Abstract:
Provided is technology which can prevent the circumferential section of the end surface of a tip end opening from being damaged when an intraocular lens is extruded from an insertion apparatus, even when an insertion tube of the intraocular lens insertion apparatus has been further reduced in size. Provided is an intraocular lens insertion apparatus in which the end surface of a tip end opening ( 10   j ) in a tip end section ( 10   a ) of an insertion tube is an inclined surface that is inclined with respect to a surface (M) perpendicular to a central axis (L) of the insertion tube, and also the angle of inclination, with respect to the surface (M) perpendicular to the central axis (L) of the insertion tube, of the end surface of the tip end opening is larger toward a base end section ( 101 ) than toward a tip end section ( 100 ), wherein a predetermined region of the circumferential section toward the base end section ( 101 ) of the end surface of the tip end opening ( 10   j ) has a curved shape that protrudes toward the outside, and has a radius of curvature (R 4 ) that is equal to or less than the radius of curvature of another region of the circumferential section.

Description:
TECHNICAL FIELD  
       [0001]    The present invention relates to an intraocular lens insertion apparatus which is used to insert an intraocular lens into a patient&#39;s eyeball. 
       BACKGROUND ART  
       [0002]    Hitherto, in a surgery such as cataract, a treatment is performed in which an incision is provided in an eye tissue such as a cornea (sclera) or an anterior lens capsule in an eyeball, a lens inside a capsule is extracted and removed through the incision, and then an intraocular lens as a replacement for the lens is inserted from the incision into an eye so as to be disposed inside the capsule. 
         [0003]    Particularly, in recent years, an insertion apparatus to be described below is used in many cases when inserting the intraocular lens from the incision into the eyeball. That is, the intraocular lens is inserted into the eyeball in a manner such that a leading end opening of an insertion tube provided in a leading end of the apparatus body is inserted into an eyeball through an incision and the intraocular lens is extruded by a rod-like plunger from the leading end opening of the insertion tube while being compactly deformed inside the apparatus body. Since such an insertion apparatus is used, the intraocular lens may be simply inserted into the eyeball using the incision provided to extract and remove the lens. For this reason, the surgery may be simplified and hence an occurrence of astigma or infection after the surgery may be suppressed. 
         [0004]    Furthermore, there is known an intraocular lens insertion apparatus in which a leading end opening end surface at a leading end of an insertion tube is formed as an inclined surface inclined with respect to a plane perpendicular to the center axis of the insertion tube, an inclination angle of the leading end opening end surface with respect to the plane perpendicular to the center axis of the insertion tube at the base end of the leading end opening end surface is larger than that of the leading end thereof, and the circumferential edge of the leading end opening end surface is formed in a sharp edge shape by a tapered outer peripheral surface shape (for example, see Patent Literature 1). Accordingly, it is possible to suppress the popping-out of the intraocular lens. Thus, it is possible to stably extrude the intraocular lens to the edge of the leading end of the insertion tube and to smoothly insert the insertion tube into the incision. 
         [0005]    Incidentally, in the operation of inserting the intraocular lens, there is a demand to further decrease the sizes of the incision and the leading end of the insertion tube in the insertion apparatus in order to reduce the patient&#39;s burden during the surgery. However, when the leading end of the insertion tube decreases in size, the thickness of the leading end of the insertion tube needs to be decreased. Meanwhile, when the insertion tube decreases in size, the intraocular lens is compressed during the passage through the insertion tube, and hence there is a tendency that the restorative force acting on the insertion tube during the extrusion becomes stronger. As a result, there is a case in which the circumferential edge of the leading end opening end surface is broken when extruding the intraocular lens from the insertion apparatus. 
       CITATION LIST  
     Patent Literature 
       [0006]    Patent Literature 1: Japanese Patent Application Laid-Open (JP-A) No. 2009-160153 
         [0007]    Patent Literature 2: JP-A No. 2009-183367 
         [0008]    Patent Literature 3: JP-A No. 2009-28223 
       SUMMARY OF INVENTION  
     Technical Problem 
       [0009]    The invention is made in view of the above-described problems of the related art, and it is an object of the invention to provide a technique capable of suppressing a circumferential edge of a leading end opening end surface from being broken when extruding an intraocular lens from an insertion apparatus even when an insertion tube of the intraocular lens insertion apparatus further decreases in size. 
       Solution to Problem 
       [0010]    According to the invention, there is provided an intraocular lens insertion apparatus in which a leading end opening end surface at a leading end of an insertion tube is formed as an inclined surface inclined with respect to a plane perpendicular to the center axis of the insertion tube, a shape in a predetermined region of a circumferential edge near a base end of the leading end opening end surface is formed as a curved shape protruding outward, and a curvature radius thereof is set to be equal to or smaller than a curvature radius of a region in the other region of the circumferential edge. 
         [0011]    More specifically, there is provided an intraocular lens insertion apparatus which includes a substantially tubular apparatus body for accommodating an intraocular lens therein and extrudes the intraocular lens through an insertion tube provided in the axial leading end of the apparatus body so as to insert the intraocular lens into an eyeball while moving the intraocular lens forward in the axial direction and compactly deforming by an extrusion member inserted into the apparatus body from the rear side in the axial direction, characterized in that; 
         [0012]    a leading end opening end surface at the leading end of the insertion tube is formed as an inclined surface which is inclined with respect to a plane perpendicular to the center axis of the insertion tube, and 
         [0013]    a cross-section of the insertion tube when viewed in a direction perpendicular to the center axis in a predetermined region of a circumferential edge near a base end opposite to the leading end of the leading end opening end surface is formed in a curved shape protruding outward and the curvature radius of the curved shape is set to be equal to or smaller than the curvature radius in the other region of the circumferential edge. 
         [0014]    Here, in the intraocular lens insertion apparatus, a case will be considered in which the leading end opening end surface at the leading end of the insertion tube is formed as the inclined surface inclined with respect to the plane perpendicular to the center axis of the insertion tube. In this case, there is a tendency that the thickness of the insertion tube at the circumferential edge near the base end of the leading end opening end surface becomes the thinnest. Then, there is an increasing risk that the portion may be broken when the intraocular lens passes therethrough. 
         [0015]    On the contrary, in the invention, the cross-sectional shape of the insertion tube in the predetermined region of the circumferential edge near the base end of the leading end opening end surface is formed in a curved shape protruding outward, and the curvature radius of the curved shape is set to be equal to or smaller than the curvature radius in the other region of the circumferential edge. 
         [0016]    Accordingly, a structure may be obtained in which the thickness of the insertion tube at the circumferential edge near the base end of the leading end opening end surface is thickened to the extremely vicinity of the end surface portion. Accordingly, it is possible to suppress a problem in which the circumferential edge near the base end of the leading end opening end surface is broken when the intraocular lens passes therethrough. 
         [0017]    Further, in the invention, the circumferential edge of the leading end opening end surface maybe formed in a sharp edge shape by a tapered outer peripheral surface shape, and 
         [0018]    a cross-section of the tapered outer peripheral surface shape when viewed in a direction perpendicular to the center axis in the predetermined region of the circumferential edge near the base end of the leading end opening end surface is formed in a curved shape protruding outward and the curvature radius of the curved shape is set to be smaller than the curvature radius in the other region of the tapered outer peripheral surface shape. 
         [0019]    That is, in the intraocular lens insertion apparatus, when the circumferential edge of the leading end opening end surface is formed in a sharp edge shape by the tapered outer peripheral surface shape, there is a tendency that the thickness of the portion with the tapered outer peripheral surface shape near the base end of the leading end opening end surface further decreases. Then, there is an increasing risk that the portion with the tapered outer peripheral surface shape may be broken when the intraocular lens passes through the portion. 
         [0020]    On the contrary, in the invention, the cross-sectional shape of the tapered outer peripheral surface shape in the predetermined region of the circumferential edge near the base end of the leading end opening end surface is formed in a curved shape protruding outward, and the curvature radius of the curved shape is set to be equal to or smaller than the curvature radius in the other region of the tapered outer peripheral surface shape. Accordingly, it is possible to suppress a problem in which the portion with the tapered outer peripheral surface shape near the base end of the leading end opening end surface is broken when the intraocular lens passes therethrough. Furthermore, the tapered outer peripheral surface shape of the invention includes not only a case in which the entire circumference of the circumferential edge of the leading end opening end surface is formed in a tapered shape but also a case in which a part of the circumferential edge of the leading end opening end surface (for example, only the base end side) is formed in a tapered shape. 
         [0021]    Further, in the invention, an inclination angle of the leading end opening end surface with respect to a plane perpendicular to the center axis of the insertion tube at the base end of the leading end opening end surface may be set to be larger than that at the leading end thereof. Then the curvature radius in the predetermined region of the circumferential edge near the base end of the leading end opening end surface may be set to be smaller than the curvature radius in the leading end side of the base end of the leading end opening end surface when viewed in a direction perpendicular to the center axis of the insertion tube. 
         [0022]    Here, when the inclination angle of the leading end opening end surface with respect to the plane perpendicular to the center axis of the insertion tube at the base end thereof is set to be larger than that of the leading end thereof, an inclined shape may be a case of a linear shape (a curvature radius=infinity) or a case of a curved shape with a curvature radius. In any case, when the curvature radius of the tapered outer peripheral surface shape of the circumferential edge near the base end of the leading end opening end surface is set to be smaller than the curvature radius in the leading end side of the base end of the leading end opening end surface when viewed in a direction perpendicular to the center axis of the insertion tube, a structure maybe obtained in which the thickness of the portion with the tapered outer peripheral surface shape at the circumferential edge near the base end of the leading end opening end surface is thickened to the extremely vicinity of the end surface portion. Accordingly, it is possible to further reliably suppress a problem in which the circumferential edge near the base end of the leading end opening end surface is broken when the intraocular lens passes therethrough. 
         [0023]    Further, in the invention, the curved shape of the cross-section in the predetermined region of the circumferential edge near the base end of the leading end opening end surface may be formed so as to be continuous to an outer shape from the base end to the rear side thereof in the insertion tube. Then, the shape which is continued backward from the base end side circumferential edge of the leading end opening end surface of the insertion tube may be formed in a smoother shape. As a result, the apparatus body may be more easily inserted into the incision. 
         [0024]    Further, in the invention, the curvature radius of the cross-section in the predetermined region of the circumferential edge near the base end of the leading end opening end surface may be set to be equal to or larger than 0.3 mm and equal to or smaller than 0.4 mm. In this way, it is possible to sufficiently suppress a problem in which the circumferential edge near the base end of the leading end opening end surface is broken when the intraocular lens passes therethrough. 
         [0025]    Further, in the invention, at least a part of a shape in the leading end side of the base end of the leading end opening end surface when viewed in a direction perpendicular to the center axis of the insertion tube may have a linear shape, and the thickness of the predetermined region of the circumferential edge near the base end of the leading end opening end surface may be increased by the range of 0.02 mm to 0.03 mm compared to a case where the circumferential edge has a shape in which the shape of the leading end side of the base end of the leading end opening end surface continues to rear side when viewed in a direction perpendicular to the center axis of the insertion tube. Accordingly, it is possible to sufficiently suppress a problem in which the circumferential edge near the base end of the leading end opening end surface is broken when the intraocular lens passes therethrough. Furthermore, this is more effective in a case where at least the base end side circumferential edge of the leading end opening end surface is formed in a tapered outer peripheral surface shape. 
         [0026]    Furthermore, the above-described means for solving the problems of the invention may be used in combination as much as possible. 
       Advantageous Effects of Invention 
       [0027]    According to the invention, even when the insertion tube of the intraocular lens insertion apparatus further decreases in size, it is possible to suppress a problem in which the circumferential edge near the base end of the leading end opening end surface from being broken when the intraocular lens passes therethrough. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0028]      FIG. 1  is a diagram illustrating a schematic configuration of an intraocular lens insertion apparatus of Embodiment 1 of the invention. 
           [0029]      FIG. 2  is a diagram illustrating a schematic configuration of the intraocular lens of Embodiment 1 of the invention. 
           [0030]      FIG. 3  is a diagram illustrating a schematic configuration of a nozzle body of Embodiment 1 of the invention. 
           [0031]      FIG. 4  is a diagram illustrating a schematic configuration of a positioning member of the embodiment of the invention. 
           [0032]      FIG. 5  is a diagram illustrating a schematic configuration of a plunger of the embodiment of the invention. 
           [0033]      FIG. 6  is a plan view specifically illustrating the vicinity of a leading end of a nozzle body of Embodiment 1 of the invention. 
           [0034]      FIG. 7  is a side view specifically illustrating the vicinity of the leading end of the nozzle body of Embodiment 1 of the invention. 
           [0035]      FIG. 8  is a cross-sectional view specifically illustrating the vicinity of the leading end of the nozzle body of Embodiment 1 of the invention. 
           [0036]      FIG. 9  is a cross-sectional view illustrating the vicinity of the leading end of the nozzle body of the embodiment of the invention when viewed at three positions from the rear direction. 
           [0037]      FIG. 10  is a graph illustrating a lens deformation ratio and a horizontal dimension of a penetration hole of the embodiment of the invention. 
           [0038]      FIG. 11  is a cross-sectional view illustrating the vicinity of a lower leading end portion of Embodiment 1 of the invention. 
           [0039]      FIG. 12  is an enlarged cross-sectional view of the lower leading end portion of Embodiment 1 of the invention. 
           [0040]      FIG. 13  is a diagram illustrating the vicinity of the lower leading end portion of Embodiment 1 of the invention when viewed from the downside. 
           [0041]      FIG. 14  is a cross-sectional view illustrating the vicinity of a leading end of a nozzle body of Embodiment 2 of the invention. 
           [0042]      FIG. 15  is a cross-sectional view illustrating the vicinity of the lower leading end portion of Embodiment 2 of the invention. 
       
    
    
     DESCRIPTION OF EMBODIMENTS  
       [0043]    Hereinafter, embodiments of the invention will be described by referring to the drawings. 
       Embodiment 1  
       [0044]      FIG. 1  illustrates a schematic configuration of an intraocular lens insertion apparatus  1  (hereinafter, simply referred to as the insertion apparatus  1 ) of the embodiment.  FIG. 1(   a ) illustrates a plan view and  FIG. 1(   b ) illustrates a side view. The insertion apparatus  1  includes a nozzle body  10  that serves as an apparatus body which is formed with a cross-section having a substantially rectangular tube shape so that one side is largely opened (hereinafter, the largely opened side is referred to as a trailing end  10   b ) and the other side end is provided with a nozzle portion  15  as a thinly narrowed insertion tube and an obliquely opened leading end  10   a  and a plunger  30  that serves an extrusion member which is inserted into the nozzle body  10  so as to move in a reciprocating manner. Furthermore, in the description below, the direction directed from the leading end  10   a  of the nozzle body  10  toward the trailing end  10   b  is set as the front to rear direction, the direction perpendicular to the drawing paper of  FIG. 1(   a ) is set as the up to down direction, and the direction perpendicular to the front to rear direction and the up to down direction is set as the left to right direction. 
         [0045]    The vicinity of the trailing end  10   b  of the nozzle body  10  is integrally provided with a hold portion  11  which projects in a plate shape and is used for a user to hold the hold portion by fingers when the plunger  30  is pressed toward the leading end of the nozzle body  10 . Further, the nozzle body  10  which is positioned on the trailing end side of the nozzle portion  15  is provided with a stage portion  12  which is used to set an intraocular lens  2  thereon. When a stage cover portion  13  is opened from the stage portion  12 , the upside of the nozzle body  10  (the front side perpendicular to the drawing paper of  FIG. 1(   a )) is opened. Further, the stage portion  12  is mounted with a positioning member  50  from the downside of the nozzle body  10  (the rear side perpendicular to the drawing paper of  FIG. 1(   a )). By the positioning member  50 , the intraocular lens  2  is stably held inside the stage portion  12  before the usage of the lens (during the carriage of the lens). 
         [0046]    That is, in the insertion apparatus  1 , the intraocular lens  2  is set on the stage portion  12  while the stage cover portion  13  is opened and the positioning member  50  is mounted to the stage portion  12  at the manufacturing process. Then, when the insertion apparatus is shipped and sold, a user separates the positioning member  50  while closing the stage cover portion  13 , and then pushes the plunger  30  toward the leading end of the nozzle body  10 , so that the intraocular lens  2  is pressed by the plunger  30  and the intraocular lens  2  is extruded from the leading end  10   a.  Furthermore, the nozzle body  10 , the plunger  30 , and the positioning member  50  of the insertion apparatus  1  are formed of a resin such as polypropylene. The polypropylene is a material which has been used in a medical instrument and has high reliability in chemical resistance or the like. 
         [0047]      FIG. 2  is a diagram illustrating a schematic configuration of the intraocular lens  2 .  FIG. 2(   a ) illustrates a plan view and  FIG. 2(   b ) illustrates aside view. The intraocular lens  2  includes a lens body  2   a  which has a predetermined refractive power and two beard-like support portions  2   b  and  2   b  which are provided in the lens body  2   a  so as to hold the lens body  2   a  inside the eyeball. The lens body  2   a  is formed of a flexible resin. 
         [0048]      FIG. 3  illustrates a plan view of the nozzle body  10 . As described above, in the nozzle body  10 , the intraocular lens  2  is set on the stage portion  12 . Then, in this state, the intraocular lens  2  is pressed by the plunger  30  so as to be extruded from the leading end  10   a . Furthermore, the nozzle body  10  is provided with a penetration hole  10   c  of which the cross-sectional shape changes in response to a change in the outer shape of the nozzle body  10 . Then, when extruding the intraocular lens  2 , the intraocular lens  2  is deformed in response to a change in the cross-sectional shape of the penetration hole  10   c  inside the nozzle body  10 , and is deformed into a shape that the lens may be easily inserted into the incision formed in the patient&#39;s eyeball. 
         [0049]    The stage portion  12  is provided with a stage groove  12   a  which has a width slightly larger than the diameter of the lens body  2   a  of the intraocular lens  2 . The dimension of the stage groove  12   a  in the front to rear direction is set to be larger than the maximum width including the support portions  2   b  and  2   b  extending toward both sides of the intraocular lens  2 . Further, a set surface  12   b  is formed by the bottom surface of the stage groove  12   a . The position of the set surface  12   b  in the up to down direction (the position in a direction perpendicular to the drawing paper of FIG.  3 ) is set to the upside in relation to the height position of the bottom surface of the penetration hole  10   c  of the nozzle body  10  (the front side in a direction perpendicular to the drawing paper of  FIG. 3 ), and the set surface  12   b  is connected to the bottom surface of the penetration hole  10   c  by a bottom inclined surface  10   d.    
         [0050]    The stage portion  12  is integrally formed with the stage cover portion  13 . The dimension of the stage cover portion  13  in the front to rear direction is equal to that of the stage portion  12 . The stage cover portion  13  is connected by a thin plate-like connection portion  14  which is formed by extending the side surface of the stage portion  12  toward the stage cover portion  13 . The connection portion  14  is formed so that the connection portion maybe bent at the center thereof, and the stage cover portion  13  may cover the stage portion  12  from the upside thereof by bending the connection portion  14 . 
         [0051]    In the stage cover portion  13 , the surface facing the set surface  12   b  when covering the stage portion is provided with ribs  13   a  and  13   b  which reinforce the stage cover portion  13  so as to stabilize the position of the intraocular lens  2 . Further, a guide protrusion  13   c  is provided as the guide of the plunger  30 . 
         [0052]    The positioning member  50  is detachably mounted to the lower side of the set surface  12   b  of the stage portion  12 .  FIG. 4  illustrates a schematic configuration of the positioning member  50 .  FIG. 4(   a ) illustrates a plan view and  FIG. 4(   b ) illustrates aside view. The positioning member  50  is formed separately from the nozzle body  10 , and has a structure in which a pair of side wall portions  51  and  51  is connected by a connection portion  52 . The lower ends of the respective side wall portions  51  are provided with holding portions  53  and  53  which extend outward. 
         [0053]    Then, the upper ends of the respective side wall portions  51  and  51  are provided with a pair of first placement portions  54  and  54  which protrudes upward so as to have a circular-arc shape when viewed from the upside. Further, the outer peripheral side of the upper end surface of the first placement portion  54  is provided with the first positioning portions  55  and  55  which are formed in a protruding manner. The distance between the inner diameters of the first positioning portions  55  is set to be slightly larger than the diameter of the lens body  2   a  of the intraocular lens  2 . 
         [0054]    Further, both ends of the connection portion  52  in the front to rear direction are provided with a pair of second placement portions  56  and  56  which protrude upward so as to have a rectangular shape when viewed from the upside. The height of the upper surface of the second placement portion  56  is set to be equal to the height of the upper end surface of the first placement portion  54 . Moreover, the outer portions of the upper surfaces of the second placement portions  56  and  56  are provided with second positioning portions  57  and  57  which protrude upward further throughout the left to right direction of the second placement portions  56  and  56 . The gap between the inner surfaces of the second positioning portions  57  is set to be slightly larger than the diameter of the lens body  2   a  of the intraocular lens  2 . Moreover, as illustrated in  FIG. 4(   b ), the upper end of the second placement portion  56  is provided with locking claws  58  and  58  which slightly protrude in the front to rear direction throughout the left to right direction. 
         [0055]    In the embodiment, the positioning member  50  may be assembled from the downside of the set surface  12   b  of the nozzle body  10 . The set surface  12   b  of the nozzle body  10  is provided with set surface penetration holes  12   c  which are formed at four positions so as to penetrate the set surface  12   b  in the thickness direction. The outer shape of the set surface penetration hole  12   c  is formed in a shape almost similar to the shapes of the first placement portion  54  and the second placement portion  56  of the positioning member  50  when viewed from the upside so as to be slightly larger than the shapes. Then, when the positioning member  50  is mounted to the nozzle body  10 , the first placement portions  54  and  54  and the second placement portions  56  and  56  are inserted from the downside of the set surface  12   b  into the set surface penetration hole  12   c  so as to protrude toward the upside of the set surface  12   b.    
         [0056]    At this time, the locking claws  58  and  58  which are provided in the second placement portions  56  and  56  protrude toward the set surface  12   b  through the set surface penetration holes  12   c  and are locked to the upper surface of the set surface  12   b . Accordingly, the positioning member  50  is assembled from the downside of the nozzle body  10 , and the first placement portions  54  and  54  and the second placement portions  56  and  56  are fixed while protruding from the set surface  12   b . Then, when setting the intraocular lens  2  to the set surface  12   b , the bottom surface of the outer peripheral portion of the lens body  2   a  is placed on the upper surfaces of the first placement portions  54  and  54  and the second placement portions  56  and  56 . Further, the position of the lens body  2   a  is regulated by the first positioning portions  55  and  55  and the second positioning portions  57  and  57  in the front to rear direction and the left to right direction. 
         [0057]      FIG. 5  illustrates a schematic configuration of the plunger  30 . The plunger  30  has a length slightly larger than that of the nozzle body  10  in the front to rear direction. Then, the plunger includes a leading end side operation portion  31  which is basically formed in a columnar shape and a trailing end side insertion portion  32  which is basically formed in a rectangular rod shape. Then, the operation portion  31  includes a column portion  31   a  which is formed in a columnar shape and a thin plate-like flat portion  31   b  which is widened in the left to right direction of the column portion  31   a.    
         [0058]    The leading end of the operation portion  31  is provided with a notch  31   c.  As understood from  FIG. 5 , the notch  31   c  is formed in a groove shape which is opened toward the upside of the operation portion  31  and penetrates the operation portion in the left to right direction. Further, as understood from  FIG. 5(   b ), the leading end side end surface of the notch  31   c  is formed as an inclined surface which faces the upside as it goes toward the leading end of the operation portion  31 . 
         [0059]    Meanwhile, the insertion portion  32  has a substantially H-shaped cross-section as a whole, and the dimensions thereof in the left to right direction and the up to down direction are set to be slightly smaller than those of the penetration hole  10   c  of the nozzle body  10 . Further, the trailing end of the insertion portion  32  is provided with a disk-like pressure plate portion  33  which is widened in the up to down direction and the left to right direction. 
         [0060]    The leading end side portion in relation to the center of the insertion portion  32  in the front to rear direction is provided with a claw  32   a  which protrudes toward the upside of the insertion portion  32  and is movable up and down by the elasticity of the material of the plunger  30 . Then, when the plunger  30  is inserted into the nozzle body  10 , the claw  32   a  engages with a locking hole  10   e  which is provided in the upper surface of the nozzle body  10  in the thickness direction, so that the relative position between the nozzle body  10  and the plunger  30  at the initial state is determined. Furthermore, the positions to be provided with the claw  32   a  and a locking hole  10   d  are set so that, in the engagement state, the leading end of the operation portion  31  is positioned behind the lens body  2   a  of the intraocular lens  2  set to the stage portion  12  and the support portion  2   b  behind the lens body  2   a  may be supported by the notch  31   c  from the downside. 
         [0061]    Before using the insertion apparatus  1  with the above-described configuration, the plunger  30  is inserted into the nozzle body  10  so as to be disposed at the initial position. Further, the positioning member  50  is mounted to the stage portion  12  from the downside of the set surface  12   b  as described above. Accordingly, the first placement portion  54  and the second placement portion  56  of the positioning member  50  are maintained so as to protrude toward the set surface  12   b.    
         [0062]    Further, the lens body  2   a  of the intraocular lens  2  is placed and positioned on the upper end surfaces of the first placement portion  54  and the second placement portion  56  while the support portions  2   b  and  2   b  face the front to rear direction of the nozzle body  10 . In this state, the intraocular lens  2  is supported without applying any load to the center thereof because the outer peripheral portion of the lens body  2   a  contacts the first placement portion  54  and the second placement portion  56 . Further, in this state, the support portion  2   b  of the intraocular lens  2  is supported by the bottom surface of the notch  31   c  of the plunger  30 . 
         [0063]    Further, in this state, a stopper which restricts the advancing movement of the plunger  30  is formed by the second placement portion  56 , and hence the plunger  30  may not advance as long as the positioning member  50  is not detached from the nozzle body  10 . 
         [0064]    In a case where the intraocular lens  2  is inserted into the patient&#39;s eyeball by using the insertion apparatus  1 , the positioning member  50  is first separated from the nozzle body  10 . Accordingly, the first placement portion  54  and the second placement portion  56  which support the lens body  2   a  of the intraocular lens  2  are retracted from the set surface  12   b , so that the intraocular lens  2  is placed on the set surface  12   b . Since the set surface  12   b  is formed as a flat surface, the intraocular lens  2  may be stably placed thereon. Further, since the width of the stage groove  12   a  is set to be slightly larger than the diameter of the lens body  2   a  of the intraocular lens  2 , the rotation of the intraocular lens  2  in the circumferential direction on the set surface  12   b  is also suppressed. 
         [0065]    Subsequently, the leading end  10   a  of the nozzle body  10  is inserted into the incision provided in the eye tissue. Then, the leading end  10   a  is inserted into the incision. Subsequently, in this state, the pressure plate portion  33  of the plunger  30  is presses toward the leading end of the nozzle body  10 . Accordingly, the leading end of the operation portion  31  of the plunger  30  comes into contact with the outer periphery of the lens body  2   a  of the intraocular lens  2  set on the set surface  12   a,  and the intraocular lens  2  is guided toward the leading end  10   a  by the plunger  30 . 
         [0066]    Next, a configuration in the vicinity of the leading end  10   a  of the nozzle body  10  will be described in detail.  FIG. 6  illustrates a specific plan view in the vicinity of the leading end  10   a  of the nozzle body  10 . The outer shape of the nozzle body  10  is formed in a shape which becomes gradually tapered as it goes from the stage portion  12  toward the leading end  10   a  as a whole. The penetration hole  10   c  is provided with a tapered portion  10   f  of which the cross-sectional area gradually decreases. The tapered portion  10   f  is formed so that the cross-sectional area thereof decreases by decreasing the widths of the bottom surface and the upper surface as it goes toward the leading end  10   a . Here, the trailing end side bottom surface of the tapered portion  10   f  is provided with an inclined surface  10   g  which is inclined upward as it goes toward the leading end, and a step is formed by the inclined surface  10   g.    
         [0067]    The vicinity of the tapered portion  10   f  of the bottom surface of the penetration hole  10   c  is provided with a pair of guide protrusions  10   h  which extends in the front to rear direction of the nozzle body  10  with the center of the bottom surface in the left to right direction interposed therebetween. The guide protrusions  10   h  are provided throughout the front to rear direction of the inclined surface  10   g  in the axial direction, and slightly protrude upward from the trailing end side bottom surface of the tapered portion  10   f  so that linear shapes extend in parallel. Here, the leading end of the guide protrusion  10   h  is formed so as to have the same height as the inclined surface  10   g  at the leading end of the inclined surface  10   g , because the height of the inclined surface  10   g  is gradually increased as goes toward the leading end. Further, the distance between the guide protrusions  10   h  is set to a dimension slightly larger than the width of the operation portion  31  of the plunger  30 . 
         [0068]    Then, the nozzle portion  15  is formed near the leading end of the tapered portion  10   f  in the penetration hole  10   c , but the penetration hole  10   c  in the nozzle portion  15  is formed so as to extend straightly with a substantially constant cross-sectional area. The penetration hole  10   c  in the leading end  10   a  is opened, so that a leading end opening  10   j  is formed.  FIG. 7  illustrates a side view in the vicinity of the leading end  10   a . As illustrated in  FIG. 7 , the leading end opening  10   j  is formed by cutting the nozzle portion  15  in the nozzle body  10  so that the leading end opening is inclined backward as it goes downward. That is, an upper leading end portion  100  of the upper end of the leading end  10   a  is formed so as to extend forward in relation to a lower leading end portion  101  of the lower end thereof. Furthermore, the lower leading end portion  101  corresponds to the base end of the embodiment. 
         [0069]      FIG. 8  illustrates a cross-sectional view in the vicinity of the leading end  10   a . In  FIG. 8 , the leading end opening  10   j  is provided with a linear portion  102  which has a predetermined dimension and is formed in a linear shape with a constant inclination angle with respect to a plane M as a plane perpendicular to the center axis L of the nozzle portion  15  in a direction from the upper leading end portion  100  toward the lower leading end portion  101 . Then, a curved portion  103  is formed from the linear portion  102  so that the inclination angle with respect to the plane M gradually increases. The trailing end of the curved portion  103  is connected to the lower leading end portion  101 . 
         [0070]    Here, the inclination angle of the curved portion  103  with respect to the plane M is set to be larger than the inclination angle of the linear portion  102  with respect to the plane M. Accordingly, the leading end opening  10   j  is formed in a curved shape which protrudes outward in the side view thereof. 
         [0071]    In  FIG. 8 , the inclination angle a of the line N connecting the upper leading end portion  100  to the lower leading end portion  101  with respect to the plane M is not particularly limited, but may be set in the range of 60° to 80°. That is, when the inclination angle a is smaller than 60°, the leading end opening  10   j  becomes similar to a simple round opening which is widened in a direction perpendicular to the axis. Thus, it is difficult to suppress the intraocular lens  2  from popping out from the leading end  10   a . Also, there is a concern that a problem may occur in which the insertion resistance of the nozzle portion  15  inside the eyeball increases or the incision in the eyeball is widened to increase the patient&#39;s burden. 
         [0072]    Meanwhile, when the inclination angle a is larger than 80°, the opening dimension of the leading end opening  10   j  in the axial direction increases too much, and hence there is a concern that the intraocular lens  2  may not be reliably held in the vicinity of the leading end  10   a . In addition, the inclination angle β of the linear portion  102  with respect to the plane M is not particularly limited, but may be set in the range of 40° to 60°. That is, when the inclination angle β is smaller than 40°, there is a concern that the leading end  10   a  may not be easily inserted into the incision or the incision may be widened to increase the patient&#39;s burden. Further, when the inclination angle β is larger than 60°, there is a concern that the intraocular lens  2  may not be reliably held. In the embodiment, the inclination angles are set such that α=70° and β=50°. 
         [0073]    Further, the curved portion  103  is formed so that the curvature radius of the portion near the linear portion  102  and the curvature radius of the portion near the lower leading end portion  101  are different from each other. In the embodiment, the portion near the linear portion  102  is formed in a curved shape with a curvature radius R 1 =4.5 mm and the portion near the lower leading end portion  101  is formed in a curved shape with a curvature radius R 2 =20 mm. That is, the opening end surface of the leading end opening  10   j  includes a portion which is formed in a linear shape from the upper leading end portion  100  to the lower leading end portion  101  and a plurality of curved portions of which the curvature radiuses gradually increase in the cross-sectional view of  FIG. 8 . Furthermore, in the cross-sectional view, the leading end opening  10   j  maybe entirely formed as only the curved portion and maybe formed so that the curvature gradually changes. Further, the leading end opening may be formed by the combination of the curved portion and the linear portion. 
         [0074]    As described above, the leading end opening  10   j  is formed in a shape of an opening end surface which is opened obliquely downward. Furthermore, the length of the leading end opening  10   j  in the front to rear direction may be set in the range of 2.5 mm to 5.0 mm. That is, when the length of the leading end opening  10   j  in the front to rear direction is smaller than 2.5 mm, the leading end opening becomes a simple round opening which is substantially widened in a direction perpendicular to the axis. Accordingly, it is difficult to suppress the popping-out of the intraocular lens  2 . On the other hand, when the length of the leading end opening  10   j  in the axial direction is larger than 5.0 mm, it maybe difficult to hold the intraocular lens  2  until the intraocular lens is guided to the upper leading end portion  100 . In the embodiment, the length of the leading end opening  10   j  in the axial direction is set to 3.70 mm. 
         [0075]    Further, the inner diameter of the penetration hole  10   c  in the vicinity of the leading end  10   a  may be set in the range of 1.0 mm to 2.5 mm. That is, when the inner diameter of the penetration hole  10   c  is smaller than 1.0 mm, the compressing deformation of the intraocular lens  2  excessively occurs, so that the intraocular lens  2  may easily pop out vigorously from the leading end opening  10   j  due to the restorative force thereof. Meanwhile, when the inner diameter of the penetration hole  10   c  is larger than 2.5 mm, the curving deformation applied to the intraocular lens  2  is small, and the abutting force against the penetration hole  10   c  as the reaction force of the deformation decreases. As a result, there is a concern that the intraocular lens  2  may not be held until the intraocular lens is guided to the upper leading end portion  100 . In the embodiment, the penetration hole  10   c  in the vicinity of the leading end  10   a  is formed in an oval shape with a dimension of 1.5 mm×2.0 mm. 
         [0076]    Further, as illustrated in  FIGS. 7 and 8 , the outer peripheral surface of the leading end  10   a  is provided with a tapered surface  104  which is formed throughout the entire circumference so as to be widened outward as it goes toward the rear side in the axial direction. Accordingly, the circumferential edge of the leading end opening  10   j  is formed in a sharp edge shape throughout the entire circumference. Here, the inclination angle y of the tapered surface  104  with respect to the center axis L is not particularly limited, but may be set in the range of 5° to 15°. That is, when the inclination angle γ is smaller than 5°, a result is substantially obtained in a case without the tapered surface  104 , and hence there is a concern that the nozzle portion  15  may not be easily inserted into the incision. Further, when the inclination angle γ is larger than 15°, the circumferential edge of the leading end opening  10   j  is not formed in a sharp edge shape, and also there is a concern that the nozzle portion  15  may not be easily inserted into the incision. 
         [0077]    Furthermore, in the embodiment, the tapered surface  104  is formed in a curved shape of which the inclination angle with respect to the center axis L gradually changes, and the tapered surface  104  which is formed in the upper leading end portion  100  is formed as a curved surface with a curvature radius R 3 =5.0 mm. That is, in the embodiment, the circumferential edge of the leading end opening  10   j  is provided with the tapered surface  104  which has a curved longitudinal cross-sectional shape protruding outward in the entire circumference and extends outward in the axial direction. Accordingly, the curved portion  103  is smoothly connected to the tapered surface  104 . Furthermore, the inclination angle of the tapered surface  104  does not need to be constant in the entire circumferential edge of the leading end opening  10   j.    
         [0078]    In the intraocular lens insertion apparatus  1  of the embodiment, since the shape in the vicinity of the leading end  10   a  of the nozzle body  10  is formed as the above-described shape, the nozzle portion  15  may be more easily inserted into the incision. Accordingly, it is possible to improve the operability of the operator and to further decrease the size of the incision necessary when inserting the nozzle portion  15  thereinto. Accordingly, the patient&#39;s burden may be reduced. 
         [0079]    Further, according to the nozzle body  10 , since the inclination angle of the leading end opening  10   j  is set to be large at the side of the lower leading end portion  101  in relation to the side of the upper leading end portion  100 , the leading end opening  10   j  is formed in a shape which protrudes outward in the side view and the opening amount near the lower leading end portion  101  is set to be small. Accordingly, it is possible to ensure a long region surrounding the intraocular lens  2  at both sides thereof in the front to rear direction and to suppress the intraocular lens  2  from popping out from the leading end  10   a . Further, since the intraocular lens  2  is exposed to a sufficiently large region, the intraocular lens  2  may be inserted into the eyeball so as to fall in such an opening direction, and hence the intraocular lens  2  may be stably inserted into a position which is desired by the operator. 
         [0080]      FIG. 9  illustrates a cross-sectional view at three positions in the vicinity of the leading end  10   a  of the nozzle body  10 .  FIG. 9(   a ) is a diagram illustrating a cross-section taken along the line A-A of  FIG. 6 ,  FIG. 9(   b ) is a diagram illustrating a cross-section taken along the line B-B, and  FIG. 9(   c ) is a diagram illustrating a cross-section taken along the line C-C. In any drawing of  FIGS. 9(   a ) to  9 ( c ), both upper and lower surfaces of the penetration hole  10   c  are provided with upper and lower flat surfaces  105   a  and  105   b  which extend in the left to right direction in substantially parallel. Then, both ends of the upper and lower flat surfaces  105   a  and  105   b  are connected with left and right curved surfaces  107   a  and  107   b  which extend in the left or right direction at both upper and lower portions and are curved in the inward depressing direction. Here, the left and right curved surfaces  107   a  and  107   b  are smoothly connected to the upper and lower flat surfaces  105   a  and  105   b  so as to have a common tangent and not to have any break point. 
         [0081]    In the cross-section taken along the line A-A illustrated in  FIG. 9(   a ), the horizontal dimension of the penetration hole  10   c  is indicated by wa 1  and the vertical dimension thereof is indicated by hat. Further, the horizontal dimension of the nozzle portion  15  is indicated by wa 2  and the vertical dimension thereof is indicated by ha 2 . In this case, a relation of wa 1 ≧ha 1  and wa 2 ≧ha 2  is established. In the cross-section taken along the line B-B illustrated in  FIG. 9(   b ), the horizontal dimension of the penetration hole  10   c  is indicated by wb 1  and the vertical dimension thereof is indicated by hb 1 . Further, the horizontal dimension of the nozzle portion  15  is indicated by wb 2  and the vertical dimension thereof is indicated by hb 2 . In the cross-section taken along the line B-B, the horizontal dimensions of the nozzle portion  15  and the penetration hole  10   c  become larger than those of the cross-section taken along the line A-A. Meanwhile, the vertical dimensions of the nozzle portion  15  and the penetration hole  10   c  substantially do not change. That is, a relation of wb 1 &gt;wa 1 , wb 2 &gt;wa 2 , hb 1 ≈ha 1 , and hb 2 ≈ha 2  is established. Further, the horizontal thickness of the nozzle body  10  in the nozzle portion  15 , that is, the outer horizontal thickness of the penetration hole  10   c  in the nozzle body  10  in the cross-section taken along the line B-B becomes thicker than that of the cross-section taken along the line A-A. 
         [0082]    In the cross-section taken along the line C-C illustrated in  FIG. 9(   c ), the horizontal dimension of the penetration hole  10   c  is indicated by wc 1  and the vertical dimension thereof is indicated by hc 1 . Further, the horizontal dimension of the nozzle portion  15  is indicated by wc 2  and the vertical dimension thereof is indicated by hc 2 . In the cross-section taken along the line C-C, the horizontal dimensions of the nozzle portion  15  and the penetration hole  10   c  become considerably larger than those of the cross-section taken along the line B-B. Further, the vertical dimension of the nozzle portion  15  also increases. Meanwhile, the vertical dimension of the penetration hole  10   c  substantially does not change. 
         [0083]    That is, a relation of wc 1 &gt;wb 1 , wc 2 &gt;wb 2 , hc 2 &gt;hb 2 , and hc 1 ≈hb 1  is established. Further, the thickness of the nozzle body  10 , that is, the outer thickness of the penetration hole  10   c  in the nozzle body  10  in the cross-section taken along the line C-C in the up to down direction and the left to right direction becomes thicker than that of the cross-section taken along the line B-B. As understood from the comparison of  FIGS. 9(   a ) to  9 ( c ), in the nozzle portion  15 , there is a tendency that the thickness of the nozzle body  10  becomes thinner in the up to down direction and the left to right direction as it goes toward the leading end  10   a . In particular, the tendency becomes apparent in the left to right direction. 
         [0084]    With regard to the surgery in which the intraocular lens  2  is inserted into the patient&#39;s eyeball by using the above-described intraocular lens insertion apparatus  1 , in recent years, there is a demand that the dimension in the vicinity of the leading end  10   a  of the nozzle body  10  needs to be decreased further and the diameter of the incision in the eye tissue needs to be decreased in order to reduce the patient&#39;s burden. Specifically, there is a demand to particularly decrease wa 1 , wa 2 , wb 1 , and wb 2  in  FIG. 9 . In fact, there is an attempt to decrease the respective dimensions by about 0.1 mm. 
         [0085]      FIG. 10  illustrates a graph with respect to the lens deformation ratio and the horizontal dimension wa 1  of the penetration hole  10   c  before and after performing the above-described improvement (a decrease in dimension).  FIG. 10(   a ) illustrates an example of a relation of the distance from the leading end  10   a  and wa 1  in the penetration hole  10   c  before and after the improvement. The horizontal axis indicates the distance from the leading end  10   a  and the vertical axis indicates the horizontal dimension wa 1  of the penetration hole  10   c.  Further,  FIG. 10(   b ) illustrates an example of a relation between the lens deformation ratio and the distance from the leading end  10   a  before and after the improvement. The horizontal axis indicates the distance from the leading end  10   a  and the vertical axis indicates the lens deformation ratio. As apparently understood from  FIGS. 10(   a ) and  10 ( b ), the horizontal dimension wa 1  of the penetration hole  10   c  decreases in the vicinity of the leading end  10   a , for example, the lower leading end portion  101 , so that the lens deformation ratio increases. 
         [0086]    In this case, the thickness of the nozzle body  10  is further thinned in the vicinity of the leading end  10   a  of the nozzle portion  15 , for example the lower leading end portion  101 . Further, the restorative force of the intraocular lens  2  intensively acts in the vicinity of the lower leading end portion  101  of the nozzle body  10  due to the increased lens deformation ratio. For this reason, there is a concern that a crack occurs in the nozzle body  10  at the lower leading end portion  101 . 
         [0087]    On the contrary, according to the invention, in the cross-sectional view in the vicinity of the leading end  10   a  of the nozzle portion  15  illustrated in  FIG. 8 , the sharp edge shape particularly in the lower leading end portion  101  is formed with a curvature radius smaller than the curvature radius of the other region in the sharp edge shape or the curvature radius according to a change in the inclination angle of the leading end opening  10   j.  Accordingly, a problem such as a crack is suppressed by ensuring the thickness of the nozzle body  10  in the vicinity of the lower leading end portion  101 . 
         [0088]      FIG. 11  is a diagram illustrating a difference in the cross-sectional view in the vicinity of the lower leading end portion  101  due to the existence of the application (improvement) of the invention.  FIG. 11(   a ) illustrates a diagram before the improvement and  FIG. 11(   b ) illustrates a diagram after the improvement. Further, in  FIGS. 11(   a ) and  11 ( b ), the left diagrams are cross-sectional views in the vicinity of the leading end  10   a , and the right diagrams are enlarged views in the vicinity of the lower leading end portion  101 . As illustrated in  FIG. 11(   a ), before the improvement, the inclined curve of the leading end opening  10   j  from the upper leading end portion  100  to the lower leading end portion  101  with respect to the plane M is continuously formed by the line and the curves with different curvature radiuses as described above. Then, the same curvature radius R 2  before and after the lower leading end portion  101  is employed. In this case, the inclination angle of the leading end opening  10   j  in the lower leading end portion  101  with respect to the plane M largely increases and the thickness of the nozzle body  10  in the lower leading end portion  101  considerably decreases. 
         [0089]    Meanwhile, after the improvement of the invention, as illustrated in  FIG. 11(   b ), the curvature radius R 4  satisfying the relation of R 4 &lt;R 2  is employed in the sharp edge shape in the vicinity of the lower leading end portion  101 . Further, the curvature radius R 4  satisfies the relation of R 4 &lt;R 1  and R 4 &lt;R 3 . Accordingly, the thickness of the sharp edge shape in the vicinity of the lower leading end portion  101  may be suddenly increased as it goes backward from the lower leading end portion  101 , and hence the strength of the nozzle body  10  at the portion may be considerably improved. 
         [0090]      FIG. 12  illustrates an example of an enlarged view in the vicinity of the lower leading end portion  101  of the embodiment. In this example, the curvature radius of about R 4 =0.3 to 0.4 is employed as the curvature of the sharp edge shape of the lower leading end portion  101 . In this case, compared to the case where, for example, the inclined curve of the leading end opening  10   j  with respect to the plane M is continuously formed by the line and the curves with different curvature radiuses as described above and the same curvature radius R 2  is employed before and after the lower leading end portion  101 , the thickness in the vicinity of the lower leading end portion  101  of the nozzle body  10  may be increased by 0.02 mm to 0.03 mm. Further, at this time, the width of the thickness increasing region (hereinafter, referred to as a thickened region  10   k ) becomes 0.3 to 0.4 mm. 
         [0091]      FIG. 13(   a ) illustrates a diagram obtained by viewing the thickened region  10   k  of the embodiment from the downside.  FIG. 13(   b ) illustrates a case without the thickened region  10   k  for comparison. In  FIG. 13(   a ), the hatching region is the thickened region  10   k.  Further, in  FIGS. 13(   a ) and  13 ( b ), the region surrounded by the dashed line is the tapered surface  104  with the sharp edge shape of the circumferential edge of the leading end opening  10   j.  The tapered surface  104  may be an actual tapered surface with a linear cross-section (the curvature radius=infinity) and may be a tapered surface of which the cross-section has the curvature as described above. Anyway, the strength of the thickened region  10   k  may be remarkably improved by decreasing the curvature radius of the thickened region  10   k  compared to the curvature radius in the other region of the tapered surface  104 . 
       Embodiment 2  
       [0092]    Next, Embodiment 2 of the invention will be described. In the embodiment, an example will be described in which the invention is applied to a nozzle body  60  with a leading end  60   a  different from that of Embodiment 1. 
         [0093]      FIG. 14  illustrates a cross-sectional view in the vicinity of the leading end  60   a . As illustrated in  FIG. 14 , as in Embodiment 1, a leading end opening  60   j  is formed by cutting a nozzle portion  65  of the nozzle body  60  so that the nozzle portion is inclined backward as it goes downward. That is, in the leading end  60   a , an upper leading end portion  200  of the upper end protrudes forward in relation to a lower leading end portion  201  of the lower end thereof. 
         [0094]    In  FIG. 14 , the leading end opening  60   j  is provided with a curved portion  202  which is formed with a predetermined dimension from the upper leading end portion  200  toward the lower leading end portion  201  so that the inclination angle with respect to the plane M as the plane perpendicular to the center axis L of the nozzle portion  65  gradually increases. Then, a linear portion  203  is formed which is connected to the curved portion  202  and is formed by a line inflected so that the inclination angle with respect to the plane M further increases, and the trailing end of the linear portion  203  is connected to the lower leading end portion  201 . Furthermore, in the embodiment, in  FIG. 14 , the inclination angles are set such that β=53.3°, δ=75°, and α=67.2°. Further, the length parallel to the center axis L of the leading end opening  60   j  becomes about 3.6 mm. 
         [0095]    In the embodiment, the opening end surface of the leading end opening  60   j  is formed by two regions of the curved portion  202  and the linear portion  203  as described above. In the embodiment, the curvature radius R 1  with respect to the curved portion  202  becomes 8.55 mm and the curvature radius R 2  with respect to the linear portion  203  becomes infinite. Further, the upper portion of the upper leading end portion  200  becomes an R-surface with a curvature radius R 3  of 0.3 mm. Even in the embodiment, since the shape in the vicinity of the leading end  60   a  of the nozzle body  60  is formed as described above, the nozzle portion  65  may be more easily inserted into the incision and hence the operator&#39;s operability may be improved. 
         [0096]    Further, even in the nozzle body  60 , since the inclination angle of the leading end opening  60   j  with respect to the plane M in the linear portion  203  is set to be larger than that of the curved portion  202 , the leading end opening  60   j  is formed in a shape which protrudes outward in the side view and the opening amount in the lower leading end portion  201  is set to be small. Accordingly, it is possible to ensure a long region surrounding the intraocular lens at both sides thereof in the front to rear direction and to suppress the intraocular lens from popping out from the leading end  60   a . Further, since the intraocular lens is exposed to a sufficiently large region, the intraocular lens may be inserted into the eyeball so as to fall in such an opening direction, and hence the intraocular lens may be stably inserted into a position which is desired by the operator. 
         [0097]      FIG. 15  is a diagram illustrating a difference in the cross-sectional view in the vicinity of the lower leading end portion  201  due to the existence of the application (referred to as the improvement) of the invention with respect to the nozzle portion  65  of the embodiment.  FIG. 15(   a ) illustrates a diagram before the improvement and  FIG. 15(   b ) illustrates a diagram after the improvement. Further, in  FIGS. 15(   a ) and  15 ( b ), the left drawings are cross-sectional views in the vicinity of the leading end  60   a , and the right drawings are enlarged views in the vicinity of the lower leading end portion  201 . As illustrated in  FIG. 15(   a ), before the improvement, the inclined curve of the leading end opening  60   j  from the upper leading end portion  200  to the lower leading end portion  201  with respect to the plane M is formed by the curved portion  202  and the linear portion  203  as described above. In this case, in the lower leading end portion  201 , the inclination angle of the leading end opening  20   j  of the linear portion  203  with respect to the plane M becomes 75°, and the thickness of the nozzle body  60  in the lower leading end portion  201  is very thin. 
         [0098]    Meanwhile, after the improvement by the application of the invention, as illustrated in  FIG. 15(   b ), the curvature radius R 4  of 0.3 mm is employed in the cross-sectional view in the vicinity of the lower leading end portion  201 . The R 4  satisfies a relation of R 4 &lt;R 1  (=8.55 mm), R 4 &lt;R 2  (=∞), and R 4 ≦R 3 . By employing R 4 , the thickness of the edge of the nozzle body  60  in the vicinity of the lower leading end portion  201  may be suddenly increased as it goes backward from the lower leading end portion  201 , and the strength of the nozzle body  60  of the portion may be remarkably improved. 
         [0099]    Even in the embodiment, as in the drawing illustrated in  FIG. 12 , it is possible to increase the thickness in the vicinity of the lower leading end portion  201  of the nozzle body  60  by 0.02 mm to 0.03 mm compared to the case where R 4  is not provided in the vicinity of the lower leading end portion  201 . Further, even at this time, the width of the thickness increasing region (thickened region) becomes 0.3 to 0.4 mm. Further, the drawing obtained by viewing the thickened region from the downside in the embodiment becomes the hatching portion illustrated in  FIG. 13(   a ). 
       REFERENCE SIGNS LIST  
       [0100]      1  INSERTION APPARATUS 
         [0101]      2  INTRAOCULAR LENS 
         [0102]      10 ,  60  APPARATUS BODY 
         [0103]      10   a ,  60   a  LEADING END 
         [0104]      10   c  PENETRATION HOLE 
         [0105]      10   j,    60   j  LEADING END OPENING 
         [0106]      10   k  THICKENED REGION 
         [0107]      12  STAGE PORTION 
         [0108]      12   b  SET SURFACE 
         [0109]      13  STAGE COVER PORTION 
         [0110]      13   a  RIB 
         [0111]      13   b  RIB 
         [0112]      13   c  GUIDE PROTRUSION 
         [0113]      30  PLUNGER 
         [0114]      50  POSITIONING MEMBER 
         [0115]      100 ,  200  UPPER LEADING END PORTION 
         [0116]      101 ,  201  LOWER LEADING END PORTION 
         [0117]      104  TAPERED SURFACE