INTRAOCULAR LENS INSERTION APPARATUS

An intraocular lens insertion apparatus includes a substantially tubular insertion member configured to be inserted into an eye, an opening part provided at a tip end of the insertion member to eject an intraocular lens into the eye, and an intraocular lens push member which pushes the intraocular lens to move the intraocular lens through the insertion member and ejects the intraocular lens from the opening part into the eye. An opening direction of the opening part is tilted with respect to a direction in which the insertion member extends, and a recess having a predetermined depth and extending in the extending direction is provided at an outer peripheral surface of the insertion member on an insertion member rear end side of the opening part.

FIELD

The present invention relates to an intraocular lens insertion apparatus used to insert an intraocular lens into the eye through an incision made in the eyeball.

BACKGROUND

In treatment of a cataract, an intraocular lens that is to be inserted as a substitute lens to replace a human opaque lens for refraction correction has become available. In an intraocular lens insertion surgery for cataract treatment, a few millimeter wound by incision (an incision) is made for example at an edge of the cornea or sclera, and the lens may be pulverized and removed through the incision by phacoemulsification, so that the intraocular lens is inserted and fixed by an intraocular lens insertion apparatus.

Stress on the ocular tissues should be smaller as the incision is smaller. Therefore, various intraocular lens insertion apparatuses have been proposed for the purpose of allowing the intraocular lens to be inserted into the eye with high operability and without damaging the incision (PTL 1).

CITATION LIST

Patent Literature

[PTL 1] Japanese National Publication of international Patent Application No. 2001-517976

SUMMARY

Technical Problem

However, despite the above-described feature, the shape of the tip end of the intraocular lens insertion apparatus may still differ between before and after insertion of the intraocular lens into the eye. For example, a hinge at the tip end of the intraocular lens insertion apparatus disclosed in PTL 1 having a valley fold shape before insertion of the intraocular lens may form a mountain fold after insertion of the intraocular lens. In this case, the hinge may damage the ocular tissues of the incision when the intraocular lens insertion apparatus is removed from the incision.

With the foregoing in view, it is an object of the present disclosure to provide an intraocular lens insertion apparatus capable of stably inserting an intraocular lens while reducing stress on ocular tissues.

Solution to Problem

An intraocular lens insertion apparatus disclosed herein includes a substantially tubular insertion member configured to be inserted into an eye, an opening part provided at a tip end of the insertion member to eject an intraocular lens into the eye, and an intraocular lens push member which pushes the intraocular lens to move the intraocular lens through the insertion member and ejects the intraocular lens from the opening part into the eye, an opening direction of the opening part is tilted with respect to a direction in which the insertion member extends, a recess having a predetermined depth and extending in the extending direction is provided at an outer peripheral surface of the insertion member on an insertion member rear end side of the opening part, and the recess enlarges and contracts the opening part by elastic deformation when the insertion member is inserted into the eye and when the intraocular lens moves through the insertion member. With this configuration, when an operator inserts the intraocular lens into the eye with the intraocular lens insertion apparatus, the insertion member of the intraocular lens insertion apparatus can more easily be inserted into the incision made in the eye, and the intraocular lens can more smoothly move through the insertion member.

A curved surface part which connects the recess and an outer peripheral surface of the insertion member may be provided. The curved surface part may have a radius of curvature of 0.5 mm or less in a plane orthogonal to the extending direction of the insertion member. The recess of the insertion member may be kept from abutting on an inner peripheral surface of the insertion. member, and the recess may have a length of 0.5 mm or more in the extending direction of the insertion member. The recess may have a depth which keeps the recess from going beyond a substantial center of a section of the insertion member in a plane orthogonal to the extending direction of the insertion member. The recess may be formed by secondary working performed after the insertion member and the opening part are formed.

Advantageous Effects of Invention

According to the present disclosure, an intraocular lens insertion apparatus capable of stably inserting an intraocular lens while reducing stress imposed on ocular tissues can be provided.

DESCRIPTION OF EMBODIMENTS

FIG. 1schematically illustrates an outline of the configuration of an intraocular lens insertion apparatus1used. to insert an intraocular lens into the eye.FIG. 1(a)is a plan diagram of the intraocular lens insertion apparatus1when a stage lid part13is opened, andFIG. 1(b)is a side diagram of the intraocular lens insertion apparatus1when the stage lid part13is closed. The nozzle main body10of the intraocular lens insertion apparatus1is a tubular member having a substantially rectangular cross section and has a rear end part10bhaving a large opening at one end, and a tapered nozzle part15and a tip end part10aat another end. As illustrated inFIG. 1(b), the tip end part10ahas a cylindrical shape with a smaller diameter, and the tip end part10ahas an end opened obliquely with respect to the extending direction of the nozzle main body10. A plunger30is inserted in the nozzle main body10and can move back and forth therein. Note that the tip end part10ais an example of the substantially tubular insertion member inserted into the eye, and the plunger30is an example of the intraocular lens push member.

In the description hereinafter, the direction from the rear end part10bto the tip end part10aof the nozzle main body10is assumed as the forward direction, the opposite direction thereto is assumed as the rearward direction, and inFIG. 1(a), the front side of the paper sheet surface is assumed as the upper side and the opposite side thereto is assumed as the lower side, while inFIG. 1(b), the front side of the paper sheet surface is assumed as the leftward direction, and the opposite side thereto is assumed as the rightward direction. In this case, the upper side corresponds to the front side of the optical axis of the lens main body2aas will be described, the lower side corresponds to the rear side of the optical axis of the lens main body2a, the front side corresponds to the front side in the pushing direction by the plunger30, and the rear side corresponds to the rear side in the pushing direction by the plunger30.

The nozzle main body10is provided integrally with a plate-shaped projecting holding part11in the vicinity of the rear end part10bof the nozzle main body10, and the operator can hook the finger on the projecting holding part and push the plunger30toward the tip end of the nozzle main body10. A stage part12to which the intraocular lens2is set is provided behind the nozzle part15of the nozzle main body10. The stage part12configured to open the upper side of the nozzle main body10when the stage lid part.13is opened. A positioning member50is attached to the stage part12from the lower side of the nozzle main body10. The positioning member50stably holds the intraocular lens2in the stage part12before use (during transport).

More specifically, when the intraocular lens insertion apparatus1is manufactured, the intraocular lens2is set to the stage part12so that the front side of the optical axis is set on the upper side while the stage lid part13is opened and the positioning member50is attached to the stage part12. The stage lid part13is then closed before shipment and distribution. The user dampens the lens for example with a viscoelastic material or perfusate while the stage lid part13is closed, then removes the positioning member50, and then pushes the plunger30toward the tip end side of the nozzle main body10.

In this way, the intraocular lens2is pushed by the plunger30to move to the nozzle part15, and the intraocular lens2is ejected into the eye from the tip end part10a. Note that the nozzle main body10, the plunger30, and the positioning member50of the intraocular lens insertion apparatus1are formed using a resin material such as polypropylene. Polypropylene has been proven in the field of medical apparatus and is a highly reliable material for example for is chemical resistance. The intraocular lens insertion apparatus1according to the embodiment is a preset type in which the intraocular lens2is preset in the intraocular lens insertion apparatus1before shipment, but the apparatus may also be a so-called separate type in which the intraocular lens2is set by the operator in the intraocular lens insertion apparatus1before operation.

A part of the stage lid part13is thinned, whereby a check window17is formed. How thin the check window17should be in the stage lid part13may be determined as appropriate on the basis of the material of the stage lid part13and the visibility of the intraocular lens from the check window17. The presence of the check window17may probably reduce shrinkage when the stage lid part.13is formed. The stage lid part13is provided with a lubricant supply hole18for injecting a viscoelastic material as a lubricant into the stage part12before the work of inserting the intraocular lens2into the eye. The lubricant supply hole18connects the outside of the stage part12to the intraocular lens2stored in the stage part12when the stage lid part13is closed.

The stage lid part13is provided with a guide wall19for guiding, to the lubricant supply hole18, an injection member such as a needle used to inject the viscoelastic material into the space which stores the intraocular lens2. The guide wall19is provided to surround at least a part of the lubricant supply hole18, so that the operator moves the tip end of the injecting member for injecting the viscoelastic material into abutment against the guide wall19and further moves the tip end of the injection member to the lubricant supply hole18. In this manner, the guide wall19is used as a member for guiding the injecting member for injecting the viscoelastic material to the lubricant supply hole18.

FIG. 2is a schematic diagram illustrating an outline of the configuration of the intraocular lens2according to this embodiment.FIG. 2(a)is a diagram illustrating a plan view, andFIG. 2(b)is a diagram illustrating a side view. Note that the direction of the intraocular lens2are not the same between FIGS.2(a) and2(b). The intraocular lens2is what is called one-piece type lens including a lens main body and supports integrally formed from the same material, and the material of the lens is a flexible resin material. The intraocular lens2includes a lens main body2ahaving a predetermined refractive power and two long flat plate-shaped supports2bconnected to the lens main body2ato hold the lens main body2ainside of the eyeball. The lens main body2aand the support2bare connected with each other through a connecting part2d. Note that in the following description, the intraocular lens2according to the embodiment is a one-piece type lens, while the lens may be a three-piece type lens having a lens main body and supports made of different materials.

According to the embodiment, the intraocular lens2is set in the stage part12so that one of the two supports2bis arranged on the rear side of the lens main body2sand the other support2bis arranged on the front side of the lens main body2ain the intraocular lens insertion apparatus1. The support arranged on the front side of the lens main body2ais a front support, and the support arranged on the rear side of the lens main body2ais a rear support.

The supports2bof the intraocular lens2in the embodiment are roughened. In this way, the supports2bcan be prevented from sticking to the lens main body2awhen the intraocular lens2is folded in the nozzle main body10.

FIG. 3is a plan view of the nozzle main body10. As described above, the intraocular lens2is set in the stage part12in the nozzle main body10in this state, the intraocular lens2is pushed by the plunger30and is ejected from the tip end part10a.Note that a through hole10con the tip end side and a through hole10fon the rear end side are provided in the nozzle main body10, and the cross-sectional shapes of the through holes change as the outer shape of the nozzle main body10changes. The through hole10cforms a part of the moving path through which the intraocular lens2is pushed to move, and the through hole10fis a hole into which the plunger30is to be inserted. When the intraocular lens2is ejected, the intraocular lens2deforms according to a change in the cross-sectional shape of the through hole10cin the nozzle main body10into a folded shape, and ejected in the folded shape which is easy to enter the incision made in the eyeball of the patient.

The tip end part10aof the nozzle main body10is slant as if cut off obliquely so that the upper region of the nozzle part15is ahead of the lower region. Note that the tip end part10amay have a linearly obliquely cut shape as viewed from the leftward direction and rightward direction or may be slanted to have an outwardly inflated or curved shape. The obliquely cut shape of the tip end part10amakes it easier for the operator to insert the tip end part10ainto an incision made in the eyeball of the patient compared to the case in which the tip end part10adoes not have an obliquely cut shape.

A stage groove12ahaving a width slightly greater than the diameter of the lens main body2aof the intraocular lens2is formed in the stage part12. The size of the stage groove12ain the front-back direction is set greater than the maximum width including the supports2b,2bwhich extend on both sides of the intraocular lens2. The bottom surface of the stage groove12aforms a set surface12b. The set surface12bis positioned above the height level of the bottom surface of the through hole10fof the nozzle main body10, and the set surface12band the bottom surface of the through hole10fare connected to each other by a bottom slope10d.

The stage part12and the stage lid part13are integrally formed. The stage lid part13has a size equal to the stage part12in the front-back direction. The stage lid part13is connected by a thin plate-like connecting part14formed by a part of the side of the stage part12extended toward the stage lid part13The connecting part14is formed to be bendable at the center, and the stage lid part13can cover and close the stage part12from above by bending the connecting part14.

The surface of the stage lid part13facing the set surface12bwhen the lid is put on is provided with ribs13aand13bin order to reinforce the stage lid part13and stabilize the position of the intraocular lens2. A guide projection13cis also provided. as an upper guide for the plunger30.

A positioning member50is detachably provided under the set surface12bof the stage part12.FIG. 4schematically illustrates the positioning member50.FIG. 4(a)is a plan view of the positioning member50, andFIG. 4(b)is a left side view of the positioning member50. The positioning member50is formed discretely from the nozzle main body10and includes a pair of sidewalls51,51connected by a connecting part52. An outwardly extending holder53is formed at the lower end of the sidewall51.

First and second mounting parts54and63which protrude upwardly are formed on the inner side of the sidewalls51,51. A first positioning part55is formed to protrude at the outer peripheral side of the upper end surface of the first mounting part54. A pair of second positioning parts64,64is formed to protrude at the upper end surface of the second mounting part63to position the lens main body2aand the support2bof the intraocular lens2. The distance between the first positioning part55and the second positioning parts64,64is set slightly greater than the diameter of the lens main body2aof the intraocular lens2.

A pair of third mounting parts56,56which protrude upwardly is formed inside the sidewalls51,51. The levels of the upper surfaces of the first mounting part54, the second mounting part63, and the third mounting parts56,56are equal. Third positioning parts57,57which project upwardly entirely over the third mounting parts56,56in the leftward direction and rightward direction are formed at the outer part of the upper surfaces of the third mounting parts56,56. The distance between the inner sides of the third positioning parts57,57is set slightly greater than the diameter of the lens main body2aof the intraocular lens2.

A fourth mounting part58on which a part of the front support of the supports2bof the intraocular lens2is mounted is formed inside the sidewalls51,51. A fourth positioning part59which protrudes upwardly further above the fourth mounting part58is formed. A part of the front support abuts against the fourth positioning part59. A fifth mounting part60on which a part of the rear support of the supports2bof the intraocular lens2is mounted is formed inside the sidewalls51,51. A fifth positioning part.61which protrudes upwardly further above the fifth mounting part60is formed. A part of the rear support abuts against the fifth positioning part61.

As illustrated in.FIG. 4(b), the levels of the upper surfaces of the fifth mounting part60and the fifth positioning part61are lower than the levels of the upper surfaces of the first to fourth mounting parts and the first to fourth positioning parts. Rotation prevention wails62are provided outside the sidewalls51,51to prevent unwanted rotation when the positioning member50is detached.

The set surface12bof the nozzle main body10is provided with set surface through holes12cthat pass through the set surface12bin a thickness-wise direction. The outer shape of the set surface through hole12chas a substantially similar shape with a slightly greater size than the shapes of the first to fifth mounting parts and the first to fifth positioning parts of the positioning member50as seen from above. When the positioning member50is mounted to the nozzle main body10, the first to fifth mounting parts and the first to fifth positioning parts are inserted from the lower side of the set surface12binto the set surface through holes12cand protrude above the set surface12b.

When the intraocular lens2is set to the set surface12b, the outer peripheral bottom surface of the lens main body2ais mounted on the upper surfaces of the first mounting part54, the second mounting part63, and the third mounting parts56,56. The lens main body2ahas its position restricted by the first positioning part55, the second positioning parts64,64and the third positioning parts57,57in the horizontal direction (the horizontal direction to the set surface12b). The two supports2bof the intraocular lens2are mounted on the upper surfaces of the fourth and fifth mounting parts58and60. The two supports2bhave their positions restricted in the horizontal direction by the fourth and fifth positioning parts59and61.

FIGS. 5(a) and 5(b)schematically illustrate an outline of the configuration of the plunger30according to the embodiment.FIG. 5(a)is a plan view of the plunger30, andFIG. 5(b)is a side view of the plunger30.

The plunger30has a length slightly greater than the nozzle main body10in the front-back direction. The plunger includes a tip end side working part31in a generally cylindrical shape and a rear end side insertion part32in a generally rectangular rod shape. The working part31includes a cylindrical. part31ain a cylindrical shape and a flat part31bin a thin plate shape extending in the leftward direction and rightward direction from the cylindrical part31a.

A notch31cis formed at the tip end of the working part31. As illustrated inFIGS. 5(a) and 5(b), the notch31cis formed in the form of a groove which opens downward of the working part31and passes in the leftward direction and rightward direction. Also as illustrated inFIG. 5(b), the groove wall of the notch31con the tip side is formed as a downward sloping surface toward the tip end side of the working part31. The insertion part32has a generally substantially H-shaped cross-section, and its horizontal and vertical sizes are set slightly smaller than the through hole10fof the nozzle main body10. A disk-shaped pushing plate part33which extends in the vertical and horizontal directions is formed at the rear end of the insertion part32.

A claw part32ais formed on the tip end side ahead of the center of the insertion part32in the front-back direction to protrude upward above the insertion part32, and the claw part32acan move up and down due to the elasticity of the material of the plunger30. When the plunger30is inserted in the nozzle main body10, an engaging hole10eprovided in the thickness-wise direction on the upper surface of the nozzle main body10illustrated inFIG. 3and the claw part32aare engaged, which determines the relative position between the nozzle main body10and the plunger30in the initial state. Note that the claw part32aand the engaging hole10eare formed so that in the engaged state, the tip end of the working part31is positioned behind the lens main body2aof the intraocular lens2set at the stage part12, and the rear support2bof the lens main body2ais arranged in a location in which the notch31ccan support the rear support from above.

FIGS. 6(a) to 6(c)illustrate the tip end part10aand the nozzle part15of the nozzle main body10.FIG. 6(a)is a plan view of the tip end part10aand the nozzle part15,FIG. 6(b)is a sectional view of the nozzle main body10taken along line A-A′ inFIG. 6(c), andFIG. 6(c)is a side view of the tip end part10aand the nozzle part15. Note thatFIG. 6(b)illustrates the nozzle part15by the dotted line when the nozzle main body10is viewed from the side of the tip end part10atoward the rear end part10b. As illustrated in the front view of the nozzle main body10inFIGS. 6(a) and 6(c), the central axis of the cylindrical nozzle part15which extends in the front-back direction of the nozzle main body10is AX (the dotted double chain line in the figure). Note that the direction in which the central axis AX extends is the direction in which the tip end part10aas an insertion member extends and matches the extending direction of the axis along which the plunger30is pushed.

As illustrated inFIGS. 6(a) to 6(c), the edge10bof the opening10gof the tip end part10aon the side of the rear end part10bof the central axis AX is recessed toward the central axis AX. As illustrated inFIG. 6(a), according to the embodiment, the length of a recess10iin the extending direction of the central axis AX is L1. As illustrated inFIGS. 6(b) and 6(c), the recess101extending along the central axis AX is formed on the outer peripheral surface of the tip end part10a. As illustrated inFIG. 6(b), the recess10iis provided so that the distance between the part of the edge10hthrough which the central axis AX passes in the plan view inFIG. 6(a)and the central axis AX is shortest.

As a method for forming the recess10i, the edge10hof the opening10gdeforms toward the central axis AX by secondary working performed after the opening10gis provided at the cylindrical member as a base for the tip end part10afor example by injection molding, in other words, secondary working performed after the insertion member and the opening part are formed, and the recess10iillustrated inFIGS. 6(a) to 6(c)is provided. One example of the secondary working is deformation by heat press fitting.

FIG. 7(a)is a schematic perspective view of the tip end part100aof a nozzle main body100before the secondary working described above is performed, andFIG. 7(b)is a schematic perspective view of the tip end part10aafter the secondary working is performed on the nozzle main body100. Before the secondary working described above is performed, the nozzle main body100is formed by injection molding. As illustrated inFIG. 7(a), although an opening100gis provided at the tip end part100abefore the secondary working, the recess10iis not formed. The recess10iis formed as illustrated inFIG. 7(b)by performing secondary working such as heat press fitting to the tip end part100a, for example, by using a mold.

Compared to the case in which the recess10iis formed by injection molding instead of the secondary working, the recess101can be formed by the secondary working to have such strength that the recess101is unlikely to break even for the thinness and have flexibility which allows the recess10ito restore upon deforming as the intraocular lens2is elected from the opening10g.

FIG. 8is an enlarged view of the tip end part10ainFIG. 6(b). As illustrated inFIG. 8, the recess10iis provided with a curved surface part10jcurved toward the central axis AX. The tip end part10ais provided with a curved surface parts10mand10nconnecting the recess10iand the outer peripheral surface of the tip end part10a. The curved surface parts10mand10ncurve toward the side opposite to the central axis AX (downward direction in the drawing)

As illustrated inFIG. 8, the radii of curvature of the curved surface parts10j,10m, and10nin the plane orthogonal to the central axis AX are R1, R2, and R3, respectively. Then, possible values for R1, R2, and R3need only be within the range from 0.1 mm to 0.5 mm. The combination of R1, R2, and R3may be determined as appropriate. For example, inFIG. 7, it is assumed that R1, R2, and R3satisfy R1>R2=R3, but the relation among the values of R1, R2, and R3is not limited to this.

Also as illustrated inFIG. 8, the depth DI of the recess10iin the plane orthogonal to the central axis AX is preferably a depth which keeps the recess10ifrom contacting the inner peripheral surface of the tip end part10a. The length L1of the recess10iis preferably 0.5 mm or more in the direction along the central axis AX. The depth D1is more preferably a depth which keeps the recess10from going beyond the central axis AX, in other words, a depth which does not go beyond an approximate center of the cross-section of the insertion member. The depth D1and the length L1of the recess10iare set as described above, so that the tip end part10amay appropriately deform, when the tip end part10ais inserted into the incision or when the intraocular lens2is ejected into the eye from the opening10g. Note that the depth D1is an example of a predetermined depth of the recess10i, and the depth D1may be changed to change the state of deformation of the tip end part10awhen the tip end part10ais inserted into the incision or the state of movement of the intraocular lens2within the tip end part10a.

The shape of the recess10iof the tip end part10aof the nozzle main body10when the operator inserts the intraocular lens2into the patient's eye using the intraocular lens insertion apparatus1will be described. First, before the intraocular lens2is stored in the intraocular lens insertion apparatus1, the plunger30is inserted into the nozzle main body10and placed in an initial position. As described above, the positioning member50is mounted to the nozzle main body10from under the set surface12b. In this way, the first mounting part54, the second mounting part63, and the third mounting parts56,56of the positioning member50are held in a protruding state at the set surface12b. Then, the lens main body2aof the intraocular lens2is mounted and positioned on the upper surfaces of the first mounting part54, the second mounting part63, and the third mounting parts56,56while the supports2bare directed in the front-back direction of the nozzle main body10. In this state, a part of the support2bon the rear side of the intraocular lens2is caught and supported. by the notch31cof the plunger30.

Next, the operator removes the positioning member50from the stage part12. In this way, the intraocular lens2is set in the stage part12. Before the tip end part10aof the nozzle main body10is inserted into the incision, the recess10iis in the state in which the curved surface parts10mand10nare separated. from each other in a plane orthogonal to the central axis AX as illustrated inFIG. 9(a).

Then, the operator inserts the tip end part10aof the nozzle main body10into an incision made in ocular tissues. Here, the tip end part10ahaving an oblique opening shape can easily be inserted into the incision. At the time, as the tip end part10ais pushed by the incision, the recess10ishrinks in the leftward direction and rightward direction due to elastic deformation in a lane orthogonal to the central axis AX as illustrated inFIG. 9(b), and the curved surface parts10mand10nabut against each other, so that the opening10gis reduced. As a result, the outer diameter of the tip end part10abecomes smaller than that before the tip end part10ais inserted into the incision, so that the tip end part10acan be more easily inserted into the incision than the case in which the outer diameter of the tip end part is unchanged. between before and after insertion into the incision. The curved surface part10jmoves toward the central axis AX in a plane orthogonal to the central axis AX. More specifically, since the curved surface part10jdoes not protrude toward the outer peripheral side of the tip end part10a, and the curved surface part10jdoes not contact the incision when the tip end part10ais inserted into the incision, it is less likely that the deformation of the tip end part10acauses stress on tissues around the incision. While the tip end part10ais inserted into the incision, the tip end part10ais kept in the state in which the outer diameter is reduced as illustrated inFIG. 9(b).

Then, the operator operates the plunger30to move the intraocular lens2set in the stage part12toward the tip end part.10a. At the time, in a plane orthogonal to the central axis AX of the tip end part10a, as the curved surface part10jis pushed by the lens main body2aof the intraocular lens2in a direction away from the central axis AX, the tip end part10astarts to deform. from the state as illustrated inFIG. 9(b), and the recess101is stretched in the leftward direction and rightward direction due to elastic deformation. At the time, as the curved surface part10jmoves away from the central axis AX, the curved surface parts10mand10nmove in directions away from each other (the leftward direction and rightward direction in the figure), and the opening10gexpands. As a result, as illustrated inFIG. 9(c), the tip end part10adeforms so that the curved surface parts10j,10m, and10nbecome part of the cylindrical shape. Since the outer diameter of the deformed tip end part10aas illustrated inFIG. 9(c)is larger than the outer diameter of the tip end part10abefore the tip end part10ais inserted into the incision, a greater space can be secured for the intraocular lens2to pass than the case in which the outer diameter of the tip end is unchanged as the intraocular lens2is ejected into the eye from the tip end, so that the intraocular lens2can move more stably. In this way, according to the embodiment, when the tip end part.10ais inserted into an incision in the eye and when the intraocular lens2moves through the tip end part10a, the recess10iprovided at the tip end part10ashrinks/expands by elastic deformation to reduce/increase the opening10g, so that stress on the ocular tissues of the incision can be reduced and the intraocular lens can stably be inserted.

When the recess101deforms as illustrated inFIG. 9(c), the tip end part.10ais pushed by the incision, so that a restoring force to bring back the recess10iinto the shape as illustrated inFIG. 9(b)is exerted. Meanwhile, when the intraocular lens2moves through the tip end part10a, the lens main body2ais curved in the tip end part10aas illustrated in.FIG. 9(c), and therefore a restoring force to bring back the lens main body2ainto the flat plate shape as illustrated inFIG. 2(b)is exerted. More specifically, when the intraocular lens2moves through the tip end part10a, the restoring force of the recess10iagainst the restoring force of the lens main body2aof the intraocular lens2acts on the lens main body2a.

Meanwhile, the presence of the recess10icauses a restoring force to bring back the tip end part10ainto the shape as illustrated inFIG. 9(a)from the shape as illustrated inFIG. 9(b). More specifically, the restoring force acts to ensure the nozzle, through which the lens passes, to have a greater inner diameter cross-sectional area. This increases the cross-sectional area in the range in which the lens passes and reduces inequalities in extrusion resistance. Since the plunger collides against the recess, the collision serves as resistance and there may be less fluctuations in extrusion load. Consequently, it can be considered that the likelihood of the lens main body2ashooting out of the opening10gof the tip end part10aat a speed unexpected by the operator or a so-called rocket launch may be reduced. As a result, when the intraocular lens2moves through the tip end part10a, it is less likely that the tip end part10asuddenly deforms into the shape as illustrated inFIG. 9(c)and that the deformation of the tip end part10aimposes excessive stress on the tissues of the incision.

It can be considered that when the recess10ideforms as described above, the restoring force of the recess101is greater than the restoring force of the part other than the recess10iof the tip end part10a. Therefore, when for example the recess10ideforms so that the curved surface parts10j,10m, and10nbecome part of the cylindrical shape as illustrated inFIG. 9(c), the recess10iregains the shape when the nozzle is inserted into the eye as illustrated inFIG. 9(b). When the recess10ideforms as described above, the stress acting on the tip end part10ais not concentrated at the recess10i, and the entire tip end part10adeforms. Therefore, it can be considered that the recess10iis unlikely to plastically deform beyond the elastic limit in the elastic deformation of the recess10i.

When the tip end part10adeforms as illustrated inFIG. 9(c), the resistance of the lens due to the restoring force of the tip end part10ais transmitted from the lens main body2ato the plunger30, so that the operator can sense the restoring force of the tip end part10athrough the plunger30when the lens main body2ais moved to the tip end part10aby the plunger30. Therefore, the restoring force of the tip end part10acan also be used as a cue to inform the operator operating the plunger30of the arrival of the lens main body2aat the tip end part10a.

When the intraocular lens2is ejected into the eye from the opening10gof the tip end part10a, the tip end part10ais pushed by the incision, and therefore the shape as illustrated inFIG. 9(c)returns to the shape as illustrated inFIG. 9(b). Then, when the tip end part10ais removed from the incision, the tip end part10areturns to the shape as illustrated inFIG. 9(a)from the shape as illustrated inFIG. 9(b). At the time, since the tip end part10adeforms according to the size of the opening of the incision, it is unlikely that the tissues of the incision are stressed such as, for example the opening of the incision is widened by the deformation of the tip end part10a.

Although the embodiment has been described, the features of the tip end part of the intraocular lens insertion apparatus or other elements are not limited by the above described embodiment, and various changes can be made within the range consistent with the technical idea of the present invention. For example, as for the radii of curvature R2and R3of the curved surface parts10mand10ninFIG. 8, the radius of curvature of one of the curved surface parts passed by the rear support of the intraocular lens2may be set smaller. In this way, spaces with different sizes are provided in the leftward direction and rightward direction of the tip end part10a, and when the intraocular lens2is inserted into the eye, pressure exerted on the lens main body2apassing through the larger space is reduced, so that increase or decrease in the extrusion resistance is reduced, and the rear support passes through the smaller space. This configuration can control the posture of the intraocular lens2until the insertion of the intraocular lens2is completed. Instead of the above-described tip end part10ahaving the shape as illustrated inFIG. 9(a), a tip end part200ahaving a recess200iin the shape as illustrated inFIG. 10(the part from10mto10nthrough200iin the figure) may be used. The recess200ihas a folded part200hcorresponding to the part10iof the tip end part10ainFIG. 9(a). When the recess200iis used, similarly to the above-described embodiment, the recess200ican deform when the tip end part200ais inserted into the incision and when the intraocular lens2is moved through the tip end part200a, so that the intraocular lens2can smoothly be inserted into the eye by the plunger30while reducing the likelihood of stress imposed on the tissues of the incision.

Embodiments of the intraocular lens insertion apparatus using the present invention is not limited to the above-described embodiment and the invention can also be applied to intraocular lenses and intraocular lens insertion apparatuses for example as disclosed in Japanese Laid-open Patent Publication No. 2017-445. More specifically, the intraocular lens is not limited to the one-piece lens illustrated in.FIG. 2and maybe a three-piece lens as disclosed in the Japanese Laid-open Patent Publication No. 2017-445. The plunger is not limited to the shape illustrated inFIG. 3and may be a plunger in a shape as disclosed in Japanese Laid-open Patent Publication No. 2017-445. The deformed shape of the lens at the time of insertion may be not only a so-called valley fold shape obtained by rounding the lens at the bottom while the top is open, as illustrated inFIG. 9(C), but also a so-called mountain fold shape obtained by turning the lens upside down and then rounding the lens at the top while the bottom is open.

REFERENCE SIGNS LIST

1Intraocular lens insertion apparatus

10a,200aTip end part

10j,10m,10nCurved surface part