Abstract:
An apparatus for inserting a folded intraocular lens through an incision into an eye comprising a tube defining a hollow passage, the tube having an ejection port through which said intraocular lens is passed from the hollow passage into an eye, an injector rod longitudinally movable within the hollow passage of the tube, the injector rod having a distal segment adapted to contact the folded intraocular lens within the hollow passage of the tube to urge the folded intraocular lens distally through the hollow passage, a housing including a distal portion adapted to hold the tube, and a proximal portion coupled to the distal portion, and a rotation assembly located relative to the distal portion so that the distal portion is axially rotated relative to the proximal portion as the injector rod is moved distally through the tube.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to apparatus and methods for inserting an intraocular lens through a small incision into an eye. More particularly, the invention relates to such apparatus and methods wherein the desired orientation of the lens being inserted in the eye is easily, controllably and effectively achieved. 
     An intraocular lens (IOL) is implanted in the eye, for example, as a replacement for the natural crystalline lens after cataract surgery or to alter the optical properties of (provide vision correction to) an eye in which the natural lens remains. IOLs often include an optic, and preferably at least one flexible fixation member or haptic, which extends 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 often involves making an incision in the eye. Making the incision as small as possible reduces trauma and speeds healing. 
     IOLs are known which are foldable (deformable) so that the IOL can be inserted into the eye through an incision smaller than the diameter of the lens. 
     The success of foldable IOLs is enhanced by the surgeon&#39;s ability to control the orientation of the IOL during lens insertion. An IOL which is not correctly oriented as it is released from the inserter apparatus into the eye may require relatively difficult reorientation and/or can damage one or more parts of the eye. 
     Some of the most generally accepted insertion apparatus employ a hollow insertion tube having a diameter which permits the folded IOL to pass freely through the tube without permanent deformation, and without causing the surgeon to apply excessive force to overcome friction between the walls of the insertion tube and the IOL. Excessive force can result in the premature ejection of the IOL before the surgeon is ready to position it within the patient&#39;s eye. It would be advantageous to provide IOL insertion apparatus and methods which facilitate the passage of a folded IOL through the apparatus and the insertion of the IOL in the eye in easy, effective and controlled manner while avoiding damage to the IOL and undue trauma to the patient. 
     In these generally accepted apparatus, the insertion tube is held in a handpiece which is coupled to a plunger rod. The plunger rod is moved distally through the insertion tube to urge the IOL to pass through the tube and into the eye. Zaleski U.S. Pat. No. 5,643,276 discloses an IOL insertion apparatus in which the rod is rotated relative to the handpiece being held by the surgeon The rod, in turn, contacts the IOL and provides the IOL in the desired orientation for insertion into the eye. The disclosure of this patent is incorporated in its entirety herein by reference. Although the apparatus disclosed in this patent is often effective in properly orienting the IOL for insertion, it would be advantageous to have a system providing even more direct rotational control to provide proper orientation of the IOL prior to insertion. 
     SUMMARY OF THE INVENTION 
     New apparatus for inserting IOLs and methods for inserting IOLs have been discovered. The present apparatus and methods address one or more of the concerns of the prior art systems, such as those noted above. The present apparatus enable the surgeon to achieve a desired orientation, for example, rotational orientation, of the IOL as the lens is released from the insertion apparatus, thus providing for the use of effective, reliable, and non-excessive amounts of force to insert a folded IOL into an eye. This desired orientation is achieved very directly so that, for example, the insertion tube carrying the IOL is axially rotated. Thus, the surgeon can easily determine, and be assured, that the desired orientation of the IOL is being obtained. In addition, the present system reduces the need for additional manipulation of the IOL by the surgeon to achieve the desired placement of the IOL within the eye. The present invention is straightforward, easy to produce and practice, and involves little or no modification of surgical techniques. In other words, surgeons need not learn a different surgical procedure for inserting an IOL into the eye, nor does the IOL need to be modified to accommodate the present apparatus and methods. 
     In one broad aspect, the present invention comprises apparatus for inserting IOLs into an eye which include a tube, such as an insertion tube or cartridge, defining a hollow passage, for example, through at least a portion of which a folded IOL can be moved. This tube has an ejection port or opening, preferably at the distal end of the tube, from which the IOL is passed for insertion into an eye. An injector rod is also included and is longitudinally or axially movable within the hollow passage of the tube. The distal segment of the rod is adapted to urge the folded IOL distally through the passage, for example, by contacting the folded IOL as the distal segment of the rod passes distally in the passage. A housing is provided and includes a distal portion adapted to hold the tube, and a proximal portion coupled, preferably rotatably coupled, to the distal portion. A rotation assembly is located relative to the distal portion of the housing so that the distal portion is axially rotated, preferably axially rotated a controlled amount, relative to the proximal portion of the housing as the injector rod is moved distally through the tube. The rotation of the distal portion of the housing directly rotates the IOL in the held tube as it moves distally through the hollow passage of the tube. Rotating the IOL provides for the IOL, and in particular the leading or superior fixation member of the IOL, to be oriented during the IOL insertion process so as to reduce, or even eliminate, the risk of eye damage as the IOL is being inserted into the eye. In addition, the surgeon can visually observe the rotation of the distal housing, and thereby be provided with increased assurance that the orientation of the IOL as it exits the insertion tube is as desired, thereby making the entire insertion process easier and reducing the risk of surgical error. Also, the present system very effectively places the IOL in the desired location in the eye so that a reduced amount of repositioning of the IOL in the eye is needed. 
     In one embodiment, the rotation assembly comprises a cam race and a cam follower. A particularly useful embodiment provides for a rotation assembly in which a cam race is disposed on the injector rod and the cam follower is disposed on the distal portion of the housing. Of course, other constructions or configurations are effective to provide the desired controlled rotation and are included within the scope of the present invention. For example, the cam race can be disposed on the distal portion of the housing and the cam follower can be disposed on the injector rod. Also, the rotation assembly can include a worm gear and a worm gear guide. Additionally, the wall of the distal portion of the housing and the injector rod can be matingly configured, for example, threaded, to facilitate the desired degree of rotation. In fact, any suitable construction which provides for axial rotation, preferably controlled rotation, of the distal portion of the housing relative to the proximal end of the housing as the rod is moved distally in the tube may be employed and is within the scope of the present invention. 
     The proximal portion and the distal portion of the housing may be coupled together in any suitable manner provided that these two housing portions are rotatable, preferably axially rotatable, relative to each other, at least to the extent necessary to achieve the desired rotation of the IOL, as described herein. Although these two housing portions need not be directly coupled, it is preferred that the distal end portion be directly coupled to the proximal end portion. The proximal end portion preferably is adapted to be held in a hand of a surgeon when the apparatus is used to insert an IOL. For example, the proximal portion of the housing may include at least one finger member, e.g., finger projection, support, ring, partial ring or the like, and preferably two finger members, extending outwardly and adapted to facilitate the effective holding of the proximal portion of the housing by a surgeon, for example, in one hand of the surgeon. 
     The distal end region of the injector rod is adapted, sized and configured to urge the IOL distally in the hollow passage of the tube as the rod is moved distally in the hollow passage. The distal end region of the rod may come into contact with the IOL as the rod is moved distally. This distal end region preferably is structured so as not to substantially interfere with or inhibit the rotation of the IOL in the insertion tube as the rod is moved distally. The distal end region of the rod preferably is substantially flat or otherwise structured to urge the IOL distally in the hollow passage substantially without otherwise interacting with the lens. The rotation imparted to the distal end of the housing and the insertion tube preferably results in substantially the same degree of rotation of the IOL in the hollow passage of the insertion tube. 
     The injector rod extends through the proximal portion of the housing and terminates proximally of the housing. At or near the proximal end of the injector rod preferably is an enlarged element effective to facilitate movement of the injector rod into and out of the hollow passage. For example, the enlarged element can be configured as a thumb support or ring which the surgeon can use in controlling the position of the injector rod in the hollow passage. In addition, the enlarged element may be sized to be effective in preventing the injector rod from being passed too far into the hollow passage. 
     The present apparatus preferably further includes a bias assembly adapted to urge the injector rod to move proximally in the tube. Substantially any suitable biasing sub-system may be employed which is effective to urge the rod proximally in the tube. With the bias assembly present, the force exerted by this assembly is overcome, for example, manually overcome, to move the rod distally in the tube. In one very useful embodiment, the bias assembly includes a spring member. This spring member, preferably located in the proximal portion of the housing, is structured to urge the injector rod to move proximally. Thus, for example, the force of the spring member is manually overcome, such as by the surgeon, when the injector rod is to be passed distally through the hollow passage. The spring member causes or urges the injector rod to move proximally when the force applied to the injector rod by the surgeon is reduced or eliminated. The spring member may be considered a return spring in the spring member urges the return of the injector rod from the hollow passage of the insertion tube. 
     Another aspect of the invention includes methods for inserting an intraocular lens into the eye. Such methods comprise: 
     placing an IOL in a folded condition in an insertion apparatus in accordance with the present invention; 
     positioning the ejector port of the apparatus in proximity to or through an incision in the eye; and 
     moving the injector rod of the apparatus distally so that the IOL is inserted into the eye. 
     In one embodiment, for example, in which the present apparatus includes a bias assembly, as described elsewhere herein, the injector rod is moved distally to urge the leading or superior fixation member or haptic out of the hollow passage. The injector rod is then moved proximally, for example, a sufficient distance to be proximal of the trailing or inferior fixation member or haptic of the IOL. At this point, the injector rod is again moved distally to cause this trailing fixation member to pass out of the ejection port and into the eye. 
     In any event, when the IOL is in the eye, the injector rod is moved proximally and the insertion tube is removed from the eye or from proximity to the eye. If necessary, the IOL in the eye can be repositioned, using conventional techniques. After the IOL is properly positioned in the eye, the incision in the eye is closed, e.g., sutured. 
     Each of the individual features of the present invention disclosed herein may be used alone or in combination with one or more other of such features, provided such features are not mutually inconsistent with each other. All apparatus and methods involving any such feature or combination of such features are included within the scope of the present invention. 
    
    
     These and other aspects of the present invention will become apparent in the following detailed description and claims, particularly when considered in conjunction with the accompanying drawings in which like parts bear like reference numerals. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of an insertion apparatus in accordance with the present invention. 
     FIG. 2 is a perspective view of a folding device shown in the open position. 
     FIG. 3 is a side view, partly in cross-section, of the distal portion of the housing and related components of the insertion apparatus shown in FIG.  1 . 
     FIG. 4 is a side view, partly in cross-section, of the proximal region of the insertion apparatus shown in FIG.  1 . 
     FIG. 5 is a schematic side view of the apparatus shown in FIG. 1 with the plunger rod substantially fully withdrawn proximally. 
     FIG. 6 is a schematic side view of the apparatus shown in FIG. 1 with the plunger rod urging the IOL distally. 
     FIG. 7 is a schematic side view of the apparatus shown in FIG. 1 showing the leading fixation member and optic of the IOL extending distally from the apparatus. 
     FIG. 8 is a schematic perspective drawing showing the placement of the distal portion of the insertion tube in the eye. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1 illustrates an IOL insertion apparatus, shown generally as  10 , in accordance with the present invention. The apparatus  10  comprises a proximal housing  12 , a distal housing  14  and a folding cartridge  16 . Proximal housing is operatively coupled to distal housing  14 . Proximal housing  12  includes a through opening  20  through which the folding cartridge  16  can be placed. Proximal housing  12  includes a forward opening  22  through which the injection tube  24  of folding cartridge  16  extends distally. Distal housing  14  includes two oppositely disposed finger supports  26  which extend outwardly from the outer peripheral surface  28  of the distal housing. 
     Apparatus  10  also includes a plunger rod  30  which includes an enlarged proximal end  32  effective to push plunger rod  30  through distal housing  14 , as will be discussed hereinafter. 
     Before proceeding to describe the operation of insertion apparatus  10 , a brief description of the operation of folding cartridge  16  is provided. With reference to FIG. 2, folding cartridge  16  includes hinged folding leafs  34  and  36  which are used to open and close folding members  38  and  40 , respectively. IOL  42  (in an unfolded state) is placed on folding members  38  and  40  by forceps  44 . The forceps  44  hold the IOL  42  in a specific and determinable planar orientation. Superior or leading fixation member or haptic  46  is placed forward of optic  48 , while the other fixation member or haptic  50  trails the optic, as shown in FIG.  2 . Hinged folding leaves  34  and  36  are moved together, which folds the deformable or foldable optic  48  of IOL  42  substantially in half. After IOL  42  is thus folded, the forceps  44  is removed. 
     The IOL  42  can be made of any suitable material or materials of construction. The IOL  42  is deformable or foldable, as described herein. Therefore, the IOL  42  should be made of material or materials having sufficient elasticity, elongation and other physical properties to be foldable, rollable or otherwise deformed so as to pass through a small incision into the eye and, thereafter, regain substantially its original shape for use in the eye. Examples of materials useful for inclusion in the optic  48  of IOL  42  include, but are not limited to, silicone polymeric materials, preferably silicone elastomeric polymeric materials, acrylic polymeric materials and the like. The haptics  46  and  50  may be made of polymeric materials, including, but not limited to, polypropylene, polymethylmethacrylate and the like. 
     The closed loading cartridge  16 , containing the folded IOL  42 , is then loaded into the proximal housing  12  through opening  20  and moved distally into narrowed through slot  52 , as shown in FIG.  1 . 
     With reference to FIG. 3, the present insertion apparatus  10  includes a spring member  60  located in the hollow interior  62  of distal housing  14 . Spring member  60  is biased to urge proximal housing  12  to extend away from distal housing  14 . Spring member  60  substantially surrounds an enlarged portion  66  of plunger rod  30 . A spring stop  67  is secured to and extends outwardly from enlarged portion  66 . The spring member  60  is effectively prevented from moving distally of spring stop  67 . Enlarged portion  66  includes a cam race  68  which extends over  1800  of the enlarged portion. Although plunger rod  30  can have any suitable cross-section, as shown, enlarged portion  66  is substantially circular in cross-section perpendicular to the longitudinal axis  70  of the apparatus  10 . 
     Proximal housing  14  includes a distal end  72  which includes an opening  74  and an inwardly extending segment  76 . Distal housing  12  includes a proximal end  78  which extends within the interior space  62  of distal housing  12 . Proximal housing  14  includes an outwardly extending flange  80  which is captured by the segment  76  of distal housing  12  and held within the interior space  62  of the distal housing. In this manner, proximal housing  14  is coupled to distal housing  12 . 
     Proximal housing  14  includes a cam follower  82  which extends into the internal hollow space  84  of proximal housing  14 . As shown in FIG. 3, cam follower  82  is located in a longitudinally extending slot  86  of enlarged portion  66  of plunger rod  30 . Longitudinal slot  86  extends from the distal end  88  of enlarged portion  66  and is part of cam race  68 . A proximal slot  90  is provided and is also a part of the cam race  68 . Proximal slot  90  terminates distally of proximal end  32  of plunger rod  30 . Both slot  86  and proximal slot  90  extend longitudinally substantially parallel to the longitudinal axis  70 . A smaller cross-section distal rod portion  92  extends longitudinally from the enlarged portion  66 . Both distal rod portion  92  and enlarged portion  66  are parts of plunger rod  30 . 
     With reference to FIG. 4, distal rod portion  92  extends distally into the interior space  84  of distal housing  12 . The distal end  94  of distal rod portion  92  is rounded so as not to damage the IOL  42  located in the hollow passage  96  of folding cartridge  16 . Other than urging IOL  42  distally as distal rod portion  92  is moved distally, the distal end  94  does not have any features which would inhibit or restrict the rotation of the IOL  42  relative to the distal rod portion  92 . The injection tube  24  extends distally from the distal opening  22  of distal housing  12 . Injection tube  24  includes a beveled distal opening  98  and a proximally extending through slot  100 . The beveled distal opening  98  is advantageously positioned so that after rotation of the proximal housing  14 , as described herein, the bevel is facing right, when viewed from above, with the injection tube  24  extending away from the viewer. 
     Insertion apparatus  10  is operated and functions as follows. When it is desired to insert IOL  42  into an eye, the apparatus  10  and IOL  42  are placed in a configuration as shown in FIGS. 4 and 5. Thus, the IOL  42  is located in the interior passage  96  defined by folding cartridge  16 . 
     With reference to FIGS. 3,  4  and  5 , the plunger rod  30  is positioned so that the cam follower  82  is in slot  86 . The distal end  94  of distal rod portion  92  is positioned just proximally of the optic  48  of IOL  42 . 
     With reference to FIG. 6, as the plunger rod  30  is moved distally, the rod  94  urges the IOL  42  into the injection tube  24  of the folding cartridge  16 . The cam follower  82  remains in the slot  86 . As shown in FIG. 6, the cam follower  82  is located substantially adjacent to the curved portion  69  of cam race  68 . 
     As the plunger rod  30  is moved distally further, the cam follower  82  transverses the curved portion  69  of cam race  68 , thereby rotating the proximal housing  14  and folding cartridge  16  180° to relative to the distal housing  12 . This rotation provides the IOL  42  in a proper orientation to be inserted into the eye. 
     As shown in FIG. 7, the superior or leading haptic  46  and the optic  48  emerge from the injection tube  24 . The cam follower  82  is located in the proximal slot  90  of the cam race  68 . At this point, the force urging the plunger rod  30  distally is reduced. This causes spring member  60  to urge the distal rod portion  92  proximally, in particular, proximally of the inferior or trailing haptic  50 . This proximal movement is relatively limited so that the cam follower  82  remains in the proximal slot  90 . Once the distal rod portion  92  is proximal of the trailing haptic  50 , the plunger rod  30  is manually urged distally again to cause the trailing haptic to emerge from the injection tube  24 . At this point, the entire IOL  42  has been removed from the injection tube  40  and placed into the eye. The force on the plunger rod  30  is again reduced, causing the distal rod portion  92  to move proximally. The injection tube  24  can then be removed from the incision in the eye. 
     Referring now to FIG. 8, the IOL  42  is to be placed in the eye  110  into an area formerly occupied by the natural lens of the eye. With the IOL  42  in its folded position within apparatus  10 , as described above, injection tube  24  is ready for insertion through an incision  112  in the sclera  114  of eye  110 . Capsular bag  116  protects the posterior segment of the eye  110  and as one of the eye&#39;s constituent parts which is not injured by the insertion of the IOL  42  with the injection tube  24  inserted within the eye  60  and the distal end opening  98  properly positioned, the surgeon advances plunger rod  30  by manually pushing the plunger rod  30  relative to distal housing  14 . This action advances distal rod portion  92  distally which, in turn, moves IOL  42  distally into injection tube  24 . As the plunger rod is moved further distally, cam follower  82  traverses curved portion  69  of cam race  68 . This causes the distal housing  12 , folding cartridge  16  and IOL  42  to rotate through 180°. The distal rod portion  92  can be partially withdrawn and then moved distally to completely pass the IOL  42  out of the distal opening  98  into a position within the eye. The distal rod portion  92  is then moved proximally and the injection tube  24  is removed from the eye. If needed, IOL  42  can be repositioned in the eye by a small, bent needle or similar tool inserted into the same position. 
     Although apparatus  10  indicates that the extent of rotation is 180°, it should be understood that the degree or extent of rotation can be any amount desired. For example, suitable extents of rotation can be in a range of about 40° or less to about 270° or more, and more preferably about 90° to about 180° or about 205°, in either direction from the IOL&#39;s original position. The extent of rotation preferably is chosen to permit the surgeon to hold insertion apparatus  10  in a position most convenient to the surgeon, while at the same time having the apparatus rotate the distal housing  12  and IOL  42  a pre-determined amount to assure its emergence from distal opening  98  in an orientation as close as possible to the desired implanted position of the IOL with a reduced risk of damage to the eye. 
     FIG. 8 shows the sclera  112  having an incision through which the distal end portion of the injection tube  24  is passed. Alternately, the incision may be made through the cornea. Injection tube  24  preferably has a sufficiently small cross-section to pass into the eye  110  through an incision of about 3.5 mm or about 3.0 mm in the sclera  112 . Once IOL  42  is properly positioned in eye  60 , an apparatus  10  is drawn from the eye, the incision in the sclera may be closed, for example, using conventional techniques. After use, folding cartridge  13 , which is made of a polymeric material, such as polypropylene, preferably is disposed of. Remaining portions of apparatus  10 , which preferably are made of metal, such as surgical grade stainless steel, may be reused after sterilization and disinfection. Any suitable material or materials of construction may be employed in the various components of the apparatus in accordance with the present invention. 
     The present IOL insertion apparatus and methods effectively and straightforwardly control the orientation of the IOL as it is being inserted into the eye. This IOL orientation control is achieved without undue reliance on the technique and dexterity of the surgeon. Controlling the orientation of the IOL in such a direct manner as described herein reduces the risk of damaging components of the eye and facilitates positioning the IOL in the eye in the desired location. 
     While this invention has been described with respect of 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.