Patent Publication Number: US-8968328-B2

Title: Instrument for inserting intraocular lens

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 12/095,172, filed May 28, 2008 now U.S. Pat. No. 8,523,941, which was the U.S. national phase under 35 U.S.C. §371 of PCT International Application No. PCT/JP2006/324054, which has an International filing date of Dec. 1, 2006, and claims the benefit of Japanese Application No. 2005-354968, filed Dec. 8, 2005, each of which are incorporated by reference herein. 
    
    
     TECHNICAL FIELD 
     The present invention relates to an intraocular lens insertion instrument used to insert an intraocular lens into an aphakic eye after cataract surgery or to an intraocular lens insertion instrument used to insert an intraocular lens to a phakic eye during refractive surgery. More specifically, the present invention relates to a preset intraocular lens insertion instrument wherein a lens has been preset in an injector. 
     BACKGROUND ART 
     In cataract surgery, there has been widely performed removal of opacified lenses by phacoemulsification (PEA) followed by implantation of intraocular lenses into aphakic eyes. Intraocular lenses are classified into hard intraocular lenses whose optics are made of a hard material such as PMMA and soft intraocular lenses whose optics are made of a flexible material such as silicone elastomer or soft acrylic. Upon use of a hard intraocular lens, the lens needs to be inserted through an incision having been cut in a cornea or sclera in a width approximately the same as the diameter of the optic of the lens. On the other hand, by folding the optic of a soft intraocular lens, the lens can be inserted through an incision smaller than the diameter of the optic. In order to reduce the risk of post-surgery cornea astigmatism or infection, insertion of a lens through a small incision is preferable. Consequently, soft intraocular lenses tend to be preferred. In addition, dedicated injectors having a mechanism to lead a lens to an eye through a slender tube are used in some cases in order to insert lenses into eyes. By using such injectors dedicated to intraocular lens insertion, a lens can be inserted through an incision smaller than 3 mm. 
     Recently, in order to eliminate the possibility of microbial contamination and operational mishandling at the time of dealing with lenses, preset injectors having lenses preset therein have been available on the market. Some of such preset injectors have a lens holding mechanism and a lens moving mechanism. The lens holding mechanism holds a lens inside of an injector in a state of non-stress on the optic of the lens so that the lens can be changed from a stationary state at the time of shipment to an operable state upon use. The lens moving mechanism moves the lens to a position where the lens can be moved by a push-out mechanism (see Patent Documents 1 and 2, for example).
     Patent Document 1: Japanese Patent Application Laid-Open (JP-A) Publication No. 2003-325570   Patent Document 2: JP-A No. 2003-325572   

     DISCLOSURE OF INVENTION 
     Problems to be Solved by the Invention 
     Nonetheless, the moving mechanism to move the lens from the preset position to the releasable position is complex in the preset injectors described in the above-mentioned Patent Documents 1 and 2, which increases the production cost thereof. Moreover, the possibility of malfunctioning is not eliminated. In order to solve these problems, the inventors of the invention have invented a mechanism whereby a lens can be pushed out as it is at a preset position. 
     However, even in this mechanism, the lens may stick to the setting section in the case where an intraocular lens has been stored in close contact with a lens setting section of an injector. In this case, the lens is stressed excessively if the lens is pushed out parallel to a surface thereof, and may be damaged or become behaviorally unstable. Specifically, in the case where the lens is made of a soft acrylic material or a silicone material, the lens tends to stick more to the lens setting section. Furthermore, in a combination of the lens made of such a material and polypropylene or polyethylene generally used as a material of disposable injectors, the lens tends to stick even more to the lens setting section. 
     The present invention has been conceived in view of the above-mentioned problems, and an object of the present invention is therefore to provide an intraocular lens insertion instrument that enables smooth push-out operation of a preset lens. 
     Means for Solving the Problems 
     In order to achieve the object described above, the invention according to a first aspect thereof is an intraocular lens insertion instrument having: a main body comprising a lens setting section for setting an intraocular lens thereon, a transition section for deforming the intraocular lens, and a nozzle piece for discharging the intraocular lens; and a lens push-out mechanism for pushing out the intraocular lens set on the lens setting section, characterized in that the instrument further comprises a releasing means for releasing the intraocular lens pushed by the lens push-out mechanism from the lens setting section. 
     The invention according to a second aspect thereof is characterized in that the releasing means has a posture holding mount for holding the lens with a forward tilt relative to an axial line of lens movement. 
     The invention according to a third aspect thereof is characterized in that the posture holding mount has a passage through which the lens push-out mechanism passes. 
     The invention according to a fourth aspect thereof is characterized in that the lens push-out mechanism has a scooping surface for scooping the lens. 
     Effects of the Invention 
     According to the intraocular lens insertion instrument as the first aspect of the invention, the presence of the releasing means enables the lens in close contact with the lens setting section to be released from the lens setting section when the lens push-out mechanism pushes the lens. Therefore, the lens can be pushed out smoothly, and damage to the lens and unstable behavior of the lens can be prevented. 
     According to the intraocular lens insertion instrument as the second aspect of the present invention, the presence of the posture holding mount enables the lens to be held with the forward tilt relative to the axial line of lens movement. Therefore, when the lens push-out mechanism pushes the lens, the rear end of the lens is lifted, enabling air to move in between the lens and the lens setting section. In this manner, the lens can be released from the lens setting section and pushed out smoothly. 
     According to the intraocular lens insertion instrument as the third aspect of the present invention, the presence of the passage prevents the posture holding mount from hindering movement of the lens push-out mechanism at the time the lens push-out mechanism pushes the lens out. Therefore, the lens can be pushed out more smoothly. 
     According to the intraocular lens insertion instrument as the fourth aspect of the present invention, scooping the rear end of the lens by the scooping surface at the time of lens push-out enables air to move in between the lens and the lens setting section. Consequently, the lens is released from the lens setting section and can be pushed out more smoothly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows the overall structure of an intraocular lens insertion instrument of the present invention, in which (A) is a front view thereof and (B) is a plan view thereof. 
         FIG. 2  is a perspective view showing the structure around a lens setting section. 
         FIG. 3  shows the structure of the lens setting section, in which (A) is a longitudinal cross-sectional view thereof while (B) is a transverse cross-sectional view thereof. 
         FIG. 4  shows modifications to a lens contact area, in which (A) is a longitudinal cross-sectional view thereof with a protruding lower end while (B) is a longitudinal cross-sectional view thereof with a diagonally cut lower end. 
         FIG. 5  is a perspective view showing a state in which a lens has been set on the lens setting section. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Hereinafter, a preferred embodiment of the present invention will be described with reference to the accompanying drawings. 
     An intraocular lens insertion instrument  1  shown in  FIG. 1  is used to discharge a deformable intraocular lens  2  (hereinafter simply referred to as the lens  2 ) safely and swiftly into an eye. The intraocular lens insertion instrument  1  is specifically a preset intraocular lens insertion instrument in which the lens  2  has been preset inside the instrument  1 . More specifically, the intraocular lens insertion instrument  1  comprises a main body  3  that houses the lens  2  and inserts the lens  2  into an eye, and a lens push-out mechanism  4  that pushes out the lens  2 . In this embodiment, a lens having an optic  2   a  and looped haptic elements  2   b  is used as the lens  2 . 
     The main body  3  comprises a tubular proximal member  5  and a distal member  6  whose tapered end is relatively narrower than the proximal member  5 . The proximal member  5  and the distal member  6  are united with each other in a detachable manner in an engagement section  7 . Various materials can be used for the main body  3 . For example, not only a metal such as stainless steel or titanium but also a synthetic resin or the like can be used for the main body  3 . 
     The proximal member  5  has a lens setting section  8  at one end thereof and a slit  9  formed in a tubular sidewall thereof along a longitudinal direction thereof. Engagement projections  10  to engage with a grip unit that will be described later are formed on an outer periphery surface of the proximal member  5 . The slit  9  is formed between an edge of the one end and a substantial center of the proximal member  5 . 
     The intraocular lens insertion instrument  1  has a releasing means  11  as shown in  FIG. 2 , whereby the lens  2  in close contact with the lens setting section  8  can be released and moved smoothly at the time the lens push-out mechanism  4  pushes the lens  2  having been set on the lens setting section  8 . 
     The releasing means  11  releases the lens  2  from the lens setting section  8  by pushing forward the lens  2  stored on the lens setting section  8  with a forward tilt. The releasing means  11  comprises the lens push-out mechanism  4  and a posture holding mount  12  for holding the lens  2  on the lens setting section  8  with the forward tilt. 
     The lens setting section  8  comprises a setting section body  13  protruding from the one end of the proximal member  5 , the posture holding mount  12  formed on an upper surface of the section body  13 , and sidewalls  14  formed outside the posture holding mount  12 . The setting section body  13  is made of a plate member whose surface is smooth and parallel to an axial line A of lens movement so that the lens  2  set thereon can be held stably. 
     The posture holding mount  12  is configured so as to hold the lens  2  with the forward tilt. On an upper surface of the posture holding mount  12 , the mount  12  has slopes  12   a  inclined downward toward the distal end of the lens setting section  8 . A passage  15  through which the lens push-out mechanism  4  passes is also provided in the center of the posture holding mount  12 . The passage  15  comprises an elongated groove that is parallel to the axial line A of lens movement. 
     The sidewalls  14  are formed so that the center of the lens  2  can align with the axial line A of lens movement. The sidewalls  14  can also prevent the lens  2  from falling sideways when the lens  2  is placed on the lens setting section  8 . Therefore, assembling the instrument becomes easy. The sidewalls  14  are made of plate members that protrude from both sides of the setting section body  13  and are elongated along a longitudinal direction of the body  13 . 
     The distal member  6  comprises a nozzle piece  21  for inserting the lens  2  set on the lens setting section  8  into an eye, and a transition section  22  that connects the nozzle piece  21  with the proximal member  5 . The transition section  22  is substantially funnel-shaped, tapering toward the distal end thereof, and connects the nozzle piece  21  at the distal end. The nozzle piece  21  is formed in such a size that an outside diameter thereof enables insertion thereof into an incision. The lens  2  is folded while passing through the transition section  22  by being pushed by the lens push-out mechanism  4 . The distal member  6  also has a stopper  23  for stopping a hereinafter-described slider, at a predetermined position. The stopper  23  comprises projections that lock a hereinafter-described handling element of the slider. 
     As shown in  FIG. 1 , the lens push-out mechanism  4  comprises the slider  25  used for an initial operation to insert the lens  2 , and a plunger  26  for inserting the lens  2  into an eye. 
     The plunger  26  is to insert the lens  2  folded by the slider  25  into an eye, and comprises a push rod  27  for pushing out the lens  2  and the grip unit  28  located at the proximal end of the push rod  27 . The push rod  27  is loosely fitted into a hole  29  formed in the grip unit  28 , and pivotally supported by the grip unit  28  at the bottom of the hole  29 . A female screw  29   a  is formed in the hole  29 . The female screw  29   a  formed in the grip unit  28  is to be screwed together with the engagement projections  10 . The engagement projections  10  are made up of portions of a male screw that is to be screwed into the female screw  29   a . Forming the engagement projections  10  as the male screw portions enables not only preventing of the engagement projections  10  from interfering with the slit  9  or the like but also secure screwing into the female screw  29   a  for pushing in the grip unit. The grip unit  28  thus pushes the push rod  27  along the axial line A of lens movement. The grip unit  28  is formed into a shape that enables easy push of the plunger  26 . 
     As shown in  FIG. 3 , the slider  25  is formed so as to enable the lens  2  set on the lens setting section  8  to be pushed out toward the distal end of the main body  3  without local stress on the lens  2  and to be folded in a predetermined direction. The slider  25  engages with the slit  9  in the main body  3 . The slider  25  comprises a slider body  30  that supports the slider  25  along the axial line A of lens movement, a lens contact area  31  in contact with the lens  2  in an area larger than the plunger  26 , a guide groove  32  that supports the plunger  26  along the axial line A of lens movement and functions as an insertion passage, and a looped-element guide  34  that catches one of the looped haptic elements  2   b  of the lens  2 . 
     The lens contact area  31  is formed by an arc whose curvature radius is substantially the same as that of the outside diameter of the lens  2 . The form of the lens contact area  31  enables smooth execution of the initial operation without locally stressing the lens  2 , by contacting the lens  2  in a larger area. 
     The lens contact area  31  also has a scooping surface  31   a . The scooping surface  31   a  enables scooping of the rear end of the lens  2  set on the lens setting section  8 . The scooping surface  31   a  is shaped into a downward slope toward the distal end thereof. By having the sloped shape, the scooping surface  31   a  can gradually scoop up the lens  2 , which enables more secure release of the lens  2 . 
     As shown in  FIG. 4(A) , the scooping surface  31   a  may protrude from the lower end of the lens contact area  31 . By having the protrusion at the distal end of the scooping surface  31   a , the end of the scooping surface  31   a  can be pushed in between the lens  2  and the lens setting section  8 . Consequently, air can move to around the center of the lens  2 , enabling the lens  2  to be easily released from the lens setting section  8 . 
     Alternatively, the scooping surface  31   a  may be formed to have a wedge-like shape, as shown in  FIG. 4(B) . By pushing in the wedge-shaped scooping surface  31   a  between the lens  2  and the lens setting section  8 , the rear end of the lens  2  can be lifted upward. Consequently, the lens  2  can be easily released from the lens setting section  8 . 
     The guide groove  32  is formed so as to allow the plunger  26  to slide thereon, and to allow the distal end of the plunger  26  to protrude from the lens contact area  31 . The guide groove  32  is formed substantially in the center of one surface of the slider  25  over the entire length thereof, and comprises a groove that is parallel to the axial line A of lens movement. A cross section of the guide groove  32  is formed substantially in the same shape as the contour of the plunger  26 . A fan-shaped leading passage  21   a  is formed at the proximal end of the guide groove  32 . Thus, the push rod  27  is inserted through the guide groove  32  formed in the slider  25 , and slides within the guide groove  32  in a longitudinal direction of the slider  25 . Alternatively, the guide groove  32  may be a hole that pierces parallel to the axial line A of lens movement. 
     The slider body  30  enables the slider  25  to be held substantially in the center of the main body  3  while enabling the slider  25  to move along the axial line A of lens movement, by engaging with the slit  9 . Therefore, the plunger  26  is held in the center of the main body  3 , and movable along the axial line A of lens movement due to the presence of the guide groove  32 . The handling element  33  enables easy movement of the slider  25 . 
     The looped-member guide  34  is formed on another surface of the slider  25  on which the guide groove  32  is not formed. The looped-element guide  34  fixes the lens  2  by catching one of the looped haptic elements  2   b . The looped-member guide  34  is formed by a groove similar to the curvature of the looped haptic elements  2   b . The looped-member guide  34  is formed in the curvature on the side of the distal end of the slider  25  so as not to physically stress the looped haptic elements  2   b.    
     As shown in  FIG. 5 , the slider  25  has the handling element  33  for pushing the slider  25  in and out. The handling element  33  is a pair located on right and left sides of the axial line A of lens movement, and connected to an end of the slider body  30  while protruding from the proximal member  5 . The handling element  33  is formed so as to bulge more when viewed toward the distal end of the main body  3 . Although not shown in the drawings, the handling element  33  may have a corrugated surface formed by a plurality of grooves that are substantially perpendicular to the axial line A of lens movement. Alternatively, an arrow indicating a direction of movement may be shown on the surface. 
     Procedures of assembling the intraocular lens insertion instrument  1  of the above configuration will be described next. The slider  25  is firstly attached to the proximal member  5 . In order to join the slider  25  and the proximal member  5 , the slider body  30  is engaged with the slit  9  from the one end of the proximal member  5 , and the slider  25  is pushed in to the proximal end of the slit  9 . The plunger  26  is then inserted from the other end of the proximal member  5 . At this time, the distal end of the plunger  26  is aligned with a position where the distal end does not project beyond the distal end of the slider  25  having been set in the proximal member  5 . Thereafter, as shown in  FIG. 3 , one of the looped haptic elements  2   b  of the lens  2  is caught by the looped-element guide  34  of the slider  25 , and the lens  2  is set on the lens setting section  8 . At this time, as shown in  FIG. 3(A) , the lens  2  is held with the forward tilt by being set on the posture holding mount  12 . By keeping the forward tilt of the lens  2 , the looped haptic element  2   b  at the rear is set above the lens push-out mechanism  4 . Furthermore, since the lens setting section  8  has the sidewalls  14 , the center of the lens  2  can be easily aligned with the axial line A of lens movement. Thereafter, as shown in  FIG. 5 , the distal member  6  is united with the proximal member  5  in the engagement section  7 . In this manner, the intraocular lens insertion instrument  1  can be securely assembled without stress on the lens  2 . 
     Operation of the above configuration will be described next. The lens  2  has been set on the lens setting section  8  for some time, and in close contact with the lens setting section  8 . Firstly, an operator holds the handling element  33  and pushes the slider  25  forward. When the slider  25  is pushed forward, the lens contact area  31  touches the lens  2 . When the operator pushes the slider  25  forward in a state where the lens  2  is in contact with the lens contact area  31 , the rear of the lens  2  is lifted since the lens  2  is held with the forward tilt. When the rear of the lens  2  is lifted, air comes in between the lens  2  and the lens setting section  8 , releasing the lens  2  having been in close contact with the lens setting section  8  from the lens setting section  8 . By pushing the slider  25  until the slider  25  hits the stopper that is not shown in  FIG. 5 , the lens  2  can be pushed out to the transition section  22 . 
     When the slider  25  hits the stopper  23  and stops, the operator pushes the plunger  26 . In order to push the plunger  26 , the operator pushes the grip unit  28  to cause the female screw  29   a  to engage with the engagement projections  10  by screwing. Thereafter, the operator turns the grip unit  28 . While being turned, the grip unit  28  moves from the proximal end of the proximal member  5  in a direction of the axial line A of lens movement. When the grip unit  28  is moved from the proximal end in the direction of the axial line A, the push rod  27  moves in the direction of the axial line A by being pushed by the grip unit  28 , while pushing the plunger  26 . In this manner, the lens  2  is folded while passing through the narrow nozzle piece  21  by being pushed by the plunger  26 . By pushing the plunger  26  further in a state where the lens  2  is folded in such a manner, the lens  2  is inserted into an eye. 
     As has been described above, according to this embodiment, the intraocular lens insertion instrument  1  has the releasing means  11  for releasing the lens  2  pushed by the lens push-out mechanism  4  from the lens setting section  8 . Therefore, the lens  2  in close contact with the lens setting section  8  can be released from the lens setting section  8  when the lens push-out mechanism  4  pushes the lens  2 . Consequently, the lens  2  can be pushed out smoothly, which prevents damage to the lens  2  as well as unstable behavior of the lens  2 . 
     Moreover, the releasing means  11  has the posture holding mount  12  for holding the lens  2  with the forward tilt along the direction of the axial line A of lens movement. Therefore, when the lens push-out mechanism  4  pushes the lens  2 , the rear end of the lens  2  is lifted, allowing air to come in between the lens  2  and the lens setting section  8 . In this manner, the lens  2  can be released from the lens setting section  8  and pushed out smoothly. 
     Since the posture holding mount  12  has the passage  15  through which the lens push-out mechanism  4  passes, the posture holding mount  12  does not hinder the movement of the lens push-out mechanism  4  when the lens push-out mechanism  4  pushes out the lens  2 . Therefore, the lens  2  can be pushed out more smoothly. 
     Furthermore, the lens push-out mechanism  4  has the scooping surface  31   a  for scooping the lens  2 . Therefore, when the lens  2  is pushed out, the scooping surface  31   a  scoops the rear end of the lens  2 , allowing air to come in between the lens  2  and the lens setting section  8 . Consequently, the lens  2  can be released from the lens setting section  8  and pushed out smoothly. 
     In addition, the posture holding mount  12  is configured to support the both sides of the lens  2 . Therefore, even in the case where the lens  2  has been stored for a long time, deformation of the optic  2   a  can be prevented. 
     Since the posture holding mount  12  holds the lens  2  with the forward tilt, the looped haptic element  2   b  at the rear of the lens  2  can be placed above the lens push-out mechanism  4 . Therefore, damage to the looped haptic elements  2   b  associated with the movement of the lens push-out mechanism  4  can be prevented. 
     Moreover, the lens setting section  8  has the sidewalls  14 . Therefore, the lens  2  can be set easily at the center of the lens setting section  8 . Consequently, the center of the lens  2  agrees with the axial line A of lens movement, which enables smoother push-out of the lens  2 . 
     In a state of non-use, the lens  2  is in close contact with the lens setting section  8 . Therefore, the lens  2  can be held safely and securely even in the case where the looped haptic element  2   b  is not caught by the looped-element guide  34  of the slider  25 . 
     The present invention is not limited to the embodiment described above, and various modifications can be made thereto within the scope of the present invention.