Abstract:
Provided is technology which can prevent plunger deformation and further stabilize an intraocular lens insertion operation, even when an insertion tube section of an intraocular lens insertion apparatus has been further reduced in terms of the diameter thereof and has been made flatter. The intraocular lens insertion apparatus includes: a tip end region where a plunger comes into contact with an intraocular lens main body and an intraocular lens holding section; and a bar-shaped section extending from the rear end of this tip end region to the rear of the plunger. The bar-shaped section has a fixed thickness in the direction of the optical axis of the intraocular lens, and has an increasing thickness in a portion where the distance from the tip end of the tip end region is equal to or greater than a predetermined distance in a direction perpendicular to the optical axis direction and perpendicular to the plunger advancement direction.

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 in 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 (for example, see Patent Literatures 1 to 3). 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]    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 diameter of the plunger 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 resistance acting on the plunger during the extrusion becomes stronger. As a result, there is a case in which the plunger is deformed when extruding the intraocular lens from the insertion apparatus, so that the operation of inserting the intraocular lens is not stably performed. 
       CITATION LIST 
     Patent Literature 
       [0005]    Patent Literature 1: Japanese Patent Application Laid-Open (JP-A) No. 2009-160153 
         [0006]    Patent Literature 2: JP-A No. 2009-183367 
         [0007]    Patent Literature 3: JP-A No. 2009-28223 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0008]    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 further stabilizing an intraocular lens insertion operation by suppressing a deformation of a plunger when extruding an intraocular lens from an insertion apparatus even when an insertion tube of an intraocular lens insertion apparatus further decreases in size. 
       Solution to Problem 
       [0009]    According to the invention, there is provided an intraocular lens insertion apparatus, wherein a plunger includes a leading end region which contacts an intraocular lens body or an intraocular lens holding portion and a rod-like portion which extends toward the rear side of the plunger from a trailing end of the leading end region, and wherein the rod-like portion is formed so that a thickness with respect to the optical axis direction of the intraocular lens is constant and a thickness of a portion distant from a leading end of the leading end region by a predetermined distance or more increases with respect to a direction perpendicular to the optical axis direction and perpendicular to the plunger advancing direction (the intraocular lens pressing direction). 
         [0010]    More specifically, there is provided an intraocular lens insertion apparatus which inserts a deformable intraocular lens into an eyeball from an incision opening formed in an eyeball tissue, the intraocular lens insertion apparatus comprising: 
         [0011]    an apparatus body which is formed in a substantially tubular shape and includes an insertion tube formed in a leading end thereof so as to be inserted into the incision opening; 
         [0012]    an accommodation portion which is formed integrally with or separately from the apparatus body and accommodates the intraocular lens therein so as to dispose the intraocular lens inside the apparatus body; and 
         [0013]    a plunger which presses the intraocular lens accommodated in the accommodation portion by a leading end thereof so as to discharge the intraocular lens from the insertion tube into the eyeball, 
         [0014]    wherein the plunger includes a leading end region which contacts the intraocular lens body and/or a beard-like lens holding portion extending from the intraocular lens body and a rod-like portion which extends from a trailing end of the leading end region in a direction opposite to the pressing direction, and 
         [0015]    wherein the rod-like portion is formed so that a thickness with respect to the optical axis direction of the accommodated intraocular lens is constant and a thickness of a portion distant from a leading end of the leading end region by a predetermined distance or more increases with respect to a direction perpendicular to the optical axis direction and perpendicular to the pressing direction. 
         [0016]    Here, when decreasing particularly the sizes of the insertion tube and the plunger of the apparatus body, there is a concern that the plunger may be deformed when extruding the intraocular lens into the eyeball as described above. Then, according to the careful examination of the inventor, the inventor found that the deformation mainly occurred so that the rod-like portion of the plunger was curved in a direction perpendicular to the optical axis of the intraocular lens. It is considered that this problem is caused by the fact that the intraocular lens body has a substantially round shape and easily rotates in a direction perpendicular to the optical axis. 
         [0017]    Accordingly, in the invention, the dimension of the rod-like portion is made constant with respect to the optical axis direction of the accommodated intraocular lens, and the thickness of the portion distant from the leading end of the leading end region by a predetermined distance or more increases with respect to the direction perpendicular to the optical axis direction of the intraocular lens and perpendicular to the pressing direction. That is, even when a portion close to the leading end region in the rod-like portion decreases in diameter, a large load is not applied thereto. However, a large load may be applied to a portion distant from the leading end region when pressing the intraocular lens. In consideration of this state, only the portion distant from the leading end of the leading end region by a predetermined distance or more increases in thickness with respect to the direction perpendicular to the optical axis direction of the intraocular lens and perpendicular to the pressing direction. 
         [0018]    Thus, since the thickness of the plunger may be increased with respect to the portion and the direction at minimum, an increase in the dimension of the plunger may be suppressed as minimal as possible on the whole. As a result, it is possible to decrease particularly the size of the insertion tube of the apparatus body and to suppress the deformation of the plunger. As a result, it is possible to further stably insert the intraocular lens into the eyeball through the smaller incision. 
         [0019]    Further, in the invention, the predetermined distance may be equal to or longer than a distance in which the insertion tube may enter the eyeball. In the intraocular lens insertion apparatus, it is desirable to first decrease the size of at least the range of the insertion tube which may enter the eyeball. Thus, when the predetermined distance is set to be equal to or longer than the distance of the range in which the insertion tube may enter the eyeball, the small thickness of the rod-like portion of the plunger may be maintained in the range in which the insertion tube may enter the eyeball. With such a configuration, since the small diameter of the insertion tube may be maintained in the range in which the insertion tube may enter the eyeball, the incision may be also decreased in size as much as possible. 
         [0020]    Further, in the invention, the plunger may be exposed from a leading end of the insertion tube by a predetermined exposure distance, and the predetermined distance may be equal to or longer than a sum of the exposure distance and a distance of a range in which the insertion tube is able to enter the eyeball. Then, even in a configuration in which the plunger may be exposed from the leading end of the insertion tube, it is possible to further reliably maintain the small diameter of the insertion tube in the range in which the insertion tube may enter the eyeball and hence to decrease the size of the incision as much as possible. 
         [0021]    Further, in the invention, the predetermined distance may be equal to or longer than a length of the lens holding portion. Here, in the intraocular lens insertion apparatus, the lens holding portion of the intraocular lens is originally formed so as to contact the leading end region of the plunger. However, a case may be considered in which the lens holding portion is separated from the leading end region and also contacts the rod-like portion during the intraocular lens insertion operation. Thus, if the predetermined distance is set to be equal to or longer than the length of the lens holding portion, even when the lens holding portion is separated from the leading end region, the lens holding portion does not reach the thickness increasing portion of the rod-like portion. Accordingly, it is possible to suppress a problem in operation in which the lens holding portion is nipped between the rod-like portion and the apparatus body. 
         [0022]    Further, in the invention, the rod-like portion may be provided with a tapered portion which is formed in a place distant from the leading end of the leading end region by the predetermined distance so that a thickness perpendicular to the optical axis direction and perpendicular to the pressing direction substantially increases approximately in proportional to the distance from the leading end of the leading end region. That is, in a case of increasing the thickness of the portion distant from the leading end of the leading end region by a predetermined distance or more, when the thickness is increased in a stair shape, a stress concentrates on the portion, so that there is a risk that the portion may be intensively deformed. Thus, in the invention, in a case of increasing the thickness of the portion distant from the leading end of the leading end region by a predetermined distance or more, the thickness is gradually increased by forming the tapered portion. Accordingly, since the thickness of the rod-like portion may be increased without causing an unnecessary stress concentration therein, the deformation of the rod-like portion may be further reliably suppressed. 
         [0023]    Further, in the invention, a bottom surface of the accommodation portion may be provided with two bank-like rails which are provided in parallel in the pressing direction of the plunger, and the plunger may be supported by two rails inside the apparatus body. By adopting this configuration, when the thickness of the rod-like portion increases, the rod-like portion moves in a direction in which the height of the rod-like portion supported by two rails increases. Then, for example, in a case where a slight clearance is provided at the upper side of the rod-like portion so as to form a position regulation guide, when the plunger is pressed toward the front side of the apparatus body by a certain degree, it is possible to decrease the clearance between the rod-like portion and the position regulation guide and hence to increase the plunger pressing resistance. 
         [0024]    According to this configuration, it is possible to further reliably suppress the intraocular lens from carelessly popping out from the apparatus body by gradually increasing the plunger pressing resistance at the timing before extruding the intraocular lens from the insertion tube. 
         [0025]    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 
       [0026]    According to the invention, even when the insertion tube of the intraocular lens insertion apparatus further decreases in size, it is possible to further stabilize the intraocular lens insertion operation by suppressing the deformation of the plunger when extruding the intraocular lens from the insertion apparatus. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0027]      FIG. 1  is a diagram illustrating a schematic configuration of an intraocular lens insertion apparatus of Embodiment 1 of the invention. 
           [0028]      FIG. 2  is a diagram illustrating a schematic configuration of the intraocular lens of the embodiment of the invention. 
           [0029]      FIG. 3  is a diagram illustrating a schematic configuration of a nozzle body of Embodiment 1 of the invention. 
           [0030]      FIG. 4  is a diagram illustrating a schematic configuration of a positioning member of the embodiment of the invention. 
           [0031]      FIG. 5  is a diagram illustrating a schematic configuration of a plunger of the embodiment of the invention. 
           [0032]      FIG. 6  is a graph with respect to a lens deformation ratio and a horizontal dimension of a penetration hole of the embodiment of the invention. 
           [0033]      FIG. 7  is a diagram illustrating the vicinity of a leading end of the plunger of the embodiment of the invention. 
           [0034]      FIG. 8  is a diagram illustrating a schematic configuration of a nozzle body of Embodiment 2 of the invention. 
           [0035]      FIG. 9  is a diagram illustrating a relation between a height and a position of a plunger of Embodiment 2 of the invention. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0036]    Hereinafter, embodiments of the invention will be described by referring to the drawings. 
       Embodiment 1  
       [0037]      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  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  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. 
         [0038]    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 serves as an accommodation portion 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). 
         [0039]    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.    
         [0040]      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 a side 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 support portions  2   b  and  2   b  correspond to the lens holding portion in the embodiment. The lens body  2   a  is formed of a flexible resin. 
         [0041]      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 so as to be extruded. 
         [0042]    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.    
         [0043]    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 . 
         [0044]    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 . 
         [0045]    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 a side 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. 
         [0046]    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 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  1 . 
         [0047]    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 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 . 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, 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. 
         [0048]    In the embodiment, the positioning member  50  maybe 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 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.    
         [0049]    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. 
         [0050]      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.    
         [0051]    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 . 
         [0052]    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. 
         [0053]    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 illustrated in  FIG. 3  and 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 the locking hole  10   e  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  maybe supported by the notch  31   c  from the downside. 
         [0054]    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 nozzle body  10  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.    
         [0055]    Further, the lens body  2   a  of the intraocular lens  2  is placed and positioned on the upper 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 . 
         [0056]    Further, in this state, the second placement portion  56  is provided with a stopper which restricts the advancing movement of the plunger  30 , and hence the plunger  30  may not advance as long as the positioning member  50  is not detached from the nozzle body  10 . 
         [0057]    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. 
         [0058]    Subsequently, the leading end  10   a  of the nozzle portion  15  of the nozzle body  10  is inserted into the incision provided in the eye tissue. Here, since the leading end  10   a  has an inclined opening shape, the leading end may be easily inserted into the incision. Then, the nozzle portion  15  is inserted into the incision. Subsequently, in this state, the pressure plate portion  33  of the plunger  30  is pressed 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 . 
         [0059]    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 needs to be decreased in order to reduce the patient&#39;s burden. Specifically, there is an attempt to decrease the horizontal dimensions of the nozzle portion  15  and the penetration hole  10   c  by about 0.1 mm. 
         [0060]      FIG. 6  illustrates a graph with respect to the lens deformation ratio and the horizontal dimension of the penetration hole  10   c  before and after performing the above-described improvement (a decrease in dimension).  FIG. 6(   a ) illustrates an example of a relation of the distance from the leading end  10   a  to the penetration hole  10   c  and the horizontal dimension of 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 of the penetration hole  10   c.  Further,  FIG. 6(   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. 6(   a ) and  6 ( b ), the horizontal dimension of the penetration hole  10   c  decreases in the vicinity of the leading end  10   a,  so that the lens deformation ratio increases. 
         [0061]    In a case where this improvement is performed, when the intraocular lens  2  is pressed by the plunger  30  so as to move forward inside the nozzle body  10 , the deformation ratio of the intraocular lens  2  further increases, so that the resistance against the pressing operation of the plunger  30  further increases. Further, there is a need to decrease the diameter of the operation portion  31  of the plunger  30  in accordance with a decrease in the size of the penetration hole  10   c.  As a result, since the operation portion  31  of the plunger  30  is thin, there is a concern that deformation such as bending of the operation portion  31  occurs. Then, it is difficult to accurately transmit the movement of the plunger  30  to the intraocular lens  2 , and hence there is a case in which the intraocular lens  2  may not be easily and stably inserted into the patient&#39;s eyeball. 
         [0062]    When extruding the intraocular lens  2  from the leading end  10   a  of the nozzle body  10 , the intraocular lens is extruded in a deformed state. For this reason, there is a concern that a problem may occur in which the intraocular lens  2  pops out due to the elastic force generated when restoring the shape of the intraocular lens  2 , and hence it is important to stably control the plunger  30  during the extrusion. Thus, it is desirable that the deformation of the operation portion  31  of the plunger  30  is as small as possible. 
         [0063]    Furthermore, since the lens body  2   a  of the intraocular lens  2  has a substantially disk shape, the lens body  2   a  may easily rotate inside the nozzle body  10  about the optical axis when the intraocular lens  2  is pressed by the plunger  30 . Thus, in many cases, the deformation direction of the operation portion  31  of the plunger  30  is the horizontal direction. On the contrary, in the embodiment, the horizontal width is set to be larger than the vertical width in rear of a predetermined place of the column portion  31   a  of the operation portion  31 , so that the curving of the operation portion  31  is suppressed. 
         [0064]      FIG. 7  illustrates a specific configuration of the operation portion  31  of the plunger  30  of the embodiment.  FIG. 7(   a ) is a diagram when viewed from the upside,  FIG. 7(   b ) is a diagram when viewed from the left to right direction, and  FIG. 7(   c ) is a diagram when viewed from the leading end direction. In the embodiment, a tapered portion  31   d  is provided at the center of the column portion  31   a  in the front to rear direction, and an elongated column portion  31   e  is provided by increasing the horizontal width of the column portion  31   a  at the rear side of the tapered portion  31   d.    
         [0065]    In other words, the vertical dimensions of the column portion  31   a,  the tapered portion  31   d,  and the elongated column portion  31   e  of the operation portion  31  are set to be constant, and only the horizontal dimensions thereof are increased in the middle of the operation portion. Thus, since only the dimension in a direction in which the operation portion  31  is easily deformed increases, it is possible to further efficiently suppress the deformation of the operation portion  31  and to suppress the increase amount in dimension as minimal as possible. Further, since the direction of increasing the dimension of the operation portion  31  is set to only the left to right direction, the structure in the up to down direction is simplified, and hence the structure of the plunger  30  may be totally simplified. Furthermore, since the direction of highly precisely managing the dimension may be limited to the left to right direction, it is possible to simplify the mold manufacturing process and the product dimension management. Furthermore, in the operation portion  31  of  FIG. 7 , the notch  31   c  and the leading end side portion of the notch  31   c  correspond to the leading end region. The column portion  31   a  at the trailing end side of the notch  31   c,  the tapered portion  31   d,  and the elongated column portion  31   e  correspond to a rod-like portion. 
         [0066]    Here, in  FIG. 7 , it is desirable to set the distance from the leading end of the operation portion  31  to the tapered portion  31   d  to be equal to or longer than the length in the front to rear direction of the range in which the leading end  10   a  of the nozzle body  10  is inserted into the patient&#39;s eyeball. For example, when a mark representing the insertion range is present in the nozzle portion  15  of the nozzle body  10 , the distance may be set to be equal to or longer than the distance from the leading end  10   a  to the mark. In this way, the dimension of the operation portion  31  may be suppressed in the insertion range inside the patient&#39;s eyeball, and hence the horizontal dimension of the portion inserted into the patient&#39;s eyeball in the nozzle body  10  may be suppressed as small as possible. Accordingly, it is possible to further suppress the size of the incision provided in the patient&#39;s eye tissue as small as possible. 
         [0067]    Furthermore, in the operation of inserting the intraocular lens  2 , in a case where the plunger  30  may protrude (be exposed) from the leading end  10   a  of the nozzle body  10 , the distance from the leading end of the operation portion  31  to the tapered portion  31   d  may be set to be equal to or longer than the sum of the protruding (exposing) length of the plunger  30  and the length of the insertion range of the leading end  10   a  of the nozzle body  10  inside the patient&#39;s eyeball. Then, even in a configuration in which the plunger  30  may protrude (be exposed) from the leading end  10   a  of the nozzle body  10 , the horizontal dimension of the portion inserted into the patient&#39;s eyeball in the nozzle body  10  may be further reliably suppressed as small as possible. 
         [0068]    Moreover, the distance from the leading end of the operation portion  31  to the tapered portion  31   d  may be set to be equal to or longer than the length of the support portion  2   b  of the intraocular lens  2 . Here, 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 . However, when pressing the intraocular lens  2  by the plunger  30  in the operation of inserting the intraocular lens  2 , there is a case in which the support portion  2   b  is separated from the notch  31   c.  In this case, there is a concern that the support portion  2   b  is nipped between the plunger  30  and the nozzle body  10 , so that the plunger  30  may not easily move. 
         [0069]    On the contrary, when the distance from the leading end of the operation portion  31  to the tapered portion  31   d  is set to be equal to or longer than the length of the support portion  2   b  of the intraocular lens  2 , the support portion  2   b  does not reach the tapered portion  31   d  if the support portion  2   b  is separated from the notch  31   c.  Accordingly, it is possible to suppress a problem in operation in which the support portion  2   b  is nipped between the plunger  30  and the nozzle body  10 . 
         [0070]    Furthermore, in the above-described embodiment, the distance from the leading end of the operation portion  31  to the tapered portion  31   d  corresponds to a predetermined distance. Further, in the above-described embodiment, the horizontal dimension of the operation portion  31  is increased by providing the tapered portion  31   d  in the operation portion  31 . However, the method of increasing the horizontal dimension of the operation portion  31  is not limited to the above-described example. For example, the same effect may be substantially obtained even when increasing the dimension by a step shape, a stair shape, and a curved surface shape. 
       Embodiment 2  
       [0071]    Next, Embodiment 2 of the invention will be described. Even in the embodiment, as described in Embodiment 1, a configuration is employed in which the operation portion  31  of the plunger  30  is provided with the tapered portion  31   d  so as to increase only the horizontal dimension at the elongated column portion  31   e.  Then, in the embodiment, in addition to this configuration, the plunger  30  is supported by two rails at the bottom surface of the penetration hole of the apparatus body. Hereinafter, this embodiment will be described. 
         [0072]      FIG. 8  illustrates the nozzle body  10  according to the embodiment. The nozzle body  10  according to the embodiment is different from that of Embodiment 1 in that the operation portion  31  of the plunger  30  is supported by two rails  10   f  and  10   f  in the set surface  12   b  of the stage portion  12 . Further, as illustrated in  FIG. 8 , a set surface penetration hole  12   d  is provided so as to be disposed differently from the set surface penetration hole  12   c  of Embodiment 1. This is because a space for providing the rails  10   f  and  10   f  needs to be ensured in the set surface  12   b.    
         [0073]      FIG. 9  illustrates an operation in which the plunger  30  of the embodiment is pressed toward the leading end of the nozzle body  10  so as to extrude the intraocular lens  2 .  FIG. 9(   a ) illustrates a state where the plunger  30  is present at the initial position,  FIG. 9(   b ) illustrates a state where the leading end of the operation portion  31  of the plunger  30  has passed through the stage portion  12 , and  FIG. 9(   c ) illustrates a state where a flat portion  31   b  of the plunger  30  reaches the stage portion  12  and the flat portion  31   b  is supported by two rails  10   f  and  10   f.  Further, in  FIGS. 9(   a ) to  9 ( c ), the left drawings represent the top views, and the right drawings represent the cross-sectional views of the operation portion  31  which is supported by two rails  10   f  and  10   f.    
         [0074]    Furthermore, as illustrated in the right drawings of  FIGS. 9(   a ) to  9 ( c ), the operation portion  31  of the plunger  30  is supported by two rails  10   f  and  10   f  from the downside and the position of the upper side thereof is regulated by the guide protrusions  13   c  and  13   c  and the rib  13   b  in a state where the stage cover portion  13  is closed. Furthermore, in the left drawings of  FIGS. 9(   a ) to  9 ( c ), the configuration of the stage cover portion  13  is indicated by the thin chain line in order to easily understand the operation of the plunger  30 . 
         [0075]    In  FIG. 9(   a ), the column portion  31   a  of the operation portion  31  is supported by the inner inclined surfaces of the rails  10   f  and  10   f.  In this case, the height of the lower end of the column portion  31   a  from the set surface  12   b  becomes “h1”. Further, the position of the upper side of the column portion  31   a  is regulated by the guide protrusions  13   c  and  13   c  and the rib  13   b . However, since the horizontal dimension of the column portion  31   a  is equal to the vertical dimension thereof, the clearance C1 between the column portion  31   a  and the rib  13   b  is comparatively large. In this state, the operation resistance of the plunger  30  is very small, and hence the operation of pressing the intraocular lens  2  may be smoothly performed. 
         [0076]    In  FIG. 9(   b ), the lower side of the elongated column portion  31   e  is supported by the inner inclined surfaces of the rails  10   f  and  10   f,  and the position of the upper side of the elongated column portion  31   e  is regulated by the guide protrusions  13   c  and  13   c  and the rib  13   b.  In this state, since the horizontal dimension of the elongated column portion  31   e  is longer than the horizontal dimension of the column portion  31   a,  the height of the lower side of the elongated column portion  31   e  from the set surface  12   b  becomes “h2” higher than that of FIG. b(a). Since the vertical dimension of the elongated column portion  31   e  is equal to that of the column portion  31   a,  the clearance C2 between the rib  13   b  and the upper side of the elongated column portion  31   e  is smaller than that of the state illustrated in  FIG. 9(   a ). As a result, in the state of  FIG. 9(   b ), the operation resistance of the plunger  30  increases compared to the state of  FIG. 9(   a ). 
         [0077]    In  FIG. 9(   c ), the flat portion  31   b  is supported by the apexes of the rails  10   f  and  10   f  and the position of the upper side of the elongated column portion  31   e  is regulated by the guide protrusions  13   c  and  13   c  and the rib  13   b.  In this state, since the flat portion  31   b  is placed on the rails  10   f  and  10   f,  the height of the elongated column portion  31   e  from the lower set surface  12   b  becomes the higher height “h3”. In this case, the clearance between the rib  13   b  and the upper side of the elongated column portion  31   e  becomes a minus value C3, so that interference between the elongated column portion  31   e  and the rib  13   b  occurs. Thus, in this state, the operation resistance of the plunger  30  further increases. 
         [0078]    As described above, in the embodiment, only the horizontal dimension is halfway increased by providing the tapered portion  31   d  in the operation portion  31  of the plunger  30 , and the plunger  30  is supported by two rails  10   f  and  10   f  at the stage portion  12  of the nozzle body  10 . Thus, the operation resistance of the plunger  30  increases as the plunger  30  is gradually pressed toward the leading end of the nozzle body  10 , so that the operation of the plunger  30  immediately before extruding the intraocular lens  2  from the nozzle body  10  may be further stabilized. As a result, it is possible to further reliably suppress a problem in which the intraocular lens  2  carelessly pops out from the nozzle body  10  into the eyeball. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           1  insertion apparatus 
           2  intraocular lens 
           10  apparatus body 
           10   a  leading end 
           10   b  trailing end 
           10   f  rail 
           12  stage portion 
           12   b  set surface 
           13  stage cover portion 
           13   a  rib 
           13   b  rib 
           13   c  guide protrusion 
           30  plunger 
           31  operation portion 
           31   a  column portion 
           31   b  flat portion 
           31   d  tapered portion 
           31   e  elongated column portion 
           50  positioning member