Patent Publication Number: US-2015073550-A1

Title: Biased accommodating intraocular lens

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of Ser. No. 13/472,893, filed May 16, 2012, which is based on U.S. Provisional Application No. 61/519,098, filed on May 17, 2011, the contents and disclosures of which are fully incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Premium intraocular lenses (IOLs) implanted during cataract surgery are categorized three ways: accommodating, multifocal and toric intraocular lenses. 
     The best visual acuity is achieved with the single focus accommodating lenses. The optic of these lenses moves forward and backward upon constriction and relaxation of the ciliary muscle. However, for reading in dim lighting conditions, or for small print, week reading glasses are often necessary. 
     The multifocal lenses focus light on the retina at either two or three focal lengths. Thus, there is more than one image on the retina simultaneously. This creates problems since the amount of light in focus is divided between the multiple focal points, and contrast sensitivity is thereby reduced, making vision at all distances difficult in dim lighting. In addition, there are severe problems when driving at night when the pupil is dilated. Many patients experience severe glare and halos and many have had to have the multifocal lenses explanted and replaced with a single vision standard lens, because of this problem. However, the near vision with the multifocal lenses is superior to that of the current accommodating lens. 
     The toric lenses correct the eyes that have significant astigmatism. 
     The currently marketed plate accommodating intraocular lenses provide excellent distance and intermediate vision but sometimes require weak, +1.00, reading glasses for prolonged reading, for seeing small print, or reading in dim lighting conditions. 
     Furthermore, it is important for intraocular lenses to have a consistent location along the axis of the eye to provide good uncorrected distance vision and to center in the middle of the vertical meridian of the eye. Without excellent uncorrected distance vision there is no point in implanting lenses designed to give seamless vision from far to near. 
     The original intraocular lens consisted of a single optic. These lenses frequently de-centered and dislocated and it was discovered that there was a need to center and fixate the lens optic in the vertical meridian of the eye. 
     Attachments to the optic that center and fixate the lens within the capsular bag are called haptics. Traditionally, haptics consist of multiple flexible loops of various designs, J loops, C loops, closed loops and flexible radial arms. Recently, traditional haptics have been replaced in some lens designs with oblong, flat flexible plates, called plate haptics. These plate haptics usually made from silicone, are solid, flat, flexible and between 3.0 and 6.0 mm in width, 0.20 to 0.75 mm thick, and may have tapered, rounded or parallel sides. Plate haptics often have flexible loops or fingers that help center and fixate the lens within the capsular bag. These flexible fingers extend beyond the distal or outer end of the plate haptics and slightly beyond the diameter of the capsular bag and are designed to flex centrally to center and fixate the lens and its optic within the capsular bag. 
     An intraocular lens (IOL) is a lens implanted into the eye, usually replacing a normal human lens that has been clouded over by a cataract, or can replace a normal human lens as a form of refractive surgery to change the eye&#39;s optical power. 
     An accommodating IOL (AIOL) permits refocusing of the eye by means of movement along the optical axis in response to the constriction or relaxation of ciliary muscles. Near vision results from a forward movement of the optic upon constriction of the ciliary muscle which increases the pressure in the posterior part of the eye with a simultaneous decrease in pressure in the anterior part of the eye. Distance vision results from the reverse pressure change that takes place upon relaxation of the ciliary muscle and the resultant backwards movement of the lens. The movement of the optic enables the patient implanted with the lens to automatically change their vision between far, intermediate and near. 
     AIOLs are known to consist of opposing haptics positioned on either side of a lens optic. Once a patient&#39;s cataract is removed, by e.g. phacoemulsification, the IOL is placed into the empty capsular bag. The haptics help to center the IOL and fixate it within the capsular bag by fibrosis. Such AIOLs are described in U.S. Pat. No. 5,674,282, U.S. Pat. No. 5,476,514, and U.S. Pat. No. 5,496,366, to Cumming, herein incorporated by reference in its entirety. 
     And although current AIOLs provide patients with significantly restored distance and intermediate vision, adequate near vision is commonly lacking—often requiring that patients use weak reading glasses to enhance near vision. Multi-focal and toric lens solutions suffer from the disadvantages identified above. 
     SUMMARY OF THE INVENTION 
     An accommodating intraocular lens according to an embodiment of the present invention is described that overcomes the deficiencies of present designs noted above. 
     The field of the invention is a single focus accommodating intraocular lens that provides seamless vision from distance to near automatically by relaxation and constriction of the ciliary muscle. 
     An accommodating intraocular lens is provided whose lens optic is coupled to at least one haptic and is biased with respect thereto. The accommodating intraocular lens may have an optic coupled to a plate haptic via a member that substantially promotes the optic&#39;s response to a vitreous pressure change. 
     Other features and advantages of the present invention will become apparent from the following more detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the presently described apparatus and method of its use. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Illustrated in the accompanying drawing(s) is at least one of the best mode embodiments of the present invention In such drawing(s): 
         FIG. 1  illustrates a side plan view of an AIOL as inserted into a human eye, according to at least one embodiment of the present invention; 
         FIGS. 2A and 2B  illustrate top plan views of various AIOLs according to at least one embodiment of the present invention; 
         FIGS. 3A and 3B  illustrate side plan views of AIOL vaulting according to at least one embodiment of the present invention; 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The above described drawing figures illustrate the described invention in at least one of its preferred, best mode embodiment, which is further defined in detail in the following description. Those having ordinary skill in the art may be able to make alterations and modifications to what is described herein without departing from its spirit and scope. Therefore, it should be understood that what is illustrated is set forth only for the purposes of example and should not be taken as a limitation on the scope of the present invention. 
     A preferred embodiment will now be described with reference to  FIG. 1 . 
     An accommodating intraocular lens (AIOL)  100  comprises: an optic  200  coupled to at least one haptic  300  such that the optic  200  is biased with respect to the haptic  300 . 
     The AIOL  100  is placed into the capsular bag of a patient&#39;s eye after cataract surgery via known techniques such as, for example, phacoemulsification. The lens is centered so that the optical axis of the lens coincides with that of the patient&#39;s eye. The haptics  300  contact the capsular bag and the natural fibrosis of the tissue secures the haptics  300 , and consequently the AIOL  100 , in place. 
     The optic  200  is preferably a single focus optic that gathers the incoming light and focuses it on the retina of the patient so as to effect vision. The optic  200  may be bioconvex, refractive, diffractive, plano-convex, Fresnell, spheric, aspheric, toric, or of any other type that is substantially single focus. In order to permit the optic  200  to be inserted into the eye through a small incision, the optic  200  is preferably made of a flexible optical material, such as, for example, silicone, acrylic, hydrogel, or other flexible optical material now known or hereafter developed. 
     As shown in  FIG. 1 , the optic  200  is coupled to at least one haptic  300  having distal  320  and proximal  340  ends. A flexion  342  biases the optic  200  with respect to the distal end  320  of the haptic  300 , and comprises the proximal end  340  set at a non-straight angle with respect to the distal end  320 . 
     In a preferred embodiment, the flexion  342  biases the optic  200  anteriorly with respect to the distal end  320  and sets a positive angle between the proximal  340  and distal  320  ends, as measured from the direction of the optic  200 . Thus, while the inserted AIOL  100  is in a neutral state (i.e. one with little to no vitreous pressure applied in either direction) the optic  200  is anteriorly biased—that is, the optic  200  is more anterior (or forward) than the proximal end  340  of the haptic  300 . 
     In an alternative embodiment, the flexion  342  biases the optic  200  posteriorly with respect to the distal end  320  and sets a negative angle between the proximal  340  and distal  320  ends, as measured from the direction of the optic  200 . Thus, while the inserted AIOL  100  is in a neutral state the optic  200  is posteriorly biased—that is, the optic  200  is more posterior (or rearward) than the proximal end  340  of the haptic  300 . 
     In some embodiments, the optic  200  may be coupled in series with opposing haptics  300  and may be anteriorly biased with respect to one while posteriorly biased to the other. However, whether wholly posterior, wholly anterior, or partially posterior and partially anterior, the bias operates to increase the range of accommodation that would otherwise be present, as discussed herein. For example, with an anterior bias the optic  200  requires less vitreous pressure and ciliary muscle contraction to move to the same forward position as without the bias. Thus, patients whose eyes are not able to exert the necessary pressure for optimal near vision with non-biased AIOLs can nonetheless exert the pressure required for optimal near vision with anteriorly biased AIOLs  100 . 
     Turning again to  FIG. 1 , the haptic  300  may be coupled to the optic via a connecting portion  360  made of the same flexible material of the optic  200 . The connecting portion  360  may comprise a hinge  362  that traverses the connecting portion  360  that operates to weaken the connecting portion  360  so that vitreous pressure and end-to-end compression of opposing haptics  300  can stretch the base of the hinge  362  like an elastic band to allow the optic  200  to move forward. This increases the range of focusing abilities—especially in the near range. Because the lens can move further forward, near focus is improved. The connecting potion  360  may also comprise one or more straps. The straps further assist in accommodation in that they decrease the resistance to the pressure that pushes the optic forward. Exemplary connecting portions are described in U.S. patent Ser. Nos. 13/017,189; 13/092,359; 13/111,599; and 13/155,327, incorporated herein by reference in their entireties. 
     In at least one embodiment, the connecting portion  360 , for example, the flexible extension of the optic  200  coupling the optic to the haptic  300 , may have a flexible hinge  362  extending transversely across either or both sides. 
     Turning now to  FIGS. 2A and 2B , the at least one haptic  300  is preferably a plate haptic comprising: a body  310 , having distal  320  and proximal  340  ends angularly set so as to form the substantially rigid flexion  342 . 
     The plate haptic  300  may comprise projections  384 , the haptic and projections operable to engage, fixate and center the haptic into the capsular bag. Since, on insertion into the eye, the AIOL is vaulted posteriorly, the plate haptic moves centrally and posteriorly in response to ciliary muscle contraction, as shown in  FIGS. 3A and 3B , such movement, combined with the change in vitreous pressure, causing the optic to vault anteriorly. The haptic body may be substantially flexible in the transverse direction and substantially rigid in the longitudinal direction so as to enable the AIOL  100  to be folded and inserted into the eye via a small incision. One of ordinary skill will appreciate that while substantial rigidity may promote vaulting; the degree of rigidity imposed is not intended to preclude an effective vault of the optic at the connecting portion  360 . It is preferable that the haptic body be constructed of the same or similar flexible material as the optic, including, but not limited to: silicone, hydrogel, acrylic, or similar material. Non-biased plate haptics having similar features are discussed in U.S. patent Ser. Nos. 13/017,189; 13/092,359; 13/111,599; and 13/155,327, incorporated herein by reference in their entireties. 
     Returning now to  FIGS. 2A and 2B , a frame  380  may be embedded within the haptic body so as to promote the longitudinal rigidity thereof. The frame  380  may be formed of polyimide, prolene, polymethylmethanylate (PMMA), titanium, or similar material. Such exemplary frames are discussed in U.S. patent Ser. Nos. 13/017,189; 13/092,359; 13/111,599; and 13/155,327, incorporated herein by reference in their entireties. As shown in  FIGS. 2A and 2B , the frame  380  may comprise an anchor  382  extending into the proximal end  340  of the haptic  300  and forming the flexion with the distal end  320  and associated rest of the frame  380 . The anchor  382  operates to set and maintain the angle of the flexion  342 . 
     As shown in  FIGS. 2A and 2B , the haptic  300  may comprise projections  384 , or fingers, extending from the distal end  320  to engage the capsular bag and secure and center the AIOL  100  thereto. The projections  384  may be homogeneous with the frame  380  and may be made of either polyimide, PMMA, acrylic or any other inert material. In some embodiments, the projections may be molded into the flexible plate haptic  300  as a T-shaped cross bar projection. Such exemplary projections are discussed in U.S. patent Ser. Nos. 13/017,189; 13/092,359; 13/111,599; and 13/155,327, incorporated herein by reference in their entireties. 
     As discussed herein, the haptic  300  may be coupled to the optic via connecting portion  360  that operates to permit contraction of the ciliary muscles to cause an end-to-end compression of opposing haptics with an increase in vitreous pressure, thus moving the optic substantially forward. 
     In at least one embodiment, the longitudinal length of the IOL (i.e. from distal end to distal end) may be between approximately 9.0-11.0 mm, with the diameter as measured from the tips of the lateral projections being between approximately 11.5-12.0 mm. The haptics  300  are preferably between 3.0-6.0 mm wide and 0.20-0.75 mm thick, while the optic may be approximately 5.0 mm. 
     In a preferred embodiment, the plate haptic  300  are designed to be flexible transversely, but rigid longitudinally. At the distal ends  320  of the plate haptics  300  are transverse flexible arms  384  designed to center and fixate the AIOL  100  within the capsular bag. The rigid polyimide frame  380  molded within the plate haptic may be flexed anteriorly at the proximal end and is designed to push the edge of the optic  200  forwards upon end-to-end compression of the AIOL  100  with contraction of the ciliary muscle. 
     In at least one embodiment, the rigid plate haptics  300  are flat, with the rigid flexion  382  in the longitudinal rigid frame  380  molded into the transversely flexible plate haptic  300 , the flexion  382  being located at the proximal end  320  of the haptic body  310  across the width of the rigid components  380  in the haptic body  310 , as seen, for example, in  FIG. 1 . 
     In at least one embodiment, the plate haptic  300  is curved, with a rigid curve in the longitudinal rigid frame  380  molded into the transversely flexible plate haptic  300 , as seen, for example in  FIGS. 3A and 3B . In at least one embodiment the longitudinally rigid plates  300  are bowed backwards when the AIOL  100  is placed into the eye. 
     In at least one embodiment, the optic  200  will move forward upon constriction of the circular ciliary muscle which increases vitreous pressure and with the reduction in its diameter applies end-to-end pressure on the haptics  300 . Relaxation of the ciliary muscle causes an increase in the diameter of the ciliary muscle and a reduction in vitreous cavity pressure with an increase in pressure in the anterior part of the eye such that the optic  200  moves posteriorly to the distant vision position. 
     Turning now to  FIG. 5 , the AIOL  100  is shown where the optic  200  is coupled in series to opposing plate haptics  300 —one rigid and one flexible, the rigid plate haptic being positioned at the 12 o&#39;clock position in the eye and the flexible plate haptic being positioned at the 6 o&#39;clock position in the eye. As discussed herein, the rigid plate haptic  300  preferably comprises a frame  380  that in turn preferably comprises the flexion  382  located at the proximal end  320  biasing the optic  200  such that the center of the optic  200  is anterior, or in front of the plate haptic  300  having such a flexion  382 . The proximal end  320  of the rigid plate haptic  300  may be molded into the connecting portion  360 —which may be a flexible extension of the optic  200 —during the manufacturing molding process. Further, as discussed herein, each plate haptic  300  may have one or more flexible projections or fingers  384  extending from the distal ends  320  thereof. Still further, as discussed herein, respective hinges  362  of the connecting portions  360  of both haptics  300  are preferably provided so as to permit improved response to vitreous pressure changes. As discussed herein, one or more straps may couple the plate haptic  300  to the optic  200 . The straps may comprise grooves or hinges that traverse the strap and promote accommodation. 
     The enablements described in detail above are considered novel over the prior art of record and are considered critical to the operation of at least one aspect of the invention and to the achievement of the above described objectives. The words used in this specification to describe the instant embodiments are to be understood not only in the sense of their commonly defined meanings, but to include by special definition in this specification: structure, material or acts beyond the scope of the commonly defined meanings. Thus if an element can be understood in the context of this specification as including more than one meaning, then its use must be understood as being generic to all possible meanings supported by the specification and by the word or words describing the element. 
     The definitions of the words or drawing elements described herein are meant to include not only the combination of elements which are literally set forth, but all equivalent structure, material or acts for performing substantially the same function in substantially the same way to obtain substantially the same result. In this sense it is therefore contemplated that an equivalent substitution of two or more elements may be made for any one of the elements described and its various embodiments or that a single element may be substituted for two or more elements in a claim. 
     Changes from the claimed subject matter as viewed by a person with ordinary skill in the art, now known or later devised, are expressly contemplated as being equivalents within the scope intended and its various embodiments. Therefore, obvious substitutions now or later known to one with ordinary skill in the art are defined to be within the scope of the defined elements. This disclosure is thus meant to be understood to include what is specifically illustrated and described above, what is conceptually equivalent, what can be obviously substituted, and also what incorporates the essential ideas. 
     The scope of this description is to be interpreted only in conjunction with the appended claims and it is made clear, here, that the named inventor believes that the claimed subject matter is what is intended to be patented.