Abstract:
An intraocular lens (IOL) insertion system for implanting IOLs into the eye. The insertion system includes an insertion cartridge that receives the IOL and cooperates with a handpiece. The cartridge includes a longitudinal lumen from a loading chamber to an open distal mouth that gradually narrows in dimension so as to fold the IOL into a tube for insertion through an incision in the eye. A distal tip member of a plunger rod in the handpiece enters the loading chamber of the cartridge and urges the IOL therethrough. The distal tip member has a portion that enters the folded IOL and is trapped therein for maximum control of IOL advancement. A soft tip, such as silicone, may cover a longitudinally extending portion of the distal tip to effect the IOL trapping. The distal tip member further has a portion that engages and pushes the IOL optic. The pusher portion not only ensures positive advancement of the IOL, but also limits the extent to which the distal tip member becomes trapped inside the folded IOL, thus preventing potential damage thereto.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to apparatus for inserting an intraocular lens (IOL) into an eye. More particularly, the present invention relates to an insertion apparatus having a hollow tube through which an IOL is pushed with a push rod into an eye in a highly controllable manner.  
           [0002]    The human eye is susceptible to numerous disorders and diseases, a number of which attack the crystalline lens. For example, cataracts mar vision through cloudy or opaque discoloration of the lens of the eye. Cataracts often result in partial or complete blindness. If this is the case, the crystalline lens can be removed and replaced with an intraocular lens, or IOL. An IOL may also implanted in the eye to alter the optical properties of (provide vision correction to) an eye in which the natural lens remains.  
           [0003]    IOLs often include a disk-like optic, and preferably at least one flexible fixation member or haptic which extends radially outward from the optic and becomes affixed in the eye to secure the lens in position. The optic normally includes an optically clear lens. Implantation of such IOLs into the eye involves making an incision in the eye. It is advantageous, to reduce trauma and speed healing, to have an incision size as small as possible.  
           [0004]    The optics may be constructed of deformable biocompatible materials such as silicone polymeric materials, acrylic polymeric materials, hydrogel polymeric materials, and the like. The deformable materials allow the IOL to be rolled or folded for insertion through a small incision into the eye. A substantial number of instruments have been proposed to aid in inserting such a foldable lens in the eye. In a popular apparatus, the optic begins in the shape of a taco and is pushed through a gradually narrowing lumen of an insertion cartridge, progressively rolling into a tubular shape to fit through the incision. Such an exemplary insertion system is disclosed in Makker et al., U.S. Pat. No. 5,942,277, the contents of which are expressly incorporated by reference herein.  
           [0005]    In the folding IOL insertion devices such as disclosed by Makker, et al., the cartridge is a disposable polymeric item that is held within a bore of a larger handpiece. A plunger rod associated with and arranged to travel through the handpiece bore has a distal end that lines up with a proximal end of the cartridge lumen and thus can be advanced therethrough. The distal tip contacts and urges the IOL through the cartridge lumen. Various plunger rod tips are known, some pushing on the proximal edge of the IOL optic and some lodging within the taco fold of the optic and “carrying” by outward compression the IOL through the cartridge. In the latter type, such as disclosed in Vidal et al., U.S. Pat. No. 5,776,138, issued Jul. 7, 1998, a soft cover or tip is provided on the plunger rod distal tip to avoid excessive damage of the deformable optic. The soft tip extends a small distance into the optic fold and at a certain linear travel becomes “trapped” therein by compression. This “trapping” of the soft tip within the optic helps control the rate of IOL insertion, and permits rotation of the IOL by the surgeon just as the IOL is released from the cartridge into the eye. The extent of trapping is related to the force required to push the IOL through the tube and the diopter power of the IOL, which alters the thickness of the optic. Therefore, the extent of trapping varies. Unfortunately, excessive trapping can tear the optic and even crack the cartridge tube.  
           [0006]    In view of the foregoing, it would be beneficial in the art to provide an IOL insertion apparatus having a soft tip for controlling the IOL insertion rate and permitting IOL rotation which also prevents problems associated with excess trapping of the soft tip in the IOL.  
         SUMMARY OF THE INVENTION  
         [0007]    New, and preferably enhanced, systems for inserting IOLs into eyes have been discovered. The present systems are straightforward and relatively easy to manufacture and use. In addition, such systems advantageously are effective in controlling IOL insertion rate and providing for IOL rotation to reduce, or even substantially eliminate, the risks of one or more problems of the prior art systems, as noted above.  
           [0008]    In accordance with the present invention, insertion systems for inserting an IOL having an optic and at least one fixation member into a patient&#39;s eye are provided. The systems are of the type that have a handpiece in which is held an insertion cartridge having a proximal loading chamber sized to receive the IOL in a deformed or folded configuration. The loading chamber has an open proximal end. The systems comprise a plunger rod arranged to travel through the handpiece such that a distal tip member of the plunger rod lines up with the open proximal end of the loading chamber and thus can be advanced therethrough and push the IOL through the loading chamber. The plunger rod defines a longitudinal axis and the distal tip member has a longitudinally extending portion that is sized to project and become trapped within the folded intraocular lens and a pusher surface located proximal, preferably just slightly proximal or substantially directly proximal, to and sized larger than the longitudinally extending portion that contacts and pushes the folded intraocular lens optic.  
           [0009]    The pusher surface of the plunger rod distal tip member may be offset from the longitudinal axis and define a proximal end of the longitudinally extending portion. The plunger rod distal tip member may be made of a first material, and wherein a soft tip made of a second material softer than a first material covers the longitudinally extending portion and is sized to project and become trapped within the folded intraocular lens. In one embodiment, the pusher surface is formed by a distal face of an elongated mid-portion of the distal tip member. Alternatively, the soft tip also covers the elongated mid-portion and thus covers its distal face such that the pusher surface is formed by the soft tip as it conforms to the distal face. Preferably, the soft tip is made of silicone and includes a slot on its distal end. The elongated mid-portion may have a maximum dimension transverse to the longitudinal axis at its distal face. Furthermore, the distal face may be offset asymmetrically with respect to the longitudinal axis. Desirably, the maximum cross-sectional dimension of the pusher surface is more than about 105% larger than the maximum cross-sectional dimension of the longitudinally extending portion.  
           [0010]    In another aspect of the present invention, insertion systems for inserting an IOL having an optic and at least one fixation member into a patient&#39;s eye are provided. The systems are of the type that have an insertion cartridge having a proximal loading chamber sized to receive the IOL in a deformed or folded configuration, loading chamber having an open proximal end. The systems include a plunger rod having a distal tip member that fits into the proximal end of the loading chamber and thus can be advanced therethrough and push the IOL through the loading chamber. The plunger rod defines a longitudinal axis and the distal tip member has a control portion that is sized to project and become trapped within the folded IOL. The distal tip member further includes a pusher portion located proximal, preferably just slightly proximal or substantially directly proximal, to and sized larger than the control portion that contacts the folded intraocular lens optic and limits projection of the control portion therewithin.  
           [0011]    The pusher portion of the plunger rod distal tip member may be offset from the longitudinal axis and define the proximal end of the control portion. The distal tip member further may be made of a first material, wherein a soft tip made a second material softer than a first material covers the control portion and is sized to project and become trapped within the folded IOLs. In one embodiment, the pusher portion is formed by a distal face of an elongated mid-portion of the distal tip member. In an alternative embodiment, the soft tip also covers the elongated mid-portion and thus covers its distal face such that the pusher portion is formed by the soft tip as it conforms to the distal face. Desirably, the maximum cross-sectional dimension of the pusher portion is more than about 105% larger than the maximum cross-sectional dimension of the control portion.  
           [0012]    A further aspect the present invention is directed to methods of urging an IOL having an optic through an insertion cartridge into the eye of a patient. The cartridge has a loading chamber that receives the IOL with the optic in a deformed or folded configuration. The methods include providing a plunger rod having a distal tip member with a longitudinally extending portion and a pusher surface defining the proximal end of the longitudinally extending portion. The distal tip member is advanced into the cartridge such that the longitudinally extending portion projects and becomes trapped within the folded IOLs. The pusher surface contacts the folded intraocular lens optic and limits projection of the longitudinally extending portion therewithin. Further advancing the plunger rod urges the IOL through the cartridge into the eye of the patient.  
           [0013]    The longitudinally extending portion becomes trapped within the folded IOL so as to enable the direction of movement of the IOL to be reversed by pulling the distal tip member in a proximal direction. The method therefore further includes slowing the rate of advancement of the IOL through the cartridge by slowing the movement of the plunger rod. A soft tip may cover the longitudinally extending portion of the distal tip member, wherein advancing the distal tip member also advances the soft tip so that it becomes trapped within the folded IOLs.  
           [0014]    Each and every feature described herein, and each and every combination of two or more of such features, is included within the scope of the present invention provided that the features included in such a combination are not mutually inconsistent.  
           [0015]    Additional aspects, features, and advantages of the present invention are set forth in the following description and claims, particularly when considered in conjunction with the accompanying drawings in which like parts bear like reference numbers. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    [0016]FIG. 1 is a perspective view of an IOL insertion system of the present invention showing a handpiece in which a plunger rod travels and an insertion cartridge held at a distal end.  
         [0017]    [0017]FIG. 2 is a perspective view of the insertion cartridge shown isolated from the system of FIG. 1 and in an open position during an operation in which an IOL is placed in a load chamber.  
         [0018]    [0018]FIG. 3 is a perspective view of the system of FIG. 1 during an IOL insertion operation.  
         [0019]    [0019]FIG. 4 is a longitudinal sectional view of the insertion cartridge held closed in the distal end of the handpiece with an IOL therein and showing a distal tip of the plunger rod in the process of urging the lens through the load chamber.  
         [0020]    [0020]FIG. 5 is a plan view of the plunger rod isolated from the system of FIG. 1 and having a soft tip shown in phantom on a distal end.  
         [0021]    [0021]FIG. 5A is an enlarged plan view of the distal end of the plunger tip of FIG. 5.  
         [0022]    [0022]FIG. 5B is an enlarged elevational view of the distal end of the plunger tip of FIG. 5.  
         [0023]    [0023]FIG. 6A is a perspective view of an elongate member forming the distal end of the plunger tip of FIG. 5.  
         [0024]    [0024]FIGS. 6B and 6C are end and enlarged plan views, respectively, of the distal tip of the elongate member of FIG. 6A.  
         [0025]    [0025]FIG. 7A is a plan view of an alternative plunger rod of the present invention having a soft tip shown in phantom on a distal end.  
         [0026]    [0026]FIG. 7B is an enlarged plan view of the distal end of the plunger tip of FIG. 7A.  
         [0027]    [0027]FIG. 7C is an enlarged elevational view of the distal end of the plunger tip of FIG. 7A. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0028]    [0028]FIG. 1 illustrates an intraocular lens (IOL) insertion system, shown generally as  20 . The system  20  comprises handpiece  21 , and a loading cartridge  22  including a forward tube  24  having an open port  26  at its distal end. The handpiece  21  of injection system  20  is an integrally formed unit. Loading cartridge  22  has folding leaves  28   a,    28   b  which extend through an opening  30  in the outer wall of the handpiece  21 .  
         [0029]    A proximal end portion  32  of handpiece  21  can be sized to completely and closely encompass plunger  34  of a plunger rod assembly  35  (FIG. 5), which has a plunger cap  36  affixed to its proximal end. Proximal end portion  32  is hollow and includes a threaded surface  38 , the threads of which matingly engage threads  40  on the outer surface of plunger  34 .  
         [0030]    Still with reference to FIG. 1, insertion system  20  includes a slot  42  which extends from the proximal portion of opening  30  and connects therewith. Slot  42  is elongated in a direction parallel to the longitudinal axis of insertion system  20 . Slot  42  is sufficiently wide to permit the closed folding leaves  28   a,    28   b  to fit therethrough, and sufficiently long to permit loading cartridge  22  to be inserted therein, so that the loading cartridge can be subsequently moved into connecting opening  30 . At the same time, the slot  42  is sized to hold the folding leaves  28   a,    28   b  by friction in their fully closed position.  
         [0031]    [0031]FIG. 5 shows injector plunger rod assembly  35  isolated and having the plunger  34  connected in series to an intermediate elongated rod  44  and a distal tip member  46 . The plunger  34  has a locking enclosure  48  on its distal end that holds, without restricting rotation of, an injector rod cap  50  on the proximal end of the elongated rod  44 . A soft distal tip  52  is disposed on and may be considered a part of the distal tip member  46 .  
         [0032]    Distal tip  52  is desirably made of an elastomeric silicone polymer composition which is softer and more elastic than elongated rod  44 , which is typically made of titanium. Distal tip  52  is also softer and more elastic than distal tip member  46 , which is typically made of a polymeric material, such as reinforced polyamide, liquid crystal polymer and the like. For example, tip  52  is made of a material having a Shore A Hardness value in the range of about 40 to about 80 or about 90 or higher, more specifically about 70 to about 75. Viewed from a different perspective, the tip  52  preferably has a Shore A Hardness value within about 30 of the Shore A Hardness value of the material for which the optic of the IOL to be inserted is made.  
         [0033]    As shown in FIG. 4, the distal end portion  60  of handpiece  21  is hollow. When cartridge  22  is inserted into handpiece  21 , the hollow space defined by an inner wall  62  of the handpiece  21  is aligned with a hollow space  64  defined by an inner wall  66  of the loading cartridge  22 . The combination of the joined handpiece  21  and cartridge  22  can be considered a tubular member defining a hollow space through which the distal tip member  46  and a portion of the connected elongated rod  44  can pass longitudinally.  
         [0034]    Distal tip  52  desirably has a length in the range of about 2-50 mm, preferably about 5-25 mm, and more preferably about 10 mm. The length of tip  52  beyond the distal end of distal tip member  46  is in the range of about 0.25-1.0 mm, for example, about 0.75 mm. Tip  52  is generally tapered in the distal direction, with a proximal dimension larger than any other region of the tip. In addition, a distalmost end of the tip  52  is preferably configured to facilitate holding or trapping of at least a portion of the tip of the IOL. Further details of the distalmost end of the tip  52  can be found in Vidal et al., U.S. Pat. No. 5,776,138, the disclosure of which is hereby expressly incorporated by reference.  
         [0035]    Distal tip member  46  is sized and adapted to be manually connected to the elongated rod  44 . In this context, the distal tip member  46  preferably has sufficient length so as to be conveniently held in the hand of a human as it is being coupled to the rod  44 . Particularly useful is a tip member  46  having a length in the range of about 0.5-10.0 cm, more preferably in the range of about 1-5 cm.  
         [0036]    The combination of soft distal tip  52  and distal tip member  46  is preferably disposable after a single use, that is after being used to insert a single IOL into an eye. The other components of the IOL insertion system  20 , except for loading cartridge  22 , are constructed, for example, of metal, so as to be reusable after sterilization.  
         [0037]    The distal tip  52  and distal tip member  46  combination can be made in any suitable manner, provided that the tip  52  is secured to the distal tip member  46  and that both components and the combination function as described herein. In one particularly useful embodiment, the distal tip member  46  is molded, for example, using conventional techniques, into the desired form and size. Subsequently, the distal tip  52  is secured to the distal tip member  46 , for example, using conventional insert molding techniques.  
         [0038]    As seen in FIG. 5A, the distalmost end of tip  52  includes a slotted truncated cone structure  70 . A cross slot  72  is formed in the truncated cone structure  70 . This feature facilitates introducing the tip  52  into a fold of an IOL as the elongated member and tip combination is moved distally in the hollow space of a tube, as is described hereinafter. However, it should be noted that this slot structure  72  and the truncated cone structure  70  are not necessary in order to achieve substantial benefits in accordance with the present invention.  
         [0039]    Distal tip member  46  may be coupled to rod  44  in any suitable manner. The coupling between the distal tip member  46  and the rod  44  should be sufficiently strong or secure so that these two components remain joined as the IOL insertion system  20  is used to insert an IOL into an eye.  
         [0040]    Distal tip member  46  is shown in greater detail in FIGS.  5 B and  6 A- 6 C and includes a distal extension  80  that begins at a pusher surface  82 . That is, the pusher surface  82  forms the proximal end of the distal extension  80 . A proximal coupling  84  is adapted to mate with the distal end of the elongated rod  44 . The pusher surface  82  comprises the distal face of an enlarged mid-portion  86  that extends between the distal extension  80  and the proximal coupling  84 . The radial cross-section of the pusher surface  82  is larger than the rest of the mid-portion  86 . That is, as best seen in FIG. 5B, the mid-portion  86  gradually narrows in a proximal direction. The pusher surface  82  has a larger radial dimension than the distal extension  80 , which is a configuration that improves control of advancement of the IOL, as will be described below. As also see in FIG. 6B, the mid-portion  86  is laterally offset from a centerline of the tip member  46 , which centerline extends though the center of the distal extension  80 .  
         [0041]    The distal extension  80  has a generally rounded rectangular parallelpiped shape except for two pairs of oppositely directed triangular grippers  88 . The gripper  88  help retain the soft distal tip  52  on the tip member  46 . That is, whether the tip  52  is molded over the tip member  46  or simply slipped over, the grippers  88  provide a greater frictional resistance to separation thereof.  
         [0042]    [0042]FIGS. 4 and 5A- 5 B illustrate a relatively short distal tip  52  that covers just the distal extension  80  and extends slightly beyond. As mentioned above, the truncated cone structure  70  at the distalmost end of tip  52  extends between about 0.25-1.0 mm beyond the distal extension  80 . The proximal end of the tip  52  abuts the pusher surface  82 . As seen in FIG. 4, therefore, the soft distal tip  52  extends within the fold of an IOL  90 , and the pusher surface  82  may contact and push on a proximal edge of the IOL  90 . In this way, the pusher surface  82  not only provides a positive pushing surface to urge the IOL  90  through the cartridge bore defined by the inner wall  66  thereof, but also limits the extent to which the soft distal tip  52  extends within the IOL  90 . This latter feature prevents excessive trapping and the potential for consequential damage to the IOL  90 .  
         [0043]    The distal tip  52  becomes trapped within the folded IOL  90  so as to enable the direction of movement of the IOL  90  to be reversed by pulling the distal tip member  46  in a proximal direction. Consequently, the surgeon can pull the IOL  90  back or just slow the rate of advancement of the IOL  90  through the cartridge by slowing the movement of the plunger rod.  
         [0044]    Although positive engagement of the proximal edge of the IOL  90  by the pusher surface  82  is possible, the nature of the soft and lubricated material of the IOL may hinder such direct contact. However, the radial dimension (e.g., diameter)of the pusher surface  82  is such that it will not travel too far into the fold of the IOL  90  before such relative movement stops. That is, the pusher surface  82  very quickly fills the fold of the IOL  90  and compresses it against the inner lumen of the cartridge  22 . Further movement of the pusher surface  82  pushes IOL  90  along the cartridge lumen. To ensure such an interaction, the cross-sectional dimensions of the cartridge lumen, pusher surface  82 , and IOL  90  must be coordinated. Furthermore, the relative cross-sectional dimensions of the distal extension  80  and pusher surface  82  are such that the distal extension passes into the fold of the IOL  90  and assumes a frictional contact therewith, yet the pusher surface will not enter the fold or will only enter a short distance before becoming trapped.  
         [0045]    In one embodiment, the cartridge lumen is cylindrical and has a particular maximum diameter, for example 1.9 mm. One way to quantify the pusher surface  82  size is relative to the cartridge lumen. The maximum cross-sectional dimension of the pusher surface  82  is desirably about 75% or more of the diameter of the cartridge lumen, preferably more than about 90%. Alternatively, the maximum cross-sectional dimension of the pusher surface  82  is desirably about 105% or more of the maximum cross-sectional dimension of the distal extension  80 , preferably more than about 120%.  
         [0046]    FIGS.  7 A- 7 C illustrate an alternative embodiment of a plunger rod assembly  100  of the present invention. The assembly includes a plunger  102 , an elongated rod  104 , a distal tip member  106 , and a soft distal tip  108 . The first three components are as described above, and thus will not be further examined. The soft distal tip  108  is longer than the tp  52  described above, and extends from just slightly beyond the distalmost end of distal tip member  106  to a proximal coupling  110  of the tip member. In other words, the tip  108  covers both a distal extension  112  and an enlarged mid-portion  114 .  
         [0047]    The soft tip  108  is of a material that closely conforms to the contours of the distal tip member  106 , as best seen in FIG. 7C. More specifically, the tip  108  expands outward at the beginning of the enlarged mid-portion  114  to form a pusher surface  116 . The combined distal tip member  106  and soft tip  108  function in a manner similar to the first embodiment described above to urge an IOL though an insertion cartridge. In particular, the soft tip  108  extends into and is trapped within the folded IOL, and the pusher surface  116  may contact a proximal edge of the IOL, or at least will not pass far into the fold of the IOL before becoming trapped. In this way, great control over the advancement of the IOL is provided by the trapped soft tip  108 , but excess trapping is avoided. Furthermore, contact of the pusher surface  116  with the proximal edge of the IOL, or initial inner wall, provides a soft, non-damaging positive pushing force. At the same time, the trapped soft tip  108  enables the surgeon to reverse the direction of the IOL advancement if necessary.  
         [0048]    [0048]FIG. 2 illustrates the manner in which loading cartridge  22  facilitates folding an IOL  90 . The hinged folding leaves  28   a,    28   b  are used to open and close folding tubular halves  120  and  122 , respectively. IOL  90  (in an unfolded state) is placed on folding tubular halves  120  and  122 , by forceps  124 . The forceps  124  hold the IOL  90  in a specific and determinable planar orientation. Superior fixation member or haptic  126  is placed forward of optic  128 , while the other haptic  130  trails the optic. Hinged folding leaves  28   a,    28   b  are moved together, which folds the flexible or foldable optic  128  of IOL  90  in half. After IOL  90  is folded, the forceps  124  is removed.  
         [0049]    The closed loading cartridge  22 , containing the folded IOL  90 , is then loaded into handpiece  21  of insertion system  20 , as described above. An effective amount of a lubricant composition, such as a visco-elastic material, for example, a conventional sodium hyaluronate-containing aqueous material, preferably is included in the hollow space defined by the loading cartridge  22 . This lubricant composition allows the folded IOL  90  to more easily pass through the hollow space defined by loading cartridge  22 .  
         [0050]    Insertion system  20  is operated and functions as follows. When it is desired to insert IOL  90  into an eye, the system  20  is placed in a configuration as shown in FIG. 1, with distal tip member  46  (with tip  52 ) secured to rod  44 , as shown in FIG. 5.  
         [0051]    With the IOL  90  in its folded condition within system  20 , the operator (surgeon) advances plunger  34  distally by rotating cap  36 . This action advances rod  44  and distal tip member  46  distally. As rod  44  and distal tip member  46  are moved distally, the tip  52  comes into contact with folded optic  128  and is introduced into the fold of the folded optic as shown in FIG. 4. Because of the relative softness and elasticity of tip  52 , the distal movement of rod  44  and distal tip member  46  causes the tip to become trapped in the fold of the folded optic  128 . The folded optic  128  can be considered to be controlled, pulled or carried by the rod  44 , distal tip member  46  and tip  52  when the tip is trapped in the fold.  
         [0052]    Referring now to FIG. 3, the IOL  90  is to be placed in eye  140  into an area formerly occupied by the natural lens of the eye. With the IOL  90  in its folded position within system  20 , and tip  52  trapped in the fold of the folded optic  128 , forward tube  24  is ready for insertion through an incision in the sclera  142  of eye  140 . Capsular bag  144  protects the posterior segment of the eye  140 . With the forward tube  24  inserted within the eye  140  and the port  26  positioned so that the IOL  90  can unfold in the location within the eye best suited for permanent implantation, the operator advances plunger  34  by rotating cap  36 . This action advances rod  44 , distal tip member  46 , tip  52  and IOL  90  distally into the forward tube  24 .  
         [0053]    As rod  44  advances farther distally, the IOL exits the port  26  in a controlled manner and is controllably released in a location as close as possible to the IOL&#39;s final implanted position.  
         [0054]    [0054]FIG. 3 shows the sclera  142  having an incision through which the distal end portion of forward tube  24  is passed. Alternately, the incision can be made through the cornea or other portion of the eye. Forward tube  24  has a sufficiently small cross-section to pass into the eye  140  through a 3.0 mm incision in the sclera  102 . Folding leaves  28   a,    28   b,  in contact with each other when lens loading cartridge  22  is in a closed position, can be grasped by an operator and used to guide and position insertion tube  24  in its desired position within the eye.  
         [0055]    After IOL  90  has been inserted into eye  140 , forward tube  24  is removed from the eye. The tip  52  can be used to position the IOL  90  in the eye. For example, the tip  52  can be retracted (after the optic is released) and then used to push the trailing haptic  130  out of the tube and position this haptic into the eye. If needed, IOL  90  can be repositioned in the eye by a small, bent needle or similar tool inserted into the same incision.  
         [0056]    Once IOL  90  is properly positioned in eye  140  and system  20  is withdrawn from the eye, the incision in the sclera may be closed, for example, using conventional techniques. After use, loading cartridge  22  and distal tip member  46  (including tip  52 ) are preferably disposed of. Remaining portions of system  20 , in particular the plunger  34  and rod  44  can be reused after sterilization and disinfection.  
         [0057]    Enhanced lubricity resulting from a component incorporated into the material of the cartridge facilitates advancement and folding of the IOL so that a reduced amount of force is required to pass the IOL through the cartridge. Another benefit to this lubricity is that the degree of folding of the IOL may be increased so that ultimately the IOL can be inserted through an even smaller incision.  
         [0058]    While the present invention has been described with respect to various specific examples and embodiments, it is to be understood that the invention is not limited thereto and that it can be variously practiced within the scope of the following claims.