Intraocular implant for correction of myopia

Abstract

An intraocular implant includes an optic part consisting of a central diverging lens of minus optical power, whose thickness increases radially from its optical center, and a peripheral edge shaped in the manner of a converging lens, and a haptic part for supporting the optic part, on each side of the latter, wherein the implant has the function of correcting myopia and is designed to be arranged in the anterior chamber of the eye, without ablation of the crystalline lens, the central diverging lens being a corrective lens, and the peripheral converging lens being a lens for focusing the peripheral light in front of the retina.

Description

BACKGROUND OF THE INVENTION

The present invention relates to an intraocular implant intended to be inserted in the anterior chamber of the eye, by ophthalmic surgery, in order to correct the patient's myopia without ablation of the crystalline lens.

DESCRIPTION OF THE PRIOR ART

The document EP-A-0 346 245 describes and proposes an implant of the type defined hereinabove, consisting:

of an optic part, essentially comprising a diverging corrective lens of minus optical power, for example a biconcave lens, and whose thickness consequently increases generally from its optical axis toward its periphery, the latter then having an edge of relatively large thickness;

and of a haptic part comprising, for example, two support loops arranged opposite each other, for supporting the optic part, on both sides of the latter, in the anterior chamber of the corrected eye.

In accordance with the established terminology in the technical field of the present invention, the expression "optic" or "optic part" designates in a general manner that part of the implant penetrated by the light rays passing through the pupil, whatever the degree of dilation of the latter. All or part of this optic part can be occupied by the actual corrective lens itself, of an optical power appropriate to the desired correction.

As regards the expression "haptic" or "haptic part", this designates that part of the implant which essentially has no role or function with regard to the light rays passing through the pupil, and which ensures in a suitable manner the support, the deployment, and the positioning of the optic part in the anatomical seat of the eye intended to receive it.

As is known, the haptic part and the optic part can be separate, or can be obtained in monobloc fashion made from one and the same material, for example a suitable plastic material.

According to the document EP-A-0 346 245, the optic part coincides almost completely with the corrective lens, which can in this case have a relatively large diameter radius diameter of between 3.5 and 4.5 mm, whilst the radial extension of the optic part 2 or peripheral edge 5 is increased up to a circle with a radius diameter of between 4.8 and 6.5 mm. As is shown in FIG. 2, a portion of the haptic part 3, and more specifically a branch 3 of the loops, has an angle, relative to the plane of the optic part 2, of between 20° and 25°; as is shown with reference to FIG. 3, this makes it possible to maintain or position the implant at a distance from the cornea, the pupil and the crystalline lens.

The eye receiving the implant and comprising the cornea 9, the retina 10, the iris 11, the pupil 12 and the crystalline lens 13 has been shown diagrammatically in FIG. 3. The ophthalmic operation results in the deployment of the implant 1 in accordance with the optical axis of the eye, coinciding with that of the optic part 2, or lens 4. Taking into account the correction afforded by the lens 4, a ray 13 passing through the center of the pupil 12 is focused at 14 on the retina 10. In dim light, for example in night vision, the iris 11 is caused to retract, as shown in FIG. 3; in this configuration, the optic part 2 of the implant still covers the pupil 12, by virtue of the design choices according to the invention. Still in this configuration, a peripheral ray 15 is defocused relative to the retina 10 and more precisely focused at the point 16, in front of the retina 10, in such a way that a spot 17 of low luminous intensity is obtained on the retina 10. Experience shows that the corrected image 14 can be discriminated or distinguished much better by the eye, compared to the spot 17, so that the patient tolerates much better an implant according to the present invention.

Claims

1. An intraocular implant, comprising an optic part consisting essentially of a central diverging lens of minus optical power, whose thickness increases radially from its optical center, and a peripheral edge shaped in the manner of a converging lens, and a haptic part for supporting said optic part, on each side of the optic part, wherein said implant has the function of correcting myopia and is designed to be arranged in the anterior chamber of the eye, without ablation of the crystalline lens, the central diverging lens being a corrective lens, and the peripheral converging lens being a lens for focusing peripheral light in front of the retina, wherein, in combination, radial extension of the central diverging lens is limited by a circle with a radius diameter of between 3.5 and 4.5 mm, radial extension of the peripheral converging lens is increased to a circle with a radius diameter of between 4.8 and 6.5 mm, in order to cover the retina in dim light, and said peripheral converging lens has a plus power in a range between 20 and 60 diopters.

2. The implant as claimed in claim 1, wherein at least the central diverging lens is made of a material having a refractive index between 1.65 and 1.75.

3. The implant as claimed in claim 2, wherein said material is polysulfone.