Abstract:
An instrument for the insertion of an intraocular lens into an eye comprises a body portion, e.g. a barrel, a nose portion having a lumen through which the lens passes, and a push rod connected to a plunger. Within the nose portion is an insert ( 30 ) which defines a passageway ( 40 ) therethrough. The passageway has a configuration which includes a smoothly continuous undulating surface ( 42, 44 ) upon which a lens rests. A cutout ( 52 ) accommodates the trailing haptic. For acrylic lenses, the undulating surface is preferably provided by a recess in the bottom of the passageway, the recess reducing in width and depth to define an upwardly sloping surface on which the lens is deposited.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates to improvements in ophthalmic lens injectors, and is particularly concerned with lens injectors of the type described in our application WO99/33411.  
           [0002]    The lens injectors described in WO99/33411 comprise a body portion, a nose portion through which runs a passage or lumen for the lens to pass to a dispensing tip, and a plunger. The nose portion is pivotally connected to the body portion so that the barrel can be broken open for the placement of the lens into the nose portion. In the aforesaid publication the lens is preferably placed on two spaced parallel nose pins to facilitate its folding. In some of the described embodiments in the aforesaid publication there is provided also a cross pin which straddles the nose pins and under which the intraocular lens is arranged to pass. The purpose of this cross pin is to prevent lifting and tilting of the lens, so that when the plunger pushes it forwards it travels smoothly forwards and is folded properly.  
         SUMMARY OF THE INVENTION  
         [0003]    It is an object of the present invention to provide improved designs of nose assembly for ophthalmic injectors for injecting intraocular lenses. In the present invention the pins described above are replaced by a specially shaped member within the nose assembly. This member is specially shaped so that it provides an internal surface configuration to assist in guiding the lens into the lumen through which the lens has to pass.  
           [0004]    Intraocular lenses may be of silicone or acrylic material. The nose member of the present invention is appropriate for use with both types of lens, although the internal surface configuration may differ, depending on the characteristics of the lens to be inserted. Silicone lenses have haptics which are relatively thin and which are fixed to the lens body. Acrylic lenses have the lens body and haptics made in one piece, with thicker haptics. Also, acrylic material marks more easily than silicone.  
           [0005]    In accordance with the present invention there is provided an instrument for the insertion of an intraocular lens into an eye, which comprises a body portion, a nose portion forwardly of the body portion and having a lumen through which the lens is arranged to pass, and push rod means moveable through the body portion and the nose portion to push an inserted lens forwards, wherein there is provided in the nose portion means defining a passageway therethrough, the passageway having a configuration which includes a smoothly continuous undulating surface upon which a lens to be inserted is arranged to rest.  
           [0006]    Preferably, the means defining the passageway is an insert having an external configuration which makes it non-rotatable within the nose assembly. In a preferred embodiment the insert has a forwardly projecting portion shaped to match the internal configuration of the lumen through the nose assembly and providing guide means for the forward guidance of the lens.  
           [0007]    In one embodiment, particularly suitable for silicone lenses, the undulating surface comprises two upstanding arcuate ribs at the bottom of the passageway. Preferably, in order to ensure that the trailing haptic remains free, there is provided a cutout to accommodate the trailing haptic at one side of the bottom of the passageway.  
           [0008]    In another embodiment, particularly suitable for acrylic lenses, the undulating surface is provided by a recess in the bottom of the passageway. This enables a lower entry of the lens into the chamber defined by the passageway and keeps the lens away from the upper surface of the passageway. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    In order that the invention may be more fully understood, a number of presently preferred embodiments of lens injector in accordance with the invention will now be described in more detail by way of example and with reference to the accompanying drawings, in which:  
         [0010]    [0010]FIG. 1 is a side view of a lens injector in accordance with the invention incorporating a nose assembly of the present invention;  
         [0011]    [0011]FIG. 2 is a top plan view of the lens injector of FIG. 1, with the plunger retracted;  
         [0012]    [0012]FIG. 3 is a view from the other side of the lens injector of FIG. 1, with the plunger retracted;  
         [0013]    [0013]FIG. 4 is a side view of the nose of the lens injector;  
         [0014]    [0014]FIG. 5 is an end view of the nose of FIG. 4, viewed from the right-hand end of FIG. 4;  
         [0015]    [0015]FIG. 6 is a view from the other side of the nose of FIG. 4;  
         [0016]    [0016]FIG. 7 is a top plan view of the nose of FIG. 4;  
         [0017]    [0017]FIG. 8 is an end view of the nose as shown in FIG. 7, viewed from the right-hand end of FIG. 7;  
         [0018]    [0018]FIG. 9 is a side view of a first embodiment of nose insert for insertion into the nose of FIGS.  4  to  8 ;  
         [0019]    [0019]FIG. 10 is an end view of the nose insert of FIG. 9, viewed from the right-hand end of FIG. 9;  
         [0020]    [0020]FIG. 11 is a side view of a second embodiment of nose insert;  
         [0021]    [0021]FIG. 12 is an end view of the nose insert of FIG. 11, viewed from the right-hand end of FIG. 11;  
         [0022]    [0022]FIG. 13 is a side view of a third embodiment of nose insert;  
         [0023]    [0023]FIG. 14 is an end view of the nose insert of FIG. 13, viewed from the right-hand end of FIG. 13;  
         [0024]    [0024]FIG. 15 is a plan view of the nose insert of FIGS. 13 and 14;  
         [0025]    [0025]FIG. 16 is the side view of FIG. 13, showing the loading forceps in position;  
         [0026]    [0026]FIG. 17 is a side view of the centre rod used with the nose insert of FIGS. 9 and 10;  
         [0027]    [0027]FIG. 18 is a side view of the centre rod used with the nose insert of FIGS. 11 and 12; and,  
         [0028]    [0028]FIG. 19 is a side view of the centre rod used with the nose insert of FIGS.  13  to  15 . 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0029]    Referring first to FIGS.  1  to  3 , the intraocular lens injector shown there is of the general type described and shown in our patent application PCT/GB98/03917 (WO99/33411) which has a nose portion which can be “broken open” in like manner to a shotgun barrel. However, it is to be understood that the present invention is applicable to other types of intraocular lens injectors, and that the embodiments of nose assembly are described in relation to this particular type of lens injector by way of example only.  
         [0030]    The lens injector as shown in the drawings essentially comprises a body portion  10 , a plunger  12  and a nose indicated generally at  14 . The nose  14  can be “broken open” in like manner to a shotgun barrel. In the closed position as shown in the drawings the nose  14  is coaxial with the main body  10  and the plunger  12 . The body portion  10  has a finger  16  projecting from the front end of the body at the bottom of the body, and a pivot pin  18  extends through the nose and the finger to provide the pivotal mounting. The nose is pivotable through 90° from the open position to the closed position and vice versa.  
         [0031]    The nose  14  will be described in more detail hereinafter. Suffice it to say here that there is a passage completely through the nose which changes in cross-section and configuration from one end of the nose to the other. At the distal end the nose has a tip  20  through which the lens is ejected. As shown in FIG. 1, when the plunger  12  is fully depressed, a centre rod  22 , which is secured to the plunger, passes out through the tip of the nose. The plunger  12  is slidable within the body portion  10  which is in the form of a cylindrical barrel having a bore therethrough. A spring  24  provides a force against which the plunger is depressed and which urges the plunger into its retracted position as shown in FIGS. 2 and 3. For further details of the structure of the lens injector, reference should be made to the aforesaid application WO99/33411.  
         [0032]    The nose assembly  14  includes, as stated, a tip portion  20  which is shaped at its outer end to form a dispensing aperture of appropriate shape and orientation. Through the nose  14  there extends an internal passageway  26  along which the lens passes under the action of the centre rod or push rod  22 , embodiments of which are shown most clearly in FIGS.  17  to  19 .  
         [0033]    The internal shape and configuration of the nose  14  can be seen from FIGS.  4  to  8 . The rearward end of the nose  14  is recessed, as indicated at  28 , to receive a nose insert  30  which is shown most clearly in FIGS. 9 and 10, but which can also be seen, in position, in FIGS. 1 and 2. The cross-sectional configuration of the recess  28  in the nose  14  matches the external configuration of the insert  30  shown in FIGS. 9 and 10. Thus, the insert  30  as shown in FIG. 10 will fit directly into the recess  28  as presented in FIG. 8. The inside surface of the taper and of the ongoing bore of the passageway  26  through the nose  14  must have a good machined finish with a smooth transition between the taper and the subsequent bore.  
         [0034]    The insert  30  is shown most clearly in FIGS. 9 and 10. It is shaped and configured to permit the dispensing of the lens reliably and effectively through the nose without the use of pins to support and guide the lens. The nose insert shown in FIGS. 9 and 10 is particularly suited for the insertion of silicone lenses. The insert  30  is a one-piece element, for example of titanium, shaped to fit within the nose  14 . It comprises a shoulder portion  32  and a forwardly projecting arm  34 . The shoulder portion  32  has one face  36  which is flat and its otherwise circular periphery is indented at  38  for engagement by a pin to prevent rotation of the insert  30  within the nose  14 . The shoulder  32  has a bore  40  therethrough. This is generally rectangular in cross-section as shown most clearly in FIG. 10, but with the bottom surface  42  having a smoothly continuous undulating shape defining two upstanding arcuate ribs  44 . The lens to be inserted is placed in this bore  40  on the ribs  44  using forceps. The forwardly projecting arm  34  of the insert  30  is provided with a guide channel  46  which forms a continuation of the guide surface  42 , for the onward passage of the lens through the nose and into the tip. The underside  48  of the arm  34  as shown in FIG. 9 is concavely curved to match the configuration of the tapered passageway  26  within the nose  14 .  
         [0035]    Shaping the nose insert recess  40  in this way, and extending this into a tapered bore  26  through the nose, causes the lens which is inserted to be folded as it is pushed forward by the push rod  22  into the passage through the tip. The folding of the lens is effected by the shape of the encircling passageway, namely by the undulations  44  and the taper of the passageway.  
         [0036]    A second embodiment of nose insert is shown in FIGS. 11 and 12. The same or corresponding features shown in FIGS. 9 and 10 are indicated by the respective same reference numerals. In this embodiment, the internal shape of the passageway  40  is generally the same as in FIGS. 9 and 10, although the upper surface of the passageway is here slightly convex downwards. Also, the opening to the passageway  40  is here shown as chamfered at  50 . The main difference in the embodiment shown in FIGS. 11 and 12 is that a cutout  52  is provided in the input end face of the insert, from the exterior of the insert to one bottom corner of the passageway  40 , adjacent to one of the arcuate ribs  44 . This cutout  52  is to accommodate the trailing haptic, so that there is a reduced danger of this becoming trapped or otherwise being caught up upon the insertion of the lens with the forceps.  
         [0037]    The nose insert  30  of FIGS. 11 and 12 is particularly suited for use with silicone lenses. In order to enable the nose insert of FIGS. 11 and 12 to accept a 6 mm silicone lens, two small recesses  54  are provided in the passageway  40 , one on each lateral side of the passageway. These provide extra width for the 6 mm lens to be deposited in the nose insert.  
         [0038]    FIGS.  13  to  15  show a third embodiment of nose insert, here indicated generally at  60 . If one is dealing with acrylic lenses, where the lens body is integral with the haptics, the haptics are thicker than in the case of a silicone lens. Also the acrylic material marks more easily than silicone. It is therefore desirable to be able to keep the lens low on insertion into the passageway of the nose insert and in particular to keep the lens away from the upper surface of the passageway. A nose insert which enables this to be achieved is shown in FIGS.  13  to  15 . Here the passageway through the shoulder  32  of the nose insert is indicated at  62  and again has a chamfered surround  50 . However, as compared with the second embodiment, the configuration of the bottom surface of the passageway  62  is different. It is here recessed as indicated at  64 . As shown most clearly in FIGS. 13 and 15, the recess  64  extends through the shoulder portion  32  and into the projecting arm  34  of the insert, becoming shallower and tapering in width. The undulating smoothly continuous bottom surface of the passageway  62  is therefore here formed by lateral shoulders  66  and the intermediate recess  64 . This configuration enables the lens to be placed with the forceps low in the chamber and in a way which causes it to be folded as it is pushed forward. In this embodiment, only the forward end of the arm  34  is provided with a guide channel  68 . Below the recess  64 , there is provided a notch  70  in the face of the insert. This notch  70  is arranged to receive a pin  72  which projects from the underside of the forceps used to insert the lens. FIG. 16 shows the insert  60  with a pair of forceps  74  in position within the insert, positioned to deposit the lens within the chamber. Using the forceps  74  in this way, the lens is deposited on an “up” slope, namely the bottom of the recess  64  which slopes upwards from the front face of the nose insert towards the nose tip. This gives a more reliable and effective deposition of the lens, particularly with an acrylic lens.  
         [0039]    FIGS.  17  to  19  show three embodiments of centre rod  22  which are used respectively for the pushing of the lens forwards and out of the nose insert as shown in each of the three embodiments described above. In each case the centre rod is indicated at  22 . The rear end of each centre rod is connected to the plunger  12 . The shape and configuration of the front end of the push rod  22  is in each case designed to enable it to engage and hold the lens in its forward movement through the lumen. As shown, the front end is shaped to define an engaging recess  76  which “picks up” the lens when placed within the chamber in the insert. The recess  76  is preferably trapezoidal in shape in the side view as shown. As shown in FIG. 1, when the plunger is fully depressed, the push rod  22  extends fully out through the tip  20  to enable the lens to be inserted into an incision in the eye.