller than the outer region RO, light reaching the retina can easily and appropriately pass through the regions with strong refractive power, the region with reference refractive power, and the transition region. As a result, a suitable visual field is more easily obtained. Furthermore, compared to setting the number of regions closer to the outer region RO to seven or more, it is possible to suppress the increase in aberrations caused by increasing the number of regions. Also, in the fifth region R5, similar to the first region R1, a fixed strong refractive power is imparted regardless of the distance from the axis O. Therefore, it is possible to obtain a field of vision that appropriately corresponds to strong refractive power. In other words, it is possible to appropriately suppress the amount of light that the wearer cannot perceive.

[0105] In regions R1, R2, R3, R4, R5, and R6, the area ratio between all regions is within ±50%. This ensures that the areas of each of regions R1 to R6 are adequately measured. Furthermore, in the first embodiment, the area of ​​each of regions R3, R4, R5, and R6 is set to 0.6 mm. 2 This ensures that each area is adequately covered. Therefore, even when the pupil is smaller than the outer region RO, it is easy to obtain an appropriate visual field corresponding to the range from the reference refractive power to the strongest refractive power.

[0106] like Figure 3 As shown, in the transition regions (regions 2 R2, 4 R4, and 6 R6 in the first embodiment), the refractive power increases or decreases proportionally to the distance from the axis O. Therefore, compared to cases where the distance from the axis O is disproportionate to the refractive power, the possibility of significant deviations from the desired value occurring in a portion is reduced. Consequently, the design of the lens section 2 becomes easier. Furthermore, except for region 2 R2, the sizes of regions 4 R4 and 6 R6 are also formed to be larger than or equal to the area of ​​region 1 R1 (in this embodiment, the areas of regions 1 R1 to 6 R6 are all the same). As a result, a field of view corresponding to the refractive power between the reference refractive power and the strong refractive power can be obtained more appropriately.

[0107] [Strategies to address changes in pupil size]

[0108] like Figure 3 As shown, in regions 2 R2 and 4 R4, the refractive power of these two regions changes in opposite directions as the distance from axis O increases. Furthermore, regions 1 R1, 2 R2, 3 R3, and at least a portion of region 4 R4 (in this embodiment, all of region 4 R4) are arranged within a region of radius 1.5 mm, corresponding to the radius of the human pupil when it is constricted to a certain degree. Therefore, even when the wearer's pupil is constricted to a certain degree, light reaching the retina will pass through each region in the region 1 R1 (with the first refractive power), the region 3 R3 (with the third refractive power), and the transition region (regions 2 R2 and 4 R4) where the refractive power changes between the first and third refractive powers. Thus, regardless of changes in the wearer's pupil size, an appropriate visual field corresponding to the range of the first to third refractive powers can be easily obtained.

[0109] In detail, in the first embodiment, the first refractive power applied to the first region R1 is a strong refractive power, and the third refractive power applied to the third region R3 is a reference refractive power. As described above, by applying a strong refractive power stronger than the reference refractive power to the first region R1, which is not prone to aberrations, the impact of aberrations on the wearer's field of vision is reduced compared to the case where the first region R1 is applied with the reference refractive power.

[0110] like Figure 2 and Figure 3 As shown, in the first embodiment, a portion of the first region R1, the second region R2, and the third region R3 are disposed within a region centered on the axis O of the lens portion 2 and having a radius of 1.0 mm. In bright environments, the radius of a person's pupil shrinks to approximately 1.0 mm or less. When at least a portion of the first region R1, the second region R2, and the third region R3 are disposed within a region centered on the axis O and having a radius of 1.0 mm, even in very bright environments, light reaching the retina will pass through each of the first region R1, the second region R2, and the third region R3. Therefore, even when the wearer's pupil becomes very small, it is easy to obtain a suitable visual field corresponding to the range from the reference refractive power to the strong refractive power.

[0111] As described above, in the first embodiment, two regions with strong refractive power and a region with a reference refractive power between these two regions are arranged inside the outer annular region RO. That is, at least a portion of the first region R1, the second region R2, the third region R3, the fourth region R4, the fifth region R5, and the sixth region R6 may be arranged within a region with a radius of 1.5 mm centered on the axis O of the lens portion 2. Therefore, even when the wearer's pupil constricts to a certain extent, light reaching the retina can easily and appropriately pass through the two regions with strong refractive power, the region with reference refractive power, and each region in the transition region. Thus, regardless of changes in the wearer's pupil size, an appropriate visual field corresponding to the range from reference refractive power to strong refractive power can be easily obtained.

[0112] Furthermore, the structure of regions 3 (R3) to 6 (R6) can be modified. For example, similar to the outer region (RO), the reference refractive power can also be applied to regions 3 (R3) to 6 (R6). In this case, a good field of view can be obtained by using regions 1 (R1) and 2 (R2) to suppress light loss. Additionally, region 5 (R5) between region 4 (R4) and region 6 (R6) can be omitted. In this case, a field of view corresponding to the range from the reference refractive power to the strongest refractive power can also be obtained.

[0113] <Second Implementation Method>

[0114] Reference Figure 6 The intraocular lens of the second embodiment will now be described. The intraocular lens of the second embodiment differs from the intraocular lens 1 of the first embodiment only in the arrangement of the multiple regions within the lens portion 2 and the refractive power of each region; the other structures are common. Therefore, the common structures in the intraocular lens of the second embodiment that are common to the intraocular lens 1 of the first embodiment will be omitted or simplified in description. Furthermore, the intraocular lens of the second embodiment, like that of the first embodiment, satisfies the necessary condition for an intraocular lens to converge most of the incident light incident on the lens portion 2 to a predetermined focal point (a single focal point in the embodiments described later) (the condition that the MTF curve at a spatial frequency of 50 lp / mm has a maximum value in the range of defocusing amount from -0.5D to 0.5D and the number of minimum values ​​is 0).

[0115] (The area of ​​the lens)

[0116] The region of the lens portion 2 in the intraocular lens of the second embodiment will be described. For example... Figure 6 As shown, in the lens section 2, multiple regions R1 to R4 and RO are arranged in a concentric circle with axis O as the center.

[0117] Region 1 R1 is the central circular region among the multiple regions. Regions 2 R2, 3 R3, 4 R4, and the outer region RO are all annular regions. Region 2 R2 is adjacent to Region 1 R1 on the outside. Region 3 R3 is adjacent to Region 2 R2 on the outside. Region 4 R4 is adjacent to Region 3 R3 on the outside. The outer region RO is adjacent to Region 4 R4 on the outside.

[0118] (Refractive power of each region)

[0119] The refractive power of each region R1 to R4 and RO of the lens portion 2 in the second embodiment will be explained. Figure 6 In the chart shown, with Figure 3 Similarly, in the chart shown, the horizontal axis represents the distance from axis O of lens section 2, and the vertical axis represents the refractive power (diopter) of lens section 2.

[0120] The refractive power (first refractive power) applied to the first region R1 is set as the reference refractive power. In detail, for the first region R1 in this embodiment, a fixed reference refractive power is applied regardless of the distance from axis O.

[0121] In the second region R2, the refractive power increases from the first refractive power as the distance from axis O increases. Specifically, the refractive power in the second region R2 increases from the reference refractive power of the first region R1 to a third refractive power (strong refractive power) imparted to the third region R3 as the distance from axis O increases. Furthermore, in this embodiment, the refractive power in the second region R2 increases proportionally to the distance from axis O.

[0122] The refractive power (third refractive power) imparted to the third region R3 is a strong refractive power that is stronger than the reference refractive power. In detail, for the third region R3 in this embodiment, a fixed strong refractive power is imparted regardless of the distance from the axis O.

[0123] In region 4 R4, the refractive power decreases from the third refractive power as the distance from axis O increases. Specifically, the refractive power in region 4 R4 decreases from the strong refractive power of region 3 R3 towards the reference refractive power imparted to the outward region RO as the distance from axis O increases. Furthermore, a portion of region 4 R4 in this embodiment includes a region where the refractive power is fixed regardless of the distance from axis O (hereinafter referred to as the "fixed region"). However, it is also possible not to provide a fixed region in region 4 R4. In region 4 R4 of the second embodiment, excluding the fixed region, the refractive power decreases proportionally to the distance from axis O.

[0124] The refractive power applied to the outer region RO is the reference refractive power. Specifically, in this embodiment, a fixed reference refractive power is applied to the outer region RO regardless of its distance from axis O. However, the reference refractive power applied to the outer region RO may vary within the region for purposes such as aberration correction. Furthermore, in this embodiment, the value of the reference refractive power applied to the first region R1 is the same as the value of the reference refractive power applied to the outer region RO. However, the values ​​of the reference refractive power applied to the first region R1 and the outer region RO need not be strictly identical. For example, the ratio of the reference refractive power of the first region R1 to the reference refractive power of the outer region RO may be within ±30% (more preferably within ±20%). In this case, an appropriate field of vision can be obtained regardless of changes in the wearer's pupil size.

[0125] (Area of ​​each region)

[0126] In this embodiment, the area ratio between all regions—first region R1, second region R2, and third region R3—is within ±50%. Specifically, in this embodiment, the lens portion 2 is designed so that the areas of first region R1 to third region R3 are identical.

[0127] Furthermore, in this embodiment, the areas of region 1 R1, region 2 R2, region 3 R3, and region 4 R4 are all 0.6 mm². 2 That's all. Specifically, in this embodiment, the area of ​​each of the first region R1 to the fourth region R4 is 1.1 mm. 2 above.

[0128] (Suppression of light loss)

[0129] like Figure 6 As shown, a fixed first refractive power (the reference refractive power in the second embodiment) is imparted to the first region R1 regardless of the distance from axis O. Therefore, unlike cases where the refractive power decreases or increases with only a slight movement away from axis O, the wearer can appropriately identify the field of view corresponding to the first refractive power (that is, the field of view obtained using light passing through the first region R1). Thus, the amount of light that the wearer cannot identify can be suppressed, and a good field of view is easily obtained. In addition, the wearer can also obtain a field of view corresponding to a refractive power range close to the first refractive power using light passing through the second region R2. Therefore, according to the technology of this disclosure, the amount of light in the light passing through the lens section 2 that the wearer cannot identify can be suppressed, and the depth of focus can be appropriately increased.

[0130] The area of ​​the second region R2 is within ±50% of the area of ​​the first region R1. This ensures that the areas of both the first region R1 and the second region R2 are adequately measured. Furthermore, in the second embodiment, the areas of both the first region R1 and the second region R2 are set to 0.6 mm. 2 In this way, the areas of region 1 R1 and region 2 R2 are adequately ensured. Therefore, it is easier to obtain both the field of view corresponding to the first refractive power and the field of view corresponding to the range of refractive power close to the first refractive power more appropriately.

[0131] The areas of region 2 R2 and region 4 R4 are formed to be larger than or equal to the area of ​​region 1 R1. As a result, the sizes of region 2 R2 and region 4 R4, which vary with the distance from axis O, are appropriately ensured. Therefore, a field of view corresponding to a refractive power close to that of region 1 can be obtained more appropriately. In other words, the focal depth of intraocular lens 1 is more appropriately expanded.

[0132] In the second embodiment, the areas of the third region R3 and the fourth region R4 are also set to 0.6 mm. 2 This ensures that each area is adequately covered. Therefore, even when the pupil is smaller than the outer region RO, it is easy to obtain an appropriate visual field corresponding to the range from the reference refractive power to the strongest refractive power.

[0133] [Strategies to address changes in pupil size]

[0134] In regions R2 and R4, the refractive power changes in opposite directions with increasing distance from axis O. Furthermore, at least a portion of regions R1, R2, R3, and R4 are positioned within a 1.5 mm radius region corresponding to the radius of the human pupil when it is constricted to a certain degree. Therefore, even when the wearer's pupil is constricted to a certain degree, light reaching the retina will pass through each region: region R1 (with the first refractive power), region R3 (with the third refractive power), and the transition region (regions R2 and R4) where the refractive power varies between the first and third refractive powers. Thus, regardless of changes in the wearer's pupil size, an appropriate visual field corresponding to the range of the first to third refractive powers can be easily obtained.

[0135] Specifically, in the second embodiment, the first refractive power applied to the first region R1 is the reference refractive power, and the third refractive power applied to the third region R3 is the strong refractive power. In this case, the number of regions formed inside the outer region RO is as few as possible, four. The fewer the number of regions, the easier it is to suppress the amount of aberrations. Therefore, by setting the number of regions formed inside the outer region RO to four, an appropriate field of vision can be easily obtained regardless of the wearer's pupil size while suppressing the generation of aberrations.

[0136] In the second embodiment, a portion of the first region R1, the second region R2, and the third region R3 are disposed within a region centered on the axis O of the lens portion 2 and having a radius of 1.0 mm. As described above, in bright environments, the radius of a person's pupil shrinks to approximately 1.0 mm or less. When at least a portion of the first region R1, the second region R2, and the third region R3 are disposed within a region centered on the axis O and having a radius of 1.0 mm, even in very bright environments, light reaching the retina will pass through each of the first region R1, the second region R2, and the third region R3. Therefore, even when the wearer's pupil becomes very small, it is easy to obtain a suitable visual field corresponding to the range from the reference refractive power to the strong refractive power.

[0137] The technology disclosed in the above embodiments is only one example. Therefore, modifications can be made to the technology illustrated in the above embodiments. For example, only a portion of the multiple technologies illustrated in the embodiments of the first and second embodiments can be used in the intraocular lens.

[0138] Explanation of reference numerals in the attached figures

[0139] 1: Intraocular lens; 2: Lens part; 3: Support part; O: Axis; R1: Region 1; R2: Region 2; R3: Region 3; R4: Region 4; R5: Region 5; R6: Region 6; RO: Outer region.

Claims

1. An intraocular lens, characterized in that, Multiple regions, either circular or annular, are arranged concentrically around the axis of the lens portion. The multiple regions include: The first circular region, located at the very center, is endowed with the first refractive power; A second annular region, which is adjacent to the first region on the outside of the first region; The annular third region, which is adjacent to the second region on the outside, is endowed with a third refractive power different from the first refractive power; A fourth annular region, which is adjacent to the third region on the outside of the third region; and The outer region, which is a ring-shaped area located outside the fourth region, is the area endowed with a reference refractive power for focusing at distant objects. In the second region, as the distance from the axis increases, the refractive power increases or decreases from the first refractive power to the third refractive power. In the fourth region, as the distance from the axis increases, the refractive power changes in the opposite direction to the change in refractive power in the second region. At least a portion of the fourth region, the first region, the second region, and the third region are arranged within a region centered on the axis of the lens portion and having a radius of 1.5 mm. The modulation transfer function curve at a spatial frequency of 50 lp / mm, relating to light passing through a region centered on the axis of the lens with a radius of 1.5 mm, has a maximum value in the range of -0.5D to 0.5D and the number of minimum values ​​is 0.

2. The intraocular lens according to claim 1, characterized in that, The area of ​​the second region is within ±50% of the area of ​​the first region.

3. The intraocular lens according to claim 1, characterized in that, The area of ​​each of the first and second regions is 0.6 mm. 2 above.

4. The intraocular lens according to claim 1, characterized in that, The first refractive power imparted to the first region is a strong refractive power that is stronger than the reference refractive power. In the second region, the refractive power decreases from the strong refractive power in the first region as the distance from the axis increases.

5. The intraocular lens according to claim 4, characterized in that, The third region is endowed with the reference refractive power. The multiple regions also include: A fifth annular region, adjacent to the fourth region on its outer side, is endowed with the strong refractive power; and A sixth annular region, which is adjacent to the fifth region on the outer side and to the outer region on the inner side of the outer region. Specifically, in the fourth region, as the distance from the axis increases, the refractive power increases from the reference refractive power in the third region to the strong refractive power in the fifth region. In the sixth region, as the distance from the axis increases, the refractive power decreases from the strong refractive power in the fifth region toward the reference refractive power in the outer region.

6. The intraocular lens according to claim 1, characterized in that, At least a portion of the third region, the first region, and the second region are disposed within a region centered on the axis of the lens portion and having a radius of 1.0 mm.

7. The intraocular lens according to claim 5, characterized in that, At least a portion of the sixth region, the first region, the second region, the third region, the fourth region, and the fifth region are arranged within a region centered on the axis of the lens portion and having a radius of 1.5 mm.

8. The intraocular lens according to claim 1, characterized in that, The first refractive power assigned to the first region is the reference refractive power. The third refractive power imparted to the third region is a strong refractive power that is stronger than the reference refractive power. In the second region, as the distance from the axis increases, the refractive power increases from the reference refractive power in the first region to the strong refractive power in the third region. The outer region is arranged so as to be adjacent to the fourth region on the outside of the fourth region. In the fourth region, as the distance from the axis increases, the refractive power decreases from the strong refractive power in the third region toward the reference refractive power in the outer region.

Images