MULTIFOCAL LENS SYSTEM HAVING
ECCENTIC AXES AND METHOD
This application is a division of application Ser. No. 08/352,381, filed Dec. 8, 1994 abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the field of ophthalmic optics and artificial lens adapted to be affixed to an eye and more specifically relates to an artificial lens adapted to be located in an eye having a macula wherein the artificial lens comprises a multifocal optical lens system wherein each principal axis is eccentric to each other for directing light rays from each image of each lens onto the macula of an eye. In the preferred embodiment a first lens system having a prism directs paracentral light rays from a near object onto the macula and a second lens system having a prism positioned in a cooperating relationship to the first lens system directs central light rays from a distant object onto the macula of an eye.
This invention also relates to method for producing multiple images of an object for an eye using a multifocal optical lens system wherein the principal axis of each lens system is eccentric to each other.
2. Description of the Prior Art
It is known in the art that when the optical power of the natural eye is emmetropic, the eye is naturally focused for distance with the ciliary body at rest. The natural eye has the ability to change (increase or decrease) the converging power of the natural (crystalline) lens for near vision and for intermediate vision, that is vision in the range of about 10" to about 18" or 20".
With aging, the eye's natural (crystalline) lens loses its ability to adequately increase its converging power. In order to provide for a sharp focus near vision, it is known in the art to make use of artificial lens system. It is also known in the art to utilize a plurality of artificial lens systems such as glasses or spectacles, contact lens, intraocular lens, corneal lens and intracorneal lens, all of which are utilized to produce a focused near vision. Such lens systems are designed to use concentric lens system for distant and near images and the images are passed through the natural round pupil as the only entrance of light to the retina.
Glasses and spectacles are well known in the art and are selected to have a diopter power to produce the correction required to focus near vision. Also, it is known in the art that such glasses or spectacles comprise bifocal lens for near and distant vision correction or trifocal glasses for near, intermediate and distant correction vision, all of which have concentric principal axes.
Contact lens likewise are well known in the art. Typical of the known prior art which describes contact lens are U.S. Pat. No. 3,034,403 relating to a contact lens of apparent variable light absorption characteristics; U.S. Pat. No. 3,270, 099 which relates to a method for making multi-focal length, concentric contact lens and U.S. Pat. No. 4,402,579 which discloses and teaches various concentric axes contact lens structures.
Typically, contact lens are positioned over the anterior surface of the pupil. The natural crystalline lens and iris remain in place and perform their natural functions and cooperate with the contact lens to focus the appropriate images on the macula.
It is also known in the art to utilize prisms in glasses and spectacles both located along the same axis to improve the image focused on the natural crystalline lens.
It is also known in the art to utilize intraocular lens to replace the natural crystalline lens in a cataracts operation. Intraocular lens are implanted into either the anterior chamber or posterior chamber of the eye and are utilized in place of the natural crystalline lens. Typical of such intraocular lens are U.S. Pat. No. 4,010,496 which discloses a bifocal lens which is positioned within the anterior chamber; U.S. Pat. No. 4,244,060 which discloses an intraocular lens having a lens body and a plurality of lens-centering filaments extending outwardly in a common plane from spaced rim portions of the lens body; U.S. Pat. No. 4,485,499 which discloses intraocular posterior chamber lens and U.S. Pat. No. 4,976,732 which discloses an optical lens wherein the lens body has integral therewith a predetermined area which is adapted to selectively intercept and pass light through the lens body in a manner to obtain an optical effect for substitution of the loss of accommodation of a phakic, aphakic and pseudophakic eye.
U.S. Pat. No. 4,994,080 discloses an optical lens having stenopaeic openings located in the central area thereof which produces parallel light transmitting paths for passing light rays along a path defining the visual axis of the eye and forwarded onto the fovea centralis in a manner to obtain an optical effect by increasing the depth of focus of the eye in order to substitute for the loss of at least one of the focusing power and the accommodation of the eye.
Artificial lens are also known in the art which are capable of being implanted into the cornea of an eye and which become encapsulated by growth of the corneal epithelium of the cornea of the eye over the anterior surface of lens implanting the same. One such artificial lens fabricated from a collagen-hydrogel material is disclosed in U.S. Pat. No. 5,112,350.
The natural (crystalline) lens degrades as the age of an individual approaches the 40-to-50-year-age range such that the natural lens can no longer adequately change shape due to a loss of elasticity of the lens of the eye causing defective accommodation and inability to focus sharply for near vision. This condition is referred to as a presbyopia.
When this occurs, an individual requires additional converging power (plus) for near vision. This is commonly supplied by the lower lens in a bifocal artificial lens. As the individual approaches the age range of 65-to-70-years, substantially all of the natural converging powers of the lens is lost and additional convergence for near requirement must be made stronger. In such instances, the bifocal lens of the glasses, contact lens or artificial lens must supply all the convergence of light for near vision.
Following cataract extraction and intraocular lens implantation, there remains the need for additional convergence of light for near vision. With monofocal intraocular lens ("IOL") focused for distance, the near vision convergence must be completely supplied by the bifocal glasses or a single vision reading glasses.
Multiple lens IOLs are known in the art and typically create multiple light rays which are directed on the macula. The artificial lens disclosed in U.S. Pat. Nos. 3,034,403 and 4,976,732 described above produce multiple light rays for the eye. Typically, the multiple lens IOLs do not have provisions for restricting the light from near and far and spontaneously flood the macula with excess light. Also, light passing through multiple lens IOLs enters the eye through each of the optical systems resulting in both a sharp image and a blurred image of the same image impinging upon the macula. This results in: (a) loss of color purity; (b) loss of contrast; and (c) inability of the retina to adapt since the
brain perceives the flooding and receipt of extraneous light as too much light.
An intraocular lens that functions as a regular intraocular lens and, in tandem with or concentric with a high plus spectacle lens, as a Galilean telescope, was described in an 5 article entitled "The Telescopic Intraocular Lens" by Jeffrey Koziol, M.D., which appeared at pages 43 and 44 of a compilation of papers presented at the Eleventh National Science Writers Seminar in Ophthalmology, Sep. 16-Sep. 19, 1990 at Universal City, Calif, (the "Koziol Reference"). 10 The Koziol Reference describes the telescopic intraocular lens as a teledioptic lens having a peripheral convex and central concave (minus) portion which have concentric axes. A full range of visual field and normal image size is achieved with the teledioptic lens. A magnified image is obtained 15 when an image in a visual field is viewed through the minus portion of the lens and a high-plus spectacle.
SUMMARY OF THE INVENTION
None of the prior art discloses, teaches or suggests an 20 artificial lens system adapted to be affixed to an eye involving the separation of retinal images and directing light rays from both near and far images such that simultaneously different light rays of the same object strike the macula. In the preferred embodiment portions of the light rays are 25 directed to locations superior and inferior to the macula.
The known glasses or spectacles having a prism do not place the prism on a selected surface of a lens to produce and direct disparate images to the macula.
The intraocular lens of the prior art utilized in the eye function to pass light rays of both near and far vision images onto the macula. Under certain light conditions, the macula is flooded with excess light thereby making it more difficult for the brain to interpret the image due to the presence of excess light.
In multiple lens IOLs, numerous light rays are presented to the macula through the multiple optical systems resulting in both a sharp image and a blurred image of the same object. As a result, the retina is unable to adapt to the 4Q multiple images since the brain perceives the flooding of extraneous light and the blurred image as additional light making interpretation thereof difficult.
The telescopic intraocular lens of the Koziol Reference requires use with a high plus, concentric spectacle to 45 develop a magnified image.
The present invention relates to a novel, new and unique lens which is in the form of an artificial lens including a multifocal optical lens system having eccentric axes which is affixed to an eye. The lens of the present invention 50 overcomes each of the above problems associated with the prior art while concurrently producing a system for developing specific light rays from near and distant images of objects which are focused on the macula.
The artificial lens of the present invention is adapted for 55 use in an eye and comprises means adapted to be affixed to an eye having multifocal optical lens system wherein the principal axis of each lens is eccentric to each other for directing light rays from each image of each of the multifocal lens onto a macula of an eye. In the preferred 60 embodiment, the artificial lens includes an image producing means comprising a first lens having a predetermined diopter power for receiving a near image and a prism having a preselected diopter power. The prism is positioned on a selected surface of the first lens and directs paracentral light 65 rays from a near object onto the macula of the eye and central light rays of the near object superior of the macula.
The artificial lens includes a second lens having a predetermined diopter power positioned eccentrically inferior of the first lens for receiving light rays from a distant object. The second lens includes a second prism having a preselected diopter power. The second prism is positioned on a selected surface of the second lens and directs paracentral light rays from the distant object onto a macula of the eye and central light rays from the distant object inferior of the macula. Also, a method is disclosed herein for producing multiple images for an eye comprising the step of affixing to an eye an artificial lens having a multifocal optical lens system wherein the principal axis of each lens is eccentric to each other for directing light rays from each image of each lens of the multifocal optical lens onto a macula of an eye.
Although it is known in the prior art to utilize prisms in glasses, the prior art does not disclose, teach, suggest utilizing an artificial lens within the eye having a multifocal optical lens system wherein the principal axis of each lens system is eccentric to each other for directing light rays from each image of each lens of the multifocal optical lens system onto a macula of an eye. The artificial lens of the present invention maintains a separation of light rays from images of the two lens systems such that the macula will not be simultaneously presented with a fuzzy image and a clear image of the same object.
Thus, one advantage of the present invention is that the artificial lens system in the preferred embodiment is arranged such that the first lens system located superiorly in the eye, when in use, permits light to pass therethrough onto the macula thereby directing paracentral light rays of a near object onto the macula and central light rays of the same object superior of the fovea onto the macula.
Another advantage of the present invention is that the multifocal optical system provides for near and distant correction of refractive error that does not use glasses or other similar external eye devices.
Another advantage of the present invention is that the two lens system in the multifocal lens optical system are eccentric and direct light rays from the same image onto the macula of an eye.
Another advantage of the present system is that the imaging producing means can be so arranged that when one lens system is in use, the light allowed to go through the other or unused lens system is minimized or completely eliminated. By placing the "near optical vision system" superiorly on the artificial lens, the upper eyelid position can be varied and thereby be utilized to cover up the nearest system while primarily using the "distant optical vision system" to pass selected paracentral light rays from an image onto the macula.
Another advantage of the present invention is that the pupil size can be altered or reconfigured by making the pupil larger and preferably an elongated vertically shaped elliptical natural pupil. By altering the pupil size or configuration, the quantity of available light is increased to 150% to 175% of the light that would have traversed the untreated or unaltered pupil. This is a marked improvement over the prior art lens system where the transmitted light is divided between the two lens system. Therefore, approximately 65% to 75% light (compared to the quantity of the light passing through the pupil before treatment) would be available for the lens system of the present invention to use to focus light rays from the images on the macula. If the pupil is not altered, only approximately 40% of the light is available for each optical system. This is typical of the numerous lens design of the prior art described above.
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Another advantage of the present invention is that the artificial lens of the present invention can have one or both of the imaging lens system configured with an extended objective lens to function as a light gathering means.
Another advantage of the present invention is that eccentric location of the near system in a superior position can be utilized in an unaltered pupil.
Another advantage of the present invention is that further eccentricity of the near lens system is achievable by altering the natural pupil by vertical elongation of the natural pupil or by use of an accessory pupil.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other advantages of this invention will be readily apparent when considered in light of the detailed description hereinafter of the preferred embodiment and when considered in light of the drawings set forth herein which include the following figures:
FIGS, la, lb and lc are pictorial representations of the eye illustrating rotation positions of the eye about its rotational axis showing the positional relationship between the natural crystalline lens and the macula;
FIG. 2 is a front view of an eye having an artificial lens in the form of an intraocular lens having an eccentric lens system for producing near and distant macular images;
FIG. 3 is a pictorial representation of an image producing means comprising a first lens having a predetermined diopter power and a second lens having a preselected diopter power eccentric to the first lens for focusing similar images onto the macula in an eye;
FIG. 4 is a pictorial representation of an image producing means having a first lens having a prism and a second lens having a prism for directing light rays from near and far objects onto the eye, with the near image Nj directed superior to the macula and the distant image Dt inferior of the macula;
FIG. 5 is a pictorial representation of an artificial lens of the present invention formed as an intraocular lens located in the anterior chamber of an eye;
FIG. 6 is a pictorial representation of an artificial lens of the present invention formed as an intraocular lens located in the posterior chamber of an eye;
FIG. 7 is a pictorial representation of an artificial lens of the present invention affixed to the cornea of an eye subepithelially;
FIG. 8 is a pictorial representation of an artificial lens of the present invention which is implanted as an intracorneal lens intrastromal;
FIG. 9 is a pictorial representation of an artificial lens of the present invention having a near lens system superior and a distant lens system inferiorly, in an eccentric arrangement, with the position of both lens system being below the upper eyelid;
FIG. 10 is a pictorial representation of the position of the image producing means of FIG. 9 observing images below the eyelid;
FIG. 11 is a pictorial representation of an eye having an artificial lens of the present invention wherein the image producing means includes a first lens system and a second lens system wherein the near lens system is covered by the upper eyelid resulting in only the second lens system passing light rays from a distant object to the macula of the eye;
FIG. 12 is a pictorial representation of an eye having image producing means wherein the near lens system is
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occluded by the upper eyelid resulting in only the light rays from the distant object being passed by an artificial lens of this invention to the macula of an eye;
FIG. 13 is a pictorial representation of a pupil having an 5 accessory pupil formed therein wherein a first lens system is located posteriorly to the accessory pupil and the second lens system is located posteriorly to the natural pupil;
FIG. 14 is a pictorial representation of an eye showing the front view of the eye having an accessory pupil formed 10 therein for cooperating with the first lens system and wherein the natural pupil cooperates with the second lens system;
FIG. 15 is a pictorial representation of an eye having an altered pupil to form the same into a vertical ellipitically shaped pupil for cooperating with an image producing means having a first lens system and a second lens system eccentrically arranged;
FIG. 16 is a pictorial representation of an image produc2Q ing means having a first lens system having a first lens and a prism and a second lens system having a second lens located in the accessory pupil and natural pupil, respectively;
FIG. 17a is a pictorial representation of a bi-convex lens; 25 FIG. 17b is a pictorial representation of a double convex lens having a prism operatively connected there between adapted for use as a lens system;
FIG. 17c is a pictorial representation of a first lens system having a prism and a second lens system having a prism; 30 FIG. 18 is a pictorial representation of an image producing means having a pair of extended objective lens having a lens system including a prism located at the distal end thereof for producing disparate macular images;
FIG. 19 is a pictorial representation of the distal section 35 of the lens system illustrated in FIG. 18 showing another embodiment of an image producing means;
FIG. 20 is a pictorial representation of an artificial lens of the present invention having an extended objective lens and a prism in the superior location in an altered elongated 40 natural pupil and a plano-convex lens and a prism in the normal natural pupil
FIG. 21 is a front plan view of the artificial lens of FIG. 20;
45 FIGS. 22a, 22b and 22c are pictorial representations of: (i) an artificial lens system having an extended objective lens in accessory pupil; (ii) an artificial lens having an extended objective lens in both the accessory pupil and natural pupil with a third extended objective lens alternative; and (iii) an
5q artificial lens having an extended objective lens in the natural pupil;
FIG. 23 is a front plan view of an artificial lens in the form of an intraocular lens having an extended objective lens and a prism in the superior location on the lens and an extended 55 objective lens located inferior on the lens;
FIG. 24 is an elevational end view of the intraocular lens of FIG. 23;
FIG. 25 is a pictorial representation of the eye showing the natural pupil and an accessory pupil having the intraocu60 lar lens of FIG. 23 implanted in the eye;
FIG. 26 is a pictorial representation of the eye showing the natural pupil being formed into a vertically extending ellipitical shape forming an enlarged pupil which is in lieu of an accessory pupil and having the intraocular lens of FIG. 65 23 implanted in the eye;
FIG. 27 is another embodiment of an artificial lens in the form of an intraocular lens having a lens with an extended
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