Abstract:
A lens delivery system having a cartridge and a handpiece with a lockout feature. The lockout feature helps to ensure that the appropriate combination of cartridge and handpiece is used.

Description:
[0001]     This invention relates to intraocular lenses (IOLs) and more particularly to devices use to inject IOLs into an eye.  
       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 the 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.  
         [0003]     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.  
         [0004]     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. Several methods of rolling or folding the lenses are used. One popular method is an injector cartridge that folds the lenses and provides a relatively small diameter lumen through which the lens may be pushed into the eye, usually by a soft tip plunger. The most commonly used injector cartridge design is illustrated in U.S. Pat. No. 4,681,102 (Bartell), and includes a split, longitudinally hinged cartridge. Similar designs are illustrated in U.S. Pat. Nos. 5,494,484 and 5,499,987 (Feingold) and 5,616,148 and 5,620,450 (Eagles, et al.). In an attempt to avoid the claims of U.S. Pat. No. 4,681,102, several solid cartridges have been investigated, see for example U.S. Pat. No. 5,275,604 (Rheinish, et al.) and U.S. Pat. No. 5,653,715 (Reich, et al.).  
         [0005]     These devices all anticipate a lens of relatively uniform size. As a result, the bore through the cartridge and the plunger used to express the lens out of the cartridge all have specific dimensions, allowing any cartridges and handpieces from the same manufacturer to be used interchangeably. Cartridges and handpieces from the same manufacturer, but of different sizes, may not be interchangeable. For example, a handpiece having a relatively large plunger tip may not be suitable for use with a cartridge having a relatively small bore.  
         [0006]     Accordingly, a need continues to exist for a means to assure that non-interchangeable cartridges and handpieces are not used inadvertently.  
       BRIEF SUMMARY OF THE INVENTION  
       [0007]     The present invention improves upon prior art by providing a lens delivery system having a cartridge and a handpiece with a lockout feature. The lockout feature helps to ensure that the appropriate combination of cartridge and handpiece is used.  
         [0008]     It is accordingly an objective of the present invention to provide a lens delivery system that is suitable for folding lenses made from a soft acrylic material.  
         [0009]     It is a further objective of the present invention to provide a lens delivery system having a lockout feature.  
         [0010]     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  
       [0011]      FIG. 1  is an enlarged side elevational view of a cartridge that may be used with the lens delivery system of the present invention.  
         [0012]      FIG. 2  is an enlarged partial side elevational view of a handpiece that may be used with the lens delivery system of the present invention.  
         [0013]      FIG. 3  is an enlarged side elevational view of the cartridge illustrated in  FIG. 1  installed in the handpiece illustrated in  FIG. 2 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0014]     As best seen in  FIG. 1 , lens delivery system  10  of the present invention generally includes cartridge  12  and handpiece  14 . As best seen in  FIG. 1  cartridge  12  generally has tubular body  16  and injection nozzle  18 . Cartridge  12  is molded as a single piece from any suitable thermoplastic, such as polypropylene, and the thermoplastic may contain a lubricity enhancing agent such as those disclosed in U.S. Pat. No. 5,716,364, the entire contents of which are incorporated herein by reference. Alternatively, cartridge  12  may be made from stainless steel or titanium. Nozzle  18  preferably is round, oval or elliptical in cross-section and has a cross-sectional area of between around 2.2 mm 2  to around 2.6 mm 2 . Body  16  preferably contains grips  13  that allow easier manipulation of cartridge  12  and provide a mechanism to lock cartridge  12  within notches  15  in handpiece  14 . Body  16  also contains lockout tabs  20  that interact with lockout slots  22  in handpiece  14  in the manner described below.  
         [0015]     Handpiece  14  may be of any suitable construction, such as molded thermoplastic or machined aluminum, stainless steel or titanium. Handpiece  14  is generally tubular and contains recess  24  near distal end  26  sized and shaped to receive cartridge  12 , as shown in  FIG. 3 . Recess  24  has generally flat sides  28  to align the longitudinal access of cartridge  12  with the longitudinal axis of handpiece  14  in a generally coaxial fashion, however; lockout tabs  22  prevent cartridge  12  from fitting within recess  24  in the absence of lockout slots  22 . Lockout slots  22  are slightly longer than lockout tabs  20  to allow grips  13  on cartridge  12  to be slid within notches  15  on handpiece  14 . One skilled in the art will recognize that lockout tabs  20  and lockout slots  22  can vary in shape and size so as to allow or prevent any cartridge  12 /handpiece  14  combination.  
         [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.