Abstract:
An apparatus for controllably delivering an IOL into the eye of a patient is disclosed. The device is configured for convenient and reliable positioning of a plunger rod assembly at different stages of the IOL injection procedure, such that various aspects of the insertion procedure can be performed precisely and reliably by a user of the device. The present invention may include a latch pin and a latch finger configured for engagement with the latch pin to prevent proximal lateral movement of the plunger rod assembly so that the intra-ocular lens may be accurately positioned within the eye. The device assists the user during the procedure by accurately and consistently positioning the plunger rod assembly prior to ejection of the folded or rolled IOL from the insertion device.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    The present application claims priority to U.S. Provisional Patent Application No. 60/413,512, filed Sep. 25, 2002, entitled “SYSTEM FOR IOL INSERTION,” the contents of which are fully incorporated herein by reference. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    This invention pertains to eye surgery in which an artificial intra-ocular lens (IOL) is inserted through the cornea into a lens capsule.  
           [0003]    When a natural lens becomes occluded, it is conventional practice to remove the occluded lens, such as by phaco emulsification, and to replace the natural lens with an artificial intra-ocular lens (IOL). In order to decrease the size of the corneal incision required for insertion of the IOL, IOLs can be formed of resilient material that can be “folded” or rolled for insertion into the lens capsule. Various types of devices have been proposed for folding, holding, and injecting such IOLs. Examples are shown in U.S. Pat. No. 4,681,102 which has been cited in a large number of later issued patents including U.S. Pat. Nos. 6,334,862 and 6,398,788. Each of these patents shows a cartridge into which an IOL can be inserted, followed by folding or rolling of the IOL by manipulation of components of the cartridge. The cartridge is attached to or otherwise held in an insertion device or “shooter” which can include a plunger or push rod that is forced through the cartridge. Typically the cartridge includes a distal ejection tube which is inserted into a small corneal incision and through which the folded or rolled IOL is ejected by forcing the push rod through the cartridge.  
           [0004]    The present invention provides a system for convenient and reliable positioning of the rod at different stages of the IOL injection procedure, such that aspects can be performed precisely and reliably by a skilled technician rather than the surgeon. In addition, the present invention assists the surgeon during the procedure by accurately and consistently positioning the push rod, prior to ejection of the folded or rolled IOL from the insertion instrument. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]    Other features and advantages of the present invention will be seen as the following description of particular embodiments progresses in conjunction with the drawings, in which:  
         [0006]    [0006]FIG. 1 is perspective view of an embodiment of an insertion device in accordance with the present invention;  
         [0007]    [0007]FIG. 2 is an exploded view of an embodiment of an insertion device in accordance with the present invention;  
         [0008]    [0008]FIG. 3 is a perspective view of an embodiment of an intra-ocular lens holding cartridge in accordance with the present invention;  
         [0009]    [0009]FIG. 4 is a perspective view of an embodiment of a cylindrical barrel in accordance with the present invention;  
         [0010]    [0010]FIG. 5 is a top plan view of an embodiment of a cylindrical barrel in accordance with the present invention;  
         [0011]    [0011]FIG. 6 is side sectional view of an embodiment of a cylindrical barrel in accordance with the present invention;  
         [0012]    [0012]FIG. 7 is a front end elevation view of an embodiment of a cylindrical barrel in accordance with the present invention;  
         [0013]    [0013]FIG. 8 is a rear end elevation view of an embodiment of a cylindrical barrel in accordance with the present invention;  
         [0014]    [0014]FIG. 9 is a perspective view of an embodiment of a clip in accordance with the present invention;  
         [0015]    [0015]FIG. 10 is a top sectional view of an embodiment of a clip in accordance with the present invention;  
         [0016]    [0016]FIG. 11 is a side sectional view of an embodiment of a clip in accordance with the present invention;  
         [0017]    [0017]FIG. 12 is an end view of an embodiment of a clip in accordance with the present invention;  
         [0018]    [0018]FIG. 13 is a sectional view of a distal end of an embodiment of a clip in accordance with the present invention;  
         [0019]    [0019]FIG. 14 is a perspective view of an embodiment of a pushing member in accordance with the present invention;  
         [0020]    [0020]FIG. 15 is a side perspective view of an embodiment of a pushing member in accordance with the present invention;  
         [0021]    [0021]FIG. 16 is an end view of an embodiment of a pushing member in accordance with the present invention;  
         [0022]    [0022]FIG. 17 is a perspective view of an embodiment of an elongate body in accordance with the present invention;  
         [0023]    [0023]FIG. 18 is a side perspective view of an embodiment of an elongate body in accordance with the present invention;  
         [0024]    [0024]FIG. 19 is a sectional view of an embodiment of an elongate body in accordance with the present invention;  
         [0025]    [0025]FIG. 20 is an end view of an embodiment of an elongate body in accordance with the present invention;  
         [0026]    [0026]FIG. 21 is a sectional view of a distal end of an embodiment of an elongate body in accordance with the present invention;  
         [0027]    [0027]FIG. 22 is a perspective view of an embodiment of a latch pin in accordance with the present invention;  
         [0028]    [0028]FIG. 23 is an end view of an embodiment of a latch pin in accordance with the present invention;  
         [0029]    [0029]FIG. 24 is a side view of an embodiment of a latch pin in accordance with the present invention;  
         [0030]    [0030]FIG. 25 is a perspective view of an embodiment of a control knob assembly in accordance with the present invention;  
         [0031]    [0031]FIG. 26 is an end view of an embodiment of a control knob assembly in accordance with the present invention;  
         [0032]    [0032]FIG. 27 is a sectional view of an embodiment of a control knob assembly in accordance with the present invention; and  
         [0033]    FIGS.  28 - 32  illustrate various stages of a method of operating an embodiment of an insertion device in accordance with the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0034]    An embodiment of the instrument  10  of the present invention is shown in FIGS.  1 - 2 , FIG. 1 illustrating the parts in assembled relationship, and FIG. 2 showing most parts in exploded relationship. FIG. 3 shows a conventional lens-holding cartridge  12  apart from the remainder of the instrument.  
         [0035]    With reference primarily to FIG. 2, as described in more detail below, the lens holding cartridge  12  can be fitted in a distal portion  14  of an elongated, generally cylindrical barrel. The barrel has a proximate portion  16  secured to the distal portion  14 . A push rod  18  is slideable fore and aft (distally and proximally) in the bore of the barrel. Push rod  18  has a distal part  20  aligned with and secured to a proximate part  22 . A transversely projecting latch pin  24  is carried by the proximate part  22 . The latch pin cooperates with a latch finger  26  carried on the barrel proximate part  14 .  
         [0036]    A helical compression spring  28  is slideable along the rod proximate part  22  and acts between the proximate end  30  of the barrel part  14  and a slide disc  32  carried on the rod proximate part  22 . Rearward travel of the slide is limited by engagement against an inturned lip of the barrel distal part  16  and/or one or more transverse pins  38  at the proximate end portion. An operating handle or knob  34  is rotatably secured to the proximate end portion of the push rod part  22 . In addition, the operating knob has coarse external threads  36  at its distal end portion which cooperate with pins  38  that project inward from the proximate end portion of the barrel part  16 .  
         [0037]    Preferably the instrument also includes a transversely projecting finger support  40  secured to the barrel part  16  at a convenient distance from its proximate end, and a protective sheath  42  spaced outward from and extending over a substantial segment of the barrel, including the portion having the latch finger  26 .  
         [0038]    As described in more detail below, the knob  34  is manipulated to control the position of the push rod  18  which extends into the lens-holding capsule  12 , and in a controlled fashion, first positions the folded or rolled IOL for projection from the cartridge, then can be used to force the IOL farther through the cartridge and hold it in a partially projected position before final injection of the IOL into the lens capsule.  
         [0039]    Lens Holding Cartridge  
         [0040]    With reference to FIG. 3, cartridge  12  is of the same general design as the cartridge shown in U.S. Pat. No. 6,398,788 and U.S. Pat. No. 6,334,862. The distal end portion of the cartridge is a hollow ejection tube  44 , leading to a larger diameter holding chamber  46 . Lens-folding wings or tabs  48  can be formed integrally with tube  44  and chamber  46  and are movable relative to each other by means of an integral hinge joint. With the tabs  48  folded “open” as shown in FIG. 3, an IOL  50  can be manually positioned centrally between the tabs as is conventional, followed by swinging the tabs together to fold or roll the lens. In the “closed” position (FIGS. 1 and 2) the tabs  48  project radially beyond the loading chamber  46  of the cartridge, and the folded or rolled IOL is aligned with the larger bore of the chamber  46 . A tapered connecting portion  51  leads from the chamber  46  to the ejection tube  44 .  
         [0041]    Barrel  
         [0042]    The distal portion  14  of the barrel has a long slot  52  extending in an axial direction. This slot communicates between the interior bore and the exterior of the barrel. A wider portion  54  of the slot allows the loaded cartridge  12  to be inserted downward into the barrel bore and slid forward (distally) to the position shown in the FIG. 1 in which the tabs  48  are held closed by engagement in the narrower distal portion of the slot  52 . Forward movement of the cartridge is limited by the continuous distal ring  56  of the barrel. The latch finger  26  is centered over the slot  52 , generally centrally of the barrel portion  14 . Finger  26  is cantilevered from a mounting ring  57  secured on barrel part  14 .  
         [0043]    The distal portion  14  of the barrel is shown in greater detail in FIG. 4 (top perspective), FIG. 5 (top plan), FIG. 6 (side elevation), FIG. 7 (front end elevation), and FIG. 8 (rear end elevation). The latch finger  26  and its mounting ring  57  are shown in more detail in FIG. 9 (top perspective), FIG. 10 (top plan), FIG. 11 (side elevation), FIG. 12 (front end elevation), and FIG. 13 (fragmentary bottom plan).  
         [0044]    Returning to FIG. 2, the proximate barrel portion  16  carries the finger support  40 . For example, the finger support can have a central aperture  58  sized for fitting over the distal end portion of barrel part  16 , such as against an annular rib or shoulder  60 . The finger support can be press-fitted on the barrel portion  16  or secured in any other convenient manner. Similarly, the protective sheath  42  is mounted to the finger support  40  or part  16  and projects distally therefrom. Barrel parts  14  and  16  are secured together end to end. In the illustrated embodiment, the distal end  30  of part  14  is formed with an externally threaded stem. The hollow interior of the proximate barrel part  16  is aligned axially with the bore of the distal barrel part  14  and has internal threads to mate with the threads of the stem  30 . The manner of connection of the two ( 14 ,  16 ) is not important. For example, either part can be partially telescoped within the other and secured by pins, press fit, or any other effective and convenient manner. The sheath  42  extends from the proximate barrel part  16  over the distal barrel part  14  so as to cover the latch finger  26 .  
         [0045]    Push Rod Assembly  
         [0046]    In general, the push rod  18  slides fore and aft in the barrel by manipulation of the operating handle or knob  34 . The distal rod part  20  (see also FIGS.  14 - 16 ) has a distal end  62  positioned to slide into the bore of the lens holding cartridge  12 . This part is secured to the proximate part  22  (see also FIGS.  16 - 21  and note that different parts are drawn to different scales; for example, the proximate end portion of part  20  shown in FIGS.  14 - 16  fits tightly in a blind socket in the distal end of part  22  of FIGS.  17 - 21 ). The proximate part  22  and corresponding sections of the barrel are configured to allow the fore and aft sliding without appreciable relative rotation. This is to reliably maintain the latch finger  24  (shown greatly enlarged in FIGS.  22 - 24 ) aligned with the barrel slot  52  and the latch finger  26 . The stem of the latch finger can be press fitted in a transversely extending bore of the distal push rod part  22 . The helical compression spring  28  fits over the proximate portion of push rod part  22 . Similarly, slide  32  is moveable along the proximate end portion of part  22 . The slide has an annular rim or shoulder against which the proximate end of the spring  28  acts. The other, distal end of the spring acts against the proximate end of the treaded stem  30 . The effect is to force the slide rearward (proximally) along the push rod, but the travel of the slide is limited by engagement against the pins  38  that project inward from the proximate end of the barrel portion  16 .  
         [0047]    The operating knob  34  (FIGS.  25 - 27 ) is rotatably connected to the proximate end portion of push rod part  22 . More specifically, the operating knob has a distally extending hub  63  with an axial bore fitted over the proximate end portion of push rod part  22 . Part  22  has an annular groove  64  aligned with a pin  65  extending inward into the bore of the hub  63 . Fore and aft movement of the operating knob, achieved conveniently by use of the larger diameter knurled end disc  66 , results in equivalent fore and aft sliding movement of the push rod  18 . However the operating knob is free to rotate relative to the push rod without corresponding rotation of the rod.  
         [0048]    The distal end portion of the operating handle hub has the external threads  36  which cooperate with the inward projecting pins  38  of barrel part  16  for a threaded fit of the operating knob with the barrel part  16  over a limited distance.  
         [0049]    Operation  
         [0050]    With reference to FIGS.  28 - 32 , and starting with FIG. 28, the instrument in accordance with the present invention is prepared for use by first fitting an IOL in the lens-holding cartridge  12 , folding or rolling the IOL by manipulation of the cartridge tabs  48 , insertion of the cartridge downward through the wider barrel slot portion  54 , and forward (distal) shifting of the cartridge such that the tabs  48  fit in the narrower distal part  52  of the barrel slot. During this procedure, the push rod  18  is retracted rearward from the wider slot portion  54 . Note that the latch pin  24  is positioned far to the rear (proximally) of the latch finger  26 ; the external threads  36  of the operating knob  34  are disengaged from the pins  28 ; and the compression spring  28  forces the slide  32  rearward (proximally) adjacent to the proximate end of the barrel part  16 .  
         [0051]    With reference to FIG. 29, the operating knob  34  then is slid forward (distally) to move the push rod  18  distally relative to the composite barrel  14 ,  16 . Threads  36  butt against pins  38  at a position in which the distal end  62  of the push rod is approximately aligned with the distal end of the lens-folding tabs, i.e., the lens is forced from between the tabs into the holding chamber  46 . Pins  38  block additional linear sliding movement of the push rod in the barrel.  
         [0052]    In order to advance the push rod farther, it is necessary to rotate the operating knob  34 . The external threads  36  cooperate with the pins  38  such that the knob may be turned in a direction to gradually advance the push rod from the position of FIG. 29 to the position of FIG. 30. At the same time, the distal end of the operating knob is engaged against the slide  32 , and the slide  32  moves distally against the force of the compression spring  28 . The axial extent of the threads  36  is limited. After a relatively short travel, sufficient to move the distal end of the push rod approximately half way into the holding chamber  46 , the proximate end of the externally threaded portion  36  clears the pins  38  and no additional advancement of the push rod occurs by continuing to rotate the operating knob  34 . Rather, the user, typically a technician, will know that this position (FIG. 30) has been reached because the end thread will “click” over the pins  38  as the slide and operating knob are biased rearward (proximally) by the compression spring  28 .  
         [0053]    In the position of FIG. 30, the latch pin  24  is positioned generally alongside the center portion of the latch finger  26 . Further advancement of the push rod and latch pin are achieved by pressing the operating knob  34  inward relative to the barrel of the instrument, such as by engagement of the knob with the thumb or palm while the fingers hook against the finger support  40 . The distal end of the push rod forces the IOL from the holding chamber  46  and farther into the ejection tube  44 , as seen in FIG. 31. As this occurs, the leading end of the latch pins engages an angled segment or ramp  64  of the pin, wedging the pin sideways, upward in the orientation of FIG. 31. The upward movement of the latch finger is contrary to its natural, centering resiliency. Once the latch pin has cleared a notched segment  66  at the distal end of the latch finger, the latch finger snaps back toward the central, relaxed position. The inward directed force on the operating knob applied by the user&#39;s hand is relieved, and the proximate end of the latch pin  24  will engage in the notch, preventing retraction of the push rod  18 . The position is shown in FIG. 32. The distal end of the push rod is maintained in a position in which the IOL is largely projecting from the end of the ejection tube  44 , but has not yet been fully pushed out of it. This allows the surgeon to place the IOL precisely without having to maintain pressure on the operating knob  34 . When the desired position has been reached, the knob can be depressed farther to eject the IOL. At the same time, the latch pin moves distally beyond the end of the latch finger, and the latch finger swings to its relaxed condition, down from the position of FIG. 32, such that the latch pin  24  will slide rearward along and past the latch finger as the force on the operating knob is relieved, and the parts return to the position of FIG. 30. The ejection tube is removed from the corneal incision, and the parts can be returned to the position of FIG. 28, for removal of the empty cartridge  12 . The instrument is ready for insertion of a new loaded cartridge.  
         [0054]    While the preferred embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.