WO2021116298A1

WO2021116298A1 - Intraocular lens and method for replacing a natural eye lens

Info

Publication number: WO2021116298A1
Application number: PCT/EP2020/085558
Authority: WO
Inventors: Benjamin SCHREIBER
Original assignee: Carl Zeiss Meditec Ag
Priority date: 2019-12-13
Filing date: 2020-12-10
Publication date: 2021-06-17
Also published as: DE102019134386A1; EP4072469A1

Abstract

The invention relates to an intraocular lens which has a lens body and is designed for insertion in the human eye. The lens body is in the form of a flat, plane-parallel, elastically resilient membrane (14) made of a transparent material on or in which membrane a Fresnel zone structure (13) is formed.

Description

Intraocular lens and method for replacing a natural lens of the eye

The invention relates to an intraocular lens which has a lens body and is designed for insertion into the human eye, as well as a method for replacing a natural eye lens.

Intraocular lens (IOL) insertion is a common treatment for treating cataracts. The lens of the eye clouded by the cataract is removed and replaced with an implanted intraocular lens. However, the insertion of an intraocular lens may also be necessary for other reasons. Lately, optical concepts have been implemented that realize the correction of presbyopia and / or correct an astigmatism. As a result, cataract surgery experienced a change from classic geriatric surgery to refractive surgery with the aim of achieving freedom from glasses over all visual distances and with the highest quality of vision. The great majority of the intraocular lenses are implanted in the remaining empty remainder of the capsular bag. To do this, the anterior capsular bag membrane is opened by a capsulorhexis, the natural lens of the eye is crushed and removed, and the posterior chamber intraocular lens is inserted into the remaining capsular bag. Posterior chamber intraocular lenses have holding devices that are referred to as “haptics” and are attached to the optically effective lens body of the intraocular lens in order to fix and position it correctly in the capsular bag. Another way to use an intraocular lens is to fix it to the iris. So-called anterior chamber intraocular lenses are used for this purpose.

With regard to known intraocular lenses, reference is made to the following publications: US 4242761, DE 2605847 A1, US 4244060, US 2008/183289, DE 2725219 A1, US 4166293, US 4177526 A, DE 2945349 A1, US 4268921 A, DE 3130278 A1, US 2002 / 128710 A,

DE 10105080 B4, DE 10134072 B4, US 5728155 A, US 2007/010881 A, WO 99/56670 A1,

WO 00/21467 A1, US 2013/190868 A, US 6007579 A, US 2003/158560 A, US 2002/143394 A, US 2007/244561 A, US 2010/204787 A, WO 2012/054854 A2, EP 1667612 A1, US 5443506 A, US 5066301, AU 2004/02852, WO 2008/077795 A2, US 9095424 B2, WO 2017/096087 A1 and CA 3002085 A1.

Both single-part and multi-part intraocular lenses are therefore known from the prior art. From X. Li et al. , "Stretchable Binary Fresnel Lens for Focus Tuning", Scientific Reports, May 2016, DOI: 10.1038, a Fresnel lens is known which is designed as a Fresnel zone plate on a flexible len substrate that can be bent differently. The focal length changes with the deflection. EP 560664 A1 and CN 104849792 A also relate to Fresnel zone plates.

A. Khan et al., "Change in human lens dimensions, lens refractive index distribution and ciliary body ring diameter with accommodation," Biomedical Optics Express, Vol. 9, No. 3, February 2018, pp. 1272-1282 with dimensions in the capsular bag and the changes in size that occur during accommodation.

S. Daya et al., “Parameters affecting anterior capsulotomy tear strength and distension,” Journal of Cataract & Refrative Surgery, Vol. 45, No. 3, March 2019, pp. 355-360, deals with aspects of anterior capsulotomy , the opening of the front of the capsular bag that occurs during cataract surgery.

The invention is based on the object of specifying an improved intraocular lens and an improved method for cataract surgery.

The invention is defined in the independent claims; the dependent claims relate to preferred developments.

The intraocular lens (IOL) has a lens body and is designed for insertion into the human eye. The lens body is designed as a flat, elastically stretchable, preferably planparal lele membrane made of transparent material. A planar focusing system is formed on or in this membrane. Due to the elastic stretchability of the transparent material, the focusing system formed in or on the diaphragm is also stretched when the diaphragm is stretched, with the stretching changing the focusing system in such a way that the focal length changes. Examples of a planar focusing system are Fresnel zone structures that can be phase and / or amplitude modulated. Diffractive structures are also possible. The intraocular lens is placed in the eye in such a way that the muscles of the eye stretch or relax the elastic-stretchable membrane while accommodating, preferably radially symmetrically. For accommodation, the membrane is elastically stretched in such a way that a change in the focal length of the intraocular lens and thus the desired adaptation that is required for visual accommodation results. As with the natural lens, the physiological forces exerted by the eye are used for accommodation. The membrane of the implanted IOL is stretched elastically by the muscles that are naturally activated during the process of accommodation. In the understanding on which this is based, planar focusing systems are planar lenses made of metamaterials, hologram-generating surfaces and / or phase- and / or amplitude-modulated systems. They are based in particular on Fresnel zone structures and their special cases. Metamaterials are systems, such as nano- or microstructures, which allow an unusual refractive power, for example less than 1 or negative values. Usually there are microresonators or plasmonic systems with dimensions in the range of hundreds of nanometers to a few micrometers. The size depends on the wavelength of the interacting light. Depending on the resonator system, the decisive structure size is usually in the range from 0.1 to 2x the wavelength. The systems are indeed three-dimensional from a microscopic point of view, but can still be viewed as planar in comparison to the thickness of the membrane.

With such metamaterials, a lens can be produced which, viewed macroscopically, also realizes a planar focusing system.

The membrane can be fastened within the capsular bag and / or over a capsulorhexis opening. For attachment to the edge of the membrane, at least one haptic is optionally provided for securely attaching the membrane to the capsular bag of the eye.

The attachment of the membrane to the capsular bag ensures that as the capsular bag is stretched by the cillary muscles, the membrane and thus the planar focusing system are also stretched. For this purpose there are, inter alia. two options:

The membrane can be provided with through openings at the edge, which allow the membrane to be sewn to the capsular bag over the capsulorhexis. Alternatively, the membrane can be introduced into the capsular bag and attached to its inner wall. For this purpose, it is preferred to design the haptics in the form of webs which protrude outward at the edge of the membrane. The haptics are particularly preferably arranged on the edge of the membrane, with several haptics being arranged in a ring on the edge of the membrane. Such haptics can particularly preferably be attached to the inner circumference of a ring, which in turn is designed to be attached to the capsular bag equator of the eye. In the surgical procedure, the ring, which can be segmented particularly preferably, is attached to the capsular bag equator, for example glued. The membrane is attached to the inside of the ring, for example glued or fastened by snap-in connections, etc.

Since the lens body is a planar structure due to the planar focusing system, the size of the intraocular lens is exclusively defined by the geometry of the membrane. The comparatively thin membrane can be rolled up tightly and can thus achieve a very small cross-section for the implantation process. The cut sizes in cataract surgery are thus reduced compared to the prior art, which leads to improved wound healing and an improved overall surgical result. At the same time, the cutting size is independent of the refractive power of the intraocular lens, which is not the case with conventional intraocular lenses.

In one embodiment, the planar focusing system has a Fresnel zone structure, which is preferably characterized by a sequence of concentric, light-absorbing rings which are each separated from one another by transparent rings. So rings that block the light are followed by rings that transmit the light. Such a Fresnel zone structure can particularly preferably be achieved by coloring a transparent, elastically stretchable material in membrane form, for example by means of corresponding particles, dyes, etc., which are printed on the membrane or introduced into the membrane.

The focal length f of this Fresnel zone structure with a ring structure results as follows:

(1 )

In this equation, l stands for the wavelength, r _n for the nth transition between a transparent and an absorbing ring area and D for the refractive power in diopters. The factor s is linked to the enlargement of the Fresnel zone structure, which is generated by the stretching of the membrane. The basic geometry of the (unstretched) Fresnel zone structure is given by the radius r _n , which defines the basic focal length fo of the unstretched structure.

In a further embodiment, the planar focusing system has a phase modulating Fresnel zone structure, which is preferably characterized by a sequence of annular thickenings of the plate. Such structures are known for so-called Fresnel lenses. Since they are formed on the elastically stretchable membrane and are made of the same material as the membrane, the expansion of the membrane also leads to a change in the position of the focus here. The change in the focal length is proportional to the expansion ratio and the following applies: i = f (s) = (A / A ₀ ) - f ₀

(2) In this equation, A stands for the area of the stretched membrane and Ao for the area of the unstretched membrane.

Such diffractive structures have the same effect in terms of expansion as an amplitude-modulated Fresnel zone structure with absorbing rings and non-absorbing ring gaps. They are made, for example, by embossing an elastic membrane and have a non-even surface. Their transmittance can be higher.

Purely diffractive systems have the advantage of lower chromatic aberration. Diffractive systems are, for example, phase or amplitude modulated systems. They generate interference by blocking or amplitude shifting and use this to generate a focus. Here nanoparticle systems, for example known from D. Werdehausen et al., “Dispersion-engineered nanocomposites enable achromatic diffractive optical elements”, Optica, 2019, can be used to increase efficiency, as they direct more light into the first diffraction order.

The elastic properties of the membrane are preferably matched to the physiology of the eye by using a very flexible material for the membrane. With a modulus of elasticity between 0.5 MPa and 1.5 MPa, preferably 1 MPa ± 10%, the force that can be achieved by the eye muscles in the ciliary body allows a membrane thickness of 30 gm to 50 gm, preferably 35 gm ± 20%, and a diameter of the membrane (measured without any haptics) of 4 mm, a change in the refractive index from about 20 diopters to 26 diopters. This corresponds to a focus adjustment from 40 cm to 4 m for a standard eye.

It was also found that a hole of up to about 200 gm in diameter, preferably up to 50 gm, can be left in the center of the membrane. This does not interfere with the visual effect and has the further advantage that the humor can flow freely in the capsular bag.

A favorable diopter adjustment range of around 3 diopters is also obtained if the material has a Shore hardness of 20A to 50A. This Shore hardness range is therefore given before. Suitable materials for producing the elastic-stretchable membrane are elastomers made of silicone, nitrile and / or latex.

The described intraocular lens is generally dependent on the wavelength with regard to the focal length, as, for example, the above equation (1) shows. This problem arises when used as an intraocular lens to a lesser extent than in conventional optical applications, since the human brain is able to correct such errors. Nevertheless, the task arises, one Lens that has a planar focusing system, for example as a Fresnel zone structure, in a flexible membrane to be designed so that the optical quality is improved. This task also arises regardless of whether it is used as an intraocular lens.

For this purpose, a lens is provided which has a lens body which is designed as a flat (preferably plane-parallel), elastically stretchable and / or elastically deformable membrane made of transparent material, on or in the planar focusing system as an amplitude-modulated Fresnel zone structure, with the Fresnel zone structure has at least two zones which differ in terms of their spectral selectivity and their geometry, where each zone acts in a spectral range in which the at least one other zone does not act.

In a preferred embodiment, the zones are sets of concentric, spectrally selective light-absorbing ring zones of the Fresnel zone structure which absorb spectrally differently in order to provide the spectrally selective effect. This Fresnel zone structure therefore has several ring zone structures, each of which is optimized for a specific wavelength or a specific wavelength range. The wavelength range is given by the range in which the respective ring zone structure absorbs. The ring zone structure is matched to the respective wavelength range in which the corresponding ring zone structure is subordinate.

The individual geometries of the zones are selected in such a way that the respective wavelength in which the corresponding zones act is obtained the same focal length as for the other zones. In this way a chromatic correction is achieved. The individual zones therefore do not interact with one another in terms of focus generation, since each zone only acts in an individual wavelength range.

As a result, the Fresnel zone structure consists of a superposition of at least two ring zone structures which absorb in an individual wavelength range in which the other ring zone structures or the other ring zone structure is transparent. These ring zone structures have ring geometries that are matched to the respective wavelength range. All ring zone structures are designed in such a way that they produce the same focal length in the wavelength range assigned to them. Since the other ring zone structures do not absorb in the wavelength range of a ring zone structure, a chromatic correction can be achieved very easily in this way. The individual ring zone structures do not interact with one another in terms of focus generation, since each ring zone structure only acts in an individual wavelength range. In this way, for example, an adjustment for blue, green and red can be generated with three ring zone structures.

This principle can of course be used particularly preferably for the intraocular lens mentioned at the beginning. However, it is also generally intended for optical systems (e.g. lenses) whose focal length is to be adjusted. The membrane does not necessarily have to be subjected to an expansion lying in one plane, as is the case with the intraocular lens. Rather, a deformation is equally possible, as described in the article by X. Li et al. is described. Insofar as the application of this principle for the further development of an intraocular lens is described below, this is not to be understood as limiting; Rather, a corresponding zone that effects a chromatic correction can also be used independently of an intraocular lens and in particular also independently of haptics or fastening techniques that are described above or below in connection with an intraocular lens.

In the embodiments, the expansion of the membrane is brought about by the natural accommodation activity. The intraocular lens is suitably connected to the capsular bag. In embodiments, this can be done in such a way that the increase in the maximum capsular bag diameter also causes the intraocular lens to expand. For this purpose, in embodiments, the intraocular lens is attached in or near the capsular bag equator. In other Ausführungsfor men, the expansion takes place indirectly, in that the axial compression of the capsular bag associated with the expansion of the capsular bag is converted into the expansion of the membrane via a mechanism. This construction has the advantage that no force-fit fastening on or near the capsular bag equator is required.

In addition to the expandable membrane, the intraocular lens can have a non-accommodating additional lens. This is particularly advantageous when the intraocular lens has to provide a comparatively high refractive power that could not be realized by the flexible membrane alone or only with optical restrictions. The additional lens can also bring advantages in other cases, since the refractive power of the planar focusing system can be reduced. The intraocular lens then additionally comprises an additional lens, which is usually curved, which is arranged, for example, posterior or anterior to the elastic membrane and which is not influenced by the accommodation activity of the eye. It provides a basic refractive power that is desirable for medical and / or optional reasons, for example. It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the specified combinations, but also in other combinations or on their own without departing from the scope of the present invention.

The invention is explained in more detail below on the basis of exemplary embodiments with reference to the accompanying drawings, which also disclose features that are essential to the invention. These exemplary embodiments are used for illustration purposes only and are not to be construed as restrictive. For example, a description of an exemplary embodiment with a large number of elements or components should not be interpreted in such a way that all of these elements or components are necessary for implementation. Rather, other exemplary embodiments can also contain alternative elements and components, fewer elements or components, or additional elements or components. Elements or components from different exemplary embodiments can be combined with one another, unless otherwise stated. Modifications and variations which are described for one of the exemplary embodiments can also be applied to other exemplary embodiments. To avoid repetition, elements that are the same or that correspond to one another are denoted by the same reference symbols in different figures and are not explained more than once. From the figures show:

Fig. 1 is a schematic representation of an eye with inserted, elastic intraocular lens,

Fig. 2 is a schematic representation to illustrate the accommodation with the intraocular lens of Fig. 1, Fig. 3 is a plan view and a sectional view of an elastic part of the intraocular lens of Figs. 1 and 2, which is designed as an amplitude-modulated Fresnel zone plate,

Fig. 4 is a schematic illustration to explain the implantation and anchoring of the intraocular lens in the eye, Fig. 5 is a plan view similar to Fig. 3, the haptics of the intraocular lens shows additional Lich,

6 shows a representation similar to FIG. 4 relating to a different type of anchoring of the intraocular lens,

7 shows an enlarged detail of FIG. 6 to explain the anchoring of the intraocular lens,

8 and 9 are schematic representations similar to FIG. 3 relating to a chromatically corrected lens,

10 absorption spectra of ring structures of the lens of FIGS. 8 and 9, 11 and 12 are sectional views similar to FIG. 3, but for an embodiment which has a phase-modulated Fresnel zone plate,

13 shows a representation similar to FIG. 4, the Fresnel zone plate being formed in a curved membrane, FIGS. 14 and 15 embodiments in which an additional lens is provided in addition to the elastically stretchable intraocular lens in order to increase the optical effect of the intraocular lens , and

16 shows an embodiment similar to that of FIG. 14, a different mechanical principle being used to convert the deformation of the capsular bag which occurs during accommodation into a stretching of an elastic part of the intraocular lens.

1 schematically shows a sectional illustration through an eye 2 which has a cornea 4. An intraocular lens 6, which can be accommodated and will be explained in detail later, is implanted in the eye 2. The intraocular lens 6 is fastened in a capsular bag 8, from which the natural lens of the eye has been removed through an opening which is not shown in detail. The capsular bag 8 is stretched by a cillary muscle 10 via cillary fibers 12 for accommodation. The fastening of the intraocular lens 6 in the capsular bag 8 is such that the intraocular lens 6 follows this expansion, that is to say is stretched when the cillary muscles 10 are shortened. The corresponding effect can be seen in FIG. The expansion of the intraocular lens 6 changes the focus length between a near focus fN and a far focus fF. The intraocular lens 6 is stretched in that it follows the enlargement of the capsular bag that occurs during accommodation. For this purpose, it is suitably fastened, for example, to the capsular bag equator or connected to the sem with tensile strength. The implementation of the activity of the ciliary muscles 10 in an expansion of the intraocular lens 6 can, however, as will be explained below, also take place in other ways. Insofar as the focus below is on fastening the intraocular lens in the area of the capsular bag equator, this is only to be understood as an example.

3 schematically shows a top view of the intraocular lens 6, although structural elements which are used to fasten the intraocular lens 6 in the eye in such a way that they can be stretched by the ciliary muscles 10 are not shown. In the embodiment shown, the intraocular lens 6 comprises an amplitude-modulated Fresnel zone structure 13 which is formed on a transparent membrane 14. A ring structure 15 made of radiation-absorbing rings 16 is formed on this transparent membrane 14. The amplitude modulation is not mandatory. Similarly, phase modulation can alternatively be used, as will be explained below with reference to FIGS. 11 and 12. It is essential that the intraocular lens has an elastic membrane 14 and on / in this has a planar focusing system, the focal length of which depends on the expansion of the elastic membrane 14 depends. As a result, an expansion of the membrane 14 is converted into a change in the refractive power and therewith the optical effect of the intraocular lens 6, so that the natural accommodation capacity is maintained or becomes possible again.

An expansion of the amplitude-modulated Fresnel zone structure 13 formed in the membrane 14 changes the geometry of the ring structure 15 (e.g. the distances between the rings 16) and thus the focal length. The same applies in the case of the phase-modulated Fresnel zone structure and / or in the case of diffractive structures. In this way, an expansion of the membrane 14, which consists of an elastically stretchable material, can be implemented for accommodation.

The intraocular lens 6 is fastened in the eye in such a way that the natural accommodation activity causes a corresponding expansion of the membrane 14 of the intraocular lens 6. It has been found to be particularly preferred that the modulus of elasticity of the membrane 14 is approximately 1 MPa ± 30%. Furthermore, the Poisson's number is preferably slightly below 0.5, particularly preferably 0.49. The value ranges mentioned above in the general part of the description have been found to be useful for generating the desired change in focal length during accommodation.

The thickness h of the transparent membrane 14 is, for example, 35 μm, its diameter d 4 mm. Since the central area of the Fresnel zone structure 13 has no optical effect, an optional hole 18 is formed here. This allows the aqueous humor to flow between sections posterior and sections anterior of the intraocular lens 6. The Fresnel zone structure 13 generates a focus and is measured in such a way that the optical effect of the removed natural lens of the eye is replaced.

For the fastening of the intraocular lens 6 in such a way that the membrane 14 is correspondingly stretched during the naturally performed accommodation activity, several variants are possible. A first variant is shown in FIG. Here, the intraocular lens 6 is provided on the edge of the flexible len membrane 14 with haptics 20, which can either be formed from the same material as the flexible membrane 14, or are more rigid. PMMA, silicone, IOL material such as hydrophobic or hydrophilic acrylate can be used as rigid material. The haptics 20 are attached on the one hand to the edge of the membrane 14 and, on the other hand, to a ring 22 which, in turn, is firmly attached in the capsular bag equator. The advantage of such a configuration with a stiffer edge is that the expansion is limited to a central area of the membrane 14, whereby a greater change in position of the focus position is possible. The ring 22 can, as the plan view of FIG. 5 shows, be segmented. It then has ring segments 24 in which the ring 22 is enlarged and designed for attaching the flaptics 20. The flaptics 20 are preferably designed as fixed webs, so that there is an opening between the individual haptics 20, which is used for fluid exchange. At the same time, the webs ensure the necessary transfer of force between the capsular bag 8 and the elastic-stretchable membrane 14. For this reason, other, in particular radially symmetrical, arrangements with more or less haptics, which ensure the transmission of force between capsule bag 8 and membrane 14, are possible. As an alternative or in addition, the haptics 20 can also have openings 24 for their part. It is equally possible to design the haptics 20 as a single ring-shaped haptic.

It is particularly preferred for the stretching to fasten the elastic-stretchable membrane 14 with the Fresnel zone structure 13 in the eye 2 in such a way that it is stretched radially symmetrically. In FIG. 5, the haptics 20 are therefore arranged in a ring with an angular spacing of 45 °. Of course, the number of haptics can also be reduced or decreased. In simplified versions, it may be sufficient to use only two haptics 20.

A second variant of the fastening of the Fresnel zone structure 13 on the elastically stretchable membrane 14 in such a way that the accommodation activity leads to an expansion of the Fresnel zone structure 13 is shown in FIG. 6 and in an enlarged detail in FIG. 7. The membrane 14 is preferably attached to the front or, alternatively, the back of the capsule bag 8. In FIG. 6, the membrane is located over the opening (which can no longer be seen as a result) that was created during the capsulorhexis in order to remove the nucleus of the lens. The membrane can be fixed to the capsular bag 8 by suitable means. Fig. 7 shows this anterior (or posterior) connecting rings which are set through one of the openings 24 and who are anchored to the capsular bag 8, for example sewn. Gluing is also possible.

As already explained in the general part of the description, the focal length for a given ring structure 15 is dependent on the wavelength. It is therefore preferred in a further development to provide two or, as FIGS. 8 and 9 show, three (alternatively also more) single ring structures 15a, 15b and 15c in the Fresnel zone structure 13, which generate the same focal length for different wavelengths. In FIG. 8, the wavelength increases from the ring structure 15a to 15b and 15c. Furthermore, the individual rings 16a, 16b and 16c of the ring structures 15a, 15b and 15c are absorbent and / or reflective in different spectral ranges. This is shown schematically in FIG. The rings 16a of the ring structure 15a have the absorption spectrum 28a, the rings 16b of the ring structure 15b the absorption spectrum 28b and the Rings 16c of the ring structure 15c the absorption spectrum 28c. The same applies in the case of reflection or backscattering for a reflection or scatter spectrum. As FIG. 10 shows, the ring structures are each absorbent in an individual spectral range and, in particular, do not absorb in the spectral range in which one of the other ring structures absorbs. Thus, each ring structure only acts within the spectral range in which it is absorbent, and the geometry of the ring structure is then also designed for this spectral range. As a result, it is sufficient that the ring structures 15a to 15c generate the same focal length in their respective spectral range. By superimposing the ring structures 15a to 15c, as shown in FIG. 9, a Fresnel zone structure which is chromatically corrected is thus obtained.

As already mentioned, the implementation of the intraocular lens 6 is not restricted to amplitude-modulated Fresnel zone structures. Likewise, alternatively or additionally phase modulating structures come into question, as shown in FIG. 11. The ring structure 15 provided on the flexible membrane 14 (e.g. produced by embossing) then has rings 16 which modulate the phase of the incident radiation and thus cause the radiation to be bundled in a focus 30. The focal length fo in the unstretched state does not correspond to the focal length in the expanded state, which is shown in FIG. Rather, the focus 30 shifts in accordance with the area ratio between the stretched and unstretched state (cf. equation 2 above). In this way, an expansion of the membrane 14 with the ring structure 15 can equally be used for accommodation. Of course, combinations of phase-modulated Fresnel zone plates according to FIG. 11/12 and amplitude-modulated Fresnel zone plates according to FIG. 3 are possible, either as two separate plates or on a single membrane 14.

Although plane-parallel membranes 14 have so far been mentioned as supports for the focusing structures in the embodiments, it is advantageous for certain configurations to provide membrane 14 with a curvature 34. This embodiment is shown in FIG. 13 purely by way of example for an amplitude-modulated Fresnel zone structure and applies equally to the phase-modulated variant of FIGS. 11 and 12. It has the advantage that the curvature 34 likewise generates an optical refractive power, so that the desired accommo dation adjustment range can be increased by an offset. This can be necessary in certain applications, namely when a comparatively high refractive power is to be provided for a patient by the implanted intraocular lens. Since the curvature 34 also changes as a result of the expansion symbolized by arrows 32 (cf. the one in Fig.

13 dashed line), the intraocular lens of FIG. 13 also has the advantage that the adjustment range that can be achieved with accommodation is enlarged. This Ausfüh approximately form is therefore not only advantageous in cases where a greater refractive power is desired but it can also be advantageous in applications that do not require a particularly large refractive power for optical correction during cataract surgery, because the necessary refractive power of the Fresnel zone plate is reduced due to the refractive power caused by the curvature 34. As a result, a larger optically active zone can be used for the Fresnel zone plate, which improves side effects such as diffraction and transmission.

When choosing the curvature, a comparison with regard to chromatic errors is preferred. It can, for example, be selected to be so small that the chromatic errors that occur are negligible.

The accommodative intraocular lens 6 can, as shown in FIGS. 14-16, additionally be supplemented by a non-accommodative part, which is provided in the form of an additional lens 36, which is either posterior or anterior to the elastic part (usually the membrane 14) Intraocular lens 6 is located. As a result, not only can the possible basic refractive power of the intraocular lens 6 be increased, but at the same time emmetropia or astigmatism can be corrected Let the spacing of the rings be chosen favorably.

16 shows how the expansion of the membrane 14 of the intraocular lens 6 can be increased by means of a lever system 38 which is supported on the non-accommodating additional lens 36.

The expansion indicated by the arrow 32 is converted by the haptics 20 with an element 38 acting as a bilateral lever into a comparatively greater expansion 40 of the flexible part of the intraocular lens 6, i.e. the membrane 14. This increases the extent of accommodation that can be achieved by enlarging the capsular bag equator, which is physiologically predetermined with regard to its maximum enlargement.

Claims

1. Intraocular lens, which has a lens body and is designed for insertion into the human eye (2), the lens body as a flat, plane-parallel, elastically stretchable

Membrane (14) is made of transparent material, on or in which a planar focus siersystem is formed, which has at least one of the following structures: a phase-modulated Fresnel zone structure, an amplitude-modulated Fresnel zone structure (13) and a diffractive structure.

2. Intraocular lens according to claim 1, characterized in that the planar focusing system has a Fresnel zone structure (13) comprising a sequence of concentric, light-blocking ring zones which are each separated from one another by transparent rings (16).

3. Intraocular lens according to claim 2, characterized in that the Fresnel zone structure (13) at least two sets (15a-c) of concentric, spectrally selectively light-absorbing ring zones (16a-c) which differ in terms of their spectral selectivity and their ring zone geometry , each set (15a-c) of ring zones (16a-c) absorbing in a spectral range (28a-c) in which the at least one other set (15a-c) of ring zones does not absorb.

4. Intraocular lens according to one of the above claims, characterized in that at least one haptic (20) for the stretch-resistant attachment of the membrane (14) to the capsular bag (8) of the eye (2) is provided on the edge of the membrane (14), so that the membrane (14) and the planar focusing system are expandable through the capsular bag.

5. Intraocular lens according to claim 3, characterized in that the haptics (20) are designed in the form of webs which protrude outward on the edge of the membrane (14).

6. Intraocular lens according to one of the above claims, characterized in that the

Membrane (14) has a plurality of through openings (24) at the edge, which are designed for the stretch-proof attachment of the membrane (14) to haptics and / or to the capsular bag (8) of the eye (2), so that the membrane (14) and the planar focusing system through the haptic ken and / or the capsular bag is stretchable.

7. Intraocular lens according to one of the above claims, characterized in that the membrane (14) has a modulus of elasticity between 0.5 and 1.5 MPa and preferably a Poisson's ratio between 0.3 and 0.5.

8. Intraocular lens according to one of the above claims, characterized in that the membrane (14) in the unstretched state has a thickness of 20 gm to 100 gm and a diameter (d) of 1 mm to 6 mm, in particular from 2 mm to 4 mm, Has.

9. Intraocular lens according to one of the above claims, characterized in that the material comprises elastomers made of silicone, nitrile and / or latex.

10. Intraocular lens according to one of the above claims, characterized in that the membrane (14) has at least one through opening (24).

11. Intraocular lens according to one of the above claims, characterized in that it additionally has an additional lens (32) which cannot be accommodated and which is designed for attachment to the capsular bag (8) posterior or anterior to the membrane (14).

12. Intraocular lens according to claim 11, characterized in that the additional lens (32) and the membrane (14) are connected via a lever structure (38) to which the haptics (20) are attached so that a bilateral lever is formed a displacement of the haptics (20) converts into an increased expansion of the membrane (14).

13. Intraocular lens according to claim 12, characterized in that the additional lens (36) and the membrane (14) are connected via a lever structure (38) and the intraocular lens (6) also has a posterior to the flexible membrane (14) on the capsular bag (8) To be attached Actuate supply structure (44, 46), which converts an axial compression of the capsular bag (8) that occurs during accommodation via the lever structure (38) into a lateral expansion of the membrane (14).

14. A method for replacing a natural lens of the eye, comprising the steps of: removing the natural lens of the eye,

Insertion of an intraocular lens which has a lens body which is designed as a flat, plane-parallel, elastically stretchable membrane (14) made of transparent material, on or in which a planar focusing system is formed, the focusing properties of the planar focusing system being dependent on a stretched state of the membrane depend and Establishing a stretch-resistant connection between the lens body and eye structures in such a way that a natural accommodation activity of the eye leads to a stretching of the membrane.

15. The method of claim 14, further comprising

Providing the planar focusing system by at least one of the following structures: a phase-modulated Fresnel zone structure, an amplitude-modulated Fresnel zone structure (13) and a diffractive structure.

16. The method of claim 15 further comprising

Providing the planar focusing system by means of a Fresnel zone structure (13) comprising a sequence of concentric, light-blocking ring zones which are each separated from one another by transparent rings (16).

17. The method of claim 16, further comprising

Provision of the planar focusing system through a Fresnel zone structure (13) comprising at least two sets (15a-c) of concentric, spectrally selective light-absorbing ring zones (16a-c), which differ in terms of their spectral selectivity and their ring zone geometry, each set ( 15a-c) absorbed by ring zones (16a-c) in a spectral range (28a-c) in which the at least one other set (15a-c) of ring zones does not absorb.

18. The method according to any one of claims 15 to 17, further comprising

Providing at least one haptic (20) on the edge of the membrane (14), the step of producing the stretch-resistant connection comprising attaching the haptic to the capsular bag (8) of the eye (2) so that the membrane (14) and the planar Focusing system is stretchable through the capsular bag.

19. The method according to any one of claims 15 to 18, further comprising

Forming webs which protrude outward at the edge of the membrane (14) in order to provide haptics.

20. The method according to any one of claims 15 to 19, further comprising

Providing the membrane (14) so that it has a plurality of through openings (24) on an edge of the membrane (14), wherein the step of establishing the stretch-resistant connection is fastening the membrane (14) to haptics and / or to the capsular bag (8 ) of the eye (2), so that the membrane (14) and the planar focusing system can be stretched through the haptics and / or the capsular bag.

21. The method according to any one of claims 15 to 19, wherein the step of inserting comprises that the intraocular lens additionally has an additional lens (32) that cannot be accommodated and the additional lens is fastened to the capsular bag (8) posterior or anterior to the membrane (14).

22. The method according to claim 20, wherein the additional lens (32) and the membrane (14) are connected via a lever structure (38) to which the haptics (20) are attached so that a two-sided lever is formed that allows a displacement the haptics (20) converts into an enlarged expansion of the membrane (14).

23. The method according to claim 21, characterized in that the additional lens (36) and the membrane (14) are connected via a lever structure (38) and the intraocular lens (6) comprises an actuating structure (44, 46) which has one at the Axial compression of the capsular bag (8) that occurs during accommodation is converted into a lateral expansion of the membrane (14) via the lever structure (38), the actuation structure (44, 46) being posterior to the flexible membrane (14)

Capsular bag (8) is attached.