where L_{w ant} is the diameter of the circle defined by the top of the bonnet actuator and L_w post is the diameter of the circle defined by the bottom of the base actuator. From the bases of the set, preferably the base is chosen that, when combined with the bonnet, achieves a thickness of the accommodative intraocular lens system that comes closest to L_t . The method moreover preferably includes a step of implanting the lens into the eye the size of the capsular bag of which was estimated or measured in the previous step.

As to the orientation of the accommodative intraocular lens system when the accommodative intraocular lens is implanted in a patient’s eye, it is preferred that the bonnet is oriented towards the cornea and the base is oriented towards the vitreous body. Preferably, the capsulorhexis is on the side of the capsular bag that is oriented towards the cornea and the bonnet lens actuator is in contact with the interior of this side of the capsular bag, while the base lens actuator is in contact with the interior of the side of the capsular bag that is oriented towards the vitreous body.

The preferred base lens is made of a uniform material. Preferably, the base lens is formed integrally with the base collar and/or the base lens actuator and/or the webs. More preferably, the entire base is formed integrally, most preferably of a uniform material. This greatly simplifies the manufacture of the base.

Similarly, the preferred bonnet lens is made of a uniform material. Preferably, the bonnet lens is formed integrally with the bonnet ring. More preferably, the entire bonnet is formed integrally, most preferably of a uniform material. This greatly simplifies the manufacture of the bonnet.

At least one of the base lens and the bonnet lens, are made of an elastic material. Suitable materials include plastic materials like, for example, hydrogel, silicone, soft acrylic polymers, or combinations thereof. If not denoted otherwise, the term “polymer” as used herein includes the term “copolymer”, ie, a polymer that has been produced based on at least two different monomers. In a preferred embodiment the lens, the base component or both are made from an acrylic-based polymer or an acrylic-based copolymer, more preferably from a soft acrylicbased polymer or a soft acrylic-based copolymer, in particular from a copolymer of hydroxyethyl methacrylate and methyl methacrylate. It is an achievable advantage of acrylicbased polymer and copolymer materials that they are elastic and have a high biocompatibility. The preferred material is hydrophilic. Preferably, both the base lens and the bonnet lens are made of an elastic material, more preferably an acrylic-based polymer or an acrylic-based copolymer.

Preferably, the base and the bonnet are made from the same plastic material. This has the advantage that both components show the same elastic behaviour, rendering the behaviour of the accommodative intraocular lens system easier to predict. Also, advantageously, their identical optical density causes the refractive power in the contact area of the base lens and the bonnet lens to vanish. In an alternative embodiment, the base is made from a first material and the bonnet is made from a second material, the second material having a different elastic modulus than the first material. Using different materials for the base and for the bonnet provides an additional degree of freedom to the design of the accommodative intraocular lens system as intrinsic properties of the materials such as stiffness can be chosen independently for both components. Preferably, the optical density of the first material and the second material is chosen to be similar or identical.

The preferred elastic modulus of the at least one of the base lens and the bonnet lens is greater than 1.5 MPa (megapascal), preferably greater than 1.8 MPa. It is an achievable advantage of materials with an elastic modulus of more thanl .5 MPa that they aid in achieving a significant difference in power between the separating position and the contact position are easier to assemble in the human eye during surgery. The preferred elastic modulus of the at least one of the base lens and the bonnet lens is smaller than 4 MPa, preferably smaller than 3.2 MPa. It is an achievable advantage of a material with an elastic modulus of less than 4 MPa that it provides sufficient elasticity to allow for a sufficiently large contact area and a sufficient extent of deformation to aid in achieving a significant difference in power between the separating position and the contact position. In the context of the present invention, the terms “elastic modulus”, also referred to as the “modulus of elasticity” and “Young’s modulus”, denotes the ratio of a stress in a body to a corresponding strain resulting from the deformation of the body caused by the application of stress. The elastic modulus is the slope of the stress-strain curve in the range of linear proportionality of stress to strain. The greater the modulus, the stiffer the material, or the smaller the elastic strain that results from the application of a given stress. The elastic modulus is measured at a temperature of 35 °C (Celcius), and a hydration of the material of 26 %, provided that the material is hydrophilic, or as appropriate for the selected material.

Brief description of the drawings

In the following, further preferred embodiments of invention are illustrated by means of examples. The invention is not limited to these examples, however.

The drawings schematically show:

Figure 1 A perspective view from the anterior side onto an assembled accommodative intraocular lens system according to the invention;

Figure 2 A cross-sectional view of the assembled accommodative intraocular lens system of Figure 2;

Figure 3 A perspective view from the anterior side onto the bonnet of the accommodative intraocular lens system according to Figure 1;

Figure 4 A perspective view from the anterior side onto the base of the accommodative intraocular lens system according to Figure 1;

Figure 5 A perspective view from the posterior side onto the base of the accommodative intraocular lens system according to Figure 1; and

Figure 6 A cross-sectional view of the posterior face of the bonnet lens, the optical axis being in the cross-sectional plane. Detailed description of an embodiment of the invention

In the following description of preferred embodiments of the invention, identical reference numerals refer to identical or similar components. For clarity, in the case of multiple identical parts in the figure generally only one of these parts is provided with a reference numeral.

Figure 1 shows a perspective view from the anterior side onto an accommodative intraocular lens system according to the invention. Figure 2 shows a cross-sectional view of the system through a central plane symbolized by the solid line in Figure 1. The accommodative intraocular lens comprises a bonnet 4 and a base 10. The bonnet 4 is oriented towards the cornea 2 of the human eye, whereas the base 10 is oriented towards the vitreous body 3. The arrows 2 and 3 denote the respective directions in the Figures.

Figure 3 shows a perspective view from the anterior side onto the bonnet 4 of the accommodative intraocular lens system. The bonnet 4 has a bonnet lens 5 with a positive refractive power optics with an optical axis 6. A bulging bonnet ring 7 annularly surrounds the central bonnet lens 5 on its circumference, the bulging bonnet ring 7 and the bonnet lens being firmly connected to each other. In the exemplary embodiment shown the bonnet is one-piece in the sense that the bonnet lens 5 and the bonnet ring 7 are integrally connected and made from the same material.

The anterior part of the bonnet ring 7 serves as a bonnet actuator, which in the intended use of the accommodative intraocular lens, when the accommodative intraocular lens is implanted in a patient’s eye, contacts the capsular bag. The apex of the bonnet ring 7 in the anterior direction forms a ring, the diameter of which is between the outer diameter of the bonnet ring 7 and the inner diameter of the bonnet ring 7, which corresponds to the outer diameter of the bonnet lens 5 of the bonnet 4. The bonnet actuator contacts the capsular bag in an annular contact region around this ring-shaped apex, applying a compression force to the bonnet lens 5 via the bonnet ring 7 when the capsular bag is stretched due to the ciliary muscle of the eye being relaxed.

The posterior part of the bonnet ring 7 has a circumferential projection 8 that extends outwards in the posterior direction 3 and that extends beyond the posterior face of the lens 5 of the bonnet 4 in the posterior direction of the optical axis 8. This projection serves to attach the bonnet to the base. The bonnet ring 7 contains four circular through holes 9 that extend from the anterior face of the bulging bonnet ring 7 to its posterior face. . In an alternative embodiment (not shown in the figures), the bonnet ring is identical to that shown in Figure 3 but has eight rather than four through holes. The through holes 9 are located on the inner side of the bonnet ring, ie, the side of the bonnet ring that is directed towards the bonnet lens so that fluid can flow from the outside the capsular bag through the capsulorhexis and the hole 9 into the space between the bonnet lens 5 and the base lens 11. The holes 9 are equally spaced along a circumferential line of the bulging ring 7.

The base 10 comprises a base lens 11 and an annular base collar 12, which surrounds the base lens. The annular collar 12 extends inwards in the anterior direction 2 thereby forming, on the inner side, an annular groove that can engage with and hold the circumferential projection 8 of the bonnet ring 7.

The base collar 12 is connected to the base lens 11 via eight elastic webs 13. Figures 4 and 5 show perspective views onto the base 10 of the accommodative intraocular lens system from the anterior side and from the posterior side, respectively. The webs 13 are separated by oblong through holes that have the general form of an angular section of a ring. An annular notch 16 is provided between the base lens 11 and the webs 13 of the base 10. Moreover, the base lens is provided with a stop 17 (best seen in Figure 4) that protrudes in anterior direction towards the bonnet lens 5 and can contact the bonnet lens 5 to limit the force with which the base lens 11 presses against the bonnet lens 5.

The base 10 further comprises a cone-shaped tubular foot 14 extending from the base lens 11 of the base 10 outwards in the posterior direction. The posterior end of the foot 14 serves as a base actuator contacting the capsular bag in an annular contact region and applying a compression force to the base lens 11 when the capsular bag is stretched due to the ciliary muscle of the eye being relaxed. The foot contains four through holes 15 that are equally spaced along the circumference of the foot 14.

The bonnet 4 and the base 10 are attached to each other. Size and shape of the projecting portion 8 of the bonnet 4 and the annular collar 12 of the base 10 are configured such that the projecting portion 8 latches into the annular collar 12. In the unaccommodated state for distance vision the posterior face of the bonnet lens 5 contacts the anterior face of the base lens 11, whereas in the accommodated state for near vision mode, ie, if no external compression force are applied to the exemplary accommodative intraocular lens system, the posterior face of the bonnet lens 5 and the anterior face of the base lens 11 are spaced apart from each other. Fig. 2 shows the accommodative intraocular lens system in the accommodated state.

Example

An accommodative intraocular lens system according to Figures 1 to 6 has been manufactured and tested for its properties. Bonnet and base were both manufactured from a copolymer of hydroxyethyl methacrylate and methyl methacrylate. The material had the following properties: swell factor of 1.13; water content at 35° C of 26 %; refractive index at 35° C hydrated of 1.460; tensile strength of 2.5 MPa; elastic modulus of 3.0 MPa and elongation to break of 250%. The bonnet and the base were both manufactured as one-piece each.

The total diameter of the bonnet was 8.5 mm. The thickness of bonnet lens inside the bonnet ring was 1.2 mm. The ring that is formed by the apex of the bulging bonnet ring in the anterior direction had a diameter of 6.6 mm. The diameter of each of the holes in the bulging bonnet ring was 0.6 mm.

The opening angle of the groove, ie, the angle between the central portion and the annular collar of the base component was 70°. The annular collar extended from the central portion of the base component in the anterior direction for 0.9 mm. The thickness of the annular collar in its radial direction was 0.3 mm. The webs connecting the annular collar with the central portion of the base component had a width in the circumferential direction of 0.3 mm each. The distance between two neighbouring webs and thus the lengths of the oblong through holes between these webs was 2.1 mm each. The thickness of the webs at their radially outward end was 0.252 mm and the thickness of the webs at their radially inward end was 0.285 mm; thus, ratio of the thickness of the webs at their radially outward end to the thickness of the webs at their radially inward end was 0.88. The depth of the annular notch between the base lens and the webs of the base component was 0.17 mm. The foot was 1.6 mm long and the foot’s annular actuator for contacting the posterior part of the capsular bag had a diameter of 8 mm. The four holes in the foot had a diameter of 0.6 mm each. The annular stop extends from the base lens 13 pm in the anterior direction and is 70 pm wide.

The thickness of the base lens was 1.3 mm. The base lens had zero refractive power. In the accommodated state, the base lens and the bonnet lens were separated by 0.3 mm, and the accommodative lens system is 3.85 mm thick as measured from the contact area of the base to the contact area of the bonnet. In the unaccommodated state, the posterior face of the bonnet lens and the anterior face of the base lens contacted each other. The contact area had a diameter of 2 mm. The lens had a refractive power of 24 dioptre for near vision. The difference in power between the separation position and the compressed position was determined to be approximately 40 %. The compression force onto the lens system was around 4.5 gram-force.

Figure 6 shows a cross section of the posterior face of the bonnet lens. The optical axis is in the cross-sectional plane. The curvature has a discontinuity at a radius of 1 mm. The discontinuity causes the lens surface to comprise of a circular inner zone with of a radius of 1 mm, and an annular outer zone surrounding and adjacent to the inner zone. The lens face’s radius of curvature in the inner zone is 20.6 mm, and the lens face’s radius of curvature in the outer zone is 34.25 mm. The smaller radius of curvature in the outer zone provides the lens face with a negative spherical aberration.

In an alternative example not shown in the figures, the outer zone differs from that described above in that is aspheric so that the lens presents a net negative spherical aberration of 0.238pm.

An exemplary set of for assembling an accommodative intraocular lens system comprises a bonnet as described above, a first base a described above and two additional bases that differ from the first base only in that the length of their foot was 1.0 mm and 1.3 mm, respectively. This renders the assembly of the bonnet with the bases 3.2 mm, 3.5 and 3.8 mm thick. The size of a capsular bag of an eye of patient was measured with the UBM (ultrasound biomicroscopy) method disclosed in C.J. Pavlin, K. Harasiewicz, M.D. Sherar, F.S. Foster; Clinical use of ultrasound biomicroscopy; Ophthalmology, 98 (1991), pp. 287- 295. With such method, the anterior capsule length (Q_ant), the posterior capsule length ( post) and the capsule equatorial diameter (C_D) were found to measure 10.4mm, 12.0mm and 9.4mm respectively. From this, using the formula

where L_{w ant} is the diameter of the circle defined by the top of the bonnet actuator and L_w post is the diameter of the circle defined by the bottom of the base actuator. The ideal thickness of the lens was determined to be L_t = 3.95mm, and accordingly, the base with a 1.6 mm long foot was chosen, because it entails a thickness of the accommodative intraocular lens system of 3.85 mm, which is closest to L_t .

The features as described in the above description, claims and figures can be relevant individually or in any combination to realise the various embodiments of the invention.

Reference numerals

1 accommodative intraocular lens system

2 anterior side

3 posterior side

4 bonnet

5 bonnet lens

6 optical axis

7 bonnet ring

8 projection

9 hole in bonnet ring

10 base

11 base lens

12 base collar

13 web

14 foot

15 hole in foot

16 notch

17 stop

Claims

1. An accommodative intraocular lens system (1) comprising a base (10) and a bonnet (4) that is attachable or attached to the base (10), wherein the base (10) includes a base lens (11) and the bonnet (4) includes a bonnet lens (5) and a bonnet ring (7) holding the bonnet lens (5), and wherein when the base (10) is attached to the bonnet (4), the base lens (11) and the bonnet lens (5) are arranged so that they are movable relatively to each other, characterised in that the bonnet lens (5) is attached to the bonnet ring (7) such that when the base (10) is attached to the bonnet (4), a compression force applied to the bonnet ring (7) and to the base (10) can move the bonnet lens (5) and the base lens (11) towards each other.

2. The accommodative intraocular lens system (1) of claim 1, characterised in that the bonnet lens (5) is provided with a bonnet lens actuator which in the intended use of the accommodative intraocular lens, when the accommodative intraocular lens is implanted in a patient’s eye, contacts the capsular bag.

3. The accommodative intraocular lens system (1) of claim 2, characterised in that the bonnet (4) comprises a bonnet ring (7) surrounding the bonnet lens (5), and an anterior portion of the bonnet ring (7) serves as the bonnet lens actuator.

4. The accommodative intraocular lens system (1) of claim 2 or 3, characterised in that the portion of the bonnet lens actuator that in the intended use of the accommodative intraocular lens, when the accommodative intraocular lens is implanted in a patient’s eye is in contact with the capsular bag, has a diameter of more than 4.5 mm.

5. The accommodative intraocular lens system (1) of any one of the preceding claims, characterised in that the bonnet ring (7) comprises at least one through hole (9) extending from the anterior side of the bonnet (4) to the posterior side of the bonnet (4).

6. The accommodative intraocular lens system (1) of any one of the preceding claims, characterised in that a base lens (11) is provided with a base lens actuator which in the intended use of the accommodative intraocular lens, when the accommodative intraocular lens is implanted in a patient’s eye contacts the capsular bag.

7. The accommodative intraocular lens system (1) of claim 6, characterised in that the base lens (11) is provided with a foot (14) on its posterior side, the foot (14) being attached to the base lens (11), the foot (14) or a part of the foot (14) serving as the base actuator.

8. An accommodative intraocular lens system (1) comprising a base (10) and a bonnet (4) that is attachable or attached to the base (10), wherein the base (10) includes a base lens (11) and the bonnet (4) includes a bonnet lens (5), and wherein when the base (10) is attached to the bonnet (5), the base lens (11) and the bonnet lens (5) are arranged so that they are movable relatively to each other, characterised in that the base lens (11) is provided with a foot (14).

9. The accommodative intraocular lens system (1) of claim 7or 8, characterised in that the foot (14) is attached to the base lens (11) such that when the base (10) is attached to the bonnet (4), compression forces applied to the foot (14) and the bonnet lens (5) can move the bonnet lens (5) and the base lens (11) towards each other.

10. The accommodative intraocular lens system (1) of any one of claim 7 to 9, characterised in that the foot (14) is a tubular ring that is tapered such that the tubular diameter increases in the posterior direction.

11. The accommodative intraocular lens system (1) of any one of claims 7 to 10, characterised in that the length of the foot (14) is greater than 0.4 mm.

12. The accommodative intraocular lens system (1) of any one of claims 7 to 11, characterised in that the foot (14) comprises at least one through hole (15) extending from an outside of the foot (14) to an inside of the foot (14).

13. The accommodative intraocular lens system (1) of any one of the preceding claims, characterised in that at least one of the base (10) and the bonnet (4) is provided with elastic webs (13) that render the bonnet lens (5) movable relatively to the base lens

14. The accommodative intraocular lens system (1) of claim 13, characterised in that the webs (13) are separated by through holes that extend from the anterior side of the base (10) to the posterior side of the base (10).

15. An accommodative intraocular lens system (1) comprising a base (10) and a bonnet (4) that is attachable or attached to the base (10), wherein the base (10) includes a base lens (11) and the bonnet (4) includes a bonnet lens (5), and wherein at least one of the base (10) and the bonnet (4) is provided with elastic webs (13) that render the bonnet lens (5) movable relatively to the base lens (11), characterised in that at the interface of at least one of the webs (13) with the base (10) or the bonnet (4) a notch (16) is provided.

16. The accommodative intraocular lens system (1) of any one of the preceding claims, characterised in that the base (10) comprises a base collar (12) surrounding and holding the base lens (11).

17. The accommodative intraocular lens system (1) of any one of the preceding claims, characterised in that the base collar (12) and the bonnet ring (7) can be mated with each other in order to attach the bonnet (4) to the base (10) so that an anterior face of the base lens (11) is located opposite a posterior face of the bonnet lens (5).

18. An accommodative intraocular lens system (1) comprising a base (10) and a bonnet

(4) that is attachable or attached to the base (10), wherein the base (10) includes a base lens (11) and the bonnet (4) includes a bonnet lens (5), and wherein when the base (10) is attached to the bonnet (4), the base lens (11) and the bonnet lens (5) are arranged so that they are movable relatively to each other and the base lens (11) and the bonnet lens (5) can assume at least one relative position in which the anterior face of the base lens (11) and the posterior face of the bonnet lens (5) press against each other forming a contact area, characterised in that at least one of the bonnet (4) and the base (10) comprises a stop (17) that protrudes from the one towards the other of the bonnet (4) and the base (10) and that can abut against the other of the bonnet (4) and the base (10) in order to limit the extent by which the anterior face of the base lens (11) and the posterior face of the bonnet lens

(5) can be moved towards each other to press against each other.

19. The accommodative intraocular lens system (1) of claim 18, characterised in that the stop (17) is an elevated ring.

20. The accommodative intraocular lens system (1) of claim 18 or 19, characterised in that the stop (17) is higher than 0.05 mm.

21. The accommodative intraocular lens system (1) of any one of the preceding claims, characterised in that when the base (10) is attached to the bonnet (4), the base lens (11) and the bonnet lens (5) are movable relatively to each other between a separating position in which the anterior face of the base lens (11) and the posterior face of the bonnet lens (5) are spaced apart from each other, and a contact position in which the anterior face of the base lens (11) and the posterior face of the bonnet lens (5) press against each other forming a contact area.

22. A set for assembling an accommodative intraocular lens system (1) suitable for implantation in capsular bags of multiple sizes, the set comprising multiple bases (10) and a bonnet (4) that is attachable to each of the bases (10), wherein the bonnet (4) has an actuator for contacting a portion of the capsular bag on one of the anterior and the posterior sides of the capsular bag, and each base has an actuator for contacting a portion of the capsular bag on the other of the anterior and the posterior sides of the capsular bag, and wherein each base (10) is shaped differently such that for each base (10) when the base (10) is attached to the bonnet (4), the length of the resulting accommodative intraocular lens as measured from the actuator of the base (10) to the actuator of the bonnet (4) is different to that of any accommodative intraocular lens formed with any of the other bases.

23. The set of claim 22, characterised in that at least two, of the multiple bases (10) comprise a foot (14).

24. The set of claim 23, characterised in that at least two, of the multiple bases (10) differ in the length of their feet (14).

25. A method of operation of an accommodative intraocular lens system (1) comprising a base (10) and a bonnet (4) that is attachable or attached to the base (10), wherein the base (10) includes a base lens (11) and the bonnet (4) includes a bonnet lens (5) and a bonnet ring (7) holding the bonnet lens (5), the base (10) is attached to the bonnet (5), the base lens (11) and the bonnet lens (5) are arranged so that they are movable relatively to each other and the bonnet lens (5) is attached to the bonnet ring (7), characterised in that the method comprises a step of compression forces being applied to the bonnet ring (7) and the base (10) moving the bonnet lens (5) and the base lens (11) towards each other.

26. A method of assembling an accommodative intraocular lens system (1) suitable for implantation in capsular bags of multiple sizes, the method comprising the steps of:

- Providing a bonnet (4) which has an actuator for contacting a portion of the capsular bag on one of the anterior and the posterior sides of the capsular bag;

- providing multiple bases (10), wherein each base (10) has an actuator for contacting a portion of the capsular bag on the other of the anterior and the posterior sides of the capsular bag, each base (10) is attachable to the bonnet (4), and each base (10) is shaped differently such that for each base (10) when the base (10) is attached to the bonnet (4), the length of the resulting accommodative intraocular lens as measured from the actuator of the base (10) to the actuator of the bonnet (4) is different to that of any accommodative intraocular lens formed with any of the other bases (10).