CA1328149C - One-piece bifocal intraocular lens construction - Google Patents
One-piece bifocal intraocular lens constructionInfo
- Publication number
- CA1328149C CA1328149C CA000596628A CA596628A CA1328149C CA 1328149 C CA1328149 C CA 1328149C CA 000596628 A CA000596628 A CA 000596628A CA 596628 A CA596628 A CA 596628A CA 1328149 C CA1328149 C CA 1328149C
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- Canada
- Prior art keywords
- lens
- lens portion
- intraocular
- focal length
- portions
- Prior art date
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- Expired - Fee Related
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- 239000007943 implant Substances 0.000 claims abstract description 33
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- 210000004556 brain Anatomy 0.000 claims description 15
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- 238000011156 evaluation Methods 0.000 claims description 7
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- 239000000565 sealant Substances 0.000 description 2
- DYUUGILMVYJEHY-UHFFFAOYSA-N 1-$l^{1}-oxidanyl-4,4,5,5-tetramethyl-3-oxido-2-phenylimidazol-3-ium Chemical compound CC1(C)C(C)(C)N([O])C(C=2C=CC=CC=2)=[N+]1[O-] DYUUGILMVYJEHY-UHFFFAOYSA-N 0.000 description 1
- VVQNEPGJFQJSBK-UHFFFAOYSA-N Methyl methacrylate Chemical compound COC(=O)C(C)=C VVQNEPGJFQJSBK-UHFFFAOYSA-N 0.000 description 1
- 101100504379 Mus musculus Gfral gene Proteins 0.000 description 1
- 229920005372 Plexiglas® Polymers 0.000 description 1
- 206010036346 Posterior capsule opacification Diseases 0.000 description 1
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Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/02—Prostheses implantable into the body
- A61F2/14—Eye parts, e.g. lenses or corneal implants; Artificial eyes
- A61F2/16—Intraocular lenses
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/02—Prostheses implantable into the body
- A61F2/14—Eye parts, e.g. lenses or corneal implants; Artificial eyes
- A61F2/16—Intraocular lenses
- A61F2/1613—Intraocular lenses having special lens configurations, e.g. multipart lenses; having particular optical properties, e.g. pseudo-accommodative lenses, lenses having aberration corrections, diffractive lenses, lenses for variably absorbing electromagnetic radiation, lenses having variable focus
- A61F2/1616—Pseudo-accommodative, e.g. multifocal or enabling monovision
- A61F2/1618—Multifocal lenses
Landscapes
- Health & Medical Sciences (AREA)
- Ophthalmology & Optometry (AREA)
- Cardiology (AREA)
- Oral & Maxillofacial Surgery (AREA)
- Transplantation (AREA)
- Engineering & Computer Science (AREA)
- Biomedical Technology (AREA)
- Heart & Thoracic Surgery (AREA)
- Vascular Medicine (AREA)
- Life Sciences & Earth Sciences (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Prostheses (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A rigid bifocal intraocular lens (60) for use as an artificial lens implant is disclosed. In one embodiment, the intraocular lens ha a rigid lens body (61) having a chord (61a) and first and second lens portions (62) and (63). The first lens portion (61) has a focal length and the second lens portion (63) has a focal length different from the focal length of the first lens portion (62). The first lens portion (62) is positioned on one side of the chord (61a) and the second lens portion (63) is positioned on the other side of the chord (61a). The first and second lens portions (62 and 63) form an integral, one-piece optical lens body (61) with the first and second lens portions being non-movable with respect to one another. In another embodiment the rigid lens body has a first central circular lens portion and a second outer annular lens portion. In a preferred form of this embodiment the inner, circular lens has a diameter of a between about 1.8 millimeters and about 2.0 millimeters, with the outer annular lens portion having a diameter of between about 6 millimeters and 7 millimeters. A preferred corrective power for the lenses used in the above-referenced embodiments is between about +15 and about +25 diopters for a distance-viewing lens portion, and a corrective power for a near-viewing portion of between about +3 and +4 diopters greater than the corrective power of the distance-viewing portion. Preferably, the lens portions are formed from molding in a manner avoiding introduction of any substantial refractive index gradient in the lens material.
A rigid bifocal intraocular lens (60) for use as an artificial lens implant is disclosed. In one embodiment, the intraocular lens ha a rigid lens body (61) having a chord (61a) and first and second lens portions (62) and (63). The first lens portion (61) has a focal length and the second lens portion (63) has a focal length different from the focal length of the first lens portion (62). The first lens portion (62) is positioned on one side of the chord (61a) and the second lens portion (63) is positioned on the other side of the chord (61a). The first and second lens portions (62 and 63) form an integral, one-piece optical lens body (61) with the first and second lens portions being non-movable with respect to one another. In another embodiment the rigid lens body has a first central circular lens portion and a second outer annular lens portion. In a preferred form of this embodiment the inner, circular lens has a diameter of a between about 1.8 millimeters and about 2.0 millimeters, with the outer annular lens portion having a diameter of between about 6 millimeters and 7 millimeters. A preferred corrective power for the lenses used in the above-referenced embodiments is between about +15 and about +25 diopters for a distance-viewing lens portion, and a corrective power for a near-viewing portion of between about +3 and +4 diopters greater than the corrective power of the distance-viewing portion. Preferably, the lens portions are formed from molding in a manner avoiding introduction of any substantial refractive index gradient in the lens material.
Description
~ 328~9 LE~IS CQNS~RUCTION
Field of the I~ve~tion This invention relates generally to intraocular ~j lenses to be used as artificial lens implants in eyes from which the cataractous natural lens has been removed, and more particularly to an improved rigid lens having multiple lenses.
Descr~ptio~ o~ the Pr~or Art The implanta~ion of an intraocular lens for restorins vision after cataract surgery is well-known in the art. In general, two forms of surgery are used to remove cataracts~ Thesa are extracapsular cataract extraction an~ intracapsulax extraction. (Discussed in U.S. Pat. Re.~ 31,626 to Hoffer.) Following extraction : of a cataractous lens, an intraocular lens i~ normally implanted in either the anterior or the posterior chamber of the eye. In an anterior chamber implant, the lens is generally situated forward of, or mounted to, the iris. In the case of posterior chamber implants, the lens is situated behind the iriæ and may be mounted within the cleft or fornix of the capsule which remains in place after extracapsular surgery. Posterior chamber implants are generally preferred, in part because thi~
: is the location from which the natural lens is removed.
; In both anterior or posterior chamber implants, the lens i~ u~ually centered and fixed in position by one or more supporting strands or haptic members Nhile available intraocular lenses incorporate haptic member(s) having various geometric shapes and configurakion~, the typical haptic member i8 a flexible : 35 strand of non-biodegradable material which is fixed to the len~ body, and exhibits specific spring-like memory qualitie~ so that the haptic member can be compressed or off-set from the normal rest position and thereafter returned to the fully extended condition when pressure ~. - .. , ~ . . , 13281~9 is removed.
The intraocular implant is an artificial lens which has one given focal length. Since the intraocular implant is made of a rigid material it cannot chan~e the focal length by deformation as the natural lens does (called accommodation). A-~ a result of this, if the focal length i~ selected to provide a sharp image for a distant object, then an object which is closer (i.e. at reading distance) will not be imaged sharply on the retina. Alternately, one could image closer ob~ects sharp by selecting a different focal length, but then, of course, distant ob~ects would appear out of focus.
Contact lenses have been made having multi-focal length~ and also having variable light absorption.
U.S. Pa$ent No. 3,270,099 issued Augu~t 30, 1966 to R.N.
Camp discl~ses a method for making a multi-focal length contact lens. Tha Camp patent deal~ with a contact lens which is not used for the same function or manner as an intraocular len~. Further, the Camp patent teaches that the eye uses the inner part of the cornea for near vision while the outer part i~ used for distant vision.
For this reason, the Camp contact lens covers the cornea with a contact lens which has one power in the inner part and another power in the outer part. As a basis for uch a lens, the Camp patant teache3 that the divergent rays which enter the peripheral portion are not focused on the retina and hence are unseen. This is~ of course, a violation of the law of physics a~
light is detected by the retina regardless of whether it is focused or unfocused.
U.S. Paten~ No~ 3,034,403 to Neefe was issued May 15, 196~ and dîsclo~es a contact lens of apparent variable light absorption. The center portion of the j contact len~ is tinted while the outer portion i3 clear.
ll 35 Bifocal intraocular lenses are known, see for j example Nielson et al, U.5. Patent No. 4,636,211. The Nielson reference dlscloses a concentrically bifocal (or ., .
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1328l~9 target) lens, i.e. a lens implant having an outer annular portion of one power, in an inner circular portion of another power. The add on power difference between the far and near vision portions of Nielson et al '211 is indicated as being +.250 diopters. The inner lens of Nielson et al ~211 is indicated a~ being, on the average/ about 2.12 mm in diameter.
The features that are possible in a bifocal intraocular lens are, to a great extent, dependent upon the method of manufacture used and/or the material from which the lens is made. A conventional method of making an in~raocular lens, is through the compression molding technique. For this technique, a mold is made by machining a cavity out of a ~iece of tool steel. The radius of curvature of the cavity is made equal to.the radius of curvature of the convex side of the lens. The cavity i5 then polished. Material for the lens, which typically has a consistency analogous to plexiglass, is generally manufactured in the form of rods preferably having an outside diameter equal to that of an intraocular lens be produced in the mold. The material of the rod is cut into small discs, which are heated and pressed in the polished mold. After cooling, the formed lens is released from th~ mold. Generally, the obtained product is ready for implantation, without any further manipulations, e~cept t~pically for sterilization. In many in~tance~ haptics will also have been added.
Bifocal intraocular lenses can be formed as a gradient index lenses. That is, they are constructed to have a refractive index gradient through the optical region, with the gradient providing for different power~. There are basically ~wo conventional ways of achieving this. A first is to produce the implant as a conventional implant, as previously described. ~he finished product, as a unifocal IOL, is then provided with a hole drilled in the center. With a second compres~ion mold, a cylinder with one planar end and one ., . . "
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4 ~3281~9 spherical end, whereby the spherical end has a radius of curvature equal to the radius of the curvature of the IOL having a hole drilled therein, is formed. The obtained cylinder i~ inserted into the bore hole of the first lens, producing a lens with a smooth outer surface. The materials chosen for the first lens (with a hole in the center) in the second cylinder ~the inner lens) are typically sufficiently different, so that the refrac~iva indice~ of the two differ enough to cause a desired bifocal arrangement.
Another conventional way to produce a gradient index IOL is to start with lens material in rod form.
The rod then ig heated from the outside, preferably with infrared radiation, to heat the material unevenly. In particular, the outside is heated more than the inside.
The induced stresses change the material'~ refractive index sli~htly, and provide a gradually changinq refractive index from the out~ide through to the inside.
After this treatment, the rod is cut into discs, and the individual di~cs are polished. In prinçiple, the discs could be flat (planar~ on both sides. However, typically the induced grading is not sufficient, so a curvature on the outer surface is needed to form a lens of appropriate power.
j 25 While the two methods of preparing a bifocal ;` intraocular lens described are possible, neither is fully desirable as a method of producing a high quality bifosal intraocular lens.
The first method described can be used to produce a bifocal lens having an appropriate resolving power. However, the wall of the internal cylinder (i.e.
the surface of interface between the two sections) will tend to produce reflection for certain angles of incidence. This will be perceived, by the wearer, as an undesirable glare~ Also, an adhesive must, typically, be used for gluing the internal cylindrical portion in position. 5uch an adhesive may be sub~ect to leaching :
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~328~9 in time, which can lead to further ocular problems.
~ he second method described is generally relatively expensive and difficult, and is not readily subject to precise control~ In particular, with the method it can be difficult to precisely develop a desired gradient.
The present invention addresses many of the problems associated with prior art intraocular lenses, especially in that they have not provided for readily obtainable, rigid multi-focal length lens. The present invention provide~ for such a multi-focal length intraocular lens.
SummarY of the I~ tio~
~he present invention is a rigid bifocal intraocular lens adapted for use as an artificial lens implant. A single rigid implant is provided having one or more additional len~es ground into it, so as to function like bifocal glasses.
In the preferred embodiment a plurality of lens portions are formed in the intraocular lens and each lens portion i~ substantially non-movable with respect - ~o the other(s3.
The intraocular lens of the first embodiment .~ 25 has an optical lens body with a central, circular, lens portion and an outer, annular, lens portion. The c~ntral, or first, len~ portion has a focal length and the sécond, or outer, annular lens portion has a focal length different from the focal length of the first lens : 30 por~ion. The relative areas of ~he two lens portions may vary, however in the first e~bodiment described the two are about the same size. Preferably the diameter of : the outer annulus is about 6-7 millimeters, whereas the overall diameter of the inner circular lens portion is between about 1.8 and about 2.2 millimeters. Most preferably the diameter of the inner len is less than about 2.0 millimeters. In general, it i8 desirable to , . . . . .
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- . ~ - . . . -~32~9 make the inner lens less than 2.0 mm, since the effective diameter of the outer lens can be reduced by the iris. Thus, by turning up the in~ensity of the reading light, and causing the iris to constrict, a user of a bifocal intraocular lens according to the first embodiment can decrease the amount of light directed through the outer lens portion, leaving a (relatively) brighter near ~ision image for the brain to preferentially select and use. A theoretical smallest diameter for the inner lens portion, of about 1.0 mm, is possible, since in general a brain requires having similar intensities on at least six receptors, before it will accept a receptor output as it picks out. However, most person' 8 iris' would not contract to this small a diameter.
The relative corrective powers of the lens portions may also vary; however, preferably, the corrective factor of the outer (annular) lens portion is between about +5 and +25 diopters~ whereas the corrective power of the inner portion i~ between about +2 and +4 diopters larger than the power of the annular portion. Nore preferably the inner portion preferably ha~ a corrective or add factor of between ~3 and ~4 diopters with respect to the outer portion. It has been observed that an add on of less than about +3 diopters is not completely desirable since it will not focus~
unless tha lens is placed in the anterior chamber, and implant i~ preferred in the posterior chamber. Also, such a small add on does not in general produce sufficiently different near and distance images for the brain to readily distinguish. Rather, with an add on less than +3 diopter~, edge poxtions of the near vision 1 portion will appear fuzzy- ~ost preferably, the add on 1 is at laast about +3.5 diopters. At this level clear, sharp, image~ from both lenses are generally discenable.
In some instances, add-ons of greater than ~4.0 diopters may be de~irable and usaful.
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, ~3281~9 The first and second lens portions preferably form an integral, one-piece, bifocal optical lens body.
A preferred method of formation has been found, which avoids the prior art and which yields an advantageous construction. In general, khe method involves preparing a mold by pre-machining a cavity out of a piece of tool steel, to a radius of curvature approximately equal to the curvature of the convex part of the lowest power (for the preferred embodiment, the outer annular) len~.
After this initial pre-machining of the mold, the radius of curvatuxe for the lens portion having the highest power (for the preferred embodiment the inner lsns) is machined and polished. The polished surface is then protected with a sealer, such as a wax. Then the radius of curvature of the lower power lens (for the preferred embodiment the outer len~) is precisely machined and polished into the mold. Since this radiu~ is larger than the one previously cut, the part of the mold which was machined first is not disturbed~ The wax cover protects against damage during a final polishing proces~. A bifocal len can be readily made, by molding lens material in the mold.
In this manner, a bifocal intraocular lens which is not a gradient index lens, is readily manufactured. A high degree of precision can be obtained, in a relatively inexpensive manner.
The intraocular lens of an alternate embodiment has an optical len~ body having a chord and first and second lens portions. The first lens portion has a focal length and the second lenc portion has a focal length different from the focal length o~ the first lens portion. The first len~ portion is positioned on one side of the chord and the second lens portion i8 positioned on the other side of the chord. The first and second lens portion~ form an integral, one-piece~
bifocal optical len~ body wherein the first and second lens portions are substantially non-movable with respect .
~32~9 to one another. Preferably, for the alternate embodiment the lens body is substantially circular and the chord is a diameter of the lens body.
Intraocular lenses according to this alternate embodiment, can be readily manufactured using an analogue of the previously described preferred manufacturiny process. In particular, the portion of the lens mold having the shortest radius of curvature machined, polished, and then protected with wax. Next, the portion of the lens mold having the highest radiu~
of curvature, would be foxmed and polished. The lens can be readily made, by then molding leads material in more or les 5 conventional manner.
For best results, the images from both lens portions for either embodiment should end up in the same plane. That is, the powers of the two lens portions should be selected so that the image from infinity projected through the second lens portion will be focused in about the same plane as the image from a close object being located at standard reading distance projected through the first lens portion. As a result of this construction, when a user wearing the intraocular implant uses same to view, both of the first and second lens portions may produce images substantially superimposed on one another. Depending on the distance to the object(s) being viewed and the amount of light present, one of the images will appear sharp and the other sufficiently defocused to permit the user's brain to select the sharper image for evaluation.
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~ 328~49 8a other aspects of this invention are as ~ollows:
A rigid bifocal intraocular lens adapted for use as an artificial lens implant, said intraocular lens comprising:
(a) an optical lens body having first and second lens portions and a chord at an interface region between said first and second lens portions;
(b) said first lens portion have a focal length;
(c) said second lens portion having a focal length different from said focal length of said first lens portion; and, said first lens portion having an add on power of at ; least +3.0 diopters relative to said second lens portion;
(d) said first lens portion positioned on one side of said chord and said second lens portion positioned on the other side of said chord;
(e) said first and second lens portions forming a unitary optical lens body having no substantial refractive index gradient therein; and, (f) haptic elements cooperatively connected to said lens body.
A bifocal intraocular lens adapted for use as an artificial lens implant in the posterior chamber of the eye, said intraocular lens comprising:
(a) a circular optical lens body having a chord and first and second lens portions;
(b) said first lens portion having a focal : length;
i ,j `~j. ~
-,~,,,,?,i :
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~32~
8b (c) said second lens portion having a focal length different from said focal length of said first lens portion; and, said first lens portion has an add on power of at least +3.0 diopters relative to said second lens portion;
(d) said first lens portion being positioned on one side of said chord and said second lens portion being positioned on the other side of said chord (e) said first and second lens portions forming a unitary op~ical lens body having no substantial refractive index gradient ' therein;
(f) haptic elements cooperatively connected to said lens body for positioning said lens body posterior to the iris of the eye;
. and, (g~ wherein said first lens portion has a focal length that is for viewing near objects and said second lens portion has a focal length that is for viewing distant objects, wherein when viewing an object, `~ said portions will each produce an imags on the retina, said images being : superimposed and, depending on the distance of the object, one of said images will be sharp and the other of said images sufficiently blurred, to indu~e a wearer~s brain to evaluate the image in a manner i inducing perception of only one, sharp, image.
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B
, ~32~9 8c A rigid intraocular lens adapted for use as an artificial lens implant, said intraocular lens comprising:
ta) means for non-movably retaining said lens implant within a chamber of a user~s eye;
and, (b) a lens body including a first lens portion and a second lens portion;
(i) ~aid first lens portion ha~ing a focal length and being non-movably mounted in said intraocular lens;
(ii) said second lens portion being non-movably mounted in said intraocular lens and having a focal length different from said focal length of said first lens; said second lens portion being in cooperative engagement with said first lens portion to form an optical region of said lens body having no substantial refractive index gradient therein;
(iii) said first lens portion being ' construc~ed and arranged for viewing relatively near objects and having an optical power of at least about +3.0 `, diopters greater than said second lens portion;
(iv) said second lens portion being constructed and arranged for viewing relatively distant ob~ects and having an optical power of between about ~15 and about +25 diopters;
tv) said first lens portion being constructed and arranged to project focused images created ther~by in substantially the same plane as second images projected by said B second len~ portion;
;~ : . . . .......... . .
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~328~9 8d ":, (c) whereby when a user wearing said intraocular lens uses same to view, both of said first and second lens portions may produce images substantially superimposed upon one another with, depending generally on the distance of the object being viewed ; and the amount of light presen~ r one of the images appearing sharp and the other image defocused to permit the user's brain to select the sharper image for evaluation.
rigid intraocular lens implant adap~ed for use as an artificial lens implant in a posterior chamber ~ of an eye; said intraocular lens comprising:
:~ (a) means for non-movably retaining said lens . implant within a posterior chamber of a I user's eye; and, (b) a lens body comprising a material having a ~' first index of refraction and substantially no index of refraction gradient therein; said lens body having a first circular lens portion and a second ~:. annular lens portion, said second annular ~ lens portion surrounding said fir6t :~, circular lens portion;
(i) said first lens portion . comprising a portion of said lens body having said first index of refraction and a first radius of curvaturP defining a first optical power;
(ii) said second lens portion comprising a portion of said lens body having said first index of refraction and a second j radius of curvature defining a second optical power;
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132~
8e (iii) said second lens portion being constructed and arranged for viewing relatively distant objects and having an optical power of between about +15 and about +25 diopters;
(iv) said first lens portion being constructed and arranged or viewing relatively near objects and having: a ; power o at least ~3.0 diopters greater than said second lens portion; and, a diameter of no greater than about 2.0 r~.
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8f ~3281~9 Brief ~escription o~ the Drawin~s Fig. 1 is a cross-sectional view of the eye and shows a lens incorporating our present invention implanted in the posterior chamber of the eye.
Fig. 2 is a top plan view of the lens of Fis.
1, shown according to a first embodiment of the invention.
~ 328~9 g Fig. 2A is generally the ame as Fig. 2, except Fig. 2A is reduced, is fra~mentary, and show~ different relative sizes between various lens portions.
Fig. 3 is a side elevational view of the lens shown in Fig. 1.
Fig. 4 is a top plan view of a second embodiment of the present invention.
Fig. 5 is a side elevational view o~ the lens shown in Fig. 4.
:l 10 Fig. 6 is a cross-sectional view, taken along the line 6-6 of Fig. 4.
Fig. 7 is a cxoss-sectional view, of th~ eye and shows a lens incorporating an embodiment of our present inven~ion implanted in the posterior chamber of the eye; the lens being a plano-convex variation of the em~odiment shown in Fig. 1.
: Fig. 8 is a top plan viéw of the lens of , ~ .
. Fig. 7.
Fig. 8A is generally the same as Fig. 8, except Fig. 8A is reduced, is fragmentary, and show~ different .', relative sizes between the variou lens portions.
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I Referring to the drawings, wherein like i 25 numeral represent like part~ throughout the several views, an intraocular lens, designated generally as 10, ~ is shown in Fig3 . 1 through 3, with Fig. 2A showing a : variation described below. The intraocular lens 10 includes a rigid optical region or len~ body 11 which .: 30 includes a first lens portion or lens 12 cooperatively i connected to a second lens portion or lens 13 to form a ;~ lens body or optical region 13.
~: In a preferred e~bodiment the first lens 12 is an inner lens having an axis 12a. The second lens 13 is an annular lens having an axis 13a. The lens body 11, or optic portion of the intraocular lens 10, i~ centered and retained within the ey~ by retaining means such as .
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~3281~L~
haptic members 14 and 15 having first ends 14a and 15a and second ends 14b and 15b respectively. The first ends 14a and l5a are cooperatively connected to the len~
body 11 by methods well known in the art. Further, the construction and specific configuration of the haptic members 14 and 15 may be any suitable construction, such construction being well known in the art.
In a preferred embodiment, the haptic members 14 and 15, inner lens 12 and annular lens 13 are formed as an integral one-piece structure by a forging and machining process. However, it will be appreciated that the intraocular lens 10 may also be produced by other suitable method~ such as injection molding and lathing.
As a result, the inner len~ 12 and annular len~ 13 are substantially non-movable with respect to one another.
I The unitary intraocular lens body 11, including .~ the first lens 12 and second lens 13, is made of a biological tolerable and optically suitable material uch as polymethylmethacrylate (PMMA). The haptic members 14 and 15 may be made of a flexible, compressible, resilient plastic material such as PMMA or polypropylene, or other materials as well kno~n in the art. Preferably, the entire intraocular len~ 1~ is of an int~gral one-piece structure and is made of PMMA.
Preferably the integral one-piece-intr~ocular ~ len~ i~ formed via the previously described method, - wherein a mold i8 ~irst formed with a curved portion `~ haviny a radius of curvature equal to the higher power len3 portion of the arrangement 10. This portion is then poli3hed, and protected with sealant or wax. Next, the mold i~ ground to provide for the lower power lens por ion, i.e. the portion having a larger radius curvature. Thi3 portion is then polished. The sealant is removed, and the lens material is pressed into the mold to form the preferred arrangement. In this manner a unitary tructure having len~ portions of different power can be re~dily, and accurately, provided. The ~, . : . . . .:
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~328~9 problems previously discussed with gradient index lens arrangements, are avoided.
The posterior chamber type intraocular leni 10 will typically be utilized following extra capsular cataract extraction. As illustrated in Fig. 1, the lens 10 is implanted in a human eye 40, in the posterior chamber 42 behind the iris 44. Preferably, the cataract has been extracted from the capsular bag 46, leaving intact the posterior wall 46a and an annular flap portion 46b forming a cleft of fornix 46c. ~he capsular bag 46 is connected to the ciliary muscle in the eye wall 48 via suspensory ligaments 50. Vitreous humor in the region 52 behind the capsular bag 46 is prevented from flowing forward by the posterior wall 46a. It is, of course, understood that the present invention may also be used in the anterior chamber of the eye 40.
The intraocular lens 10 may serve as a bifocal vision system, with one lens 12 for reading and the other len~ 13 for distant viewing. As shown in the -I 20 preferxed embodiment, the axis 12a of the inner lens 12 is coaxial with the axis 13a of the annular lens 13.
However, it i~ llnderstood that th~ certain principles of the present invention will also be applicable where the axes 12a and 13a are ~ot coaxial. The different portions 12 and 13 will be understood to have different radii of curvature.
Nany prior art methods of providing bifocal vision system~, ~uch as bifocal glasses, are exclusive;
meaning one can either read or look in the distance.
Generally, there is a blurred region in between, which is awkward. With the present application thiis would not be the case. The first lens portion has a focal length that is for viewing near objects and the second lens portion has a focal length that is for viewing distant objects. Such a combination of lenses will produce two images on the retina which are superimposed. Alwayi, one of the two images will appear blurred. If an object :.
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~37~
up close is viewed, the image produced through the second lens will appear bluxred; or, if the object is viewed at a distance, the image through the first lens will appear blurred. The user's brain can select the S sharper image for evaluation.
In a preferred embodiment, as shown in the figures, the first lens 12 is a center lens having a focal length for reading and the second lens 13 is an annular ring shaped lens having a focal length for distant viewing. The area of each lens 12 and 13 will i~eally be computed individually for each patient, depending upon the patient's iris reflexes, as described more fully hereafter. In actual practicet a whole series of lenses would probably be provided, having different corrective properties, so that an appropriate lens could be selected for any given patient.
In one of the parent cases, it was indicated that preferably the area of the fir~t lens 12 would be from approximately 30% to 50% of the area of the lens body 11. Further, it was indicated as preferred that the first lens 12 be approximately 40%of the total area of the lens body 11 or, otherwise stated, the area of the first lens 12 be approximately equal to ~he area of the second lens 13. Thi~ is sho~n in Fig. 2.
A preferred arrangement outside of the above-stated range has been found. Fig. 2A show~ an arrangement which i~ substantially identical to Fiy. 2 in sub~tance, but for the relative sizes of the lens portions 12' and 13', to indicate the alternate and preferred possibility. For thi~ arrangement, it will generally be preferred that the annulax portion have a diameter of about 6.0 to about 7.0 millimeters while the inner portion has a diameter of about 1.8 to about 2.2 millimeters. Thu~, the area of the first len~ portion is between about 6% and 14~ of the combined areas of the first and second lens portions. Nost preferably, when the inner portion i~ the near vi~ion portion, it has a .
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13~81~9 diameter of less than 2mm. A reason for this is that interference between the two projected images will be les li~ely. That is, when the wearer reads, light can ; be adjusted to be relatively bright, the light r~flected off the page will be fairly intense, and the iri~ will contract at least partially blocking the distance vision portion. In distance viewing, the light intensity will generally be lower, and the iris more opened. A
relatively small image projected by the near vision ; 10 portion will be more easily discarded by the brain. In Fig. 2A reference numerals 10', 11', 12', 13', 14', 14a', 15' and 15a' indicate parts generally analogous, in form and function, to parts 10, 11, 12, 13, 14, 14a, 15 and 15a respectively.
lS It is also foreseen that the desirsd relative powers between the two lens portions may vary from patient to patient. Generally, for mo~t uses an operable embodiment will have a corrective power of about +15 to about +25 diopters, for the outer lens portion, the portion used for distance viewing; and, a ~orrective power of about +2 to about +4 diopter~ larger than the outer lens portion for the inner portion, i.e.
that portion used for near viewing. For preferred posterior lens implant3, preferably the add on will be at least ~3 diopter~, or the lens will not focus, in typical uses. Mo t preferably, the add on is at least +3.5 diopters.
If a distant ob~ect i3 viewed in moderately bright illumination, the iris 44 will be open and the image created by the annular lens 13 (which is sharp) will overpower the blurred and also less bright image created by the inner lens 12. The overpowering process ; is made possible by the fact that blurred edges are less intense than sharp edges, and by the way the image evaluation system of the brain works.
Reading activity usually takes place indoors, and bright illumination can readily be applied. The . - :
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~328~49 iris 44 will close, and the area of the annular lens 13 will be reduced so that the image of the inner lens 12 - (which is now sharp) will overpower the blurred, less bright, image generated by the annular lens 13.
Therefore, by the management of the intensity of the images, as is accomplished in the present invention, there can be two superimposed images one of which is blurred and one of which is sharp. The brain's evaluation system will accordingly see the sharp image.
The image evaluation system of the brain searches for sharp edge~ and, once it find~ a sharp edge, it exaggerates the edge. Therefore, generally, as long as the blurred image is weaker in inten~ity that the ~harp one, the brain will evaluate the images and "~ee" the sharp image.
I It is understood that any suitable combination such as plano-convex, biconcave, meniscus or other combination of lenses may be used with either an add on center or a distance on center to provide for the inner lens 12~ It i8 necessary for one skilled in the art to make a suitable combination of such lenses to provide l for a focal length for one of the lense3 12 or 13 for distance reading and a focal length for the other of the lenses 12 or 13 having a focal length for viewing near objects, preferably with both of the lenses having a positive power.
Another embodimPnt of the present in~ention is sho~n in Figs. 2-6. Thi3 lens would also be positioned i the eye a~ shown in Fig. 1. The second embodiment of the implantable intraocular lens 60 includes a rigid bifocal optical region or lens body 61 which includes a first lens portion 62 and a second lens portion 63, the bases of which are coplanarO The lens body 61 has a chord 61a between lens portions 62 and 63. This embodiment i3 also adapted to be implanted in the ; posterior chamber, although the concept can be utilized in an anterior chamber lens as well.
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Preferably, the unitary optical len~ body 61 is substantially circular, the chord 61a is a diameter of the lens body 61 and the lens portions are semicircular.
Thus, for this embodiment the first and second lens portions may preferably be of about the same size and the len~ portions axe substantially non-movable with respect to one another. The powers for the near vision and distance vision section~ are preferably previously described for the first embodiment.
The lens body 61, or optic portion of the intraocular lens 60, is centered and retained within the eye by ret~ining mean~ such a~ haptic member~ 64 and 55 having first ends 64a and 65a and second ends 64b and 65b, respectively. The first end~ 64a and 65a are cooperatively connected to ths lens body 61 by methods well known in the art. Further, the construction of a specific configuration of the haptic members 64 and 65 may be any suitable con~truction, ~uch construction being well known in the art.
Preferably, the haptic member~ 64 and 65, the ~irst lens 62 and second len~ 6~ are molded as an integral one-piece structureO ~08t preferably, a method of molding involving a mold made a~ previously de~cribed i~ used, in order to provide efficient production without the pxoblem~ involved in producing gradient index lenses. The unitary intraocular len~ body 61, including the first lens 62 and second len~ 63, i~ made of a biological tolerable and optically ~uitable ma~erial ~uch a~ PMMA. The haptic me~bers 64 and 65 may be made of a flexible, compres~ible, resilient plastic material such as PMMA or polypropylene, or other ~ materials as well known in the art. Preferably, the ; entire intraocular len~ 60 is made of an integral one-piece structure and also i~ made of PMMA. The intraocular lens 60 may serve as a bifocal vision sy~item, with one len~ 62 for reading and the other len~
63 for distant viewing.
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:` 13281~9 lS
As previously discussed, many prior art methods of providing bifocal vision systems, such as bifocal glasses, are exclusive. With the present embodiment this would not be the case. One of the lens portions would have a focal length that is for viewing near ob~ects and the other of the lens portions would have a focal length different from the first lens por~ion and that is for viewing distant objects. Such a combination of lense~ will produce two images on the retina which are superimposed. Always t one of the two images will appear blurrad. The eye is constantly scanning the images created on the retina and selectively chooses the image (the sharp one) to see. By having an intraocular lens 60 that is equally split, with the chord 60a being a horizontal diameter, the iri~ of the eye will alway~
be in position in front of both lens portions 62 and 63 and therefore the retina will al~ays have an image ;, formed on it from both the lens portions 62 and 63. The area of the first lens portion 62 i8 preferably approximately equal to the area of the second lens portion 63.
Again, when the two lens portions are equal, the chord 61a is substantially a diameter of the lens body 61. ~owever, the chord 61a could be offset from the center without departing from the invention.
As is clearly shown in Fig. 6, the lens body 61 has a planar bottom surface 61b that extends across both the first lens portion 62 and second lens portion 63.
The first lens portion 62 has an upper convex sur~ace 62a and the second lens portion 63 ha~ an upper convex surface 63a, the latter one having a different radius of curvature than ~he first. Reference numeral 66 generally indicates a transition region between the two lens portions which for the preferred embodiment shown, :; 35 i3 chord 61a. In Fig. 6 plane 67 represents a division of the len3 61 into its two halves 62 and 63 of different powers. While different radii of curvatures ~.
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are drawn, the difference is ~mall and hard to see. It ; will nevextheless be understood to be present.
Fig. 7 is a cros~-sectional view of a lens incorporating the pre~ent invention taken from a point of view generally analogous to the use for Fig. 1, but showing an alternate thereto. In particulax, the lens body of Fig. 7 is shown having a plano-convex structure.
That is, it is generally planar on one ~ide and convex on the other. This arrangement may be advantageous, in that it is potentially easier to construct. For the arrangement shown in Fig. 7, the reference numeral 100 generally designates the eye, and the reference numeral 111 the lens. The arrangement ~ill be understood to be analogou~ to that shown in Figs. 1-3, but for the utilization for a plano-convex structure for the lens.
The near ~ision portion 112 of the lens may be, for example, of the relativQ diameter to the distant vision ; portion 113, as previously described for Figs. 1-3. In the alternative, that ratio of areas described ` 20 previously for Fig. 2A, may also, preferably, be used.
Desirable corrective factors for the two portions may be ; as previously indicated; that is, preferably, with the distance portion having a corrective power of between about +15 and +25 diopters, and with the corrective power of the inner, near vision, len~ portion preferably having an add on power of bet~een about +3 and about +4 diopters, and more preferably at least about +3.5 " diopters.
In Fig. 8 a top plan view of the lens of Fig. 7 - 30 is ~hown. Again, except for the plano-convex structure, the arrangem2nt i~ analogou~ to that shown in Fig. 2.
Finally, in Fig. 8A an alternate ~o the arrangement shown in Fig. 7 and 8 is shown, wherein the ` inner lens portion 112' is constructed smaller, with respect to the ou~er len portion 113'. Specifically, for this arrangement it will generally be preferred that the annular portion have a diameter of about 6.0 to -~, - .. . - ,: .
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~s ~32~49 ` 18 :; ., ; about 7.0 millimeters, while the inner portion has a ` diameter of about 1.8 to about 2.0 millimeters. Thu~, the arrangement is generally analogou~ to that ~hown in Fig. 2A, but for the plano-convex structure.
In general, arrangements according to Figs. 7, 8 and 8A are more readily susceptible to manufacture according to the de~cribed method of molding, than are the embodiments of Figs. 1-6. A rea~on for this is that molds having a target arrangement providing for an inner concave region of one diameter and an outer conca~e ~1 region of another diameter can be fairly easily ground.
- Although the preferred embodiment of the inv0ntion i~ a bifocal lens, it should be understood that one or more additional lenses may be incorporated to correct for different distance~.
~- Other modification of the invention will be apparent to tho~e skilled in the art in light of the foregoing de~cription. ~his de~cription i~ intended to provide specific example~ of individ~al embodiments which clearly disclo~e the pre~ent invention.
Accordingly, the in~ention i3 not limited to th ~e embodimen~s or to the use of elements having specific configurations and shapes as presented herein. All i alternative modifications and variation~ of the present invention which follow in the spirit and broad scope of the appended claim~ are included.
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Field of the I~ve~tion This invention relates generally to intraocular ~j lenses to be used as artificial lens implants in eyes from which the cataractous natural lens has been removed, and more particularly to an improved rigid lens having multiple lenses.
Descr~ptio~ o~ the Pr~or Art The implanta~ion of an intraocular lens for restorins vision after cataract surgery is well-known in the art. In general, two forms of surgery are used to remove cataracts~ Thesa are extracapsular cataract extraction an~ intracapsulax extraction. (Discussed in U.S. Pat. Re.~ 31,626 to Hoffer.) Following extraction : of a cataractous lens, an intraocular lens i~ normally implanted in either the anterior or the posterior chamber of the eye. In an anterior chamber implant, the lens is generally situated forward of, or mounted to, the iris. In the case of posterior chamber implants, the lens is situated behind the iriæ and may be mounted within the cleft or fornix of the capsule which remains in place after extracapsular surgery. Posterior chamber implants are generally preferred, in part because thi~
: is the location from which the natural lens is removed.
; In both anterior or posterior chamber implants, the lens i~ u~ually centered and fixed in position by one or more supporting strands or haptic members Nhile available intraocular lenses incorporate haptic member(s) having various geometric shapes and configurakion~, the typical haptic member i8 a flexible : 35 strand of non-biodegradable material which is fixed to the len~ body, and exhibits specific spring-like memory qualitie~ so that the haptic member can be compressed or off-set from the normal rest position and thereafter returned to the fully extended condition when pressure ~. - .. , ~ . . , 13281~9 is removed.
The intraocular implant is an artificial lens which has one given focal length. Since the intraocular implant is made of a rigid material it cannot chan~e the focal length by deformation as the natural lens does (called accommodation). A-~ a result of this, if the focal length i~ selected to provide a sharp image for a distant object, then an object which is closer (i.e. at reading distance) will not be imaged sharply on the retina. Alternately, one could image closer ob~ects sharp by selecting a different focal length, but then, of course, distant ob~ects would appear out of focus.
Contact lenses have been made having multi-focal length~ and also having variable light absorption.
U.S. Pa$ent No. 3,270,099 issued Augu~t 30, 1966 to R.N.
Camp discl~ses a method for making a multi-focal length contact lens. Tha Camp patent deal~ with a contact lens which is not used for the same function or manner as an intraocular len~. Further, the Camp patent teaches that the eye uses the inner part of the cornea for near vision while the outer part i~ used for distant vision.
For this reason, the Camp contact lens covers the cornea with a contact lens which has one power in the inner part and another power in the outer part. As a basis for uch a lens, the Camp patant teache3 that the divergent rays which enter the peripheral portion are not focused on the retina and hence are unseen. This is~ of course, a violation of the law of physics a~
light is detected by the retina regardless of whether it is focused or unfocused.
U.S. Paten~ No~ 3,034,403 to Neefe was issued May 15, 196~ and dîsclo~es a contact lens of apparent variable light absorption. The center portion of the j contact len~ is tinted while the outer portion i3 clear.
ll 35 Bifocal intraocular lenses are known, see for j example Nielson et al, U.5. Patent No. 4,636,211. The Nielson reference dlscloses a concentrically bifocal (or ., .
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1328l~9 target) lens, i.e. a lens implant having an outer annular portion of one power, in an inner circular portion of another power. The add on power difference between the far and near vision portions of Nielson et al '211 is indicated as being +.250 diopters. The inner lens of Nielson et al ~211 is indicated a~ being, on the average/ about 2.12 mm in diameter.
The features that are possible in a bifocal intraocular lens are, to a great extent, dependent upon the method of manufacture used and/or the material from which the lens is made. A conventional method of making an in~raocular lens, is through the compression molding technique. For this technique, a mold is made by machining a cavity out of a ~iece of tool steel. The radius of curvature of the cavity is made equal to.the radius of curvature of the convex side of the lens. The cavity i5 then polished. Material for the lens, which typically has a consistency analogous to plexiglass, is generally manufactured in the form of rods preferably having an outside diameter equal to that of an intraocular lens be produced in the mold. The material of the rod is cut into small discs, which are heated and pressed in the polished mold. After cooling, the formed lens is released from th~ mold. Generally, the obtained product is ready for implantation, without any further manipulations, e~cept t~pically for sterilization. In many in~tance~ haptics will also have been added.
Bifocal intraocular lenses can be formed as a gradient index lenses. That is, they are constructed to have a refractive index gradient through the optical region, with the gradient providing for different power~. There are basically ~wo conventional ways of achieving this. A first is to produce the implant as a conventional implant, as previously described. ~he finished product, as a unifocal IOL, is then provided with a hole drilled in the center. With a second compres~ion mold, a cylinder with one planar end and one ., . . "
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4 ~3281~9 spherical end, whereby the spherical end has a radius of curvature equal to the radius of the curvature of the IOL having a hole drilled therein, is formed. The obtained cylinder i~ inserted into the bore hole of the first lens, producing a lens with a smooth outer surface. The materials chosen for the first lens (with a hole in the center) in the second cylinder ~the inner lens) are typically sufficiently different, so that the refrac~iva indice~ of the two differ enough to cause a desired bifocal arrangement.
Another conventional way to produce a gradient index IOL is to start with lens material in rod form.
The rod then ig heated from the outside, preferably with infrared radiation, to heat the material unevenly. In particular, the outside is heated more than the inside.
The induced stresses change the material'~ refractive index sli~htly, and provide a gradually changinq refractive index from the out~ide through to the inside.
After this treatment, the rod is cut into discs, and the individual di~cs are polished. In prinçiple, the discs could be flat (planar~ on both sides. However, typically the induced grading is not sufficient, so a curvature on the outer surface is needed to form a lens of appropriate power.
j 25 While the two methods of preparing a bifocal ;` intraocular lens described are possible, neither is fully desirable as a method of producing a high quality bifosal intraocular lens.
The first method described can be used to produce a bifocal lens having an appropriate resolving power. However, the wall of the internal cylinder (i.e.
the surface of interface between the two sections) will tend to produce reflection for certain angles of incidence. This will be perceived, by the wearer, as an undesirable glare~ Also, an adhesive must, typically, be used for gluing the internal cylindrical portion in position. 5uch an adhesive may be sub~ect to leaching :
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~328~9 in time, which can lead to further ocular problems.
~ he second method described is generally relatively expensive and difficult, and is not readily subject to precise control~ In particular, with the method it can be difficult to precisely develop a desired gradient.
The present invention addresses many of the problems associated with prior art intraocular lenses, especially in that they have not provided for readily obtainable, rigid multi-focal length lens. The present invention provide~ for such a multi-focal length intraocular lens.
SummarY of the I~ tio~
~he present invention is a rigid bifocal intraocular lens adapted for use as an artificial lens implant. A single rigid implant is provided having one or more additional len~es ground into it, so as to function like bifocal glasses.
In the preferred embodiment a plurality of lens portions are formed in the intraocular lens and each lens portion i~ substantially non-movable with respect - ~o the other(s3.
The intraocular lens of the first embodiment .~ 25 has an optical lens body with a central, circular, lens portion and an outer, annular, lens portion. The c~ntral, or first, len~ portion has a focal length and the sécond, or outer, annular lens portion has a focal length different from the focal length of the first lens : 30 por~ion. The relative areas of ~he two lens portions may vary, however in the first e~bodiment described the two are about the same size. Preferably the diameter of : the outer annulus is about 6-7 millimeters, whereas the overall diameter of the inner circular lens portion is between about 1.8 and about 2.2 millimeters. Most preferably the diameter of the inner len is less than about 2.0 millimeters. In general, it i8 desirable to , . . . . .
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- . ~ - . . . -~32~9 make the inner lens less than 2.0 mm, since the effective diameter of the outer lens can be reduced by the iris. Thus, by turning up the in~ensity of the reading light, and causing the iris to constrict, a user of a bifocal intraocular lens according to the first embodiment can decrease the amount of light directed through the outer lens portion, leaving a (relatively) brighter near ~ision image for the brain to preferentially select and use. A theoretical smallest diameter for the inner lens portion, of about 1.0 mm, is possible, since in general a brain requires having similar intensities on at least six receptors, before it will accept a receptor output as it picks out. However, most person' 8 iris' would not contract to this small a diameter.
The relative corrective powers of the lens portions may also vary; however, preferably, the corrective factor of the outer (annular) lens portion is between about +5 and +25 diopters~ whereas the corrective power of the inner portion i~ between about +2 and +4 diopters larger than the power of the annular portion. Nore preferably the inner portion preferably ha~ a corrective or add factor of between ~3 and ~4 diopters with respect to the outer portion. It has been observed that an add on of less than about +3 diopters is not completely desirable since it will not focus~
unless tha lens is placed in the anterior chamber, and implant i~ preferred in the posterior chamber. Also, such a small add on does not in general produce sufficiently different near and distance images for the brain to readily distinguish. Rather, with an add on less than +3 diopter~, edge poxtions of the near vision 1 portion will appear fuzzy- ~ost preferably, the add on 1 is at laast about +3.5 diopters. At this level clear, sharp, image~ from both lenses are generally discenable.
In some instances, add-ons of greater than ~4.0 diopters may be de~irable and usaful.
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, ~3281~9 The first and second lens portions preferably form an integral, one-piece, bifocal optical lens body.
A preferred method of formation has been found, which avoids the prior art and which yields an advantageous construction. In general, khe method involves preparing a mold by pre-machining a cavity out of a piece of tool steel, to a radius of curvature approximately equal to the curvature of the convex part of the lowest power (for the preferred embodiment, the outer annular) len~.
After this initial pre-machining of the mold, the radius of curvatuxe for the lens portion having the highest power (for the preferred embodiment the inner lsns) is machined and polished. The polished surface is then protected with a sealer, such as a wax. Then the radius of curvature of the lower power lens (for the preferred embodiment the outer len~) is precisely machined and polished into the mold. Since this radiu~ is larger than the one previously cut, the part of the mold which was machined first is not disturbed~ The wax cover protects against damage during a final polishing proces~. A bifocal len can be readily made, by molding lens material in the mold.
In this manner, a bifocal intraocular lens which is not a gradient index lens, is readily manufactured. A high degree of precision can be obtained, in a relatively inexpensive manner.
The intraocular lens of an alternate embodiment has an optical len~ body having a chord and first and second lens portions. The first lens portion has a focal length and the second lenc portion has a focal length different from the focal length o~ the first lens portion. The first len~ portion is positioned on one side of the chord and the second lens portion i8 positioned on the other side of the chord. The first and second lens portion~ form an integral, one-piece~
bifocal optical len~ body wherein the first and second lens portions are substantially non-movable with respect .
~32~9 to one another. Preferably, for the alternate embodiment the lens body is substantially circular and the chord is a diameter of the lens body.
Intraocular lenses according to this alternate embodiment, can be readily manufactured using an analogue of the previously described preferred manufacturiny process. In particular, the portion of the lens mold having the shortest radius of curvature machined, polished, and then protected with wax. Next, the portion of the lens mold having the highest radiu~
of curvature, would be foxmed and polished. The lens can be readily made, by then molding leads material in more or les 5 conventional manner.
For best results, the images from both lens portions for either embodiment should end up in the same plane. That is, the powers of the two lens portions should be selected so that the image from infinity projected through the second lens portion will be focused in about the same plane as the image from a close object being located at standard reading distance projected through the first lens portion. As a result of this construction, when a user wearing the intraocular implant uses same to view, both of the first and second lens portions may produce images substantially superimposed on one another. Depending on the distance to the object(s) being viewed and the amount of light present, one of the images will appear sharp and the other sufficiently defocused to permit the user's brain to select the sharper image for evaluation.
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~ 328~49 8a other aspects of this invention are as ~ollows:
A rigid bifocal intraocular lens adapted for use as an artificial lens implant, said intraocular lens comprising:
(a) an optical lens body having first and second lens portions and a chord at an interface region between said first and second lens portions;
(b) said first lens portion have a focal length;
(c) said second lens portion having a focal length different from said focal length of said first lens portion; and, said first lens portion having an add on power of at ; least +3.0 diopters relative to said second lens portion;
(d) said first lens portion positioned on one side of said chord and said second lens portion positioned on the other side of said chord;
(e) said first and second lens portions forming a unitary optical lens body having no substantial refractive index gradient therein; and, (f) haptic elements cooperatively connected to said lens body.
A bifocal intraocular lens adapted for use as an artificial lens implant in the posterior chamber of the eye, said intraocular lens comprising:
(a) a circular optical lens body having a chord and first and second lens portions;
(b) said first lens portion having a focal : length;
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8b (c) said second lens portion having a focal length different from said focal length of said first lens portion; and, said first lens portion has an add on power of at least +3.0 diopters relative to said second lens portion;
(d) said first lens portion being positioned on one side of said chord and said second lens portion being positioned on the other side of said chord (e) said first and second lens portions forming a unitary op~ical lens body having no substantial refractive index gradient ' therein;
(f) haptic elements cooperatively connected to said lens body for positioning said lens body posterior to the iris of the eye;
. and, (g~ wherein said first lens portion has a focal length that is for viewing near objects and said second lens portion has a focal length that is for viewing distant objects, wherein when viewing an object, `~ said portions will each produce an imags on the retina, said images being : superimposed and, depending on the distance of the object, one of said images will be sharp and the other of said images sufficiently blurred, to indu~e a wearer~s brain to evaluate the image in a manner i inducing perception of only one, sharp, image.
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, ~32~9 8c A rigid intraocular lens adapted for use as an artificial lens implant, said intraocular lens comprising:
ta) means for non-movably retaining said lens implant within a chamber of a user~s eye;
and, (b) a lens body including a first lens portion and a second lens portion;
(i) ~aid first lens portion ha~ing a focal length and being non-movably mounted in said intraocular lens;
(ii) said second lens portion being non-movably mounted in said intraocular lens and having a focal length different from said focal length of said first lens; said second lens portion being in cooperative engagement with said first lens portion to form an optical region of said lens body having no substantial refractive index gradient therein;
(iii) said first lens portion being ' construc~ed and arranged for viewing relatively near objects and having an optical power of at least about +3.0 `, diopters greater than said second lens portion;
(iv) said second lens portion being constructed and arranged for viewing relatively distant ob~ects and having an optical power of between about ~15 and about +25 diopters;
tv) said first lens portion being constructed and arranged to project focused images created ther~by in substantially the same plane as second images projected by said B second len~ portion;
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~328~9 8d ":, (c) whereby when a user wearing said intraocular lens uses same to view, both of said first and second lens portions may produce images substantially superimposed upon one another with, depending generally on the distance of the object being viewed ; and the amount of light presen~ r one of the images appearing sharp and the other image defocused to permit the user's brain to select the sharper image for evaluation.
rigid intraocular lens implant adap~ed for use as an artificial lens implant in a posterior chamber ~ of an eye; said intraocular lens comprising:
:~ (a) means for non-movably retaining said lens . implant within a posterior chamber of a I user's eye; and, (b) a lens body comprising a material having a ~' first index of refraction and substantially no index of refraction gradient therein; said lens body having a first circular lens portion and a second ~:. annular lens portion, said second annular ~ lens portion surrounding said fir6t :~, circular lens portion;
(i) said first lens portion . comprising a portion of said lens body having said first index of refraction and a first radius of curvaturP defining a first optical power;
(ii) said second lens portion comprising a portion of said lens body having said first index of refraction and a second j radius of curvature defining a second optical power;
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8e (iii) said second lens portion being constructed and arranged for viewing relatively distant objects and having an optical power of between about +15 and about +25 diopters;
(iv) said first lens portion being constructed and arranged or viewing relatively near objects and having: a ; power o at least ~3.0 diopters greater than said second lens portion; and, a diameter of no greater than about 2.0 r~.
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8f ~3281~9 Brief ~escription o~ the Drawin~s Fig. 1 is a cross-sectional view of the eye and shows a lens incorporating our present invention implanted in the posterior chamber of the eye.
Fig. 2 is a top plan view of the lens of Fis.
1, shown according to a first embodiment of the invention.
~ 328~9 g Fig. 2A is generally the ame as Fig. 2, except Fig. 2A is reduced, is fra~mentary, and show~ different relative sizes between various lens portions.
Fig. 3 is a side elevational view of the lens shown in Fig. 1.
Fig. 4 is a top plan view of a second embodiment of the present invention.
Fig. 5 is a side elevational view o~ the lens shown in Fig. 4.
:l 10 Fig. 6 is a cross-sectional view, taken along the line 6-6 of Fig. 4.
Fig. 7 is a cxoss-sectional view, of th~ eye and shows a lens incorporating an embodiment of our present inven~ion implanted in the posterior chamber of the eye; the lens being a plano-convex variation of the em~odiment shown in Fig. 1.
: Fig. 8 is a top plan viéw of the lens of , ~ .
. Fig. 7.
Fig. 8A is generally the same as Fig. 8, except Fig. 8A is reduced, is fragmentary, and show~ different .', relative sizes between the variou lens portions.
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I Referring to the drawings, wherein like i 25 numeral represent like part~ throughout the several views, an intraocular lens, designated generally as 10, ~ is shown in Fig3 . 1 through 3, with Fig. 2A showing a : variation described below. The intraocular lens 10 includes a rigid optical region or len~ body 11 which .: 30 includes a first lens portion or lens 12 cooperatively i connected to a second lens portion or lens 13 to form a ;~ lens body or optical region 13.
~: In a preferred e~bodiment the first lens 12 is an inner lens having an axis 12a. The second lens 13 is an annular lens having an axis 13a. The lens body 11, or optic portion of the intraocular lens 10, i~ centered and retained within the ey~ by retaining means such as .
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~3281~L~
haptic members 14 and 15 having first ends 14a and 15a and second ends 14b and 15b respectively. The first ends 14a and l5a are cooperatively connected to the len~
body 11 by methods well known in the art. Further, the construction and specific configuration of the haptic members 14 and 15 may be any suitable construction, such construction being well known in the art.
In a preferred embodiment, the haptic members 14 and 15, inner lens 12 and annular lens 13 are formed as an integral one-piece structure by a forging and machining process. However, it will be appreciated that the intraocular lens 10 may also be produced by other suitable method~ such as injection molding and lathing.
As a result, the inner len~ 12 and annular len~ 13 are substantially non-movable with respect to one another.
I The unitary intraocular lens body 11, including .~ the first lens 12 and second lens 13, is made of a biological tolerable and optically suitable material uch as polymethylmethacrylate (PMMA). The haptic members 14 and 15 may be made of a flexible, compressible, resilient plastic material such as PMMA or polypropylene, or other materials as well kno~n in the art. Preferably, the entire intraocular len~ 1~ is of an int~gral one-piece structure and is made of PMMA.
Preferably the integral one-piece-intr~ocular ~ len~ i~ formed via the previously described method, - wherein a mold i8 ~irst formed with a curved portion `~ haviny a radius of curvature equal to the higher power len3 portion of the arrangement 10. This portion is then poli3hed, and protected with sealant or wax. Next, the mold i~ ground to provide for the lower power lens por ion, i.e. the portion having a larger radius curvature. Thi3 portion is then polished. The sealant is removed, and the lens material is pressed into the mold to form the preferred arrangement. In this manner a unitary tructure having len~ portions of different power can be re~dily, and accurately, provided. The ~, . : . . . .:
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~328~9 problems previously discussed with gradient index lens arrangements, are avoided.
The posterior chamber type intraocular leni 10 will typically be utilized following extra capsular cataract extraction. As illustrated in Fig. 1, the lens 10 is implanted in a human eye 40, in the posterior chamber 42 behind the iris 44. Preferably, the cataract has been extracted from the capsular bag 46, leaving intact the posterior wall 46a and an annular flap portion 46b forming a cleft of fornix 46c. ~he capsular bag 46 is connected to the ciliary muscle in the eye wall 48 via suspensory ligaments 50. Vitreous humor in the region 52 behind the capsular bag 46 is prevented from flowing forward by the posterior wall 46a. It is, of course, understood that the present invention may also be used in the anterior chamber of the eye 40.
The intraocular lens 10 may serve as a bifocal vision system, with one lens 12 for reading and the other len~ 13 for distant viewing. As shown in the -I 20 preferxed embodiment, the axis 12a of the inner lens 12 is coaxial with the axis 13a of the annular lens 13.
However, it i~ llnderstood that th~ certain principles of the present invention will also be applicable where the axes 12a and 13a are ~ot coaxial. The different portions 12 and 13 will be understood to have different radii of curvature.
Nany prior art methods of providing bifocal vision system~, ~uch as bifocal glasses, are exclusive;
meaning one can either read or look in the distance.
Generally, there is a blurred region in between, which is awkward. With the present application thiis would not be the case. The first lens portion has a focal length that is for viewing near objects and the second lens portion has a focal length that is for viewing distant objects. Such a combination of lenses will produce two images on the retina which are superimposed. Alwayi, one of the two images will appear blurred. If an object :.
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~37~
up close is viewed, the image produced through the second lens will appear bluxred; or, if the object is viewed at a distance, the image through the first lens will appear blurred. The user's brain can select the S sharper image for evaluation.
In a preferred embodiment, as shown in the figures, the first lens 12 is a center lens having a focal length for reading and the second lens 13 is an annular ring shaped lens having a focal length for distant viewing. The area of each lens 12 and 13 will i~eally be computed individually for each patient, depending upon the patient's iris reflexes, as described more fully hereafter. In actual practicet a whole series of lenses would probably be provided, having different corrective properties, so that an appropriate lens could be selected for any given patient.
In one of the parent cases, it was indicated that preferably the area of the fir~t lens 12 would be from approximately 30% to 50% of the area of the lens body 11. Further, it was indicated as preferred that the first lens 12 be approximately 40%of the total area of the lens body 11 or, otherwise stated, the area of the first lens 12 be approximately equal to ~he area of the second lens 13. Thi~ is sho~n in Fig. 2.
A preferred arrangement outside of the above-stated range has been found. Fig. 2A show~ an arrangement which i~ substantially identical to Fiy. 2 in sub~tance, but for the relative sizes of the lens portions 12' and 13', to indicate the alternate and preferred possibility. For thi~ arrangement, it will generally be preferred that the annulax portion have a diameter of about 6.0 to about 7.0 millimeters while the inner portion has a diameter of about 1.8 to about 2.2 millimeters. Thu~, the area of the first len~ portion is between about 6% and 14~ of the combined areas of the first and second lens portions. Nost preferably, when the inner portion i~ the near vi~ion portion, it has a .
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13~81~9 diameter of less than 2mm. A reason for this is that interference between the two projected images will be les li~ely. That is, when the wearer reads, light can ; be adjusted to be relatively bright, the light r~flected off the page will be fairly intense, and the iri~ will contract at least partially blocking the distance vision portion. In distance viewing, the light intensity will generally be lower, and the iris more opened. A
relatively small image projected by the near vision ; 10 portion will be more easily discarded by the brain. In Fig. 2A reference numerals 10', 11', 12', 13', 14', 14a', 15' and 15a' indicate parts generally analogous, in form and function, to parts 10, 11, 12, 13, 14, 14a, 15 and 15a respectively.
lS It is also foreseen that the desirsd relative powers between the two lens portions may vary from patient to patient. Generally, for mo~t uses an operable embodiment will have a corrective power of about +15 to about +25 diopters, for the outer lens portion, the portion used for distance viewing; and, a ~orrective power of about +2 to about +4 diopter~ larger than the outer lens portion for the inner portion, i.e.
that portion used for near viewing. For preferred posterior lens implant3, preferably the add on will be at least ~3 diopter~, or the lens will not focus, in typical uses. Mo t preferably, the add on is at least +3.5 diopters.
If a distant ob~ect i3 viewed in moderately bright illumination, the iris 44 will be open and the image created by the annular lens 13 (which is sharp) will overpower the blurred and also less bright image created by the inner lens 12. The overpowering process ; is made possible by the fact that blurred edges are less intense than sharp edges, and by the way the image evaluation system of the brain works.
Reading activity usually takes place indoors, and bright illumination can readily be applied. The . - :
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~328~49 iris 44 will close, and the area of the annular lens 13 will be reduced so that the image of the inner lens 12 - (which is now sharp) will overpower the blurred, less bright, image generated by the annular lens 13.
Therefore, by the management of the intensity of the images, as is accomplished in the present invention, there can be two superimposed images one of which is blurred and one of which is sharp. The brain's evaluation system will accordingly see the sharp image.
The image evaluation system of the brain searches for sharp edge~ and, once it find~ a sharp edge, it exaggerates the edge. Therefore, generally, as long as the blurred image is weaker in inten~ity that the ~harp one, the brain will evaluate the images and "~ee" the sharp image.
I It is understood that any suitable combination such as plano-convex, biconcave, meniscus or other combination of lenses may be used with either an add on center or a distance on center to provide for the inner lens 12~ It i8 necessary for one skilled in the art to make a suitable combination of such lenses to provide l for a focal length for one of the lense3 12 or 13 for distance reading and a focal length for the other of the lenses 12 or 13 having a focal length for viewing near objects, preferably with both of the lenses having a positive power.
Another embodimPnt of the present in~ention is sho~n in Figs. 2-6. Thi3 lens would also be positioned i the eye a~ shown in Fig. 1. The second embodiment of the implantable intraocular lens 60 includes a rigid bifocal optical region or lens body 61 which includes a first lens portion 62 and a second lens portion 63, the bases of which are coplanarO The lens body 61 has a chord 61a between lens portions 62 and 63. This embodiment i3 also adapted to be implanted in the ; posterior chamber, although the concept can be utilized in an anterior chamber lens as well.
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Preferably, the unitary optical len~ body 61 is substantially circular, the chord 61a is a diameter of the lens body 61 and the lens portions are semicircular.
Thus, for this embodiment the first and second lens portions may preferably be of about the same size and the len~ portions axe substantially non-movable with respect to one another. The powers for the near vision and distance vision section~ are preferably previously described for the first embodiment.
The lens body 61, or optic portion of the intraocular lens 60, is centered and retained within the eye by ret~ining mean~ such a~ haptic member~ 64 and 55 having first ends 64a and 65a and second ends 64b and 65b, respectively. The first end~ 64a and 65a are cooperatively connected to ths lens body 61 by methods well known in the art. Further, the construction of a specific configuration of the haptic members 64 and 65 may be any suitable con~truction, ~uch construction being well known in the art.
Preferably, the haptic member~ 64 and 65, the ~irst lens 62 and second len~ 6~ are molded as an integral one-piece structureO ~08t preferably, a method of molding involving a mold made a~ previously de~cribed i~ used, in order to provide efficient production without the pxoblem~ involved in producing gradient index lenses. The unitary intraocular len~ body 61, including the first lens 62 and second len~ 63, i~ made of a biological tolerable and optically ~uitable ma~erial ~uch a~ PMMA. The haptic me~bers 64 and 65 may be made of a flexible, compres~ible, resilient plastic material such as PMMA or polypropylene, or other ~ materials as well known in the art. Preferably, the ; entire intraocular len~ 60 is made of an integral one-piece structure and also i~ made of PMMA. The intraocular lens 60 may serve as a bifocal vision sy~item, with one len~ 62 for reading and the other len~
63 for distant viewing.
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:` 13281~9 lS
As previously discussed, many prior art methods of providing bifocal vision systems, such as bifocal glasses, are exclusive. With the present embodiment this would not be the case. One of the lens portions would have a focal length that is for viewing near ob~ects and the other of the lens portions would have a focal length different from the first lens por~ion and that is for viewing distant objects. Such a combination of lense~ will produce two images on the retina which are superimposed. Always t one of the two images will appear blurrad. The eye is constantly scanning the images created on the retina and selectively chooses the image (the sharp one) to see. By having an intraocular lens 60 that is equally split, with the chord 60a being a horizontal diameter, the iri~ of the eye will alway~
be in position in front of both lens portions 62 and 63 and therefore the retina will al~ays have an image ;, formed on it from both the lens portions 62 and 63. The area of the first lens portion 62 i8 preferably approximately equal to the area of the second lens portion 63.
Again, when the two lens portions are equal, the chord 61a is substantially a diameter of the lens body 61. ~owever, the chord 61a could be offset from the center without departing from the invention.
As is clearly shown in Fig. 6, the lens body 61 has a planar bottom surface 61b that extends across both the first lens portion 62 and second lens portion 63.
The first lens portion 62 has an upper convex sur~ace 62a and the second lens portion 63 ha~ an upper convex surface 63a, the latter one having a different radius of curvature than ~he first. Reference numeral 66 generally indicates a transition region between the two lens portions which for the preferred embodiment shown, :; 35 i3 chord 61a. In Fig. 6 plane 67 represents a division of the len3 61 into its two halves 62 and 63 of different powers. While different radii of curvatures ~.
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are drawn, the difference is ~mall and hard to see. It ; will nevextheless be understood to be present.
Fig. 7 is a cros~-sectional view of a lens incorporating the pre~ent invention taken from a point of view generally analogous to the use for Fig. 1, but showing an alternate thereto. In particulax, the lens body of Fig. 7 is shown having a plano-convex structure.
That is, it is generally planar on one ~ide and convex on the other. This arrangement may be advantageous, in that it is potentially easier to construct. For the arrangement shown in Fig. 7, the reference numeral 100 generally designates the eye, and the reference numeral 111 the lens. The arrangement ~ill be understood to be analogou~ to that shown in Figs. 1-3, but for the utilization for a plano-convex structure for the lens.
The near ~ision portion 112 of the lens may be, for example, of the relativQ diameter to the distant vision ; portion 113, as previously described for Figs. 1-3. In the alternative, that ratio of areas described ` 20 previously for Fig. 2A, may also, preferably, be used.
Desirable corrective factors for the two portions may be ; as previously indicated; that is, preferably, with the distance portion having a corrective power of between about +15 and +25 diopters, and with the corrective power of the inner, near vision, len~ portion preferably having an add on power of bet~een about +3 and about +4 diopters, and more preferably at least about +3.5 " diopters.
In Fig. 8 a top plan view of the lens of Fig. 7 - 30 is ~hown. Again, except for the plano-convex structure, the arrangem2nt i~ analogou~ to that shown in Fig. 2.
Finally, in Fig. 8A an alternate ~o the arrangement shown in Fig. 7 and 8 is shown, wherein the ` inner lens portion 112' is constructed smaller, with respect to the ou~er len portion 113'. Specifically, for this arrangement it will generally be preferred that the annular portion have a diameter of about 6.0 to -~, - .. . - ,: .
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~s ~32~49 ` 18 :; ., ; about 7.0 millimeters, while the inner portion has a ` diameter of about 1.8 to about 2.0 millimeters. Thu~, the arrangement is generally analogou~ to that ~hown in Fig. 2A, but for the plano-convex structure.
In general, arrangements according to Figs. 7, 8 and 8A are more readily susceptible to manufacture according to the de~cribed method of molding, than are the embodiments of Figs. 1-6. A rea~on for this is that molds having a target arrangement providing for an inner concave region of one diameter and an outer conca~e ~1 region of another diameter can be fairly easily ground.
- Although the preferred embodiment of the inv0ntion i~ a bifocal lens, it should be understood that one or more additional lenses may be incorporated to correct for different distance~.
~- Other modification of the invention will be apparent to tho~e skilled in the art in light of the foregoing de~cription. ~his de~cription i~ intended to provide specific example~ of individ~al embodiments which clearly disclo~e the pre~ent invention.
Accordingly, the in~ention i3 not limited to th ~e embodimen~s or to the use of elements having specific configurations and shapes as presented herein. All i alternative modifications and variation~ of the present invention which follow in the spirit and broad scope of the appended claim~ are included.
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Claims (19)
1. A rigid bifocal intraocular lens adapted for use as an artificial lens implant, said intraocular lens comprising:
(a) an optical lens body having first and second lens portions and a chord at an interface region between said first and second lens portions;
(b) said first lens portion have a focal length;
(c) said second lens portion having a focal length different from said focal length of said first lens portion; and, said first lens portion having an add on power of at least +3.0 diopters relative to said second lens portion;
(d) said first lens portion positioned on one side of said chord and said second lens portion positioned on the other side of said chord;
(e) said first and second lens portions forming a unitary optical lens body having no substantial refractive index gradient therein; and, (f) haptic elements cooperatively connected to said lens body.
(a) an optical lens body having first and second lens portions and a chord at an interface region between said first and second lens portions;
(b) said first lens portion have a focal length;
(c) said second lens portion having a focal length different from said focal length of said first lens portion; and, said first lens portion having an add on power of at least +3.0 diopters relative to said second lens portion;
(d) said first lens portion positioned on one side of said chord and said second lens portion positioned on the other side of said chord;
(e) said first and second lens portions forming a unitary optical lens body having no substantial refractive index gradient therein; and, (f) haptic elements cooperatively connected to said lens body.
2. A rigid bifocal intraocular lens arrangement according to claim 1, wherein said first lens portion has an add on power of at least +3.5 diopters relative to said second lens portion.
3. The intraocular lens of claim 2, wherein said lens body is circular and said chord is a diameter of said lens body.
4. The intraocular lens of claim 2, wherein said first lens portion has a focal length that is for viewing near objects and said second lens portion has a focal length that is for viewing distant objects, wherein when viewing an object, said portions will each produce an image on the retina, said images being superimposed and, depending on the distance of the object, one of said images will be sharp and the other of said images will be sufficiently blurred, to induce a wearer's brain to evaluate in a manner to allow clean perception of only one sharp image.
5. The intraocular lens of claim 2 wherein:
(a) said second lens portion has a power of between about +15 and about +25 diopters.
(a) said second lens portion has a power of between about +15 and about +25 diopters.
6. A bifocal intraocular lens adapted for use as an artificial lens implant in the posterior chamber of the eye, said intraocular lens comprising:
(a) a circular optical lens body having a chord and first and second lens portions;
(b) said first lens portion having a focal length;
(c) said second lens portion having a focal length different from said focal length of said first lens portion; and, said first lens portion has an add on power of at least +3.0 diopters relative to said second lens portion;
(d) said first lens portion being positioned on one side of said chord and said second lens portion being positioned on the other side of said chord;
(e) said first and second lens portions forming a unitary optical lens body having no substantial refractive index gradient therein;
(f) haptic elements cooperatively connected to said lens body for positioning said lens body posterior to the iris of the eye;
and, (g) wherein said first lens portion ha a focal length that is for viewing near objects and said second lens portion has a focal length that is for viewing distant objects, wherein when viewing an object, said portions will each produce an image on the retina, said images being superimposed and, depending on the distance of the object, one of said images will be sharp and the other of said images sufficiently blurred, to induce a wearer's brain to evaluate the image in a manner inducing perception of only one, sharp, image.
(a) a circular optical lens body having a chord and first and second lens portions;
(b) said first lens portion having a focal length;
(c) said second lens portion having a focal length different from said focal length of said first lens portion; and, said first lens portion has an add on power of at least +3.0 diopters relative to said second lens portion;
(d) said first lens portion being positioned on one side of said chord and said second lens portion being positioned on the other side of said chord;
(e) said first and second lens portions forming a unitary optical lens body having no substantial refractive index gradient therein;
(f) haptic elements cooperatively connected to said lens body for positioning said lens body posterior to the iris of the eye;
and, (g) wherein said first lens portion ha a focal length that is for viewing near objects and said second lens portion has a focal length that is for viewing distant objects, wherein when viewing an object, said portions will each produce an image on the retina, said images being superimposed and, depending on the distance of the object, one of said images will be sharp and the other of said images sufficiently blurred, to induce a wearer's brain to evaluate the image in a manner inducing perception of only one, sharp, image.
7. The intraocular lens of claim 6, wherein said first lens portion has an add on power of at least about +3.5 diopters, relative to said second lens portion.
8. The intraocular lens of claim 7, wherein said lens portions are semicircular and have coplanar bases.
9. A rigid intraocular lens adapted for use as an artificial lens implant, said intraocular lens comprising:
(a) means for non-movably retaining said lens implant within a chamber of a user's eye;
and, (b) a lens body including a first lens portion and a second lens portion;
(i) said first lens portion having a focal length and being non-movably mounted in said intraocular lens;
(ii) said second lens portion being non-movably mounted in said intraocular lens and having a focal length different from said focal length of said first lens; said second lens portion being in cooperative engagement with said first lens portion to form an optical region of said lens body having no substantial refractive index gradient therein;
(iii) said first lens portion being constructed and arranged for viewing relatively near objects and having an optical power of at least about +3.0 diopters greater than said second lens portion;
(iv) said second lens portion being constructed and arranged for viewing relatively distant objects and having an optical power of between about +15 and about +25 diopters;
(v) said first lens portion being constructed and arranged to project focused images created thereby in substantially the same plane as second images projected by said second lens portion;
(c) whereby when a user wearing said intraocular lens uses same to view, both of said first and second lens portions may produce images substantially superimposed upon one another with, depending generally on the distance of the object being viewed and the amount of light present, one of the images appearing sharp and the other image defocused to permit the user's brain to select the sharper image for evaluation.
(a) means for non-movably retaining said lens implant within a chamber of a user's eye;
and, (b) a lens body including a first lens portion and a second lens portion;
(i) said first lens portion having a focal length and being non-movably mounted in said intraocular lens;
(ii) said second lens portion being non-movably mounted in said intraocular lens and having a focal length different from said focal length of said first lens; said second lens portion being in cooperative engagement with said first lens portion to form an optical region of said lens body having no substantial refractive index gradient therein;
(iii) said first lens portion being constructed and arranged for viewing relatively near objects and having an optical power of at least about +3.0 diopters greater than said second lens portion;
(iv) said second lens portion being constructed and arranged for viewing relatively distant objects and having an optical power of between about +15 and about +25 diopters;
(v) said first lens portion being constructed and arranged to project focused images created thereby in substantially the same plane as second images projected by said second lens portion;
(c) whereby when a user wearing said intraocular lens uses same to view, both of said first and second lens portions may produce images substantially superimposed upon one another with, depending generally on the distance of the object being viewed and the amount of light present, one of the images appearing sharp and the other image defocused to permit the user's brain to select the sharper image for evaluation.
10. A lens according to claim 9, wherein said first lens portion has an add on power of at least about +3.5 diopters, relative to said second lens portion.
11. The intraocular lens according to claim 10 wherein:
(a) said first lens portion is circular and has an axis; and, (b) said second lens portion is annular and has an axis, (i) said second, annular, lens portion surrounding said first lens portion with said first lens portion axis substantially coaxial with said second lens portion axis.
(a) said first lens portion is circular and has an axis; and, (b) said second lens portion is annular and has an axis, (i) said second, annular, lens portion surrounding said first lens portion with said first lens portion axis substantially coaxial with said second lens portion axis.
12. The intraocular lens according to claim 11 wherein:
(a) said first lens portion has an area of between about 6% and 14% of a total combined area of said first and second lens portions.
(a) said first lens portion has an area of between about 6% and 14% of a total combined area of said first and second lens portions.
13. The intraocular lens according to claim 11 wherein:
(a) said first lens portion has a diameter of between about 1.8 millimeters and about 2.0 millimeters.
(a) said first lens portion has a diameter of between about 1.8 millimeters and about 2.0 millimeters.
14. A rigid intraocular lens implant adapted for use as an artificial lens implant in a posterior chamber of an eye; said intraocular lens comprising:
(a) means for non-movably retaining said lens implant within a posterior chamber of a user's eye; and, (b) a lens body comprising a material having a first index of refraction and substantially no index of refraction gradient therein; said lens body having a first circular lens portion and a second annular lens portion, said second annular lens portion surrounding said first circular lens portion;
(i) said first lens portion comprising a portion of said lens body having said first index of refraction and a first radius of curvature defining a first optical power;
(ii) said second lens portion comprising a portion of said lens body having said first index of refraction and a second radius of curvature defining a second optical power;
(iii) said second lens portion being constructed and arranged for viewing relatively distant objects and having an optical power of between about +15 and about +25 diopters;
(iv) said first lens portion being constructed and arranged for viewing relatively near objects and having: a power of at least +3.0 diopters greater than said second lens portion; and, a diameter of no greater than about 2.0 mm.
(a) means for non-movably retaining said lens implant within a posterior chamber of a user's eye; and, (b) a lens body comprising a material having a first index of refraction and substantially no index of refraction gradient therein; said lens body having a first circular lens portion and a second annular lens portion, said second annular lens portion surrounding said first circular lens portion;
(i) said first lens portion comprising a portion of said lens body having said first index of refraction and a first radius of curvature defining a first optical power;
(ii) said second lens portion comprising a portion of said lens body having said first index of refraction and a second radius of curvature defining a second optical power;
(iii) said second lens portion being constructed and arranged for viewing relatively distant objects and having an optical power of between about +15 and about +25 diopters;
(iv) said first lens portion being constructed and arranged for viewing relatively near objects and having: a power of at least +3.0 diopters greater than said second lens portion; and, a diameter of no greater than about 2.0 mm.
15. A lens implant according to claim 14, wherein said first lens portion has an area of between about 6% and 14% of a total combined area of said first and second lens portions.
16. A lens implant according to claim 15, wherein said first lens portion has a power of at least about +3.5 diopters greater than said second lens portion.
17. The intraocular lens according to claim 14, wherein:
a) said first lens portion defines a central axis of symmetry; and, b) said second lens portion defines a central axis of symmetry substantially coaxial with said central axis of symmetry defined by said first lens portion.
a) said first lens portion defines a central axis of symmetry; and, b) said second lens portion defines a central axis of symmetry substantially coaxial with said central axis of symmetry defined by said first lens portion.
18. A lens implant according to claim 17, wherein said first lens portion has a power of at least about +3.5 diopters greater than said second lens portion.
19. A lens implant according to claim 18, wherein said first lens portion has an area of between about 5% and 14% of a total combined area of said first and second lens portions.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US18225388A | 1988-04-15 | 1988-04-15 | |
| US182,253 | 1988-04-15 | ||
| US29796689A | 1989-01-17 | 1989-01-17 | |
| US297,966 | 1989-01-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1328149C true CA1328149C (en) | 1994-04-05 |
Family
ID=26877926
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000596628A Expired - Fee Related CA1328149C (en) | 1988-04-15 | 1989-04-13 | One-piece bifocal intraocular lens construction |
Country Status (4)
| Country | Link |
|---|---|
| KR (1) | KR900700061A (en) |
| AU (1) | AU3549789A (en) |
| CA (1) | CA1328149C (en) |
| WO (1) | WO1989009576A1 (en) |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE69325518T2 (en) * | 1992-10-02 | 1999-10-28 | Nestle S.A., Vevey | INTRAOCULAR LENS SYSTEM |
| US6468306B1 (en) | 1998-05-29 | 2002-10-22 | Advanced Medical Optics, Inc | IOL for inhibiting cell growth and reducing glare |
| US6884262B2 (en) | 1998-05-29 | 2005-04-26 | Advanced Medical Optics, Inc. | Enhanced intraocular lens for reducing glare |
| US6162249A (en) * | 1998-05-29 | 2000-12-19 | Allergan | IOI for inhibiting cell growth and reducing glare |
| US6648741B2 (en) | 2002-03-14 | 2003-11-18 | Advanced Medical Optics, Inc. | Apparatus for protecting the edge geometry of an intraocular lens during glass bead polishing process |
| JP4842835B2 (en) | 2003-12-09 | 2011-12-21 | アボット・メディカル・オプティクス・インコーポレイテッド | Foldable intraocular lens and manufacturing method thereof |
| US7615073B2 (en) | 2003-12-09 | 2009-11-10 | Advanced Medical Optics, Inc. | Foldable intraocular lens and method of making |
| US12036111B2 (en) | 2011-09-14 | 2024-07-16 | Medicontur Holding Ltd. | Method of implantation of an intraocular lens in a ciliary sulcus of an eye |
| US20170172733A1 (en) | 2014-04-18 | 2017-06-22 | Investmed Kft. | Secondary Intraocular Lens with Magnifying Coaxial Optical Portion |
| US11938018B2 (en) | 2014-09-22 | 2024-03-26 | Onpoint Vision, Inc. | Intraocular pseudophakic contact lens (IOPCL) for treating age-related macular degeneration (AMD) or other eye disorders |
| US12447007B2 (en) | 2014-09-22 | 2025-10-21 | Onpoint Vision, Inc. | Intraocular pseudophakic contact lens with mechanism for securing by anterior leaflet of capsular wall and related system and method |
| MX2022006993A (en) * | 2019-12-17 | 2022-07-13 | Onpoint Vision Inc | INTRAOCULAR PSEUDOPHAKY CONTACT LENS WITH FIXATION MECHANISM USING AN ANTERIOR CAPSULAR WALL VALVE, AND RELATED METHOD AND SYSTEM. |
| US11864991B2 (en) | 2020-07-28 | 2024-01-09 | Onpoint Vision, Inc. | Intraocular pseudophakic contact lens (IOPCL)-based telescopic approach for treating age-related macular degeneration (AMD) or other eye disorders |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4636211A (en) * | 1984-03-13 | 1987-01-13 | Nielsen J Mchenry | Bifocal intra-ocular lens |
| US4666446A (en) * | 1986-05-06 | 1987-05-19 | Koziol Jeffrey E | Intraocular lens with converging and diverging optical portions |
| WO1987007496A1 (en) * | 1986-06-05 | 1987-12-17 | Precision-Cosmet Co., Inc. | One-piece bifocal intraocular lens construction |
-
1989
- 1989-04-04 KR KR1019890702359A patent/KR900700061A/en not_active Ceased
- 1989-04-04 AU AU35497/89A patent/AU3549789A/en not_active Abandoned
- 1989-04-04 WO PCT/US1989/001407 patent/WO1989009576A1/en not_active Ceased
- 1989-04-13 CA CA000596628A patent/CA1328149C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| KR900700061A (en) | 1990-08-11 |
| WO1989009576A1 (en) | 1989-10-19 |
| AU3549789A (en) | 1989-11-03 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |