Abstract:
A two part lens system. The first part is a ring-like supporting component that is implanted in the capsular bag following cataract surgery. The first component is a non-optical component and contains a pair of haptics for fixating the first component within the capsular bag. The second component is an optical component that contains all of the corrective optical power of the lens system. The second component has a pair of tabs for locking the second component within the first component.

Description:
[0001]     This application is a continuation-in-part of U.S. patent application Ser. No. 10/618,954, filed Jul. 14, 2003, currently co-pending. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     This invention relates generally to the field of intraocular lenses (IOL) and, more particularly, to multi-lens IOLs.  
         [0003]     The human eye in its simplest terms functions to provide vision by transmitting light through a clear outer portion called the cornea, and focusing the image by way of a crystalline lens onto a retina. The quality of the focused image depends on many factors including the size and shape of the eye, and the transparency of the cornea and the lens.  
         [0004]     When age or disease causes the lens to become less transparent, vision deteriorates because of the diminished light which can be transmitted to the retina. This deficiency in the lens of the eye is medically known as a cataract. An accepted treatment for this condition is surgical removal of the lens and replacement of the lens function by an artificial intraocular lens (IOL).  
         [0005]     In the United States, the majority of cataractous lenses are removed by a surgical technique called phacoemulsification. During this procedure, an opening is made in the anterior capsule and a thin phacoemulsification cutting tip is inserted into the diseased lens and vibrated ultrasonically. The vibrating cutting tip liquifies or emulsifies the lens so that the lens may be aspirated out of the eye. The diseased lens, once removed, is replaced by an artificial lens.  
         [0006]     Prior to the present invention, when a cataract or other disease required the removal of the natural lens and replacement with an artificial IOL, the IOL was a monofocal lens. Most IOLs are sold in power increments of +/−0.5 diopters, and the ultimate power of the lens depends upon where the lens sits along the optical axis. The fixed increment of the lens, and the slight variation in lens placement can result in less than optimum vision. Although this situation occurs relatively infrequently, and generally is not severe, some patients ultimately are required to use a pair of spectacles or contact lenses for optimum vision. If the power of the implanted lens is incorrect, removal and exchange of a new lens is difficult because of fibrosis of the lens haptics within the capsular bag.  
         [0007]     There have been several prior suggested adjustable power IOLs, none of which have been commercially introduced. For example, U.S. Pat. No. 5,222,981 (Werblin) and U.S. Pat. No. 5,358,520 (Patel), the entire contents of which being incorporated herein by reference, suggest the use of a second or even a third optic that may be implanted and attached to a previously implanted primary optic so as to adjust the overall optic power of the multi-lens system. U.S. Pat. Nos. 5,628,798 and 5,800,533 (Eggleston, et al.), the entire contents of which being incorporated herein by reference, disclose a threadedly adjustable IOL wherein the location of the optic along the visual axis may be adjusted. U.S. Pat. No. 4,575,373 (Johnson), the entire contents of which being incorporated herein by reference, discloses an IOL having an optic and an outer ring and connections between the optic and the outer ring made from a heat-shrinkable plastic. The connections are heated with a laser to adjust the power of the IOL. U.S. Pat. Nos. 4,919,151 and 5,026,783 (Grubbs, et al.), the entire contents of which being incorporated herein by reference, disclose a lens made from a polymer that swells or otherwise changes shape. The lens is implanted or injected into the capsule bag and selectively polymerized so as to adjust the power of the optic. U.S. Pat. No. 5,571,177 (Deacon, et al.), the entire contents of which being incorporated herein by reference, discloses an IOL having haptics with frangible stiffeners. Once implanted in an eye, the stiffeners are selectively cut or heated above their t g  by laser radiation, causing the stiffness of the haptic to change and adjusting the location of the lens within the capsule bag. The multi-lens designs and the threadedly adjustable designs are not optimized for the reduction or elimination of posterior capsule opacification (PCO).  
         [0008]     Therefore, a need continues to exist for a safe and stable intraocular lens system that provides adjustment of lens power. Such a lens system could be used in cararact or clear lens exchange surgeries.  
       BRIEF SUMMARY OF THE INVENTION  
       [0009]     The present invention improves upon the prior art by providing a two part lens system. The first part is a ring-like supporting component that is implanted in the capsular bag following cataract surgery. The first component is a non-optical component and contains a pair of haptics for fixating the first component within the capsular bag. The second component is an optical component that contains all of the corrective optical power of the lens system. The second component has a pair of tabs for locking the second component within the first component.  
         [0010]     Accordingly, one objective of the present invention is to provide a safe and biocompatible intraocular lens.  
         [0011]     Another objective of the present invention is to provide a safe and biocompatible intraocular lens that is easily implanted in the posterior chamber.  
         [0012]     Still another objective of the present invention is to provide a safe and biocompatible intraocular lens that is stable in the posterior chamber.  
         [0013]     Still another objective of the present invention is to provide a safe and biocompatible adjustable lens system.  
         [0014]     Still another objective of the present invention is to provide a safe and biocompatible lens system that can be implanted through a small incision.  
         [0015]     Still another objective of the present invention is to provide a safe and biocompatible lens system that helps reduce the incidence of PCO.  
         [0016]     Still another objective of the present invention is to provide a safe and biocompatible lens system for use in cataract and/or clear lens exchange surgeries.  
         [0017]     These and other advantages and objectives of the present invention will become apparent from the detailed description and claims that follow. 
     
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0018]      FIG. 1  is an enlarged perspective view of the first embodiment of the assembled lens system of the present system.  
         [0019]      FIG. 2  is an enlarged plan view of the first embodiment of the assembled lens system of the present system.  
         [0020]      FIG. 3  is an enlarged cross-sectional view of the first embodiment of the assembled lens system of the present system taken at line  3 - 3  in  FIG. 2 .  
         [0021]      FIG. 4  is an enlarged plan view of the second component of the lens system of the present system.  
         [0022]      FIG. 5  is an enlarged cross-sectional view of the second component of the lens system of the present system taken at line  5 - 5  in  FIG. 4 .  
         [0023]      FIG. 6  is an enlarged plan view of the second embodiment of the first component of the lens system of the present system.  
         [0024]      FIG. 7  is an enlarged cross-sectional view of the second embodiment of the first component of the lens system of the present system taken at line  7 - 7  in  FIG. 6 .  
         [0025]      FIG. 8  is an enlarged partial cross-sectional view of the second component of the lens system of the present system taken at circle  8  in  FIG. 7 .  
         [0026]      FIG. 9  is an enlarged plan view of the second embodiment of the assembled lens system of the present system.  
         [0027]      FIG. 10  is an enlarged cross-sectional view of the second embodiment of the assembled lens system of the present system taken at line  10 - 10  in  FIG. 9 .  
         [0028]      FIG. 11  is an enlarged partial cross-sectional view of the second embodiment of the lens system of the present system taken at circle  11  in  FIG. 10 .  
         [0029]      FIG. 12  is an enlarged plan view of the third embodiment of the first component of the lens system of the present system.  
         [0030]      FIG. 13  is an enlarged cross-sectional view of the third embodiment of the first component of the lens system of the present system taken at line  13 - 13  in  FIG. 12 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0031]     As best seen in  FIGS. 1-3 , lens system  10  of the present invention generally consists of first, or base, component  12  and second, or optical, component  14 . Base component  12  is generally ring-like, having hollow center  11  and contains a plurality of integrally formed haptics  16  and is preferably formed in any suitable overall diameter, for example, between approximately 10.0 millimeters and 12.0 millimeters, a suitable interior diameter, for example, between approximately 7.0 millimeters and 9.0 millimeters and made from a soft, foldable material such as a soft acrylic. Alternatively, base component  12  may be made from a material that is stiffer relative to optical component  14  or less stiff relative to optical component  14 . By way of example, component  12  may be made of rubber elastomers, such as butyl rubber, latex rubber, natural rubber, pure gum rubber, neoprene rubber, acrylonitrile rubber, styrene-butadiene rubber, ethylene-propylene diene monomer rubber, acrylonitrile-butadiene-styrene (ABS) rubber, epichlorohydrin rubber, hypalon rubber, silicone rubber and siloxane elastomers, such as poly(dimethylsiloxane), polyurethane rubber, viton rubber, ethylene-butylene rubber, isobutylene rubber and elastomers of polyphosphazenes, like poly(bis-trifluorethoxyphosphazene) oly(dimethylphosphazene) and poly(phenylmethylphosphazene). Preferably, base component  12  is constructed so as to allow it to be compressed and inserted into an eye through an incision of approximately 2.0 mm. Base component  12  may also be formed so as to be opaque, such as by frosting or texturing the anterior and/or posterior surfaces of base component  12 . Base component  12  may also contain a chromophore to block ultraviolet and/or blue and/or green light, such chromophore(s) being well-known in the art. As best seen in  FIG. 3 , posterior surface  13  of base component  12  preferably has a plurality of posterior circumferential rings or bands  18  that present a sharp, square edge against the posterior capsule, such sharp edges being widely believed to help inhibit PCO. Interior surface  19  of base component  12  contains locking slot  20  into which optical component  14  fits in the manner described below.  
         [0032]     As best seen in  FIGS. 4-5 , optical component  14  is generally circular with an optic  15  having diameter D, for example, between approximately 4.0 millimeters and 7.0 millimeters. Optical component  14  tapers from being relatively thick in the middle to having a relatively thin, or sharp, edge that contains a plurality of tabs  22  integrally formed with optic  15  so as to give optical component  14  overall length L between approximately 7.5 millimeters and 8.5 millimeters and preferably, is made from a soft, foldable material such as a soft acrylic. Lens component  14  may also contain a chromophore to block ultraviolet and/or blue light, such chromophore(s) being well-known in the art, but unlike base component  12 , lens component  14  is optically clear.  
         [0033]     As best seen in  FIGS. 2 and 3 , lens system  10  is assembled by placing tabs  22  of lens component  14  in wide portions  21  of slots  20  and rotating lens component  14  slightly clockwise so as to lock tabs  22  within slots  20 . In such an assembly, optical component  14  does not compress and vault during contraction of the capsular bag, because tabs  22  can slide inward and outward within slots  20  during compression of haptic  16  and base component  12 . Such a construction makes lens component  14  very axially stable.  
         [0034]     In a second embodiment of the present invention, best seen in  FIGS. 6-11 , lens system  10 ′ of the present invention generally consists of first, or base, component  12 ′ and second, or optical, component  14 . Base component  12 ′ is generally ring-like, having hollow center  11 ′ and contains a plurality of integrally formed haptics  16 ′ and is otherwise constructed in a manner similar to base component  12 . As best seen in  FIG. 8 , posterior surface  13 ′ of base component  12 ′ preferably has a plurality of posterior circumferential rings or bands  18 ′ that present a sharp, square edge against the posterior capsule, such sharp edges being widely believed to help inhibit PCO. Interior surface  19 ′ of base component  12 ′ is smooth and contains lip  23  into which optical component  14  fits in the manner described below.  
         [0035]     As best seen in  FIGS. 9-11 , lens system  10 ′ is assembled by placing tabs  22  of lens component  14  under lip  23 . In such an assembly, optical component  14  does not compress and vault during contraction of the capsular bag, because tabs  22  can slide inward and outward on lip  23  during compression of haptic  16 ′ and base component  12 ′. Such a construction makes lens component  14  very axially stable. Another advantage of such a construction is that no rotation of component  14  is necessary, allowing component to be implanted more easily and in any rotational position. Being able freely to locate component  14  rotationally can be an advantage, particularly with toric components  14 .  
         [0036]     In a third embodiment of the present invention, best seen in  FIGS. 12 and 13 , component  12 ″ generally ring-like, and generally of a construction similar to component  12  and  12 ′ except that component  12 ″ contains a plurality of integrally formed haptics  16 ″ that are of a closed-loop design and connected to component  12 ″ on both ends  17 .  
         [0037]     This description is given for purposes of illustration and explanation. It will be apparent to those skilled in the relevant art that changes and modifications may be made to the invention described above without departing from its scope or spirit.