EYE IMPLANT AND METHOD FOR MANUFACTURING SAME

Abstract

An eye implant with an optical implant region for correcting an imaging error of the eye, wherein starting with biometrically determined data of optically effective components located in front of the retina of the eye, respectively data obtained through wave front measurement, the optical implant region is adjusted for a monofocal vision with a visual acuity of at least 0.7 (70%) within a field of focus depth of at least 2 diopters.

Claims

1. An eye implant with an optical implant region for correcting an imaging error of the eye, wherein starting with biometrically determined data of optically effective components located in front of the retina of the eye, respectively data obtained through wave front measurement, the optical implant region is adjusted for a monofocal vision with a visual acuity of at least 0.7 (70%) within a field of focus depth of at least 2 diopters.

2. The eye implant according to claim 1, having a visual acuity of at least 0.8 (80%) within the field of focus depth.

3. The eye implant according to claim 1, having a field of focus depth of at least 3 diopters.

4. The eye implant according to claim 1, wherein the adjusted imaging characteristics of the optical implant region ensure the desired visual acuity in case the seating of the implant in the eye deviates from the pre-computed position, within the range of a rotational angle of up to 5, around the line of vision axis and in the range of rotational angles of up to 3, around the lateral axes which are perpendicular thereto.

5. The eye implant according to claim 1, wherein the adjusted imaging characteristics of the optical implant region ensure the desired visual acuity in case the seating of the implant in the eye deviates from the pre-computed position within the range of a displacement of up to 0.2 mm, in the direction of the line of vision axis and in the range of displacements of up to 0.4 mm, in the direction of the lateral axes which are perpendicular thereto.

6. The eye implant according to claim 1, for which the optical implant region is embodied for generating the highest light intensity for the image projected onto the retina, for the average field of focus depth.

7. The eye implant according to claim 1, wherein the optical region for implanting the implant is formed on the front surface that faces the cornea of the eye, respectively on the back surface that faces the retina of the eye.

8. The eye implant according to claim 1, wherein it is embodied as implant for replacing the natural eye lens, or as a lens that can be implanted in addition to an implant replacing the natural eye lens, or as replacement for an implant replacing the natural eye lens.

9. A method for producing an eye implant according to claim 1, wherein following the determination of a desired topography for at least one of the two surfaces of the optical implant region, controlled by the specific desired topography, at least one of the two surfaces of a standard blank is processed either by machining or laser irradiation, or is produced through direct casting with correspondingly designed casting molds, and that the topography produced in this way is measured on at least one implant surface and is compared to the desired topography.

10. The method according to claim 9, wherein for determining the desired topography, the optical data from at least two of the following eye components are measured biometrically: cornea, anterior chamber, natural lens, position of the natural lens or the artificial lens previously implanted to replace the natural lens opposite the cornea, axial length of the eye ball.

11. The method according to claim 9, wherein geometric data, respectively refraction indices of the eye components, are used for determining the desired topography.

12. The method according to claim 9, wherein the seating for the intraocular lens to be implanted in the eye is determined based on the biometrically obtained data of the eye.

13. The method according to claim 9, wherein the measuring data of the topography produced through mechanical machining or a laser processing on the lens surface, respectively the data for the desired topography, are converted to a uniform format for the comparison.

14. A device for producing an eye implant according to claim 1, wherein the device is adapted to perform the following steps: following the determination of a desired topography for at least one of the two surfaces of the optical implant region, controlled by the specific desired topography, at least one of the two surfaces of a standard blank is processed either by machining or laser irradiation, or is produced through direct casting with correspondingly designed casting molds, and that the topography produced in this way is measured on at least one implant surface and is compared to the desired topography.

Description

[0030] The invention is now explained further with the aid of the Figures, which show in:

[0031] FIG. 1 An exemplary representation of the visual acuity achieved with an eye implant according to one embodiment of the invention, within a specific field of focus depth;

[0032] FIG. 2 An example of the light-intensity distribution of the image generated on the retina of the eye, according to the embodiment;

[0033] FIG. 3 An exemplary embodiment of the operational steps for producing the eye implant according to this embodiment, as shown with a flow chart.

[0034] FIG. 1 shows the visual acuity achieved with an eye implant according to one embodiment of the invention, within a specific field of focus depth, in this case 3 diopters. This visual acuity is (0 diopters) for the distance vision and (3 diopters) 0.7 (70%) for the near vision. The visual acuity refers to the ability of the eye with optimum correction through the eye implant to perceive two object points separately. This is possible if in the fovea centralis of the retina, the cone located between two stimulated cones is not stimulated more than 70%. The grid size in this case is 2 m.

[0035] FIG. 2 shows the light intensity distribution of the image projected by the eye implant onto the retina of the eye which causes a lateral signal processing on the retina, making it possible to achieve an optimum field of focus depth with a visual acuity of at least 0.7 (70%) for the distance vision and the near vision.

[0036] Prior to the implantation, the eye is measured biometrically (topography of front and back surfaces of the cornea; axial length of the eyeball and, with phakic implants and intraocular implants, the position and topography of the front and back surfaces of the implant). The surface topography as the desired topography for the implant to be implanted into the eye is computed from these measuring values in combination with the planned position for the eye implant and the refractive index of the material. The data required for computing the optical implant region can furthermore be determined through a wave front measurement of the imaging components, in particular for additional lenses to be implanted in phakic or pseudo-phakic eyes.

[0037] The front eye section is preferably examined to determine the characteristics of the refractive components of the eye. Suitable for this is a Scheimpflug camera, for example, which can be used to take sectional images of the anterior eye chamber in a non-contacting way. These pictures permit an analysis of the complete cornea, the anterior chamber and the natural lens. In the process, geometric data such as central radii, cornea sphericity, different curvatures of the cornea, chamber angle, chamber volume and height of the anterior chamber as well as the lens clouding can be analyzed. Such an analysis of the front eye section is known, for example, from EP 1074214 B1.

[0038] The position of the implant in the eye can advantageously also be predicted based on the analysis data.

[0039] A desired topography for one of the two implant surfaces or both implant surfaces can be computed based on the data obtained through analysis and the known refractive indices, in particular the cornea and the aqueous humor of the eye, wherein the material used for the implant is also taken into consideration. This material refers to commercially available polymers, for example MMA/HEMA copolymers. A suitable material is also known, for example, from WO 2007/062864.

[0040] However, the implant can be produced from any implantable material having optical quality.

[0041] Standard methods are used for producing the optic for the eye implant, in particular the individual implantable lens, wherein one of the optic surfaces can have a standard geometry (spherical, aspherical or toric) and can be produced through turning, molding or injection compression molding. The second optic surface is preferably produced with a programmable lathe or through irradiation with a laser, in particular post-processing with a laser, suitable for creating free-form surfaces, wherein operational steps are preferred which dispense with a subsequent polishing of the surface. The production through direct molding with correspondingly formed molding tools is also possible.

[0042] Based on the desired topography, machine data are computed which are suitable for controlling the processing of a standard blank surface by mechanical machining or laser post-processing. In dependence on these machine data, the machining of the standard blank surface then takes place, for example in a suitable lathe or milling machine. A lathe or milling machine is preferably used that permits processing of the surface with such precision that a subsequent polishing is not necessary, wherein a diamond tool is advantageously used for this in the lathe. The standard blank for producing the implant, in particular the individual intraocular lens, through machining or laser processing is advantageously a blank produced through injection compression molding. In this way, a blank is obtained with precisely specified dimensions for the surface, which dimensions serve as starting point for producing the desired topography through machining or laser processing.

[0043] When using the process of injection compression molding, the haptic used to secure the implant in the eye can also be molded on.

[0044] The quality control of the topography of the optics designed as free-form surfaces preferably involves analyzing the measured and in particular the reflected wave front, wherein the desired surface is selected as mathematical reference and deviations from the topography are computed by analyzing the measured wave front as compared to the expected wave front. The wave front is preferably measured at a wavelength where the non-reflected light is absorbed by the implant material, so as to minimize the super-imposition of the reflected wave front of the optic front surface through reflections of the back surface of the optic.

[0045] A wave front sensor embodied as Shack-Hartmann sensor, for example, can be used to measure the topography of the implant surface. The Shack-Hartmann sensor contains an arrangement of micro lenses with a local-resolution light sensor arranged in its focal plane, e.g. embodied as CCD sensor. The measured topography causes wave fronts which trigger a deflection of the focal points of the micro lens arrangement on the local resolution light sensor. Measuring results can thus be obtained for the topography created on the implant surface.

[0046] The measurement with the aid of the Shack-Hartmann sensor makes use of the transmitted light method, for which the light used for the measurement is radiated through the optical implant region. However, a measuring method using light reflected on the implant surface and detected by the Shack-Hartmann sensor can advantageously also be used. These measuring methods are known, for example, from DE 20 2008 004 608 A1 for detecting implant errors.

[0047] A topographic sensor that scans the surface of the optical implant region and is embodied as distance sensor or angle sensor can also be used for measuring the topography of the implant surface. A topographic sensor of this type is known, for example, from WO 2009/124767.

[0048] The measured topography of the optical implant region is compared to the desired topography. For this, the measuring results are converted to the format of the desired topography. However, it is also possible to adapt the desired topography to the format of the measured topography for a comparison.

[0049] On the implant, the desired topography can be produced on one of the two implant surfaces. However, it is also possible to produce the respective topographies on both implant surfaces (front and back surfaces of the eye implant) which are designed individually, in order to correct the defective vision resulting from the eye components.

[0050] The flow chart in the attached FIG. 3 shows the various steps for producing an eye implant, in particular an intraocular lens, according to one exemplary embodiment.