JP6500484B2 - Multifocal intraocular lens - Google Patents

Description

  The present disclosure relates to a multifocal intraocular lens having a plurality of focal points and installed in the eye of a subject.

  As an intraocular lens to be inserted into the eye instead of the crystalline lens in cataract surgery, there is known a single-focus intraocular lens that focuses incident light on an optical unit to a single focal point. Also, in recent years, a multifocal intraocular lens is known that can distribute incident light to an optical unit to a plurality of focal points and condense the light so as to give a simulated accommodation power to a subject's eye. As such a multifocal intraocular lens, a diffractive multifocal intraocular lens is known which distributes incident light to a plurality of different focal points by a diffractive area formed on a base curve of an optical section. (See, for example, Patent Document 1).

JP, 2011-072348, A

  Here, in the multifocal intraocular lens, if a large amount of unnecessary refraction, reflected light or diffracted light is generated, the contrast of the image formed on the retina of the subject is lowered and the subject is near There is a possibility that it is not possible to comfortably perform vision (looking near) or far vision (looking far).

  Therefore, the present disclosure is made to solve the above-mentioned problems, and it is an object of the present disclosure to provide a multifocal intraocular lens capable of reducing the generation of unnecessary light.

A multifocal intraocular lens according to an exemplary embodiment of the present disclosure is a multifocal intraocular lens to be inserted into an eye of a patient's eye, having a front optical surface and a rear optical surface, and the incident light And an optical unit for condensing light, wherein the optical unit is formed in a partial area of the optical surface, and is provided with a diffraction area provided with a diffraction grating for diffracting the incident light to condense at least a first focal position. And forming the curved surface or plane in an area other than the diffraction area among the optical surfaces provided with the diffraction area, and collecting the incident light at a second focus position farther or closer than the first focus position. A non-diffraction region to be illuminated, the diffraction region and the non-diffraction region are sequentially formed in the circumferential direction of the optical unit, and the incident light is condensed to the nearer one of the diffraction region and the non-diffraction region The area of the area to be Ratio in the region inside of a circle around the becomes smaller as the diameter of the circle is larger, that the phase difference of the diffractive region is 1, and wherein.

  According to the multifocal intraocular lens of the present disclosure, generation of unnecessary light can be reduced.

It is a front view of the multifocal intraocular lens in 1st Embodiment. It is an AA end view of FIG. It is a BB end view of FIG. It is a CC end view of FIG. It is an end elevation (an end elevation corresponding to Drawing 3) of an optic part in the 1st modification of a 1st embodiment. It is a front view of the multifocal intraocular lens in 2nd Embodiment. It is the DD end view of FIG. It is the EE end view of FIG. It is a front view of the multifocal intraocular lens in 3rd Embodiment. It is the FF end view of FIG. It is a figure which shows a comparative example.

  Hereinafter, embodiments of the present disclosure will be described based on the drawings.

First Embodiment
[Description of the Intraocular Lens]
The multifocal intraocular lens in the present embodiment (hereinafter referred to as “intraocular lens 1”) includes an optical unit 10 and a support 12 as shown in FIG.

  The optical part 10 of this embodiment is formed in disk shape, as shown to FIGS. The optical unit 10 has an anterior surface 20 (optical surface of the anterior surface) which is on the cornea side when placed in the eye, and a posterior surface 22 (optical surface of the posterior surface) which is on the retina side. In the example shown in FIGS. 2 and 3, both surfaces of the front surface 20 and the rear surface 22 are convex.

  The optical unit 10 is formed of, for example, a hard material such as PMMA (polymethyl methacrylate), a single material such as silicone, or a foldable material made of a composite material of acrylic ester and methacrylic ester. The optical unit 10 may be integrally formed by a mold or the like, or may be formed by cutting. The details of the optical unit 10 will be described later.

  The support unit 12 is for fixing and supporting the optical unit 10 in the eye of the subject. The support part 12 of this embodiment is formed in a pair. The support portion 12 has a loop shape in which one end (proximal end) is joined to the optical portion 10 side and the other end (distal end) is a free end. The support 12 may be formed of a resin such as PMMA (polymethyl methacrylate), polypropylene, or polyimide. The support portion 12 of the present embodiment is bonded to the front surface 20 of the optical portion 10 at a predetermined angle (for example, about 0 to 10 degrees). Thereby, the optical part 10 is suitably arrange | positioned in the state by which the back surface 22 of the optical part 10 was pressed in the capsule.

  In FIG. 1, a three-piece type intraocular lens in which the optical unit 10 and the support unit 12 are separately formed and then integrated is taken as an example. However, the present embodiment can also be applied to a one-piece intraocular lens in which the optical part 10 and the support part 12 of the same material are integrally formed by cutting and molding.

[Detailed Description of Optical Section]
The optical part 10 in this embodiment equips the back surface 22 with base curve Cr, as shown in FIGS. The optical unit 10 also has a base curve Cf1 on the front surface 20 thereof. The base curve indicates the smooth overall shape of each of the front surface 20 and the rear surface 22 when the presence of the diffraction grating 42 (described later) of the diffraction region 30 is ignored. Here, the base curves Cr and Cf1 in the present embodiment are curved shapes for refracting the incident light by the refractive power and focusing the refracted light on the far focus f0. Note that one of the base curves Cr and Cf1 may have a planar shape.

  The optical section 10 of the present embodiment includes a diffractive area 30 and a non-diffracting area 32 on the rear surface 22. Then, the diffractive region 30 and the second region 32 b of the non-diffracting region 32 are formed in order in the circumferential direction of the optical unit 10. The diffraction area 30 of the present embodiment is an area for condensing incident light to the near focus f1 (a focus position closer to the far focus f0). That is, the incident light is diffracted by passing through the diffraction area 30, and is condensed at the near focus f1. The non-diffraction area 32 of the present embodiment is an area for condensing incident light at a predetermined far focus f0 (a focal position farther than the near focus f1). That is, incident light is condensed to the far focus f0 by passing through the non-diffraction region 32.

  In this embodiment, a plurality of focal points are given to the intraocular lens 1 by adding the addition degree generated by the diffractive region 30 to the dioptric power obtained by the refractive index and the curvature of the optical unit 10. In this embodiment, a predetermined distance focus f0 (distance power) for the subject having the intraocular lens 1 installed in the eye to perform distance vision, and a predetermined for the subject to perform near vision Of the near focus f1 (near power).

  The diffractive region 30 of the present embodiment is formed in a partial region of the rear surface 22. Specifically, four diffraction regions 30 are formed on the back surface 22. The four diffraction regions 30 are located on the outer peripheral portion 10 a side of the central portion (the first region 32 a of the non-diffraction region 32 and the central region) of the optical portion 10 in the radial direction of the optical unit 10. They are formed at equal intervals (every 90 °) in the circumferential direction. That is, a total of two pairs of diffraction areas 30 formed symmetrically about the optical axis O (the central axis of the optical unit 10) are formed.

  In the present embodiment, the width δA of the diffractive region 30 in the circumferential direction of the optical unit 10 changes in accordance with the radial position of the optical unit 10. Specifically, the width δA gradually increases in the radial direction of the optical unit 10 from the optical axis O toward the outer peripheral portion 10a and then gradually decreases.

  In the diffraction area 30 of the present embodiment, a plurality of arc bodies 40 formed in a concentric arc shape around the optical axis O are formed. The cross section of each arc 40 when viewed in a plane including the optical axis O is formed in a substantially sawtooth shape (see FIG. 3). Then, the diffraction grating 42 is provided at the boundary portion between the arc bodies 40 adjacent to each other in the radial direction of the optical unit 10. The diffraction grating 42 is formed on the surface on the optical axis O side of each of the arcs 40.

  The phase difference P of the diffraction region 30 of the present embodiment is one. As a result, the diffraction efficiency (distribution of light focused to a predetermined focal point) of primary light (light to be focused to the near focus f1) is approximately 100%. That is, in the diffraction area 30, incident light is diffracted by the diffraction grating 42 and condensed to approximately 100% near focus f1. The phase difference P is preferably 1, but may be in the vicinity of 1. In detail, the diffraction efficiency of the primary light obtained in the diffraction region 30 is preferably 80% or more. More preferably, the diffraction efficiency of the primary light obtained in the diffraction region 30 is preferably 90% or more. As the diffraction efficiency of the first-order light approaches 100%, it is possible to suppress the diffracted light of the unnecessary order generated in the diffraction region 30.

  In the multifocal intraocular lens of the known diffractive model, instead of providing a plurality of focal points in the diffractive area, unnecessary multiple order diffracted light generated in the diffractive area is generated. For example, assuming that the phase difference P is 0.5, the energy distribution to far vision (0th order light) and near vision (1st order light) is approximately 40% each, and the remaining approximately 20% is unnecessary multiple order diffracted light Become. The unnecessary diffracted light causes unpleasant light such as glare and halo.

  On the other hand, the intraocular lens 1 of the present embodiment raises the diffraction efficiency of primary light instead of providing only one focal point (primary light) in the diffractive area 30. By this, unnecessary diffracted light generated in the diffraction area 30 is suppressed. Thus, while suppressing generation of unnecessary diffracted light, the diffractive region 30 and the non-diffraction region 32 provide a plurality of focal points.

Here, the phase difference P is a parameter related to the energy distribution of 0th-order light (light to be focused on the far focus f0) and 1st-order light. That is, with the phase difference P, the light quantity of the light condensed to a predetermined focal point (in this embodiment, the near focus f1 in the present embodiment) by the diffraction grating 42 of the diffraction region 30 is q, and is collected by the diffraction grating 42 of the diffraction region 30 When the light quantity of all incident light to be emitted is Q, it is calculated by the following formula.
[Equation 1]
P = q / Q

Further, the height H in the direction of the optical axis O in the diffraction grating 42 is constant in the radial direction of the optical unit 10. When the design wavelength is λ, the refractive index of the peripheral medium (for example, water) is n1, and the refractive index of the material of the optical unit 10 is n2, the height H is a value calculated by the following equation Set to
[Formula 2]
H = (P × λ) / (n2-n1)

  Here, as an example, the phase difference P is 1, the design wavelength λ is 546 nm, the refractive index n1 is 1.336, and the refractive index n2 is 1.52. Then, the height H of the diffraction grating 42 is 0.00297 mm.

  The diffraction grating 42 is not formed in the non-diffraction region 32 of the present embodiment, and a base curve Cr is formed. That is, the curvature of the lens surface in the non-diffraction region 32 is equal to the curvature of the base curve Cr.

  The non-diffraction region 32 of the present embodiment includes a first region 32a and a second region 32b. The first region 32 a is formed in the central portion (a circular portion centered on the optical axis O) of the optical unit 10. The second region 32 b is formed in a portion between the diffraction regions 30 adjacent to each other in the circumferential direction of the optical unit 10 at a position closer to the outer peripheral portion 10 a than the first region 32 a.

  In the example shown in FIG. 1, the diameter d1 of the first region 32a is 25% of the diameter d2 of the optical portion 10, but is not particularly limited thereto, and is 20% to 70%. Is preferred.

  The width δB of the circumferential direction of the optical unit 10 in the second region 32b of the non-diffraction region 32 of the present embodiment changes in accordance with the position of the optical unit 10 in the radial direction. Specifically, the width δB becomes larger as it goes from the optical axis O side to the outer peripheral portion 10a side in the radial direction of the optical portion 10. Thereby, while the ratio occupied by the diffraction region 30 in the circumferential direction of the optical unit 10 decreases as going toward the outer peripheral portion 10a in the radial direction of the optical unit 10, the non-diffraction region 32 occupies in the circumferential direction of the optical unit 10 The proportion will increase.

  In other words, the overlapping ratio of the diffraction region 30 on the circumference of the virtual circle centered on the optical axis O decreases as the diameter of the virtual circle increases. On the other hand, the rate at which the non-diffraction region 32 overlaps on the circumference of the imaginary circle increases as the diameter of the imaginary circle increases. However, in the present embodiment, when the diameter of the imaginary circle is larger than the diameter (diameter d1) of the first region 32a, the above relationship is established.

  In other words, the explanation will be made. The diameter of the virtual circle centered on the optical axis O is larger than the diameter of the first region 32a (in this embodiment, larger than the minimum pupil diameter of the patient's eye (generally about 3 mm) ) Consider the peripheral area above. In the present embodiment, at least in the peripheral region, the ratio of the area of the diffraction region 30 in the region inside the virtual circle decreases as the diameter of the virtual circle increases. On the other hand, the proportion of the area of the non-diffraction region 32 in the region inside the virtual circle increases as the diameter of the virtual circle increases. In this case, at least in the peripheral region, the larger the pupil diameter of the patient's eye, the closer the energy distribution (that is, the ratio of the light amount of the light collected to the near focus f1 to the light amount of the light passing through the pupil) ) Becomes smaller. Therefore, when the pupil of the patient's eye is widely opened to perform far-field distance vision, light focused on the near focus f1 is less likely to be recognized by the patient as glare or halo.

  As an example, as illustrated in FIG. 1, the ratio of the non-diffraction region 32 in the circumferential direction of the optical unit 10 is the position of the boundary portion between the first region 32 a and the second region 32 b in the radial direction of the optical unit 10 It is 30% (or 20% to 70) at (the position closest to the optical axis O in the diffraction region 30), and 100% at the position closest to the outer peripheral portion 10a.

  Here, in order to obtain far vision and near vision, for example, a comparative example in which a plurality of regions having different curvatures of the lens surface are provided on the back surface 102 of the optical unit 100 (multifocal intraocular lens called refractive design) Assume. Then, in this comparative example, as shown in FIG. 11, the step h0 at the boundary between the regions (regions 104 and 106) becomes large. Normally, in the refractive structure, the boundary of the step h 0 is connected by a smooth curve, but there may be a large amount of unnecessary refraction and reflection light at the boundary. Then, for example, the contrast of the image formed on the retina of the subject is lowered, and the subject may not be able to comfortably perform near vision or far vision.

  On the other hand, according to the intraocular lens 1 of the present embodiment, the optical unit 10 includes the diffraction region 30 in which the diffraction grating 42 for diffracting the incident light is formed, and the non-diffraction region 32 in which the base curve Cr is formed. And.

  Then, since the height H of the diffraction grating 42 is very small, as shown in FIG. 4, the step h at the boundary between the diffraction area 30 and the non-diffraction area 32 is much higher than the height h 0 in the comparative example. Small. Therefore, it becomes difficult to generate unnecessary refracted and reflected light other than the zero-order and first-order diffracted lights in the step h. Therefore, for example, the contrast of the image formed on the retina of the subject hardly decreases. Therefore, the subject can comfortably perform near vision and far vision.

  Further, the width δB of the non-diffraction region 32 changes in the radial direction of the optical unit 10. Thereby, in the radial direction of the optical unit 10, distribution of energy for far vision and near vision (0th-order light (amount of light to be focused on far focus f0) and primary light (for near focus f1) Distribution of the amount of light) can be freely adjusted.

  Further, in the present embodiment, the diffraction area 30 is an area for condensing incident light on the near focus f1, and the non-diffraction area 32 is an area for condensing incident light on the far focus f0. Then, the ratio of the second region 32b to the non-diffraction region 32 in the circumferential direction of the optical unit 10 increases in the radial direction of the optical unit 10 toward the outer peripheral portion 10a. As a result, at least in the peripheral region, the energy for distance increases toward the outer peripheral portion 10 a side in the radial direction of the optical unit 10 (the distribution of 0th-order light increases). When performing far-field distance vision at night, the pupil of the subject is in a wide open state, so the proportion of near-use energy causing glare and halo is relatively small. Therefore, the subject can comfortably perform distance vision. For example, the subject can comfortably drive the car at night during which the pupil tends to widely open, with glare, halo, and the like being suppressed. Further, inside the peripheral area, the diffractive area 30 and the non-diffracting area 32 coexist at an appropriate ratio. Thus, for example, when the pupil of the subject is pupillated to perform near vision (a phenomenon called near vision reflection), the patient appropriately performs near vision with the light collected by the diffraction region 30. be able to.

  Further, since the phase difference P of the diffractive region 30 is 1 in the intraocular lens 1 of the present embodiment, unnecessary diffracted light in the diffractive region 30 with respect to the multifocal intraocular lens of the known diffraction type design described above The generation of (for example, secondary light) is suppressed. Therefore, for example, the occurrence of glare or halo is suppressed. Therefore, the reduction in contrast of the image formed on the retina of the subject is suppressed.

  In addition, the first region 32a of the non-diffraction region 32 is formed in the central portion of the optical unit 10 (the location of the first region 32a in FIG. 1, in other words, the central region). By thus reducing the area in which the diffraction grating 42 is formed in the central portion of the optical unit 10, molding of the optical unit 10 becomes easy. Therefore, the productivity of the intraocular lens 1 is improved.

  Further, two pairs of diffraction regions 30 formed symmetrically about the optical axis O are formed. That is, a plurality of diffraction regions 30 of the present embodiment are formed with a space between them in the circumferential direction of the optical unit 10, and the non-diffraction regions 32 are formed between the diffraction regions 30 adjacent in the circumferential direction of the optical unit 10. Be done. Thus, for example, even if the positional deviation of the intraocular lens 1 occurs in the eye of the subject, the subject can comfortably perform near vision and far vision. Also, for example, even if the intraocular lens 1 of the present embodiment is installed on a subject whose center of the pupil is decentered with respect to the visual axis, or a subject whose shape of the pupil is non-circular (for example, elliptical) The subject can comfortably perform near vision or far vision. Further, in the intraocular lens 1 of the present embodiment, the diffraction regions 30 are formed at equal intervals in the circumferential direction. As a result, for example, the influence of the positional deviation described above is less likely to be affected.

  As a first modified example in which a portion of the intraocular lens 1 of the first embodiment is formed, the incident light that has passed through the diffraction area 30 is focused on the near focus f1 as it goes further in the radial direction of the optical unit 10. The diffraction grating 42 of the diffraction region 30 may be formed so that the proportion of the light collected is reduced. As an example, as shown in FIG. 5, the height H of the diffraction grating 42 may be smaller toward the outer peripheral portion 10a in the radial direction of the optical unit 10 (that is, the intraocular lens 1 has an apodization characteristic) May). In this case, as the pupil widens to perform far-field night vision, the relative proportion of near-use energy is further reduced. Thus, glare and halo are further reduced. Even in this case, it is desirable that the phase difference P of the diffraction region 30 be close to 1 at a portion close to the center of the optical unit 10.

  Moreover, the number in which the diffraction area | region 30 is formed is not specifically limited. For example, as a second modification, eight diffraction regions 30 may be formed on the back surface 22.

  In addition, the diffractive region 30 and the non-diffracting region 32 may be formed on the front surface 20, or may be formed on both the front surface 20 and the rear surface 22. Further, in the first embodiment, the first region 32 a is formed at the central portion of the optical unit 10. However, the portion where the first region 32 a is formed may be replaced with the diffractive region 30. In this case, the closer to the optical axis O in the radial direction of the optical unit 10, the larger the proportion of energy for near use (the distribution of primary light becomes higher). Therefore, when the pupil of the subject is in a state of miosis for near vision, the ratio of energy for distance vision becomes relatively low. Therefore, the subject can comfortably perform near vision.

  Next, the second embodiment and the third embodiment will be described. The components equivalent to those of the first embodiment and the other embodiments are denoted by the same reference numerals and descriptions thereof will be omitted, and different points will be described. I will focus on it.

Second Embodiment
The optical part 10 in this embodiment equips the back surface 22 with base curve Cr, as shown in FIGS. 6-8. The optical unit 10 also has a base curve Cf2 on the front surface 20 thereof. Here, the base curves Cr and Cf2 in the present embodiment are curved shapes for refracting incident light with a refractive power and focusing the refracted light on the near focus f1.

  Here, the curvature of the base curve Cf2 in the second embodiment is set larger than the curvature of the base curve Cf1 in the first embodiment. Further, the base curve Cr of the first embodiment and the base curve Cr of the second embodiment are the same. Therefore, the base curves Cr and Cf2 of the second embodiment condense incident light at a closer distance than the base curves Cr and Cf1 of the first embodiment. Thereby, incident light is condensed to the near focus f1 when passing through the base curve Cf2 and the base curve Cr.

  The optical section 10 of the present embodiment includes a diffractive area 50 and a non-diffracting area 52 on the rear surface 22. Then, the diffraction region 50 and the second region 52 b of the non-diffraction region 52 are sequentially formed in the circumferential direction of the optical unit 10. The diffraction area 50 in the present embodiment is an area for condensing incident light on the far focus f0. That is, the incident light is diffracted by passing through the diffraction area 50, and is condensed at the far focus f0. The non-diffraction area 52 of the present embodiment is an area for condensing incident light on the near focus f1. That is, incident light is condensed to the near focus f 1 by passing through the non-diffraction area 52.

  The diffraction region 50 of the present embodiment is formed in a partial region of the rear surface 22. Specifically, four diffraction regions 50 are formed on the back surface 22. The four diffraction regions 50 are in the circumferential direction of the optical unit 10 at a position closer to the outer peripheral portion 10 a than the central portion (the first region 52 a of the non-diffraction region 52) in the radial direction of the optical unit 10 They are formed at equal intervals (every 90 °) with intervals. That is, a total of two pairs of diffraction areas 50 formed symmetrically about the optical axis O are formed.

  The width δA in the circumferential direction of the optical unit 10 in the diffraction region 50 of the present embodiment changes in accordance with the position of the optical unit 10 in the radial direction. Specifically, the width δA becomes larger as it goes from the optical axis O side to the outer peripheral portion 10a side in the radial direction of the optical portion 10. As a result, while the ratio of the second region 52b to the non-diffraction region 52 in the circumferential direction of the optical unit 10 decreases in the radial direction of the optical unit 10 toward the outer circumferential portion 10a side, the ratio in the circumferential direction of the optical unit 10 decreases. The proportion of the diffraction region 50 is increased.

  In the diffraction area 50 of the present embodiment, a plurality of arc bodies 60 formed in a concentric arc shape around the optical axis O are formed. The cross section of each arc 60 as viewed in a plane including the optical axis O is formed in a substantially sawtooth shape (see FIG. 8). Then, the diffraction grating 62 is provided at the boundary between the arcs 60 adjacent to each other in the radial direction of the optical unit 10. The diffraction grating 62 is formed on the surface on the outer peripheral portion 10 a side of the optical unit 10 in each arc body 60.

  The phase difference P of the diffraction region 50 of the present embodiment is one. As a result, the diffraction efficiency of zero-order light in the diffraction grating 62 becomes approximately 100%, disregarding the reflection loss on the surface of the diffraction area. That is, in the diffraction area 50, the incident light is diffracted by the diffraction grating 62 and condensed to approximately 100% on the far focus f0.

  The diffraction grating 62 is not formed in the non-diffraction region 52 of the present embodiment, and a base curve Cr is formed. That is, the curvature of the lens surface in the non-diffraction region 52 is equal to the curvature of the base curve Cr.

  The non-diffraction region 52 of the present embodiment includes a first region 52a and a second region 52b. The first region 52 a is formed in the central portion of the optical unit 10. The second region 52 b is formed in a portion between the diffraction regions 50 adjacent to each other in the circumferential direction of the optical unit 10 at a position closer to the outer peripheral portion 10 a than the first region 52 a.

  The width δB of the circumferential direction of the optical unit 10 in the second region 52b of the non-diffraction region 52 of the present embodiment changes in accordance with the position of the optical unit 10 in the radial direction. Specifically, the width δB gradually increases in the radial direction of the optical unit 10 from the optical axis O side to the outer peripheral portion 10a side and then gradually decreases.

  According to the present embodiment, the diffraction area 50 is an area for condensing incident light on the far focus f0, and the non-diffraction area 52 is an area for condensing incident light on the near focus f1. Then, the ratio of the diffraction region 50 in the circumferential direction of the optical unit 10 increases as the radial direction of the optical unit 10 is closer to the outer peripheral portion 10 a. Thereby, the energy for distance is increased toward the outer peripheral portion 10 a in the radial direction of the optical portion 10 at a position closer to the outer peripheral portion 10 a than the central portion of the optical portion 10 (the first region 52 a of the non-diffraction region 52). Will increase. Therefore, when the pupil of the subject is in a wide-opened state in order to perform distant vision at night, the unnecessary near-use energy becomes relatively low, and the subject can comfortably perform far vision. For example, the subject can comfortably drive the car at night during which the pupil tends to widely open, with glare and halo suppressed. Moreover, the energy for near use increases as it goes to the optical axis O side in the radial direction of the optical unit 10. Therefore, when performing near vision, the pupil of the subject is in a small open state, but the subject can perform near vision comfortably.

  As a first modified example in which a part of the intraocular lens 1 of the second embodiment is formed, the distance focus f0 of incident light having passed through the diffraction region 50 as it goes further to the radial direction of the optical unit 10 The diffraction grating 62 of the diffraction region 50 may be formed so as to reduce the proportion of light collected. As an example, the height H of the diffraction grating 62 may be smaller toward the outer peripheral portion 10 a in the radial direction of the optical unit 10. That is, the intraocular lens 1 may have an apodization characteristic.

  Moreover, the number in which the diffraction area | region 50 is formed is not specifically limited. For example, as a second modification, eight diffraction regions 50 may be formed on the back surface 22.

Third Embodiment
In the present embodiment, as shown in FIGS. 9 and 10, the diffractive region 30 is within the range of the central angle α1 centered on the O axis in the circumferential direction of the optical unit 10 and the diameter of the optical unit 10 It is formed in a fan shape from the position of the optical axis O in the direction to the position in the vicinity of the outer peripheral portion 10a. The diffraction area 30 diffracts incident light and focuses it on the near focus f1. The non-diffraction region 32 focuses incident light to the far focus f0. The central angle α1 is 120 ° in the example shown in FIG. 9, but is not particularly limited to this, and preferably 90 ° to 270 °. In the present embodiment, the shapes of the diffraction region 30 and the non-diffraction region 32 are simplified as compared with the first embodiment and the second embodiment. Therefore, the manufacture of the intraocular lens 1 is facilitated.

  As a first modification in which a portion of the intraocular lens 1 of the third embodiment is formed, the height H of the diffraction grating 42 is smaller toward the outer peripheral portion 10 a in the radial direction of the optical unit 10. Good. That is, the intraocular lens 1 may have an apodization characteristic.

  As a second modification, the non-diffraction region 52 may be substituted for the diffraction region 30, and the diffraction region 50 may be substituted for the non-diffraction region 32.

  The embodiment described above is merely an example, and does not limit the present disclosure in any way, and it goes without saying that various improvements and modifications can be made without departing from the scope of the invention.

  For example, the diffraction area 30 of the first embodiment and the diffraction area 50 of the second embodiment may be formed up to the position of the optical axis O in the radial direction of the optical unit 10.

  Further, the front surface 20 and the rear surface 22 may be configured by a combination of a convex surface, a concave surface, and a flat surface.

  Further, a plurality of diffraction regions 30 of the third embodiment may be formed. Also, each of the plurality of diffractive regions 30 may provide a different focus. In this case, for example, the intraocular lens 1 is provided with three or more focal points by preparing plural kinds of diffraction areas different in focal position while setting the phase difference P of each of the plural diffraction areas 30 to 1. Can be provided.

  Further, in the embodiment of FIG. 1 (first embodiment), two types of focal points are given by the diffraction region 30 and the non-diffraction region 32. However, each of the two types of focal areas may be both diffractive areas. That is, the non-diffraction region is not necessarily required. In this case, the base curves of the respective diffraction regions may be the same. It is needless to say that the phase difference of each diffraction region is preferably 1. However, in this case, the ratio of the diffraction region formed in the optical unit 10 is larger than that in the first to third embodiments. In the diffractive region, unintended refraction and scattering of light are more likely to occur than in the non-diffraction region. Therefore, in the first to third embodiments, unintended refraction and scattering of light are less likely to occur than in the case where the non-diffraction region is not used.

DESCRIPTION OF SYMBOLS 1 intraocular lens 10 optical part 10a outer peripheral part 12 support part 20 front surface 22 rear surface 30 diffraction area 32 non-diffraction area 32a first area 32b second area 40 arc body 42 diffraction grating 50 diffraction area 52 non-diffraction area 52a first area 52b Second region 60 Arc body 62 Diffraction grating Cr (for back surface) Base curve Cf1 (for front surface) Base curve Cf2 (for front surface) base curve f0 Far focus f1 Near focus O Optical axis δA Width δA Width δB Width P Phase difference q Light intensity Q Light quantity H Height λ Design wavelength n1 Refractive index n2 Refractive index d1 Diameter (for first region) Diameter d2 (for optical part) Diameter h Step α1 Central angle

Claims (3)

A multifocal intraocular lens inserted into the eye of a patient's eye, comprising:
An optical unit having an optical surface on the front surface and an optical surface on the rear surface, and condensing incident light;
The optical unit is
A diffraction area provided in a partial area of the optical surface and provided with a diffraction grating that diffracts the incident light and condenses the incident light to at least a first focal position;
Of the optical surface provided with the diffractive region, a curved surface or a flat surface is formed in a region other than the diffractive region, and the incident light is collected at a second focal position farther or closer than the first focal position. The non-diffracting region
Equipped with
The diffraction region and the non-diffraction region are sequentially formed in the circumferential direction of the optical unit,
The ratio of the area of the area of the diffraction area and the non-diffraction area to which the incident light is condensed to the near side in the area inside the circle centered on the optical axis of the optical unit is the diameter of the circle The bigger it gets smaller,
That the phase difference of the diffraction region is 1;
Multifocal intraocular lens characterized by The multifocal intraocular lens of claim 1, wherein
The width in the circumferential direction of the optical unit in the region for condensing the incident light to the near side among the diffractive region and the non-diffraction region is the optical axis from the optical axis side of the optical unit in the radial direction of the optical unit And then gradually become smaller toward the outer periphery of the part,
Multifocal intraocular lens characterized by The multifocal intraocular lens according to claim 1 or 2,
The multifocal intraocular lens, wherein the non-diffraction region is formed at least in a central region centered on the optical axis of the optical unit.

Images