JP2763293B2 - Intraocular bifocal lens - Google Patents

Description

BACKGROUND OF THE INVENTION The present invention relates to the treatment and vision recovery of patients after cataracts,
For example, the present invention relates to an intraocular bifocal lens that can be implanted in a human eye in place of a natural lens extracted in cataract surgery.
Typically, thick eyeglasses have been used to correct the vision of patients after cataracts. However, it is clear that spectacles have disadvantages related to their size and weight. The present invention eliminates the need to wear heavy eyeglasses by creating a pseudo lens, or plastic microconvex lens eye to replace the excised cataract. The concept of creating concentric bifocal lenses can be found in contact lenses. U.S. Pat. No. 3,726,587 is an example. Contact lenses have a half-moon shaped convergent lens that conforms to the rounded shape of the cornea. Such a shape cannot be applied to intraocular implantation. Other types of multifocal contact lenses are also known and patented
No. 3,794,414 describes a lens having a light-passing area interrupted by opaque parts spaced at regular intervals. U.S. Pat. No. 3,962,505 shows a substantially concentric portion of a contact lens for bifocal vision. Most prior art techniques relating to intraocular lenses deal with fixing means for fixing the lens in either the posterior or anterior chamber of the eye. U.S. Pat. No. 4,010,496 describes an intraocular lens having high and low index refractive segments for viewing near and far. SUMMARY OF THE INVENTION Pseudophakic eyes are usually photopic and have a pupil diameter of 4 mm
Pupils rarely shrink to less than 2 mm in diameter. It is also known that the pupil contracts slightly when trying to focus close to the eye. The eye acts not only as a mechanism for viewing but also as a mechanism for collecting light. No matter how the diameter of the pupil is given, light enters the pupil and is collected on the retina. By changing the path of some light, bi-vi
sion) is possible. For example, to illuminate a 3mm pupil in candle lighting 200 feet away (brightness typically found in modern offices) with a refractive power to see close and to see far away around it When juxtaposed with an optical element having a diameter of 2.12 mm, which is concentrically surrounded by the optical element described above, a multifocal point can be obtained. In the above example, half of the pupil region is provided with a refractive power for viewing near, and the other half is provided with a refractive power for viewing far away. When focused closer, the central portion of the lens creates an image on the retina, and the pupil contracts slightly to help focus. Pupil contraction helps but is not required for concentric lenses. When the eye looks at a distant object, the power of the focal point for seeing closer is automatically out of focus, and the refractive power for looking farther concentrically replaces it and makes the distance appear clearer. This is because the optical integration area is large in a portion for viewing the lens concentrically far away. Even if a very bright object in the distance stimulates the pupil to increase the contraction, as the depth of focus increases,
It is possible to cope with blurring from the optical element for viewing near in the center. The use of sunglasses to reduce the irritating brightness seen in the distance caused the pupil to relax, increasing the light collected by the concentric lens for viewing in the distance and reducing the depth of focus. cancel. Therefore, even if the light decreases, the far part can be clearly seen. The difference in effective power between seeing far and near is about +2.50 diopters for the average patient,
It can be seen that sufficient discrimination of the focal point speeds up neurotransfer from afar to near. This phenomenon, and the appropriate light collection area for a given pupil area,
The efficacy of the intraocular optical element design of the present invention is provided. To maintain the validity of the design, the range of power of the lens for viewing far away is limited to +10.00 to +30.00 diopter effective power, and the optical refraction for viewing close The range of power is limited to +10.00 to +40.00 diopter effective power. The diameter of the lens can be varied as needed, but 6 mm is the average. Optics for viewing near the center can vary in diameter as needed, but for a 3.0 mm pupil stimulated by candle lighting about 200 feet away.
2mm is the average. The lenses can be plano-convex or bi-convex and can be manufactured by lathe cutting, compression or injection molding or electroforming. An optical element for seeing near can be disposed on both sides with appropriate correction of refractive power. It is an object of the present invention to provide an intraocular bifocal lens for post-cataract patients, eliminating the need for heavy and uncomfortable glasses. Another object of the present invention is to provide an intraocular bifocal lens that allows a post-cataract patient to clearly see both near and far. It is yet another object of the present invention to provide a monolithic intraocular lens. It is yet another object of the present invention to be able to see both near and far at the same time without the natural lens. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of an intraocular bifocal lens. FIG. 2 is a sectional view of a plano-convex intraocular lens. FIG. 3 is a sectional view of a biconvex intraocular bifocal lens. FIG. 4 is a cross-sectional view of a human eye with an intraocular bifocal lens implanted in the anterior chamber. FIG. 5 is a cross-sectional view of a human eye with an intraocular lens implanted in the posterior chamber. DETAILED DESCRIPTION OF THE INVENTION In FIG. 1, an intraocular bifocal lens is indicated by reference numeral 1. The unitary body has a central portion, designated by the numeral 3, that is optically refractive in order to see near, and optically refractive around it to see far away. There is a given part 2. The two parts are concentric and coaxial. The main body has each part given optical refractive power 2
Although it is roughly divided into two parts, the main body itself is an integral structure. The main body, in cross section, can be either a plano-convex shape as shown in FIG. 2 or a bi-convex shape as shown in FIG. After cataract surgery to remove the natural lens from the human eye, an intraocular bifocal lens can be implanted in either the anterior or posterior chamber of the eye. FIG. 4 shows the human eye with the lens implanted in the anterior chamber, and FIG. 5 shows the lens implanted in the posterior chamber. The lenses are fixed in place in either room. This fixation can be achieved in various ways. The multiple suspension or fixing method has been present in a general form in recent years and can be applied to the present invention. In FIG. 4, the eye is designated by the numeral 10. The anterior chamber 8 is defined by the cornea 7 and the inner wall of the iris 11. The pupil 9 extends from the front chamber 8 to the rear chamber 9. The retina is indicated by the number 6. The central portion of the lens or a portion for viewing near is aligned with the pupil 9 in the axial direction. The central portion is aligned with the pupil as shown in FIG. 5 when the lens is located in the rear chamber. Under normal light conditions, the diameter of the pupil 9 is slightly larger than the part for viewing near the center of the lens. In either FIG. 4 or FIG. 5, light passes through the pupil 9 and is collected on the retina 6. By altering some of the light paths, the intraocular concentric bifocal lens creates double vision. If the pupil is 3 mm in diameter, the intraocular bifocal lens most preferably has a portion for viewing near the center of 2.12 mm in diameter. Half of the pupil region is provided with a refractive power for viewing near, and the other half is provided with a refractive power for viewing far away. When focused close, the central part forms an image on the retina 6. Although the pupil contracts somewhat to clarify the image, it is not necessary. When the eye 10 looks at a distant symmetrical object, the part for the near view is automatically defocused, and the part for the distant view is enabled so that the distant view is clearly visible. This is because the optical integration area of the part for viewing the lens far away is large. Although the invention has been described by way of example herein, it will be understood that modifications are possible.

Claims (1)

(57) [Claims] An intraocular lens that can be implanted into the human eye and is fixedly mounted in the eye instead of the injured natural lens, and is optically refracted to look close A transparent portion having a first portion disposed at a first portion and a second portion concentrically disposed at the first portion and optically refracted so as to look far away, the first portion having a diameter of about 2.12 mm. And the body has a diameter of about 6 mm, the body is located in either the anterior chamber or the posterior chamber of the human eye, and the first portion has a range of +10.00 to +30.00 diopters effective power. Within the range of +10.00 to +30.00 diopter effective power, to provide an optically refractive power within a range of +10.00 to +30.00 diopters of effective refractive power to reliably discriminate focus and close proximity. To speed up the nerve transmission between seeing and looking far The difference in effective optical power is the average +2.50 dioptre effective power lens between the first portion and the second portion. 2. The lens of claim 1, wherein the transparent body is fixed in place in either the anterior chamber or the posterior chamber of the eye such that the portion for viewing near is aligned with the pupil. 3. An intraocular lens that is intended to be implanted in the human eye, a first part that is optically refracted and permanently fixed in the center to look closer, and looks far away A transparent integral lens body having an optically refractive power and a second portion concentrically disposed on the first portion, wherein said first portion has an average diameter of about 2.12 mm and said body has The first portion has an average diameter of about 6 mm, the first portion is optically powered within a range of +10.00 to +30.00 diopter effective power, and the second portion is
Optically powered within the range of 10.00-30.00 diopter effective power, to reliably distinguish the focus and to quickly perform nerve transmission between looking closer and looking far away A lens wherein the difference in effective power between the first and second portions is an average plus 2.50 diopters effective power. 4. 4. The lens of claim 3, wherein the transparent body is configured to be fixed in place in the anterior chamber of the eye such that a portion for viewing near is aligned with the pupil. 5. 4. The lens of claim 3, wherein the transparent body is configured to be fixed in place in the posterior chamber of the eye such that a portion for viewing near is aligned with the pupil.