Abstract:
A foldable lens having a reinforced haptic/optic intersection that allows the optic to vault posteriorly unidirectionally while still providing stable fixation of the lens within the eye.

Description:
[0001]    This invention relates to intraocular lenses (IOLs) and more particularly to soft, foldable intraocular lenses.  
         BACKGROUND OF THE INVENTION  
         [0002]    The human eye in its simplest terms functions to provide vision by transmitting and refracting light through a clear outer portion called the cornea, and further focusing the image by way of lens onto the retina at the back of the eye. The quality of the focused image depends on many factors including the size, shape and length of the eye, and the shape and transparency of the cornea and lens. When trauma, age or disease cause 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. The treatment for this condition is surgical removal of the lens and implantation of an artificial lens or IOL.  
           [0003]    While early IOLs were made from hard plastic, such as polymethylmethacrylate (PMMA), soft foldable IOLs made from silicone, soft acrylics and hydrogels have become increasingly popular because of the ability to fold or roll these soft lenses and insert them through a smaller incision. While early foldable lenses either had a plate-style haptic (e.g., U.S. Pat. No. 4,664,666 (Barrett), the entire contents of which being incorporated herein by reference) or were of a multi-piece design with independently formed, relatively rigid haptic attached to the soft optic (e.g., U.S. Pat. No. 5,118,452 (Lindsey, et al.), the entire contents of which being incorporated herein by reference), newer lens designs are of an open-loop variety and manufactured from a single piece (e.g., U.S. Pat. No. 5,716,403, (Tran, et al.), the entire contents of which being incorporated herein by reference). The problem with soft, single-piece, open loop IOLs is that the haptics lack force sufficient to vault the optic posteriorly away from the iris and ensure firm contact with the posterior capsule.  
           [0004]    Accordingly, a need continues to exist for a vaulted, single-piece, open loop, soft intraocular lens.  
         BRIEF SUMMARY OF THE INVENTION  
         [0005]    The present invention improves upon prior art single-piece, open loop, soft intraocular lenses by providing a foldable lens having a reinforced haptic/optic intersection that allows the optic to vault posteriorly unidirectionally while still providing stable fixation of the lens within the eye.  
           [0006]    It is accordingly an object of the present invention to provide a stable intraocular lens.  
           [0007]    It is a further object of the present invention to provide a vaulted, single-piece, open loop, soft intraocular lens.  
           [0008]    It is a further object of the present invention to provide a single-piece, open loop, soft intraocular lens having a stiffened haptic/optic intersection that allows the optic to vault posteriorly.  
           [0009]    Other objectives, features and advantages of the present invention will become apparent with reference to the drawings, and the following description of the drawings and claims. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 is a top plan view of a first embodiment of an intraocular lens of the present invention.  
         [0011]    [0011]FIG. 2 is a partial cross-sectional view of the lens illustrated in FIG. 1.  
         [0012]    [0012]FIG. 3 is a top plan view of a second embodiment of an intraocular lens of the present invention.  
         [0013]    [0013]FIG. 4 is a partial cross-sectional view of the lens illustrated in FIG. 3. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0014]    As best seen in FIGS. 1 and 2, in a first embodiment of the present invention, lens  10  generally consists of optic  12  and at least one haptic  14 . Optic  12  has an anterior face  16  and a posterior face  18 . The overall design of lens  10  may be any suitable single-piece, open loop design made from a soft, foldable material, such as silicone, hydrogel or soft acrylic. One suitable design is illustrated in FIG. 1, and another suitable design is disclosed in U.S. Pat. No. 5,716,403, (Tran, et al.). Haptic  14  intersects edge  20  of optic  12  at an angle relative to the plane of the optic (the plane of the optic being perpendicular to optical axis  32 ), preferably between 1° and 20°, and most preferably between 5° and 10° but other suitable angles may also be used. Haptic  14  contains joint  22  that acts like a hinge to allow distal section  24  of haptic  14  to pivot anteriorly. Thickened section  26 , on the posterior side of haptic  14 , helps to assure that flexing of haptic  14  about joint  22  causes distal section  24  of haptic  14  to pivot anteriorly. Proximal portion  28  of haptic  14  contains convex anterior side  30  which assists in transferring compressive forces on haptic  14  into posterior movement of optic  12  along optical axis  32 . While any suitable dimensions can be used, haptic  14  preferably is between about 0.10 mm and 0.25 mm thick, with around 0.20 mm being most preferred. Thickened section  26  of haptic  14  preferably is between about 0.40 mm and 0.65 mm thick, with around 0.55 mm being most preferred. Proximal portion  28  of haptic  14  preferably is between about 0.25 mm and 0.55 mm thick, with around 0.40 mm being most preferred. Convex anterior side  30  of proximal portion  28  of haptic  14  preferably is formed with a radius of between about 0.2 mm and 0.6 mm, with around 0.4 mm being most preferred.  
         [0015]    As best seen in FIGS. 3 and 4, in a second embodiment of the present invention, lens  110  generally consists of optic  112  and at least one haptic  114 . Optic  112  has an anterior face  116  and a posterior face  118 . The overall design of lens  110  may be any suitable single-piece, open loop design made from a soft, foldable material, such as silicone, hydrogel or soft acrylic. One suitable design is illustrated in FIG. 3, and another suitable design is disclosed in U.S. Pat. No. 5,716,403, (Tran, et al.). Haptic  114  intersects edge  120  of optic  112  at an angle relative to the plane of the optic (the plane of the optic being perpendicular to optical axis  132 ), preferably between 1° and 20°, and most preferably between 5° and 10° but other suitable angles may also be used. Haptic  114  contains joint  122  that acts like a hinge to allow distal section  124  of haptic  114  to pivot anteriorly. Thickened section  126 , on the anterior side of haptic  114  and located distally of joint  122 , helps to assure that flexing of haptic  114  about joint  122  causes distal section  124  of haptic  114  to pivot anteriorly. Edge  120  of optic  112  contains circumferential stiffening rib  130  at the intersection of joint  122  and edge  120  which assists in transferring compressive forces on haptic  114  into posterior movement of optic  112  along optical axis  132 . While any suitable dimensions can be used, haptic  114  preferably is between about 0.10 mm and 0.25 mm thick, with around 0.20 mm being most preferred. Thickened section  126  of haptic  114  preferably is between about 0.20 mm and 0.40 mm thick, with around 0.29 mm being most preferred, with a radius of between about 0.2 mm and 0.4 mm, with around 0.3 mm being most preferred. Joint  122  preferably is between about 0.05 mm and 0.10 mm thick, with around 0.08 mm being most preferred.  
         [0016]    While certain embodiments of the present invention have been described above, these descriptions are given for purposes of illustration and explanation. Variations, changes, modifications, and departures from the systems and methods disclosed above may be adopted without departure from the scope or spirit of the present invention.