NL2023829B1

NL2023829B1 - Intraocular lens

Info

Publication number: NL2023829B1
Application number: NL2023829A
Authority: NL
Inventors: P M Luyten Gré; M Beenhakker Jan-Willem; Van Vught Luc
Original assignee: Academisch Ziekenhuis Leiden
Priority date: 2019-09-13
Filing date: 2019-09-13
Publication date: 2021-05-18

Abstract

An intraocular lens (IOL) is provided, the intraocular lens comprises an optic and at least one haptic. The IOL has an asymmetry caused by either haptic decentring or tilting the optic; and/or a refractive index and/or diffractive design of the optic varying along an axis perpendicular to its optical axis, such that the intraocular lens has no rotational symmetry; and/or decentration of optical centre of the anterior and/or posterior surfaces such that said optical centre is not the same as the geometric centre of the said surface; and/or any combination of thereof.

Description

INTRAOCULAR LENS

FIELD OF THE INVENTION The present invention relates to an intraocular lens (IOL), in particular, but not exclusively, an intraocular lens which takes into account asymmetries in the human eye and can lessen orremove the effects of refractive conditions.

BACKGROUND TO THE INVENTION An Intraocular Lens (IOL) is an artificial lens that is surgically placed into the eye either as replacement of the natural, crystalline, lens after it has been removed, or in addition to the crystalline lens or in addition to an already implanted IOL. Such an IOL consists of an optic and, optionally, one or more haptics. The optic is the part of the IOL that affects vision, consisting of at least an anterior and posterior surface with arbitrary shapes. Haptics are structures that are used to retain the optic in the eye in a desired position and orientation. Current IOL designs do not take into account asymmetries in the eye, except for astigmatism. The eye is however not symmetric, as can for example clearly be seen in the differences between the left and right eye. Furthermore, some refractive conditions, only occur at a specific laterality. Additionally, some eyes either have a more outwardly tilted iris, or per se are rotated more outwardly resulting in a tilted iris, or a decentred pupil centre, which can both be related to refractive disorders. [Reference: Van Vught et al. Distinct differences in anterior chamber configuration and peripheral aberrations in negative dysphotopsia]. Despite advances in IOL implantation, residual refractive error occasionally occurs, which can manifest as shadows, halos, or missing areas of the peripheral temporal visual field. Clinical evaluations of patients reporting these symptoms often find no abnormalities with the IOL position. However, optical ray tracing simulations reveal that such symptoms can indeed occur, under conditions such as non-refracted light passing through a gap between the iris and the IOL. The gap between the iris and the IOL exists due to various asymmetries in the eye. A conventional IOL implanted in or on an eye having such asymmetry may therefore not work optimally.

SUMMARY According to a first aspect there is provided an intraocular lens comprising: an optic having an optical axis, an anterior surface and a posterior surface, the anterior and posterior surfaces each having an optical centre and; a first haptic attached to said optic,

the intraocular lens having an asymmetry caused by a) the haptic decentring and/or tilting the optic; b) a refractive index and/or diffractive design of the optic varying along an axis perpendicular to its optical axis, such that the intraocular lens has no rotational symmetry; ©) decentration of optical centre of the anterior and/or posterior surfaces such that said optical centre is not the same as the geometric centre of the said surface; and/or any combination of a) — Cc). Advantageously, an IOL which takes into account the complex shape of the eyes of patients, such as asymmetries, will be capable of reducing or removing common post implantation visual complaints.

The present invention mitigates or alleviates the problem by taking these asymmetries into account during design of the IOL and/or by inducing an asymmetry in the refraction of light within the eye to either alleviate pre-existent ocular asymmetries or to alleviate visual complaints.

According to an embodiment of the present invention, a thickness of the optic varies along a second axis which is substantially perpendicular to said optical axis, such that the optic has no rotational symmetry.

A gap between the iris and the IOL can also occur in patients that have a smaller, more decentred pupil, therefore an IOL which takes this into account by varying the thickness of the optic to encourage the amount of light being refracted at specified angle is beneficial.

According to an embodiment of the present invention, the anterior surface and the posterior surface are shaped such that the optic has no rotational symmetry.

Inducing an asymmetry in the refraction of light within the eye can alleviate pre-existent ocular asymmetries and/or alleviate visual complaints.

According to an embodiment of the present invention, the anterior surface and the posterior surface are differently shaped from one another.

According to an embodiment of the present invention, the optical centre of the optic is not the geometric centre of the optic.

Various combinations of asymmetries including varying the location of the optical centre relative to the geometric centre may be beneficial when designing a patient specific IOL.

According to an embodiment of the present invention, the diffractive design of the anterior surface is such that the optic has no rotational symmetry.

According to an embodiment of the present invention, the diffractive design of the posterior surface is such that the optic has no rotational symmetry. According to an embodiment of the present invention, the interocular lens further comprises a prism. According to an embodiment of the present invention, the interocular lens comprises a Fresnel prism. With a Fresnel prism, the direction of travel of light can be changed. This could be used for patients who have no central vision, such that the light is directed at a different part of the retina. This may correct for a tilt/asymmetry in the eye, which causes a rotation in the eye. The Fresnel prism can change the direction of the light, so that when a patient looks straight ahead, the central light rays will hit the macula. According to an embodiment of the present invention, the interocular lens comprises one or more further haptics attached to said optic. According to an embodiment of the present invention, said first haptic is attached to the optic at a first angle with respect to said second axis and one of said further haptics is attached to the optic at a second angle with respect to said second axis. According to an embodiment of the present invention, at least one of said further haptics has a different length, shape and/or thickness to said first haptic. According to an embodiment of the present invention, at least one of said further haptics is attached to the optic such that the intraocular lens has no rotational symmetry. According to an embodiment of the present invention, said first haptic and/or at least one of said further haptics has a varying diameter. According to an embodiment of the present invention there is provided a set of intraocular lenses comprising, a first and a second intraocular lens, each as described in any of the preceding paragraphs, wherein said left intraocular lens has no rotational symmetry with said right intraocular lens.

DESCRIPTION OF THE DRAWINGS Embodiments of the present invention are described below, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a prior art intraocular lens. Figures 2 — 8 a and b are side views of embodiments of an intraocular lens according to the present invention; and.

Figures 9a — 9c are top views of intraocular lenses according to further embodiments of the present invention. Figure 10 is a side view of a diffractive optic with diffractive elements of varying size.

DETAILED DESCRIPTION Figure 1 shows an intraocular lens (IOL) 10 constructed in accordance with the prior art. The IOL comprises an optic 20 and first and second haptics 12, 14. The intraocular lens 10 is symmetrical such that light is focused on some point behind the intraocular lens. This does not take into account asymmetries in the eyes of patients and therefore may lead to the patient experiencing aberrations in their vision after having such an IOL implanted.

Figure 2 shows an IOL 100 according to the present invention, comprising an optic 120 with an anterior surface 122 and a posterior surface 124. The optical axis O of the lens runs through the anterior surface 122 and a posterior surface 124 and a second axis 200 runs perpendicular to the optical axis. Attached to the lens are a first haptic 112 and a second haptic 114. The first haptic 112 is attached to the optic at an angle 8 relative to the second axis, whereas the second haptic 114 is attached such that it is substantially parallel to the second axis 200. The angle at which the first haptic 112 is attached to the optic may account for an asymmetry in the eye of a patient and thereby reduce aberrations perceived by the patient. The size of angle 6 may also be determined by a difference in the shape of the optic at the point at which the haptic is attached.

Figure 3 shows an IOL 100 according to the present invention, comprising an optic 120 with an anterior surface 122 and a posterior surface 124. The optical axis O of the lens runs through the anterior surface 122 and a posterior surface 124 and a second axis 200 runs perpendicular to the optical axis. Attached to the lens are a first haptic 112 and a second haptic 114. The first haptic 112 is attached to the optic at an angle 0 relative to the second axis. The second haptic is attached to the optic at an angle ¢ relative to the second axis. The angle at which the first haptic 112 and the second haptic 114 are attached to the optic may account for an asymmetry in the eye of a patient and thereby reduce aberrations perceived by the patient.

Figure 4 shows an IOL 100 according to the present invention, comprising an optic 120 with an anterior surface 122 and a posterior surface 124. The optical axis O of the lens runs through the anterior surface 122 and a posterior surface 124 and a second axis 200 runs perpendicular to the optical axis. Attached to the lens are a first haptic 112 and a second haptic 114, although only one haptic may be required for this embodiment. The thickness of the optic varies along the second axis 200 such that light passing through the optic parallel or nearly parallel to the optical axis will pass through a different amount of optic material depending on the point and angle of incidence. The thickness (T) of the optic can vary to take into account asymmetries in the eyes of a patient such that light is focussed to an appropriate point, preventing the patient from perceiving light aberrations. Figure 5 shows an IOL 100 according to the present invention, comprising an optic 120 with 5 an anterior surface 122 and a posterior surface 124. The optical axis O of the lens runs through the anterior surface 122 and a posterior surface 124 and a second axis 200 runs perpendicular to the optical axis. Attached to the lens are a first haptic 112 and a second haptic 114, although only one haptic may be required for this embodiment. The refractive index (RI) of the optic varies along the second axis 200 such that light passing through the optic parallel or nearly parallel to the optical axis will pass through a material with a different refractive index depending on the point and angle of incidence. The refractive index of the optic can vary to take into account asymmetries in the eyes of a patient such that light is focussed to an appropriate point, preventing the patient from perceiving light aberrations. Figure 6 shows an IOL 100 according to the present invention, comprising an optic 120 with an anterior surface 122 and a posterior surface 124. Attached to the lens are a first haptic 112 and a second haptic 114. The first haptic 112 has a different length to the second haptic

114. The relative length of the haptics attached to the optic may account for an asymmetry in the eye of a patient and thereby reduce aberrations perceived by the patient. Figure 7 shows an IOL 100 according to the present invention, comprising an optic 120 with an anterior surface 122 and a posterior surface 124. The optical axis O of the lens runs through the anterior surface 122 and a posterior surface 124 and a second axis 200 runs perpendicular to the optical axis. Attached to the lens are a first haptic 112 and a second haptic 114. The first haptic 112 is attached to the optic at a position and angle such that the IOL has no rotational symmetry. The angle and position at which the first haptic 112 and the second haptic 114 are attached to the optic may account for an asymmetry in the eye of a patient and thereby reduce aberrations perceived by the patient. Figure 8a shows an IOL 100 according to the present invention, comprising an optic 120 with an anterior surface 122 and a posterior surface 124. The optical axis O of the lens runs through the anterior surface 122 and a posterior surface 124 and a second axis 200 runs perpendicular to the optical axis. Attached to the lens are a first haptic 112 and a second haptic 114. The shape of the optic is such that its optical centre and geometric centre are different and such that the optic has no rotational symmetry. Figure 8b shows an IOL 100 according to the present invention, comprising an optic 120 with an anterior surface 122 and a posterior surface 124. The optical axis O of the lens runs through the anterior surface 122 and a posterior surface 124 and a second axis 200 runs perpendicular to the optical axis. Attached to the lens are a first haptic 112 and a second haptic 114. The shape of the optic is such that its optical centre and geometric centre are not coincident such that the optic has no rotational symmetry.

Figure 9a shows an IOL 100 according to the present invention, comprising an optic 120 and a haptic 113. The haptic 113 in this embodiment is non-circular and wherein the distance from the centre 125 of the optic to the edge 113E of the haptic “d” varies, such that the IOL has no rotational symmetry.

Figure 9b shows an IOL 100 according to the present invention, comprising an optic 120 and plate haptics 118 and 119. The haptics 118, 119 in this embodiment are non-circular and are sized differently to one another such that the IOL has no rotational symmetry.

Figure 9c shows an IOL 100 according to the present invention, comprising an optic 120 and plate haptics 121 and 123. The haptics 121, 123 in this embodiment are curved and have a different curvature such that the IOL has no rotational symmetry. The haptics may also have different lengths rather than different curvatures.

Figure 10 shows a side view of an optic 300 with a diffractive design in the form of diffractive elements 301 on its surface. The diffractive elements 301 may be constructed to be different such that the height “h” and/ or width “w” of each element is not identical. The heights and widths may vary such that the diffractive elements 301 are smaller further from the centre relative to those closer to the centre, or they may vary such that the optic has no rotational symmetry. These features may be combined with a normal overall refractive design shape. The height and width of the diffractive elements may be significantly larger than the wavelength of visible light or similar to the wavelength of visible light or shorter than the wavelength of visible light.

It is expressly intended that although a specific shape is shown for each of the haptics in the above described figures, any appropriate haptic {including leg and plate haptics) that falls within the scope of the claims could be included in the embodiments described.

It will be appreciated that features of any of the embodiments described above may be combined. For example, a combination of varying thickness and varying refractive index may lead to improved peripheral vision.

Whilst specific embodiments of the present invention have been described above, it will be appreciated that departures from the described embodiments may still fall within the scope of the present invention.

It will be appreciated that any of the aforementioned apparatus may have other functions in addition to the mentioned functions, and that these functions may be performed by the same apparatus.

The applicant hereby discloses in isolation each individual feature described herein and any combination of two or more such features, to the extent that such features or combinations are capable of being carried out based on the present specification as a whole in the light of the common general knowledge of a person skilled in the art, irrespective of whether such features or combinations of features solve any problems disclosed herein, and without limitation to the scope of the claims.

The applicant indicates that aspects of the present invention may consist of any such individual feature or combination of features.

It should be understood that the embodiments described herein are merely exemplary and that various modifications may be made thereto without departing from the scope of the claims.

Claims

CONCLUSIONS

An intraocular lens comprising: an optical system having an optical axis, an anterior surface and a posterior surface, the anterior and posterior surfaces each having an optical center, and; a first haptic associated with said optical system, wherein the intraocular lens exhibits an asymmetry caused a. by the haptic decentering and/or tilting the optical system; b. in that a refractive index and/or a refractive design of the optical system varies along an axis perpendicular to its optical axis in such a way that the intraocular lens exhibits no rotational symmetry; c. by a misalignment of the optical center from the anterior and/or posterior surface, in such a manner that said optical center is not the same as the geometric center of said surface; d. and/or by any combination of (a) through (c).

An intraocular lens according to claim 1, wherein a thickness of the optical system varies along a second axis substantially perpendicular to said optical axis in such a way that the optical system does not exhibit rotational symmetry.

An intraocular lens according to claim 1 or claim 2, wherein the anterior surface and the posterior surface are formed in such a way that the optical system exhibits no rotational symmetry.

The internal ocular lens of claim 3, wherein the anterior surface and the posterior surface are shaped differently from each other.

An internal ocular lens according to any one of the preceding claims, wherein the optical center of the optical system is not the geometric center of the optical system.

An internal ocular lens according to any preceding claim, wherein the refractive anterior surface is such that the optical system exhibits no rotational symmetry.

An internal ocular lens according to any one of the preceding claims, wherein the refractive design of the posterior surface is such that the optical system exhibits no rotational symmetry.

An intraocular lens according to any preceding claim, further comprising a prism.

The internal ocular lens of claim 8, wherein the prism is a Fresnel prism.

An internal ocular lens according to any preceding claim, further comprising one or more additional haptics associated with said optical system.

An intraocular lens according to claim 10, wherein said first haptic is connected to the optical system at a first angle to said second axis, and one of said additional haptics is connected to the optical system at a second angle to said second axis.

An internal ocular lens according to claim 10 or claim 11, wherein at least one of said additional haptics has a different length, shape, and/or thickness than said first haptic.

An internal ocular lens according to any one of claims 10 to 12, wherein at least one of said additional haptics is connected to the optical system in such a way that the intraocular lens has no rotational symmetry.

An internal ocular lens according to any one of claims 10 to 13, wherein said first haptic and/or at least one of said additional haptics has a varying diameter.

A set of intraocular lenses comprising a first and a second intraocular lens, each according to any one of the preceding claims, wherein said left intraocular lens exhibits no rotational symmetry with said right intraocular lens.